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Tourism As Usual Amid the Political Protests in Bangkok
Published on Dec 19, 2013
When you see 30-second news clips on TV, where all the action from an entire day or two is condensed into a fraction of that time, it's easy to be misled. All too often TV news is baby food spoon fed to the masses with little context or background.
Though many countries have issued travel warnings about the state of ongoing protests in Thailand the situation is very much tourism as usual. There has been little violence. No tourists have been injured. No essential services (flights, trains, buses) have been disrupted. And very few tourists have cancelled their trips.
For the time being, the big issue for visitors is sporadic traffic gridlocks in Bangkok from protest marches. Travelers wanting to visit some of the city's most venerable attractions, like the Grand Palace and the Temple of the Emerald Buddha, or backpackers staying around Khaosan Road, will find themselves in the thick of things. The area around the Democracy Monument has been squatted by several thousand protestors for weeks now.
Even here, at ground zero, there is no angry mob and the atmosphere is serene, except for the constant blowing of whistles and some rants from rabble-rousing politicians. Many travelers walk around the area with no hassles and no strife in sight. True to that spirit for turning any occasion into a party, musicians perform on the stages between political speeches and the crowd sings and claps along.
Outside of the capital, in the other major hotspots for sun-seekers, like Phuket and Koh Samui, or up in the "northern rose" of Chiang Mai, there have been few, if any, disturbances.
Now that an election has been called for February 2nd, it's hoped that the protests will continue to simmer quietly on the backburner. Like any situation of political turmoil, there remains the possibility of volatility. Just keep an eye out, use your common sense, and make the most of your stay in the kingdom.

subset: commoncrawl


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USD/CAD remains capped by 1.3900 amid stabilizing oil
FXStreet (Mumbai) – The Canadian dollar failed to benefit from higher oil prices and edged lower in the holiday-light European trades, sending USD/CAD towards 1.39 handle.
USD/CAD tests 1.39 and retreats
Currently, the USD/CAD pair trades 0.13% higher at 1.3893, hovering close to session highs reached at 1.3902 in early Europe. USD/CAD extends gains for the second straight session and now looks to extend gains above 1.39 barrier, as the resource-linked loonie appears to completely ignore the minor-recovery seen in oil prices after falling more than 3% on Wednesday. At the moment, the US oil (WTI) rises 0.33% and remains capped below 37 barrier while the Brent oil also gains 0.63%.
Looking ahead, oil price action will continue dictate further moves in the pair while the renewed strength in the US dollar ahead of the US datasets keeps the sentiment underpinned.
USD/CAD Technical Levels
To the upside, the next resistance is located 1.3917 (Dec 28 High) levels and above which it could extend gains to 1.3936 (Dec 23 High). To the downside, immediate support might be located at 1.3869 (1h 100-SMA) and below that 1.3813 (Dec 28 Low).
(Market News Provided by FXstreet)


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TOP 100 ISO Certified Hotel Furniture Manufacturer stick to 5 star quality at 3.5 star prices with more than 8 years of experience! Owning factory covering more than 20,000 square meters ground size with 150 workers. Professional in hotel bedroom furniture, wood fixture, restaurant furniture, sofa & chair, wardrobe, wood doors and other wooden hotel furniture.
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We have a first-class ability in the design, production and marketing of hotel bedroom furniture and hotel public area furniture, which includes wooden furniture, wood doors, sofas, chairs, restaurant furniture, villa furniture, club furniture and mockup furniture etc.
Our factory covers an area of more than 19,200 SQM, and more than 180 professional staff works here.
During our 8 years of development, we have successful cooperation with big hotel brands including HILTON, HOLIDAY INN, GRAND HYATT, RAMADA, CROWNE PLAZA and so on. From which, a strict working process has been developed and strictly followed from quotation, design concept communication, workshop drawing preparation, sampling and evaluation, sample improvement, mass production, production process control and pre-shipment control.
In EASTMATE, always being "Trustable, Professional, Innovative, Win-Win" is our key value like bloods flows in each member of our company. Teamwork and continuous improvement has been a part of our corporation culture.
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EASTMATE staffs will continue its efforts to provide full satisfactory business solution for our clients with hotel furniture and hotel supply products more and more innovative, vogue, environment-friendly, decent and cost-effective.
You are welcome to contact us with your requests and suggestions always!


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The BCCK provides professional translation services to UK, international and Korean companies looking to produce documentation into Korean or English. Our staff of native-speaking business development professionals have a combined 10 years of experience in translation and the industry-specific knowledge to produce professional, well-crafted translations for internal and public use.
Our team can translate material ranging from advertising and marketing material (including PowerPoint presentations) to product and training manuals. All of our translations go through a meticulous process of editing and proofreading to ensure that the highest level of product is delivered. Our process is shown below.
The BCCK worked with Cambridge Consultants to translate their marketing collateral from English to Korean for face-to-face meetings with potential customers in Korea as part of a lead generation initiative. After an initial translation was complete, the text was reviewed by a senior manager to ensure the phrasing of the final document was of the highest quality. The document was then proofread before being sent out to Cambridge Consultant's potential customers in Korea.


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Text Box
The United Nations has designated August 9th each year as the International Day of the World's Indigenous People.
This year, to commemorate the day, the UN has prepared a program titled:
"Indigenous Media, Empowering Indigenous Voices".
The program will be webcast live
August 9
2:30-6:00 p.m.
Tentative program is listed below. Download a copy of the press release and program at the bottom of the page.
International Day of the World's Indigenous Peoples
9 August 2012
ECOSOC Chamber, UN Headquarters, New York
2:30pm – 6:00pm
"Indigenous Media, Empowering Indigenous Voices"
Screening of "Voices through time" by Chirapaq (Peru)
Traditional welcome by the Chairperson of the NGO Committee on the International Decade of the World's Indigenous Peoples, Roberto Múcaro Borrero (Taíno, Puerto Rico)
Message of the UN Secretary-General, Ban Ki-moon
Remarks by the Under-Secretary-General for Economic and Social Affairs and Coordinator of the Second International Decade of the World's Indigenous Peoples, Wu Hongbo
Remarks by the Chairperson of the UN Permanent Forum on Indigenous Issues,
Grand Chief Edward John (Tl'azt'en, Canada)
Moderated by Chandra Roy-Henriksen, Chief of the Secretariat of the UN Permanent Forum on Indigenous Issues
Kenneth Deer (Mohawk, Canada) The Eastern Door
Lily Valtchanova, Cultural Affairs Officer, United Nations Educational Scientific and Cultural Organization (UNESCO)
Nils Johan Heatta (Sápmi, Norway), Chairman, World Indigenous Television Broadcasters Network
Professor J. Kehaulani Kauanui (Kanaka Maoli, Hawaii), Center for the Americas, Wesleyan University
Angel Tibán Guala (Kichwa, Ecuador), Director, TV MICC
Monika Ille - Director of Programming, Aboriginal Peoples Television Network, Canada
Keoni Lee - General Manager, 'Ōiwi TV, Hawai'i
Emil Her Many Horses (Ogala Lakota, United States), National Museum of the American Indian, « Our voices on the Air : Reaching new audiences through indigenous radio »
Videos produced by:
Komi Television (Russian Federation)
TV MICC (Ecuador)
Indigenous Information Network, Kenya
Mr. Atama Katama (Malaysia)
Open discussion
Closing remarks by Roberto Múcaro Borrero (Taíno, Puerto Rico), Chairperson of the NGO Committee on the International Decade of the World's Indigenous Peoples
Moderated by:
Amy Stretten, Founder and Editor of NativeRemix.com
(Programme subject to change)
Organized by the Secretariat of the United Nations Permanent Forum on Indigenous Issues DSPD/DESA, the United Nations Department of Public Information and the NGO Committee on the International Decade of the World's Indigenous Peoples
What is UNA-USA? > Events & Programs >


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Formerly budget1 and Sleep&Go Preston
Trying to find quality, affordable accommodation in Melbourne that doesn't come with a massive price tag? BreakFree Bell City is a great choice, with modern accommodation at a competitive rate, so you've got no excuse not to take that Melbourne holiday you've been planning.
Located just 9 km from the CBD and only 20 minutes from the Melbourne airport, BreakFree Bell City provides real value for money. Public transport is on the doorstep with the train, tram and bus stop within 5 minutes' walk, a complimentary weekday shuttle to the CBD and surrounding universities is also available so you can explore the city's best attractions and get the most out of your Melbourne holiday. The hotel grounds are landscaped with bright gardens and leafy trees, making it an oasis in Melbourne's Northern suburbs.
Each room has wireless internet access so you can keep-up-to-date with the latest news and stay in touch with friends and family. Rooms have been designed with an ensuite bathroom and are furnished with a work desk and LCD TV with Foxtel, and tea and coffee making facilities. Feeling peckish but don't have time to wait for your meal? You'll find the shared kitchen a great option if you're on the go and need to make a quick snack or meal on the run. Or dine at one of Preston's leading restaurants located onsite at BreakFree Bell City.
If you love the resort way of life or just feel like some fresh air, then the hotel pool is a great place to relax and enjoy a swim. So dive in and don't forget to check out the hotel sauna and gym if you plan to keep fit while on holiday in Melbourne. There's also the games room to keep you entertained and the outdoor BBQ area so you can cook up a storm and chill out with a few friends.
Plan to stay back at the hotel and cook? Check out the hotel BBQ, located beside the pool, and dine alfresco while enjoying your own meals. More »
With over 600 car parks, parking is a breeze at BreakFree Bell City (fee applies). More »
All rooms have wireless internet to help you stay on top of the important matters in your life (fee applies).
If you're planning to head into the Melbourne CBD during your stay at BreakFree Bell City, the free CBD shuttle operates during weekdays.
See all room types »
*Government issued photo ID is required at the time of check in.


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The Marchesa Fall 2013 show at New York Fashion Week was inspired by 17th century romanticism, which the historian in me must point out is a bit of an anachronism, but I'll let it slide because the gowns were absolutely gorgeous. And when the amazing Jamie Beck of Ann Street Studio took photos from the runway, she captured the colors, the movement, and even the romance perfectly.
What do you think of the collection?
images via
images via


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Granite countertops are relatively easy to take care of, and such preventive maintenance as cleaning up spills quickly and avoiding setting hot pots on them will keep the surface in good repair. Properly installed granite countertops are not likely to crack, but if they do, there are steps you can take to repair them. Serious cracks and chips should be repaired by a professional.
Step 1
Clean the surface around the crack thoroughly with acetone or a 50-50 mixture of household ammonia and warm water. Dry thoroughly. Don't use a product that will damage the finish on the granite.
Step 2
Mix granite epoxy according to the manufacturer's directions. Mix only enough hardener and resin to use in 10 or 15 minutes.
Step 3
Use the color pigment kit to add color to the epoxy, again following the manufacturer's instructions.
Step 4
Spread epoxy in the crack with a small tool, such as an artist's palette knife or a foam brush. Use a toothpick in very small cracks. Quickly wipe up any messes because once the epoxy hardens it will be very difficult to remove.
Step 5
Seal the crack in the granite with granite sealer. Apply the sealer, let it set for 10 to 15 minutes, then apply another coat. Let the crack repair cure for a day.


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Jade Cong Dining Table
Jade Cong is an ancient artifact for worship of the Mother Earth. Usually made with jade, it is a round cylinder in the middle with a square shape envelop on the outside. A Jade Cong dining table by Forbidden City uses a stainless steel base, chromed in gold colour, with marble panels on all four sides. With a round or rectangular shape glass top, the table could accommodate up to 8 persons.
Materials: Marble, Stainless steel, Glass
Colours: White, Gold
Dimensions: Diameter 150cm, Height 78cm


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President Goodluck Jonathan on Tuesday said he would never be a part of any action that can lead to Nigeria's disintegration.
He said the predictions that the country would cease to exist in 2015 could have come true if he had not taken the decision to concede defeat in the March 28 Presidential election.
Looking back, he said he was happy he took that decision because Nigerians still have a country to call their own.
Jonathan spoke while receiving members of the Universal Peace Foundation who were in the Presidential Villa, Abuja, to confer on him an award of Peace-Loving Global Citizen.
He said it was his commitment to the unity of the country that made his administration to put together the National Conference in order to address the issues that tend to divide Nigerians.
The President said, "Everybody knew about the predictions (that Nigeria will cease to exist by 2015). Anything could have made those predictions become true. After all, we fought a civil war for about three years before as a nation.
"We have our challenges, the idea of that National Conference is to look at these weak cleavages we have in this country.
"We just finished that conference and were thinking of how to implement its recommendations so that Nigeria will become a stronger and more united nation.
"I cannot be a party to the disintegration of the country. I am quite pleased with what has happened. We have a country, the country will be more united.
"We only pray that the incoming government should appreciate the contributions of everybody and see how we can run Nigeria as a country that belongs to everybody: all citizens, irrespective of political affiliations or creeds."
Jonathan said Vice President Namadi Sambo who ran on the same ticket with him and the Peoples Democratic Party that provided the platform for them should also share in the encomium being showered on him.
While saying if he had won the election, Sambo too would have remained in office, the President said by that singular act, the two of them would be packing out of their offices on Friday.
He said he took the decision to concede defeat because he had always been telling those around him that there must be a nation before individuals can talk of ambitions.
He added that it has also been his position that even if he would be the President for 25 years, he would not be happy if Nigerians are killed because of him.
He said it was one thing to hold office, and it was another thing to be happy and be satisfied with one's conscience.
"Yes, there are different human beings. If you look at the behaviours of people, even among siblings, some of them could turn to be imams and pastors, while some will be armed robbers.
"Even somebody that has that kind of criminal intention or he is very vindictive or who by nature does not care if people are dying, even if half of his countrymen and women die for him to be a President, he will celebrate it.
"But for me, God did not create me that way and I cannot fit in. I believe that for us to hold any office that we want to, we must have a nation," he added.
Jonathan added that the years he had spent in office had given him an experience that no school could give.
He reinstated his position that once he leaves office, he would dedicate the remaining part of his life to issues that will bring unity and peace to the country.
He urged Nigerians to commit themselves to the strengthening of those things that can unite the country rather than things that can further divide it.
Sourced from: Punchng.com


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Friendsfavz Tv! Friends Sharing Favorites
Joining us on this episode is Laurie Cassille the owner and creator of Girly Girl Gifts! Her hand painted gifts show that you took the time to pick the perfect gift and personalize it for that special friend or family member. What fun we had visiting with Laurie sipping Girly Girl Wine on their outdoor patio on a warm fall afternoon. Our fabulous community of ladies joined us at the Girly Girl Tasting Room in Woodinville and socialized and enjoyed the gift giveaways from some local vendors.
If you would like an exclusive invite to our events make sure you sign up for our VIP list!
A special thanks to:
Cameron Baughn Photography for filming and editing If you are needing photography, filming or visual arts, Cameron is incredibly talented. (Cameron is my son! He helps me tremendously.)
Girly Girl Wines A great place to meet with friends at their tasting room in Woodinville, Wa.
Catering with Mary Jane Landau for the yummy dessert give away! Mary Jane has catered several of my events and I love how she is so customer service oriented along with providing incredible appetizers.
Merry McCallum with Vivi Jewelry gave a beautiful necklace set as a giveaway for one of the ladies in the audience! What lovely accessories by Vivi Jewelry!
Robinson Dental in Lynnwood, Wa Thanks to Brett Robinson for giving a Teeth Whitening Kit as a gift to one of the ladies in the audience! Also, for the Sonicare Toothbrush as a gift giveaway! I love the ladies at Robinson Dental that take care of my keeping my teeth healthy and Brett for the excellent service he provides!
I hope you can join us at one of our live filming events, we have so much fun! Enjoy the photos by Beautiful Butterfly Photography! Yamileth Swearingen continues to capture the great time at our events! Check out her Facebook Page and give her a "Like" while you are there.
Cheers, Karen


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Dita Von Teese, Emmy Rossum, Camilla Belle, Liz Goldwyn and Alessandra Ambrosio toasted springtime on Thursday afternoon at the Chateau Marmont at a luncheon hosted by Christian Louboutin.
But the real guest of honor was a handbag, Louboutin's new Passage handbag, to be exact.
The bag is sleek and graphic with an arch-shaped metal handle designed after the archways above the designer's first store, which opened in 1991 in Paris' Passage Véro-Dodat.
After sipping pink Champagne in the garden, where a florist was busy twisting orchids, daisies and roses into flower crowns for everyone to wear, guests adjourned to a table covered in even more beautiful spring blooms.
The designer himself was not in town (he's gearing up to launch his much-awaited beauty collection this summer), but guests sang his praises anyway.
"I don't usually keep things I wear, but I've already told them they aren't getting these back," Rossum said of her electric-blue stilettos.
Von Teese, who brought her sister Sarah Brown as a date, has been a Louboutin fan since the beginning and is lucky enough to have him make her custom creations for her stage shows and everyday life. At the lunch, she wore timeless brown crocodile Louboutin pumps with a Zac Posen velvet skirt, hourglass-shaped jacket and long leather gloves.
The burlesque queen was fresh off a trip to New York City, where she launched her namesake lingerie line at Bloomingdale's 59th Street store. "It's been selling really well," she said, "and we're working on doing an event in L.A."
Goldwyn, a style author and filmmaker, is already a fan. "I placed a huge order, and I'm wearing one of the bras now, the Madame X," she offered, unbuttoning her dress to reveal the cross-front strap.
Goldwyn, whose first book, "Pretty Things: The Last Generation of American Burlesque Queens," was published in 2006, recently completed her second book, about prostitution in 1890s Los Angeles. And she's already adapted it for a TV pilot.
Busy ladies.
Christian Louboutin's Passage collection, $1,795 for the mini-messenger to $4,995 for exotic materials, will arrive in stores in June.
Liz Goldwyn: Trends follow her
Christian Louboutin celebrates 20 years in business
Greatest of Teese: How Dita Von Teese became fashion's 'It' girl


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Being comparative is a natural human instinct. Most rational shopper wants to buy a product or a service if its price first matches his or her perceived value. Then the rational buyers might compare its price that this store offers relatively to other stores. The buyers might also have a set price in mind. Sometimes buyers do not have all of the relevant information to know how much a certain product or a service is worth, and this is where marketers can come in and assist (or trick if you have a negative view on marketing) and help buyers make buying decisions. Marketers can convince the buyers to purchase their product or service by implementing reference pricing strategy, most prominently used in discount stores. Reference prices are prices that buyers carry in their minds and refer to when looking at a given product. Reference price is one component of psychological pricing, in which the sellers consider the psychology of prices and not simply the economics.
Nordstrom Rack is a great example of a store that utilizes reference pricing to sell its product. Nordstrom Rack is the discount/clearance store for Nordstrom and it typically carries overstocked inventory from Nordstrom and other big name brands, original Nordstrom Rack brand such as Evergreen and returned merchandise from Nordstrom. There are very few instances where there will be the same product being sold at the regular store and the Rack (ex. Burberry Weekend Cologne). All the products from Nordstrom Rack are in perfect conditions, Nordstrom would never sell a damaged product even if it's at a clearance division. Therefore, products are never discounted for the lack of quality. Basically, every Nordstrom Rack products have a price tag that list the original price of the merchandize and the reduced price that the buyer would have to pay. This is a great example of reference price because it tells the buyer directly how much he or she is saving by buying the product (it does not say how much you save on the price tag but the buyer can just subtract the new price from the original price). Any rational buyers would feel like he or she is getting a bargain and this obviously would be a strong influence in buyer's purchase decision. Many Nordstrom Rack products are still relatively expensive. For example, a Hugo Boss tie might cost $49.99, but it does not match up to the perceived value for a buyer since the very same product might cost as much as up to $129.99 at a Hugo Boss department store. Once again, a rational buyer would recognize that this price is a bargain and that might very well influence his decision to purchase the product. Other times, the buyers might not have a perceived value set in mind for a product (like I wouldn't know how much a Calvin Klein dress would normally cost). In this case, the reference pricing strategy would assist the buyer by letting him or her know what the perceived value is from the original retailer's perspective and how much of a bargain the buyer would gain.
Jason Lao, Section E
Sunday, February 21, 2010
Reference Pricing
Posted by Marketing 301 Blog at 8:07 PM
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Open Access This article is
- freely available
- re-usable
2013, 14(11), 21353-21377; https://doi.org/10.3390/ijms141121353
Homogeneous Liquid–Liquid Extraction of Rare Earths with the Betaine—Betainium Bis(trifluoromethylsulfonyl)imide Ionic Liquid System
Department of Chemistry, KU Leuven, Celestijnenlaan 200F, P.O. Box 2404, Heverlee B-3001, Belgium
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Received: 27 August 2013; in revised form: 7 October 2013 / Accepted: 18 October 2013 / Published: 28 October 2013
Several fundamental extraction parameters such as the kinetics and loading were studied for a new type of metal solvent extraction system with ionic liquids. The binary mixture of the ionic liquid betainium bis(trifluoromethylsulfonyl)imide and water shows thermomorphic behavior with an upper critical solution temperature (UCST), which can be used to avoid the slower mass transfer due to the generally higher viscosity of ionic liquids. A less viscous homogeneous phase and mixing on a molecular scale are obtained when the mixture is heated up above 55 °C. The influence of the temperature, the heating and cooling times, were studied for the extraction of neodymium(III) with betaine. A plausible and equal extraction mechanism is proposed in bis(trifluoromethylsulfonyl)imide, nitrate, and chloride media. After stripping of the metals from the ionic liquid phase, a higher recovery of the ionic liquid was obtained by salting-out of the ionic liquid fraction lost by dissolution in the aqueous phase. The change of the upper critical solution temperature by the addition of HCl or betaine was investigated. In addition, the viscosity was measured below and above the UCST as a function of the temperature.
Keywords:hydrometallurgy; ionic liquids; lanthanides; neodymium; phase transitions; rare earths; solvent extraction; thermomorphic behavior; UCST
1. Introduction
Solvent extraction (SX) or liquid–liquid distribution is one of the major techniques applied for the separation and purification of metal streams [1]. The basis of this technique is the preferential distribution of a solute between two immiscible liquid phases. Generally, an aqueous solution containing the dissolved solute is brought into contact with another immiscible organic phase. The solute distributes between the two phases until equilibrium is reached. This equilibration is accelerated by strong agitation (stirring or shaking), as this will increase the phase boundary area between the organic and aqueous phase at which diffusion of the solute occurs.
Ionic liquids are organic salts that consist entirely of ions and have typically a melting point below 100 °C [2–4]. These types of compounds have recently gained a lot of interest because they have several interesting properties such as a negligible vapor pressure [5], a low flammability [6], a high thermal stability [7], and a broad electrochemical window and liquidus range [8]. Also, the tuneability of ionic liquids is one of their major advantages. Via a suitable choice of cation-anion combination, an ionic liquid with the appropriate properties for a given application can be obtained [9].
The beneficial properties of ionic liquids also gained the interest and curiosity of researchers in hydrometallurgy, searching for environmentally friendlier alternatives to volatile, flammable, and toxic organic solvents such as toluene, kerosene and chloroform which are applied in most solvent extraction systems [10–16]. Ionic liquids can be used as diluents in combination with traditional organic extracting agents. Another approach is incorporating a specific metal-coordinating group into their structure (task-specific ionic liquids or functionalized ionic liquids). It is evident that ionic liquids for use in solvent extraction systems should be immiscible with water. The ionic liquid can be made hydrophobic by choosing a cation with long alkyl chains (e.g., Cyphos® IL 101 or Aliquat® 336) [17,18]. However, in most cases hydrophobic fluorinated anions such as bis(trifluoromethylsulfonyl)imide (Tf2N−) or hexafluorophosphate (PF6−) are selected, because a larger variety of cations, with or without functionalities, can be selected for extraction of a particular metal. One of the disadvantages of using ionic liquids as diluents in extraction systems is their higher viscosity compared to molecular solvents [19,20]. For instance, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide has a viscosity of 32 cP at 20 °C if it is water-saturated [21], whereas the viscosity of conventional organic solvents is about 1 cP. Therefore, intensive mixing, shaking, and heating up are required to increase the mass transfer and to obtain equilibrium in shorter time scales.
Some ionic liquids show thermomorphic behavior which means that they become miscible with any solvent above or below a certain temperature [22–33]. The upper critical solution temperature (UCST) of an ionic liquid is the temperature above which the ionic liquid is miscible with water in all proportions. Other ionic liquid systems have a lower critical solution temperature (LCST), defined as the temperature at which one homogeneous phase is formed below that temperature. Ionic liquids showing thermomorphic behavior with water are interesting for ionic liquid solvent extraction systems because mixing on molecular scale can be obtained just by heating or cooling the biphasic mixture until one homogeneous phase is obtained [17]. Viscosity is decreased and mass transfer and kinetics are accelerated in this way. This type of extraction is called homogeneous liquid–liquid extraction (HLLE), coalescence extraction or phase-transition extraction and has been used mainly for the extraction of natural products [34–36], although some examples of HLLE for metal extraction are also known [34,37,38]. To the best of our knowledge, the only example of HLLE for metals with ionic liquids has been reported by Vaezzadeh et al. [39]. They made use of the temperature-induced phase separation principle with the ionic liquid 1-hexyl-3-methylimidazolium tetrafluoroborate [C6mim][BF4] for the determination of silver via micro-extraction. The extraction was performed by cooling a 50 °C aqueous silver solution containing 4,4-bis(dimethylamino)-thiobenzophenone, NaPF6 and a small amount of [C6mim][BF4]. Phase separation was induced by a combination of decreasing the temperature and a salting-out effect with NaPF6.
Recently, we communicated the proof-of-principle of HLLE of a large selection of metals (Ag, Cu, Zn, Fe, Co, Ni, In, Ga and several rare earths) with betaine as extractant and [Hbet][Tf2N] as organic phase (Figure 1) [40]. One homogeneous phase could be obtained by increasing the temperature of a 50 wt % ionic liquid mixture with water above the UCST of 55 °C and two phases were obtained again after cooling down, without the need for an extra salting-out agent. Stripping could be performed with HCl or HTf2N, in which a precursor for the ionic liquid [Hbet]Cl or the ionic liquid itself were obtained. In the present paper, several fundamental extraction parameters such as the kinetics (temperatures), loading, and a plausible extraction mechanism are given for HLLE of neodymium(III) with the [Hbet][Tf2N]–H2O system. Also, the influence of HCl or betaine on the UCST and the recovery of ionic liquid will be described.
2. Results and Discussion
2.1. Viscosity and Mass Transfer
The viscosity of [Hbet][Tf2N] at 60 °C is 351 cP [22], and thus significantly higher than that of conventional bis(trifluoromethylsulfonyl)imide ionic liquids used in solvent extraction systems [41]. This is due to the carboxylic group on the cation which forms an extra interaction with the anion via a hydrogen bond. [Hbet][Tf2N] takes up circa 13 wt % of water at room temperature and the viscosity of the water saturated ionic liquid at 23 °C is therefore 238 cP. It was observed that the viscosity increased if betaine was added to a water/ionic liquid mixture. After bringing 4 g of water-saturated ionic liquid in contact with 3.48 g of water containing 20 wt % of betaine, the viscosity increased to 582 cP at 23 °C. Ionic liquid extractions are often performed at higher temperatures, since there is an inverse relationship between the diffusion coefficient D and the viscosity η. The relationship can be described by the Stokes-Einstein equation:
where k is Boltzmann's constant, T is the absolute temperature and r is the radius of the molecule. A higher diffusion coefficient means that molecules are moving faster, that the contact time between different molecules is much shorter, and that extraction equilibrium is obtained faster. The viscosity decreased from 125 cP just below the UCST (40 °C) to 20 cP above the UCST at 65 °C.
The relationship between the viscosity and the temperature is given by the Arrhenius equation:
where η∞ is the viscosity at infinite temperature and R is the universal gas constant. Ea is the activation energy, which is defined as the energy barrier which the ions must overcome to move in the mixture [42]. The equation is typically extended to other functions such as Vogel-Fulcher-Tammann (VFT) or Litovitz, which are a much better fitting of the viscosity-temperature dependence of ionic liquid [43–47]. The following equation can be obtained by taking the natural logarithm of Equation (2):
A linear fitting can be obtained for ln(η) as a function of 1/RT. The slope of the curve gives the activation energy Ea for the movements of the ions in the mixture. Four data points were obtained above and four below the UCST (Figure 2). An energy barrier of 71.7 kJ·mol−1 must be overcome to move ions in the ionic liquid below the UCST in biphasic mixture whereas an energy barrier of 29.9 kJ·mol−1 was obtained in the case of a homogeneous mixture. The energy necessary to move molecules along each other in the homogeneous state is almost 2.5 times lower than in the case of a biphasic mixture.
2.2. Distribution Ratios and Percentage Extractions
Distribution ratios (DM) are calculated by the following equation:
where [M]org (mg/kg) and [M]aq (mg/kg) are the metal concentration in the organic phase (i.e., ionic liquid phase) and the aqueous phase, respectively. By measuring the metal concentration in the water phase after the extraction and taking into account the mass balance, Equation (4) can be rewritten:
where [M]aq,0 and [M]aq are the metal concentrations in the aqueous phase before and after the extraction, respectively. maq,0 and maq are the masses of the aqueous phase before and after the extraction, and morg is the mass of the organic phase after extraction. Since the mass of both phases at the end of the extraction differs from the initial mass due to the water-ionic liquid mutual solubility, maq and morg are unknown parameters. The initial masses of the aqueous and organic phase are used for these parameters as an approximation. Thus, it should also be noted that this calculated metal concentration in the organic phase is not completely correct due to the mass changes of the water and ionic liquid phase. This has also an effect on the distribution ratios and percentage extractions which are slightly overestimated. If the Total Reflection X-Ray Fluorescence (TXRF) results are consistent and seem reliable, it is recommended to use the measured organic metal concentration.
The percentage extraction (%E) of a metal is defined as:
The initial mass of ionic liquid phase and aqueous feed are used as a good approximation for maq and morg, similar as for the calculation of the metal concentration in the organic phase.
The percentage stripping (%S) is defined as:
The masses of the different phases change during back-extraction, similar to the extraction step, and this change depends on the acid concentration used. Therefore, maq and morg are unknown parameters in Equation (9), and they are approximated by the initial mass of the corresponding phase.
2.3. Extraction Parameters
Different operational parameters of the HLLE process were investigated. These include the heating time in the homogeneous phase, the temperature above UCST, the settling time, and settling temperature. In a recent communication [40], we proposed that the extraction of metals via homogeneous liquid–liquid extraction is faster than in the case of traditional extraction experiments, due to the mixing on molecular level above the UCST. To provide evidence for this hypothesis, the HLLE process has been compared with a conventional extraction process, and the influence of the heating time in the homogeneous phase above UCST on the extraction efficiency, was investigated.
Five extraction mixtures with the same composition were prepared. Each solution contained 1 g of Nd(Tf2N)3 solution with a concentration of 1500 mg/kg Nd, 288 mg of betaine and 1 g of water-saturated [Hbet][Tf2N]. Four mixtures were heated at 60 °C during varying times (3 to 18 min) and stirred further at room temperature until a total stirring time of 20 min was reached. One extraction mixture was stirred at room temperature for 20 min and did not proceed via a homogeneous stage. This temperature is about 15 °C under the UCST as we will show later that 28.8 wt % of betaine decreases the UCST to below 40 °C (Figure 3). The lower percentage extraction for the heterogeneous extraction at room temperature confirms the slower extraction kinetics of heterogeneous mixing. Once the homogeneous stage had been reached, no significant changes in the percentage extraction (%E) were observed as a function of the time.
Next, the influence of the temperature of the homogeneous stage was investigated by performing the same extraction four times, each time at a different temperature (50, 60, 70 and 80 °C). Each extraction mixture contained 1 g of [Hbet][Tf2N] and 1 g of the aqueous starting solution (890 mg/kg Nd with 20 wt % of betaine). For each extraction experiment, the distribution ratio was calculated and plotted vs. the temperature of the homogeneous stage (Figure 4). From these results, it is clear that the heating temperature during the homogeneous stage has no influence on the extraction equilibrium and the percentage extraction.
After the formation of one homogeneous phase and reaching the extraction equilibrium, the mixture is cooled to room temperature to reform the two-phase system. This is the so-called settling stage. Since the mutual solubility of [Hbet][Tf2N] and water is temperature dependent, the temperature to which the extraction mixtures are cooled during the settling stage of the extraction process, may have an influence on the extraction percentage of the metal ions. Different settling temperatures were tested, ranging from 6 to 50 °C. Each extraction mixture contained 1 g of [Hbet][Tf2N], 1 g of Nd(Tf2N)3 solution (1500 mg/kg Nd) and 200 mg of betaine (16.7 wt %). The percentage extraction showed constant values over the measured temperature range, except for the data collected at 50 °C, close to the UCST (Figure 5). This is because the aqueous and ionic liquid phases have a nearly similar composition at this temperature. We will show later on that the UCST of the [Hbet][Tf2N]–water mixture (16.7 wt % betaine) is just above 50 °C. Room temperature is therefore ideal to reinstall the two-phase equilibrium when cooling the extraction mixture during the settling stage. Small deviations at temperatures around 20 °C will not result in large differences in distribution ratios or percentage extraction.
Besides the influence of the settling temperature on the extraction process, the percentage extraction was also investigated as a function of settling time. The extraction mixture contained 5 g of [Hbet][Tf2N], 5 g of Nd(Tf2N)3 solution (1500 mg/kg Nd) and 636 mg of betaine. At different time intervals during the settling stage, a small sample was taken from both the organic and aqueous phase for analysis. The percentage extraction showed a slight increase with longer settling times (Figure 6). If the settling time was too short, the phase separation had not reached its equilibrium yet and a high amount of organic phase (with the extracted metals) was still present in the aqueous phase and vice versa. Both phases had a rather turbid appearance during the settling stage, opposite to the more transparent appearance after phase-equilibrium had been reached. During the settling stage, the metal concentration in the aqueous phase tended to be higher and the metal concentration in the organic phase tended to be lower than at equilibrium. As a result, lower extraction percentages were observed. On the other hand, it has been observed that settling can be significantly accelerated by centrifugation. A visual representation of the extraction is given in Figure 7.
2.4. Extraction Mechanism
In order to determine the extraction mechanism, a slope analysis was performed. The extraction mechanism and the corresponding equilibrium constant Kext can be written as:
The bar indicates the species in the organic phase.
The distribution ratio DNd is defined as:
where [Nd]IL indicates the concentration of neodmymium in the ionic liquid phase and [Nd]aq is the concentration of neodymium in the aqueous phase. By substitution of Equation (11) in Equation (12), the following expression Equation (13) for the distribution ratio is obtained:
By calculating the logarithm of Equation (13), a linear relationship between the logarithm of the distribution ratio and the logarithm of the betaine concentration is obtained. The [Tf2N] concentration in the water phase, as a function of the betaine concentration, is considered as a constant value, which was confirmed with Raman spectroscopy (Figure 8). Five aqueous betaine solutions (with concentrations varying between 0 and 20 wt %) were brought in contact with water-saturated [Hbet][Tf2N] in a 1:1 mass ratio and mixed until phase equilibrium was reached. The aqueous phase of the mixtures was measured with Raman spectroscopy. By comparison of the peak of betaine at 780 cm−1 with the peak of the [Tf2N] anion at 742 cm−1 in the Raman spectrum, it can be concluded that the [Tf2N] concentration in the aqueous phase is almost constant if the betaine concentration in the aqueous phase was increased.
Since also Kext is a constant, Equation (13) can be rewritten as:
From Equation (14), the number of betaine molecules per neodymium ion can be determined. For the execution of the experiment, extraction mixtures were prepared with 1 g of dry ionic liquid [Hbet][Tf2N], 1 g of aqueous Nd(Tf2N)3 solution (with a neodymium concentration of 1500 mg/kg) and a certain amount of betaine (ranging between 0 and 250 mg), added to the aqueous solution. The homogeneous phase was obtained by heating to 65 °C and two phases were obtained again by cooling down to room temperature. The slope of the linear fit through the experimental data points was 1.68 ± 0.16 (Figure 9). This indicates that probably 1.5 betaine molecules were present as ligands per neodymium ion in the extracted complex. The remaining vacant coordination sites are very likely occupied by water molecules, so that the complex formed during extraction can be described as [Nd2(bet)3(H2O)y]3+. Electrical neutrality can be achieved by bis(trifluoromethylsulfonyl)imide (or chloride or nitrate) counter ions. This is different from what has been reported in the solid state, where binuclear complexes of rare earths, surrounded by eight betaine ligands, are reported. In these cases, the counter anions are always weakly coordinating anions such as [Tf2N]− or [ClO4]−[22,50–52]. A rare-earth metal: betaine ratio of 1:2 has been found as well with chloride anions as counter ions [50,51]. It should be noted that in order to obtain higher distribution ratios, betaine must be present in a large excess compared to the concentration of neodymium(III) ions in the solution (100 or more times a higher concentration of betaine than neodymium). This large excess seems to be required in order to shift the extraction equilibrium [Equation (10)] to the right, i.e., to complex formation and extraction to the organic phase. A stoichiometric amount of betaine was found not to be sufficient for a significant degree of extraction of neodymium to the organic phase.
The extraction of NdCl3 and Nd(NO3)3 was tested as well and compared to the extraction of Nd(Tf2N)3. Feed solutions of neodymium(III) chloride, neodymium(III) nitrate, and neodymium(III) bis(trifluoromethylsulfonyl)imide) were prepared by dissolving the corresponding hydrated salt in distilled water and diluting it further until neodymium concentrations of 1500 mg/kg were obtained. Extraction from all three solutions was tested with varying betaine concentrations in the aqueous feed (5 to 20 wt %). An aliquot of 1 g of each feed solution was mixed with 1 g of water-saturated [Hbet][Tf2N]. Extraction from chloride and nitrate medium resulted in similar, but slightly lower distribution ratios compared to extraction from bis(trifluoromethylsulfonyl)imides medium (Figure 10). This deviation may be explained by the influence of different ions present in the [Hbet][Tf2N]–H2O mixture on the solubility of [Hbet][Tf2N] in the aqueous phase. As will be described further in this paper, addition of HCl, and more particularly Cl− ions, results in an increase in cloud point, whereas addition of HTf2N (i.e., Tf2N− ions) [40] has a lowering effect on the cloud point. This will also influence the solubility of [Hbet][Tf2N] in water, with a decrease in solubility for HCl and an increase for HTf2N. If more [Hbet][Tf2N] dissolves in the aqueous phase, the volume of the organic phase decreases and the concentration of neodymium in the organic phase increases, leading to higher distribution ratios. Another explanation could be the difference in extraction mechanism depending on the anion of the metal salt. The counter ion of neodymium is co-extracted with the metal in the case of a Tf2N− anion whereas ion exchange is occurring in the case of a chloride or nitrate counter anion, in which the water soluble ionic liquids [Hbet][Cl] or [Hbet][NO3] are formed with the [Hbet]+ cation. In all cases, the counter ions of Nd3+ in the organic phase are Tf2N− anions. This hypothesis was confirmed by extracting 2000 ppm Pr3+ with bromide anions to [Hbet][Tf2N] with 200 mg of betaine monohydrate. The choice went to a bromide salt because they are more sensitive for X-rays compared to nitrogen, oxygen or chlorine when analyzing concentrations with TXRF. The distribution ratio for Pr3+ was 17 whereas the distribution ratio for bromide was 0.03, which confirmed the hypothesis of cation exchange in the case of nitrate, chloride or bromide counter ions.
A slope analysis was performed again to determine the stoichiometry of betaine in the extracted neodymium(III) complex. Extraction from all three media resulted in approximately the same slope of 1.50 and hence the same stoichiometry of betaine in the extracted neodymium(III) complex, namely 1.5 betaine ligands per Nd3+ ion (Figure 10). Therefore, the anion of the salt in the feed solution has no influence on the stoichiometry of the neodymium(III)-betaine complex and the anion probably does not interact with the neodymium(III) ion itself.
Low metal feed concentrations are not of interest for extraction processes on an industrial scale. Therefore, the effect of the feed metal concentration on the extraction performance was studied. Different extraction mixtures were prepared, all containing 1 g of water-saturated [Hbet][Tf2N] and 1 g of Nd(Tf2N)3 feed with a betaine concentration of 200 g/kg. The neodymium concentration in the feed varied between 224 and 24,000 mg/kg. The percentage extraction appears to be rather independent of the neodymium feed concentration (Figure 11). This constant behavior in function of feed concentration can possibly be explained by the presence of an excess of betaine extractant. The extraction mechanism and equilibrium constant were already given in Equations (10) and (11). The factor in Equation (11) remains almost constant during the extraction because and are present in the aqueous phase in a large excess compared to neodymium in the aqueous phase and neodymium extracted to the ionic liquid phase.
Extraction of neodymium will only slightly decrease the denominator of Equation (11). In this case, Equation (11) can approximately be rewritten as:
For the above equation, one can deduce that if the concentration of [Nd3+]aq increases in the feed solutions, the amount of neodymium extracted to the ionic liquid phase will increase as well, in a similar proportion.
The extraction percentage (%E) of neodymium is defined as:
In our experiments, 1 g of water-saturated ionic liquid was mixed with 1 g of the aqueous phase (mIL = maq). Assuming that no volume or mass changes occur, Equation (16) can be rewritten as:
Or by introducing Equation (15) and replacing [Nd3+]aq:
This means that the percentage extraction is constant as long as the assumption stating that the Tf2N− anion and especially betaine are present in excess holds. It was observed that the phase volume ratio of the organic over aqueous phase increased with increasing neodymium feed concentration. This may also influence the change in calculated percentage extraction versus the neodymium feed.
2.5. Metal Stripping and Recovery of the Ionic Liquid
As reported previously, neodymium can be stripped from the ionic liquid phase by acids, such as HTf2N or HCl [40]. The influence of HTf2N on the stripping efficiency was measured by stripping a neodymium-loaded ionic liquid phase obtained by extraction of 6 mL of Nd(Tf2N)3 solution (1500 mg/kg Nd) with 1.250 g of betaine in 5 g of [Hbet][Tf2N]. HTf2N stripping solutions (500 μL) with concentrations varying between 0.1 and 1 M were mixed with 500 mg of ionic liquid phase. Stripping was also performed by heating the solution above the UCST (65 °C) for 5 min in order to obtain mixing on a molecular scale. As expected, more concentrated hydrogen bis(trifluoromethylsulfonyl)imide strip solutions resulted in higher stripping efficiencies, with a value of approximately 95% for a 1 M HTf2N solution (Figure 12). Therefore, stripping is possible with hydrogen bis(trifluoromethylsulfonyl)imide (1 M) if the extraction mixtures are cooled to 6 °C during the settling stage because no biphasic system could be obtained at higher temperature. Stripping with HTf2N is limited due to the mutual solubility of [Hbet][Tf2N] and water, which increases at higher acid concentration. By stripping with HTf2N, the ionic liquid itself is generated. Hydrogen chloride is an even better stripping agent than HTf2N. This was shown by stripping an organic phase of [Hbet][Tf2N], loaded with 1500 mg/kg Nd after extraction from a bis(trifluoromethylsulfonyl)imide aqueous solution, with HCl stripping solutions varying between 0 and 1 M. Phase separation was very easily obtained and there was no need for cooling to 6 °C during settling. The cloud point increased with higher HCl concentrations, no homogeneous phase was formed during the heating/mixing stage. This difference in phase behavior compared to HTf2N is caused by salting-in/salting-out phenomena and will be discussed further in the text. It was found that stripping efficiencies of 99% could be obtained for HCl concentrations of 0.8 M and higher (Figure 13). Lower acid concentrations were needed than in the case of HTf2N to obtain the same stripping percentage. By stripping with HCl, [Hbet]Cl is formed, and the ionic liquid [Hbet][Tf2N] can be synthesized again by a metathesis reaction with e.g., LiTf2N as described in the experimental part.
The pH of the aqueous phases after extraction was about 0.5 in a 1:1 IL/water mixture at room temperature and pKa of betaine is 1.82 [53]. Therefore, the use of acidic extractant will become problematic as these are protonated and not useful anymore at these pH values.
2.6. Influence of Betaine and HCl on the UCST of [Hbet][Tf2N]
As mentioned above and reported earlier [40], the addition of acids or betaine influences the phase behavior of the ionic liquid in water. The addition of betaine lowers the cloud point curve. The influence of different weight percentages of betaine on the UCST is shown in Figure 11. Mixtures of 500 mg of water-saturated [Hbet][Tf2N] and 500 mg of betaine aqueous solution with varying concentration were prepared. The cloud point of each mixture was determined visually and plotted vs. the betaine concentration. The addition of betaine to the IL–water mixtures resulted in a significant decrease in cloud point temperature, up to a cloud point of 42 °C for the mixture with 25 wt % betaine in the aqueous starting solution (Figure 14).
As shown above, HCl was found to be a good stripping agent for the stripping of metal loaded [Hbet][Tf2N]. To examine the influence of HCl in the stripping solution on the thermomorphic behavior of the [Hbet][Tf2N]–water system, the cloud point temperature of a 50/50 wt % [Hbet][Tf2N]sat–H2O mixture was determined as a function of the HCl concentration in the aqueous phase. Ionic liquid mixtures were prepared containing 500 mg of saturated [Hbet][Tf2N]sat and 500 mg of diluted HCl solution (concentrations ranging from 0 to 2 mol/L). The observed cloud point temperature of each mixture was plotted versus the HCl concentration in the aqueous solution (Figure 15). The cloud point increased significantly with higher HCl concentrations. A possible explanation for this observation is the increase in ionic strength by addition of chloride ions, which results in a lower solubility of the ionic liquid in water (salting-out effect) [31,54]. An increasing water miscibility between water and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide by adding HTf2N has been observed as well by Gaillard et al. [55]. They also found an increasing water miscibility when HCl was added, which is opposite from what has been observed here for the addition of HCl to [Hbet][Tf2N].
2.7. Recovery of the Ionic Liquid
One of the disadvantages of a homogeneous liquid–liquid extraction system based on ionic liquids is the high solubility of the ionic liquid in the water phase. In this way, part of the ionic liquid is lost during the extraction and stripping steps. To investigate the recovery of the ionic liquid from both aqueous phases, collected after stripping and after extraction, respectively, a typical extraction and back-extraction cycle was executed with 10.0 g of water-saturated [Hbet][Tf2N] (containing approximately 8.8 g of pure [Hbet][Tf2N]), 2.0 g of betaine and 8.0 g of La(Tf2N)3 solution (2300 mg/kg La). The mixture was heated to obtain one homogeneous phase and subsequently cooled to induce phase separation. The organic phase was isolated (9.38 g) and added to 9.38 g of a 2 M HCl stripping solution. This mixture was reheated to obtain one homogeneous phase and cooled to induce phase separation. The organic phase (7.98 g) was dried on a rotary evaporator (80 °C) and dry [Hbet][Tf2N] (6.84 g, 77% of the original amount of [Hbet][Tf2N]) was obtained. This [Hbet][Tf2N] sample was analyzed with TXRF to determine the remaining metal content. The results showed that the ionic liquid contained no significant amounts of chloride impurities and that lanthanum was completely removed.
The collected aqueous phases (after extraction and after stripping) also contained a certain amount of [Hbet][Tf2N], since this ionic liquid dissolves in water. By adding an aqueous CaCl2 solution (1.2 mol/kg) to both aqueous phases, the solubility of [Hbet][Tf2N] decreased and a second phase appeared at the bottom of the vessel. These ionic-liquid-rich phases were isolated, dried on a rotary evaporator (80 °C), and tested with TXRF on their metal content.
The ionic liquid recovered from the aqueous phase after extraction (0.90 g, 10% of the original amount of [Hbet][Tf2N]) contained high concentrations of lanthanum and calcium. The ionic liquid recovered from the aqueous phase after stripping (0.42 g, 5% of original amount of [Hbet][Tf2N]) also contained calcium and lanthanum, but in far lower concentrations, despite the higher lanthanum concentrations in this aqueous phase. This can be explained by the high HCl stripping concentrations in the solution and the absence of betaine as extractant. In comparison, no HCl but high amounts of betaine are present in the aqueous phase after the extraction, which are optimal extraction conditions. This difference in composition is probably the major reason why the metal concentrations in the recovered ionic liquid phases are different. Lanthanum impurities could be completely removed from both parts of the recovered [Hbet][Tf2N] by increasing the HCl concentration in the corresponding aqueous solution up to 4 M. The calcium concentration was only lowered to approximately 100 mg/kg. Thus, a second purification step of stripping with HCl is required to completely remove all calcium from [Hbet][Tf2N] recovered from the aqueous phases. The total recovery percentage of [Hbet][Tf2N] was 92%.
3. Experimental Section
3.1. Products
Anhydrous betaine (98%), neodymium(III) nitrate hexahydrate (99.9%), neodymium(III) oxide (99.99%) and neodymium(III) chloride (99.9%), praseodymium(III) bromide (99.9%) were purchased from Alfa Aeser (Karlsruhe, Germany). Lithium bis(trifluoromethylsulfonyl)imide (99%) and hydrogen bis(trifluoromethylsulfonyl)imide (99%) were obtained from IoLiTec (Heilbronn, Germany). Betaine monohydrate (99+%) and betaine chloride (99%) were from ACROS Organics (Geel, Belgium). Absolute ethanol and hydrogen chloride (37%) were obtained from VWR (Leuven, Belgium). A 1000 ppm gallium and dysprosium standard were obtained from Merck (Overijse, Belgium). Calcium chloride (99%) was purchased from Sigma-Aldrich (Diegem, Belgium). The silicone solution in isopropanol was obtained from SERVA Electrophoresis GmbH (Heidelberg, Germany).
3.2. Equipment
1H- and 13C-NMR spectra were recorded on the Bruker Avance 300 spectrometer (Bruker Biospin, Rheinstetten, Germany). A frequency of 300 MHz was used for recording the 1H spectra and 75 MHz for the 13C spectra. The samples were prepared by dissolving a small amount of product in deuterated dimethyl sulfoxide ([D6]DMSO) or deuterated water (D2O). Melting points of the synthesized ionic liquids were recorded on a power compensation DSC (DSC 882e, Mettler-Toledo, Greifensee, Switzerland) in a helium atmosphere. Densities were measured with a 5 mL pycnometer. Elemental analysis (carbon, hydrogen, nitrogen) was performed on a CE Instruments EA-1110 element analyzer (Interscience, Louvain-la-Neuve, Belgium). FTIR spectra were recorded on a Bruker Vertex 70 spectrometer and analyzed with OPUS software (Bruker Optics, Ettlingen, Germany). Both solid and liquid samples are examined directly without further preparation using a Platinum ATR single reflection diamond attenuated total reflection (ATR) accessory (Bruker Optics, Ettlingen, Germany). A Mettler-Toledo DL39 coulometric Karl Fischer titrator (Mettler-Toledo, Greifensee, Switzerland) was used to determine the water content in the synthesized ionic liquids. Raman spectra of the aqueous phases were recorded on a Bruker Vertex 70 spectrometer with a Ram II Raman module (Bruker Optics, Ettlingen, Germany), with 128 scans per spectrum at a laser power of 500 mW and a resolution of 4 cm−1.
3.3. Synthesis
3.3.1. Synthesis of [Hbet][Tf2N]
Betaine hydrochloride (0.195 mol, 30.005 g) and lithium bis(trifluoromethylsulfonyl)imide (0.196 mol, 56.200 g) were added to 50 mL of water and stirred for one hour. The resulting ionic liquid phase-separated from the aqueous layer. Lithium chloride, formed during the reaction, dissolved mostly in the aqueous phase. The ionic liquid was washed with ice-cold water to remove chloride impurities. The presence or absence of chloride impurities was tested by addition of silver nitrate to the aqueous phase obtained after a washing step. Finally, the remaining water in the ionic liquid was removed in vacuo on a rotary evaporator (80 °C) and the compound was obtained as a white solid product. Yield 80% (0.156 mol, 62.2 g). 1H-NMR (300 MHz, D2O, δ/ppm): 4.12 (s, 2H, CH2), 3.21 (s, 9H, 3 × CH3). 13C-NMR (75.47 MHz, D2O, δ/ppm): 167.06 (COO), 121.35 (q, 2 × CF3, J = 4.24), 63.71 (N–CH2), 53.77 (3 × CH3). Elemental analysis calculated for C7H12N2O6F6S2 (M = 398.302 g/mol) (%): C 21.11, H 3.04, N 7.03; found (%): C 21.65, H 2.53, N 6.95. Water content: 0.16 wt % (1568 ppm). Density: 1.541 g·cm−3 (at 60 °C). Melting point: 58.6 °C. FTIR (ATR, cm−1) 1768 (COOH), 1478 (CH2), 1420, 1348 (SO2), 1325 (SO2), 1180 (CF3), 1137 (SO2), 1050 (SO2), 741 (CF3), 570 (CF3), 513 (CF3).
3.3.2. Synthesis of Metal Bis(trifluoromethylsulfonyl)imides
Neodymium(III) oxide (0.005 mol, 1.676 g) was added to a solution of 80 wt % hydrogen bis(trifluoromethylsulfonyl)imide (0.030 mol, 10.56 g) in 50 mL of water and lanthanum(III) oxide (0.005 mol, 1.614 g) was added to a solution of 80 wt % hydrogen bis(trifluoromethylsulfonyl)imide (0.030 mol, 10.56 g) and dissolved as well in 50 mL of water. Both solutions were stirred under reflux conditions for one hour. The reaction mixtures turned slowly into a clear solution after approximately 30 min. Reaction was followed by measuring the pH. The product was dried in vacuo at a Schlenk line to remove remaining water.
3.4. Extraction Experiments
During a typical extraction experiment, 1 g of water saturated ionic liquid was mixed in a 1:1 mass ratio with an aqueous solution of metal ions and the betaine extractant. The choice for using mass ratios instead of the commonly used volume ratios was made because weighing the ionic liquid is easier and more precise than pipetting a viscous ionic liquid. The mixture was heated above the UCST and gently shaken with a Nemus Life Thermo Shaker TMS-200 (Nemus Life AB, Lund, Sweden) to obtain one phase (homogeneous stage). Gentle agitation was applied to speed up the formation of one phase, because no homogeneous solution is formed without shaking in the time span of the extraction process at temperatures slightly above the UCST. This is due to the large difference in density between the water phase and the ionic liquid phase. Next, the mixture was cooled to room temperature (settling stage) to return to a two-phase equilibrium and the settling process was accelerated by centrifugation. The metal content was measured in both phases with a Bruker S2 Picofox Total Reflection X-Ray Fluorescence (TXRF) spectrometer (Bruker AXS Microanalysis GmbH, Berlin, Germany). A known amount of gallium or dysprosium nitrate was added as internal standard to a small amount of the solution (typically 100 mg). The mixture was further diluted up to approximately 1 g with Milli-Q® water (Billerica, MA, USA) for aqueous samples and with ethanol for ionic liquid samples and homogenized using a vortex mixer. A small droplet of the prepared sample solution (5–10 μL) was dispensed on a quartz sample carrier and dried in the oven at 60 °C for 15 min to remove volatile solvents. To prevent droplets of aqueous solutions to spread out or roll to the side of the carrier, a small amount of SERVA silicone solution in isopropanol (20 μL) was dispensed on the quartz carrier and dried at 60 °C for 15 min prior to addition of the sample solution droplet.
3.5. Cloud Point Determinations
The following experimental set-up is used for the determination of the cloud points: a solvent mixture is placed in a small test tube (diameter: 10 mm, length: 13 mm) and stirred with a magnetic stirring bar. The mixture is placed in a temperature-controlled water (or silicone oil) bath under constant stirring and heated until phase separation disappears. The water bath was then allowed to cool gradually (maximum cooling speed of 0.6 °C/min) and the transparency of the mixtures was monitored by sight to determine the temperature at which the mixture became cloudy (cloud point).
3.6. Viscosity Measurements
Viscosity was measured with a falling-ball viscosimeter size number three (Gilmont Instruments, Barrington, IL, USA) and a glass or stainless steel ball. A 4 g sample of water-saturated ionic liquid ([Hbet][Tf2N]sat) was inserted into the viscosimeter. A 3.48 g sample of water containing 20 wt % of betaine was added to obtain a biphasic mixture with a 47/53 wt % water/[Hbet][Tf2N]sat composition similar as in the extraction experiments. The viscosimeter was closed and heated until 75 °C in a water bath. Afterwards, the mixture was manually shaken to obtain one phase, reinserted in the water bath and cooled down for two hours until the desired temperature was obtained. A stainless steel ball and a distance of descent of 6 cm were used for the temperatures under the UCST. The glass ball was used for the low viscous mixtures above the UCST and the distance of descent was, in that case, 10 cm. The viscosity was calculated by using the following formula:
Here, η is the viscosity, K is a constant (35 mPa·cm3·g−1) and specific for the applied viscosimeter, ρb is the density of the ball (ρb = 2.53 g·cm−3 for the glass ball and 8.02 g·cm−3 for the stainless steel ball), ρIL is the density of the ionic liquid, and t is the time necessary for the descent. The density of the water saturated ionic liquid at room temperature is 1.466 g·L−1. Although this value will slightly change at higher temperature due to thermal expansion and a change in composition, it was used for all measurements under the UCST. The use of a constant value is justified because the density of the ball (8.02 g·cm−3) is significantly higher than the density of the ionic liquid. The error made by using a constant value is estimated to be below 4%. A small error was made as well for the measurements above the UCST because a constant density value of 1.242 g·mL−1 was used, which is the calculated density of a 47/53 wt % water/[Hbet][Tf2N]sat mixture at 60 °C without the addition of betaine.
4. Conclusions
The ionic liquid [Hbet][Tf2N] with an UCST of 55 °C, in combination with betaine as extractant, has been used as a homogeneous liquid–liquid extraction system for neodymium. The influences of several operational parameters on the extraction were investigated: heating time, duration of the homogeneous stage, temperature of the homogeneous stage, settling time and temperature of the settling stage. Heating for 2 min just above the UCST (60 °C) and cooling down to room temperature seems to be long enough to reach equilibrium with a minimum of energy input. It was confirmed that the homogeneous stage in the extraction process has a positive influence on the extraction kinetics. The metal feed concentration had no influence on the distribution ratio and the solubility of the metal complex did not hinder extraction. Extraction is not only possible from bis(trifluoromethylsulfonyl)imide medium, but also from chloride and nitrate media, with similar distribution ratios. The extraction mechanism of neodymium was investigated by slope analysis and it was found that a complex with a betaine:neodymium ratio of 1.5 was formed. Back-extraction (stripping) was possible with acidic aqueous solutions of hydrogen bis(trifluoromethylsulfonyl)imide and hydrogen chloride. The best results were obtained for hydrogen chloride. After the back-extraction step, the ionic liquid [Hbet][Tf2N] did not contain any impurities and could be reused without further purification. The ionic liquid dissolved in the aqueous phases during extraction and back-extraction could be partially recovered by addition of CaCl2 as a salting-out agent. A drawback of this recovering process is contamination of the recovered [Hbet][Tf2N] by Ca2+ ions. However, this contamination could be minimized by the addition of HCl to the aqueous phase, together with the CaCl2 salt. The phase behavior of the [Hbet][Tf2N]–water solvent system and the influence of additives such as betaine and HCl were examined. Extraction equilibrium is obtained faster by increasing the temperature, reducing the viscosity and thus increasing the diffusion of ions, by performing the extraction above the UCST and performing the extraction on a molecular scale without the presence of phase boundaries. Moreover, the energy barrier for movement of the ionic liquid molecules along each other is 2.5 times lower above than below the UCST.
Figure 2. Arrhenius plot for [Hbet][Tf2N] in equilibrium above and under the upper critical solution temperature (UCST) with 53 wt % water containing the betaine extractant.
Figure 3. Percentage extraction (%E) as a function of the heating time (in minutes) above the UCST, for the extraction of Nd(Tf2N)3 in [Hbet][Tf2N]–H2O with betaine as extractant.
Figure 4. Percentage extraction (%E) as a function of the temperature of the homogeneous stage for the extraction of Nd(Tf2N)3 in [Hbet][Tf2N]–H2O with betaine as extractant.
Figure 5. Percentage extraction (%E) as a function of the temperature to which the extraction mixture is cooled after the homogeneous stage for the extraction of Nd(Tf2N)3 in [Hbet][Tf2N]–H2O with zwitterionic betaine as extractant.
Figure 6. Percentage extraction (%E) as a function of the settling time (in minutes) for the extraction of Nd(Tf2N)3 in [Hbet][Tf2N]–H2O with betaine as extractant.
Figure 7. Visual representation of a homogeneous liquid–liquid extraction (HLLE) with [Hbet][Tf2N] as organic phase, neodymium as metal and betaine as extractant. (a) Water phase brought on top of the IL; (b) The mixture above the UCST as a homogeneous phase; and (c) The two phases after the extraction.
Figure 8. Raman spectra (680–820 cm−1) of the aqueous phase of a [Hbet][Tf2N]–water two-phase mixture with varying concentrations of betaine: (1) 0 wt %; (2) 5 wt %; (3) 10 wt %; (4) 15 wt %; and (5) 20 wt % of betaine in the initial aqueous phase. The peak at 780 cm−1 corresponds to the γOH bending mode of betaine and the peak at 742 cm−1 corresponds to the contraction/expansion of the whole [Tf2N] anion [48,49].
Figure 9. Slope analysis for the extraction of Nd(Tf2N)3 in [Hbet][Tf2N]–H2O with zwitterionic betaine as extractant. Slope of linear fit is equal to 1.68 ± 0.16, the R-value of the fit is 0.97.
Figure 10. Slope analysis for the extraction of neodymium from chloride (▪), nitrate (□) and bis(trifluoromethylsulfonyl)imide (▴) feed solution in [Hbet][Tf2N]–H2O with zwitterionic betaine as extractant. The slope of linear fit is equal to 1.50 ± 0.10 (▪), 1.40 ± 0.10 (□), 1.45 ± 0.09 (▴), respectively.
Figure 11. Percentage extraction (%E) as a function of the neodymium feed concentration for the extraction of Nd(Tf2N)3 in water-saturated [Hbet][Tf2N] with zwitterionic betaine as the extractant.
Figure 12. Percentage stripping (%S) as a function of different HTf2N concentrations for the stripping of neodymium from [Hbet][Tf2N].
Figure 13. Percentage stripping (%S) as a function of different HCl concentrations for the stripping neodymium from [Hbet][Tf2N].
Figure 14. Influence of the betaine concentration in the aqueous phase on the cloud point of a [Hbet][Tf2N]–water mixture (50/50 wt % [Hbet][Tf2N]sat/H2O), sat: saturated.
Figure 15. Influence of the HCl concentration in the aqueous phase on the cloud point of the [Hbet][Tf2N]–water mixture (50/50 wt % [Hbet][Tf2N]sat/H2O).
This research was financially supported by the FWO-Flanders (research project G.0900.13), IWT-Flanders (SBO-project MAPIL), and KU Leuven (research project GOA 13/008 and IOF-KP RARE3). Support by IoLiTec (Heilbronn, Germany) is also gratefully acknowledged.
Conflicts of Interest
The authors declare no conflict of interest.
- Rydberg, J.; Cox, M.; Musikas, C.; Choppin, G.R. Solvent Extraction: Principles and Practice, 2nd ed; Marcel Dekker, Inc: New York, NY, USA, 2004. [Google Scholar]
- Seddon, K.R. Ionic liquids for clean technology. J. Chem. Technol. Biotechnol 1997, 68, 351–356. [Google Scholar]
- Welton, T. Room-temperature ionic liquids. Solvents for synthesis and catalysis. Chem. Rev 1999, 99, 2071–2083. [Google Scholar]
- Wasserscheid, P.; Keim, W. Ionic liquids new solutions for transition metal catalysis. Angew. Chem. Int. Ed. Engl 2000, 39, 3772–3789. [Google Scholar]
- Earle, M.J.; Esperanca, J.M.S.S.; Gilea, M.A.; Canongia Lopes, J.N.; Rebelo, L.P.N.; Magee, J.W.; Seddon, K.R.; Widegren, J.A. The distillation and volatility of ionic liquids. Nature 2006, 439, 831–834. [Google Scholar]
- Smiglak, M.; Reichert, W.M.; Holbrey, J.D.; Wilkes, J.S.; Sun, L.; Thrasher, J.S.; Kirichenko, K.; Singh, S.; Katritzky, A.R.; Rogers, R.D. Combustible ionic liquids by design: Is laboratory safety another ionic liquid myth? Chem. Commun 2006, 2554–2556. [Google Scholar]
- Fox, D.M.; Awad, W.H.; Gilman, J.W.; Maupin, P.H.; de Long, H.C.; Trulove, P.C. Flammability, thermal stability, and phase change characteristics of several trialkylimidazolium salts. Green Chem 2003, 5, 724–727. [Google Scholar]
- Matsumoto, H. Electrochemical Windows of Room-Temperature Ionic Liquids (RTILs). In Electrochemical Aspects of Ionic Liquids, 2nd ed; Ohno, H., Ed.; John Wiley & Sons, Inc: Hoboken, NJ, USA, 2011; pp. 35–54. [Google Scholar]
- Rogers, R.D.; Seddon, K.R. Ionic liquids—Solvents of the future? Science 2003, 302, 792–793. [Google Scholar]
- Berthod, A.; Ruiz-Angel, M.; Carda-Broch, S. Ionic liquids in separation techniques. J. Chromatogr. A 2008, 1184, 6–18. [Google Scholar]
- Billard, I.; Ouadi, A.; Gaillard, C. Liquid–liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: From discovery to understanding. Anal. Bioanal. Chem 2011, 400, 1555–1566. [Google Scholar]
- Billard, I. Ionic Liquids: New Hopes for Efficient Lanthanide/Actinide Extraction and Separation? In Handbook on the Physics and Chemistry of Rare Earths; Bünzli, J.C.G., Pescharsky, V., Eds.; Elsevier: Amsterdam, The Netherlands, 2013; Volume 43, pp. 213–273. [Google Scholar]
- Dietz, M.L. Ionic liquids as extraction solvents: Where do we stand? Sep. Sci. Technol 2006, 41, 2047–2063. [Google Scholar]
- Huddleston, G.; Rogers, D. Room temperature ionic liquids as novel media for "clean" liquid–liquid extraction. Chem. Commun 1998, 1765–1766. [Google Scholar]
- Liu, Y.; Chen, J.; Li, D. Application and perspective of ionic liquids on rare earths green separation. Sep. Sci. Technol 2012, 47, 223–232. [Google Scholar]
- Rao, P.R.V.; Venkatesan, K.A.; Rout, A.; Srinivasan, T.G.; Nagarajan, K. Potential applications of room temperature ionic liquids for fission products and actinide separation. Sep. Sci. Technol 2012, 47, 204–222. [Google Scholar]
- Vander Hoogerstraete, T.; Wellens, S.; Verachtert, K.; Binnemans, K. Removal of transition metals from rare earths by solvent extraction with an undiluted phosphonium ionic liquid: Separations relevant to rare-earth magnet recycling. Green Chem 2013, 15, 919–927. [Google Scholar]
- Parmentier, D.; Metz, S.J.; Kroon, M.C. Tetraalkylammonium oleate and linoleate based ionic liquids: Promising extractants for metal salts. Green Chem 2013, 15, 205–209. [Google Scholar]
- Zhang, S. Physical properties of ionic liquids: Database and evaluation. J. Phys. Chem. Ref. Data 2006, 35, 1475–1517. [Google Scholar]
- Wasserscheid, P.; Welton, T. Physico–Chemical Properties. In Ionic Liquids in Synthesis, 2nd ed; Wasserscheid, P., Welton, T., Eds.; Wiley-VCH Verlag GmbH & Co. KGaA: Weinheim, Germany, 2007; pp. 41–118. [Google Scholar]
- Jacquemin, J.; Husson, P.; Padua, A.A.H.; Majer, V. Density and viscosity of several pure and water-saturated ionic liquids. Green Chem 2006, 8, 172–180. [Google Scholar]
- Nockemann, P.; Thijs, B.; Pittois, S.; Thoen, J.; Glorieux, C.; van Hecke, K.; van Meervelt, L.; Kirchner, B.; Binnemans, K. Task-specific ionic liquid for solubilizing metal oxides. J. Phys. Chem. B 2006, 110, 20978–20992. [Google Scholar]
- Nockemann, P.; Thijs, B.; Parac-Vogt, T.N.; van Hecke, K.; van Meervelt, L.; Tinant, B.; Hartenbach, I.; Schleid, T.; Ngan, V.T.; Nguyen, M.T.; et al. Carboxyl-functionalized task-specific ionic liquids for solubilizing metal oxides. Inorg. Chem 2008, 47, 9987–9999. [Google Scholar]
- Nockemann, P.; Binnemans, K.; Thijs, B.; Parac-Vogt, T.N.; Merz, K.; Mudring, A.V.; Menon, P.C.; Rajesh, R.N.; Cordoyiannis, G.; Thoen, J.; et al. Temperature-driven mixing-demixing behavior of binary mixtures of the ionic liquid choline bis(trifluoromethylsulfonyl)imide and water. J. Phys. Chem. B 2009, 113, 1429–1437. [Google Scholar]
- Lachwa, J.; Szydlowski, J.; Makowska, A.; Seddon, K.R.; Esperanca, J.M.S.S.; Guedes, H.J.R.; Rebelo, L.P.N. Changing from an unusual high-temperature demixing to a ucst-type in mixtures of 1-alkyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide and arenes. Green Chem 2006, 8, 262–267. [Google Scholar]
- Fukaya, Y.; Sekikawa, K.; Murata, K.; Nakamura, N.; Ohno, H. Miscibility and phase behavior of water–dicarboxylic acid type ionic liquid mixed systems. Chem. Commun 2007, 3089–3091. [Google Scholar]
- Yoshimitsu, H.; Kanazawa, A.; Kanaoka, S.; Aoshima, S. Well-defined polymeric ionic liquids with an upper critical solution temperature in water. Macromolecules 2012, 45, 9427–9434. [Google Scholar]
- Fukaya, Y.; Ohno, H. Hydrophobic and polar ionic liquids. Phys. Chem. Chem. Phys 2013, 15, 4066–4072. [Google Scholar]
- Kohno, Y.; Arai, H.; Saita, S.; Ohno, H. Material design of ionic liquids to show temperature-sensitive LCST-type phase transition after mixing with water. Aust. J. Chem 2011, 64, 1560–1567. [Google Scholar]
- Kohno, Y.; Ohno, H. Temperature-responsive ionic liquid/water interfaces: Relation between hydrophilicity of ions and dynamic phase change. Phys. Chem. Chem. Phys 2012, 14, 5063–5070. [Google Scholar]
- Saita, S.; Kohno, Y.; Ohno, H. Detection of small differences in the hydrophilicity of ions using the LCST-type phase transition of an ionic liquid-water mixture. Chem. Commun 2013, 49, 93–95. [Google Scholar]
- Xie, Z.L.; Taubert, A. Thermomorphic behavior of the ionic liquids [C4mim][FeCl4] and [C12mim][FeCl4]. Chemphyschem 2011, 12, 364–368. [Google Scholar]
- Fukumoto, K.; Ohno, H. LCST-type phase changes of a mixture of water and ionic liquids derived from amino acids. Angew. Chem. Int. Ed. Engl 2007, 46, 1852–1855. [Google Scholar]
- Lamb, J.D.; Peterson, R.T. Coalescence extraction—A novel, rapid means of performing solvent extractions. Sep. Sci. Technol 1995, 30, 3237–3244. [Google Scholar]
- Schaadt, A.; Bart, H.J. Coalescence extraction—A benign extraction tool. Chem. Eng. Technol 2003, 26, 469–472. [Google Scholar]
- Ullmann, A.; Ludmer, Z.; Shinnar, R. Phase-transition extraction using solvent mixtures with critical-point of miscibility. AIChE J 1995, 41, 488–500. [Google Scholar]
- Hosseini, M.H.; Alizadeh, N. Coalescence extraction system for rapid efficient and selective separation of zirconium and hafnium. Ind. Eng. Chem. Res 2010, 49, 7068–7073. [Google Scholar]
- Alizadeh, N.; Ashtari, K. Coalescence extraction of silver(I) using the temperature-induced phase separation (TIPS) process. Sep. Purif. Technol 2005, 44, 79–84. [Google Scholar]
- Vaezzadeh, M.; Shemirani, F.; Majidi, B. Determination of silver in real samples using homogeneous liquid–liquid microextraction based on ionic liquid. J. Anal. Chem 2012, 67, 28–34. [Google Scholar]
- Vander Hoogerstraete, T.; Onghena, B.; Binnemans, K. Homogeneous liquid-liquid extraction of metal ions with a functionalized ionic liquid. J. Phys. Chem. Lett 2013, 4, 1659–1663. [Google Scholar]
- Kolarik, Z. Ionic liquids: How far do they extend the potential of solvent extraction of f-elements? Solvent Extr. Ion Exch 2013, 31, 24–60. [Google Scholar]
- Okoturo, O.O.; VanderNoot, T.J. Temperature dependence of viscosity for room temperature ionic liquids. J. Electroanal. Chem 2004, 568, 167–181. [Google Scholar]
- Seddon, K.R.; Stark, A.; Torres, M. Viscosity and Density of 1-Alkyl-3-methylimidazolium Ionic Liquids. In Clean Solvents, 819th ed; Abraham, M.A., Moens, L., Eds.; American Chemical Society: Washington, DC, USA, 2002; pp. 34–49. [Google Scholar]
- Ghatee, M.H.; Bahrami, M.; Khanjari, N. Measurement and study of density, surface tension, and viscosity of quaternary ammonium-based ionic liquids ([N222(n)]Tf2N). J. Chem. Thermodyn 2013, 65, 42–52. [Google Scholar]
- Deive, F.J.; Rivas, M.A.; Rodriguez, A. Study of thermodynamic and transport properties of phosphonium-based ionic liquids. J. Chem. Thermodyn 2013, 62, 98–103. [Google Scholar]
- Ghatee, M.H.; Zare, M.; Zolghadr, A.R.; Moosavi, F. Temperature dependence of viscosity and relation with the surface tension of ionic liquids. Fluid Phase Equilib 2010, 291, 188–194. [Google Scholar]
- Sanders, J.R.; Hussey, C.L.; Ward, E.H. Aluminum bromide-1-methyl-3-ethylimidazolium bromide ionic liquids I. Densities, viscosities, electrical conductivities, and phase transitions. J. Electrochem. Soc 1986, 133, 325–330. [Google Scholar]
- Philip, D.; Aruldhas, G. Infrared, polarized Raman, and SERS spectra of betaine hydrogen oxalate monohydrate. J. Solid State Chem 1995, 114, 129–137. [Google Scholar]
- Lassègues, J.C.; Grondin, J.; Holomb, R.; Johansson, P. Raman and ab initio study of the conformational isomerism in the 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide ionic liquid. J. Raman Spectrosc 2007, 38, 551–558. [Google Scholar]
- Fagnant, D.P.; Goff, G.S.; Scott, B.L.; Runde, W.; Brennecke, J.F. Switchable phase behavior of [HBet][Tf2N]–H2O upon neodymium loading: Implications for lanthanide separations. Inorg. Chem 2013, 52, 549–551. [Google Scholar]
- Yang, G.; Chen, H.A.; Zhou, Z.Y.; Chen, X.M. Synthesis and crystal structures of quadruply carboxylate-bridged dimeric lanthanide(III) complexes of betaine. J. Chem. Crystallogr 1999, 29, 309–316. [Google Scholar]
- Nockemann, P.; Thijs, B.; Lunstroot, K.; Parac-Vogt, T.N.; Görller-Walrand, C.; Binnemans, K.; van ecke, K.; van Meervelt, L.; Nikitenko, S.; Daniels, J.; et al. Speciation of rare-earth metal complexes in ionic liquids: A multiple-technique approach. Chem. Eur. J 2009, 15, 1449–1461. [Google Scholar]
- Dawson, R.M.C. Data for Biochemical Research; Clarendon Press: Oxford, UK, 1959. [Google Scholar]
- Freire, M.G.; Carvalho, P.J.; Silva, A.M.S.; Santos, L.M.N.B.; Rebelo, L.P.N.; Marrucho, I.M.; Coutinho, J.A.P. Ion specific effects on the mutual solubilities of water and hydrophobic ionic liquids. J. Phys. Chem. B 2009, 113, 202–211. [Google Scholar]
- Gaillard, C.; Mazan, V.; Georg, S.; Klimchuk, O.; Sypula, M.; Billard, I.; Schurhammer, R.; Wipff, G. Acid extraction to a hydrophobic ionic liquid: The role of added tributylphosphate investigated by experiments and simulations. Phys. Chem. Chem. Phys 2012, 14, 5187–5199. [Google Scholar]
© 2013 by the authors; licensee MDPI, Basel, Switzerland This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).


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Dollar sell-off continues as risk assets rally again following successful EFSF bond sale
10/Απρ/2013 • Currency Updates•
Yesterday sterling pared back the decline from the previous day against the dollar advancing close to last week's high, as the fundamental developments coming out of the UK encouraged an improved outlook for growth. Indeed, U.K. manufacturing increased 1.0% in February versus forecasts for 0.4% print, while industrial outputs climbed 0.8% after contracting a revised 1.9% during the prior month.
However, another report revealed that UK Goods Trade deficit widened to £9.4 billion in February, from £8.168 billion in January, exceeding expectations for a smaller gap of £8.550 billion. Even so, the FTSE 100 traded up a narrow 0.58%.
Today there is a lack of macro data out of the UK, and as such the pound is likely to trade at a tight range as market participants are far more concerned about debt troubles in mainland Europe and the maintenance of ultra-accommodative policies from the Fed and Bank of Japan.
The euro increased to a three week high as the European Financial Stability Facility sold 8 billion euros of five year, 0.875% bonds with an impressive demand that released a bid to cover ratio of 2:1.
Market participants took positively to Spanish Prime Minister Mariano Rajoy comments, who stated that the EU should consider revamping the European Central Bank's (ECB) mandate, while Economy Minister Luis de Guindos argued that the Governing Council should introduce measures to address fragmentation of the capital markets as the euro-area remains in recession.
With regards to sovereign ratings, Moody's has affirmed its negative outlook on Spain's Baa3 rating and highlighted elusive deficit targets as the main reason. For Portugal, S&P has found no immediate ratings impact from the constitutional court decision last Friday, while recognizing the potentially adverse impact of this development. Portugal is rated BB/Stable by S&P.
Yesterday Wolfgang Schauble, the Finance minister of Germany, met U.S. Treasury Secretary Jacob Lew, who encouraged Schauble to adopt policies that foster consumer demand as the outlook for growth remains weak in the Eurozone.
The US dollar Index plunged yesterday and consolidated above it's 200 day moving average, as sentiment in the market remained "risk on" and demand for riskier assets such as euro and Stocks climbed. The S&P, Nasdaq and Dow Jones all closed marginally up.
An important bundle of macro data will be released today on the other side of the Atlantic. Within debt markets, the US Treasury will serve a 10-Year Note Auction, expecting a lower rate from its previous 2.029%. The Monthly Budget Statement for March expected -112.5B from its previous -203.5B but the most important is the FOMC Minutes, in which as growth and inflation picks up (despite the isolated last Non-Farm Payrolls figured that showed only 88K) a greater number of Fed policy makers are likely to adopt a more hawkish tone for monetary policy, reducing its ultra-accommodative monetary policy called QE3.


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"… Let us go over to the other side of the lake."
And they launched out.
Luke 8:22
They were doing exactly what Jesus told them to do; and yet, by following His instructions, they set sail into a night that would be filled with terror.
And where was He? He was with them, of course. And don't you think He knew what was to come? He also knew that they were well-trained, competent, hardy boatmen.
Well, their "competency" got a trifle shaky, to say the least, as the winds got stronger, tossing them down into the valley of one wave and throwing them up to the peak of another. And they could have kept on trying, yelling to each other, "We can do it! Hang on! We'll make it! It's slacking!"
But they chose another tack. Someone groped his way to the back of the boat, shook Jesus and said, "Master! Wake up! We've got a big problem here!We're swamping."
Jesus calmed the waves first. Then He calmed them.
I know it would have pleased the Lord for one of them to have said, "Hey, you guys! Jesus is with us. We've all seen Him perform these mighty miracles, and we've got to rest in His presence during this storm. I'm scared just like you are. Scared to death! But He can handle it! Do you hear me? He can handle it!"
Oh, yes. They were aware of Him and His power and His authority much
More intensely after He came to their rescue. They were "fearful and amazed, saying, 'Who is this? Even the winds and water obey Him!'" It was still a good experience. They learned and God was glorified.
I wonder, though, what Jesus would have said if the story had ended differently? if they had behaved differently? He seemed discouraged when He asked them, "Where is your faith?" I wonder if any of them understood?
(Luke 8:22-25)
Lord, I would like to be a source of encouragement to You.
I get awfully scared when the winds start knocking me around
and my world is almost swamped, but I should know by now that
You can handle it. Next time, Lord, I'll remember that night so
long ago, and I'll say, "Think, now. Jesus is with us. We don't
need to be afraid. We've got to rest in His presence during the storm."
That doesn't mean my knees won't be shaking, right, Lord?


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Double room from £150
Holiday Inn Oxford Circus
Customer rating: 87%
6 minutes walk away
Double room from £88
Nearest hotels to Roti Chai
There are 19 recommended places to stay within a 15 minutes walk from Roti Chai:
Radisson Blu Edwardian Sussex Hotel ( 0 minutes)
DoubleTree by Hilton London - Marble Arch ( 1 minutes)
Hyatt Regency London The Churchill ( 2 minutes)
The Zetter Townhouse Marylebone ( 3 minutes)
The Beaumont Hotel ( 3 minutes)
Amba Hotel Marble Arch ( 4 minutes)
Mandeville Hotel London ( 5 minutes)
Holiday Inn Oxford Circus ( 6 minutes)
Radisson Blu Edwardian Berkshire Hotel ( 6 minutes)
Montagu Place Hotel London ( 7 minutes)
Holmes Hotel London ( 9 minutes)
Langham Hotel London ( 11 minutes)
Landmark London Hotel ( 11 minutes)
Chesterfield Mayfair Hotel ( 12 minutes)
No 5 Maddox Street London ( 12 minutes)
Holiday Inn London Mayfair ( 12 minutes)
Washington Mayfair Hotel ( 13 minutes)
London Hilton on Park Lane ( 13 minutes)
Park Lane Mews Hotel ( 13 minutes)
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