Isopropyl alcohol

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Isopropyl alcohol
Skeletal formula of isopropyl alcohol Ball-and-stick model of isopropyl alcohol
CAS number 67-63-0 YesY
PubChem 3776
ChemSpider 3644 YesY
UNII ND2M416302 YesY
UN number 1219
KEGG D00137 YesY
ChEBI CHEBI:17824 YesY
RTECS number NT8050000
ATC code D08AX05
Jmol-3D images Image 1
Molecular formula C3H8O
Molar mass 60.10 g mol−1
Appearance Colorless liquid
Density 0.786 g/cm3 (20 °C)
Solubility in water miscible
Solubility miscible in benzene, chloroform, ethanol, ether, glycerin
soluble in acetone
insoluble in salt solutions
Acidity (pKa) 16.5[1]
Refractive index (nD) 1.3776
Viscosity 2.86 cP at 15 °C
1.96 cP at 25 °C[2]
1.77 cP at 30 °C[2]
Dipole moment 1.66 D (gas)
MSDS External MSDS
GHS signal word Danger
GHS hazard statements H225, H319, H336
GHS precautionary statements P210, P261, P305+351+338
R-phrases R11 R36 R67
S-phrases S7 S16 S24 S25 S26
Main hazards Flammable
NFPA 704
Flash point Open cup: 11.7 °C (53.1 °F)
Closed cup: 13 °C (55 °F)
Autoignition temperature 399 °C (750 °F)
Explosive limits 2–12.7%
Threshold Limit Value 980 mg/m3 (TWA), 1225 mg/m3 (STEL)
LD50 3600 mg/kg (oral, mouse)
12800 mg/kg (dermal, rabbit)
LC50 = 53000 mg/m3 (inhalation, mouse)
Related compounds
Related alcohols 1-Propanol, ethanol, 2-butanol
Supplementary data page
Structure and
n, εr, etc.
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Infobox references

Isopropyl alcohol is a chemical compound with the molecular formula C3H8O or C3H7OH. It is a colorless, flammable chemical compound with a strong odor. It is the simplest example of a secondary alcohol, where the alcohol carbon atom is attached to two other carbon atoms sometimes shown as (CH3)2CHOH. It is a structural isomer of propanol. Isopropyl alcohol is denatured for certain uses.



Isopropyl alcohol forms an azeotrope with water, which gives a boiling point of 80.37 °C (176.67 °F) and a composition of 87.7 wt% (91 vol%) isopropyl alcohol. Water-isopropyl alcohol mixtures have depressed melting points.[4] It has a slightly bitter taste, and is not safe to drink.[4][5]


Isopropyl alcohol has a maximum absorbance at 204 nm in an ultraviolet-visible spectrum.[citation needed]



(CH3)2CHOH → (CH3)2CO + H2

Isopropyl alcohol is often used as both solvent and hydride source in the Meerwein-Ponndorf-Verley reduction and other transfer hydrogenation reactions; it is oxidized to acetone. Isopropyl alcohol may be converted to 2-bromopropane using phosphorus tribromide, or dehydrated to propene by heating with sulfuric acid.



In 1994, 1.5 million tonnes of isopropyl alcohol were produced in the United States, Europe, and Japan.[7] This compound is primarily produced by combining water and propene in a hydration reaction. It is also produced by hydrogenating acetone.[7][8]


Indirect hydration[edit]


Direct hydration[edit]


Both processes require that the isopropyl alcohol be separated from water and other by-products by distillation. Isopropyl alcohol and water form an azeotrope and simple distillation gives a material that is 87.9% by weight isopropyl alcohol and 12.1% by weight water.[9] Pure (anhydrous) isopropyl alcohol is made by azeotropic distillation of the wet isopropyl alcohol using either diisopropyl ether or cyclohexane as azeotroping agents.[7]

Hydrogenation of acetone[edit]



In 1990, 45 thousand tonnes of isopropyl alcohol were used in the United States. The vast majority of isopropyl alcohol was used as a solvent for coatings or for industrial processes. Isopropyl alcohol in particular is popular for pharmaceutical applications,[7] it is presumed due to the low toxicity of any residues. Some isopropyl alcohol is used as a chemical intermediate. Isopropyl alcohol may be converted to acetone, but the cumene process is more significant. In that year, a tiny fraction (5.4 tonnes) was consumed for household use and in personal care products. It is also used as a gasoline additive.[7]



Examples of this application include cleaning electronic devices such as contact pins (like those on ROM cartridges), magnetic tape and disk heads (such as those in audio and video tape recorders and floppy disk drives), the lenses of lasers in optical disc drives (e.g., CD, DVD) and removing thermal paste from heatsinks and IC packages (such as CPUs[11]). Isopropyl alcohol is used in keyboard, LCD and laptop cleaning, is sold commercially as a whiteboard cleaner, and is a strong but safer alternative to common household cleaning products.[which?] It is commonly used to clean prepared optical fibers just before splicing. It is used to clean LCD and glass computer monitor screens (at some risk to the anti-reflection coating on some screens[citation needed]), and used to give second-hand or worn non-vinyl phonograph records newer-looking sheen. It is effective at removing Hot-Melt Adhesive from a large variety of surfaces. It is effective at removing residual glue from some sticky labels although some other adhesives used on tapes and paper labels are resistant to it. It can also be used to remove stains[clarification needed] from most fabrics, wood, cotton, etc. In addition, it can also be used to clean paint or other oil-based products so that they may be reused, commonly known as "repainting." It is used as a wetting agent in the fountain solution used in lithographic printing, and often used as a solvent for French polishing shellac used in cabinet making.


Isopropyl alcohol is esterified to give isopropyl acetate, another solvent. It reacts with carbon disulfide and sodium hydroxide to give sodium isopropylxanthate, a herbicide[12] and an ore flotation reagent.[13] Isopropyl alcohol reacts with titanium tetrachloride and aluminium metal to give titanium and aluminium isopropoxides, respectively, the former a catalyst, and the latter a chemical reagent.[7] This compound may serve as a chemical reagent in itself, by acting as a dihydrogen donor in transfer hydrogenation.


Disinfecting pads typically contain a 60–70% solution of isopropyl alcohol in water. Water is required to open up membrane pores of bacteria, which acts as a gateway inside for isopropyl. A 75% v/v solution in water may be used as a hand sanitizer.[14] Isopropyl alcohol is used as a water-drying aid for the prevention of otitis externa, better known as swimmer's ear.[15]

Early uses as an anesthetic[edit]

Although isopropyl alcohol can be technically used for anesthesia, its many negative drawbacks prohibit this use. Isopropyl alcohol can also be used similar to ether as a solvent[16] or as an anesthetic by inhaling the fumes or orally. Early uses included using the solvent as general anesthetic for small mammals[17] and rodents by scientists and some veterinarians. However, it was soon discontinued, as many complications arose, including respiratory irritation, internal bleeding, and visual and hearing problems. In rare cases, respiratory failure leading to death in animals was observed.







Isopropyl alcohol vapor is denser than air and is flammable with a combustible range between 2 and 12.7% in air. It should be kept away from heat and open flame.[18] Isopropyl alcohol has also been reported to form peroxides, which may explode upon concentration.[19] Isopropyl alcohol is a skin irritant.[18]


Isopropyl alcohol and its metabolite, acetone, act as central nervous system (CNS) depressants. Symptoms of isopropyl alcohol poisoning include flushing, headache, dizziness, CNS depression, nausea, vomiting, anesthesia, and coma. Poisoning can occur from ingestion, inhalation, or absorption; therefore, well-ventilated areas and protective gloves are recommended. Around 15 g of isopropyl alcohol can have a toxic effect on a 70 kg human if left untreated.[20] However, it is not nearly as toxic as methanol or ethylene glycol. Isopropyl alcohol does not cause an anion gap acidosis (in which a lowered blood serum pH causes depletion of bicarbonate anion) unlike ethanol and methanol. Isopropyl alcohol does, however, produce an osmolal gap between the calculated and measured osmolalities of serum, as do the other alcohols. Overdoses may cause a fruity odor on the breath as a result of its metabolism to acetone, which is further metabolized to produce the nutrients acetate and glucose.[21] Isopropyl alcohol is oxidized to form acetone by alcohol dehydrogenase in the liver.





  8. ^ Logsdon, John E. and Loke, Richard A. (December 4, 2000 (online)). "Isopropyl Alcohol". Kirk‑Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 
  9. ^ CRC Handbook of Chemistry and Physics, 44th ed. pp 2143–2184
  10. ^ Market Study Solvents, Ceresana, published Apr 2012
  11. ^ Arctic Silver thermal compound.
  12. ^ "proxan-sodium". Retrieved 2012-06-17. 
  14. ^ "Guide to Local Production: WHO-recommended Handrub Formulations". World Health Organization. August 2009. 
  15. ^ Otitis Externa (Swimmers Ear). Medial College of Wisconsin
  18. ^ a b "Isopropanol". Sigma-Aldrich. 2012-1-19. Retrieved 7/6/2012. 
  20. ^ Calculated from TDLO listed at Oxford University MSDS, assuming weight of 70 kg

External links[edit]