US  8,785,686  B2  54  53  bis(2-ethylhexyl)hydrogen  phosphate,  perfluorooctanoic  acid, or a combination  thereof.  9.  The process according  to claim  1  wherein the diluent  comprises pentane,  hexane, heptane,  decane, methylcyclo› hexane, methylene  chloride, chlorobenzene,  dichloroben- ze~e, 1  :2-dichloroethane,  benzene, toluene,  xylene, isoparaf› fimc mixed  hydrocarbons having  a boiling range between  90  and 325°  C., or a  combination thereof.  10.  The process according  to claim  1,  further comprising  11.  The process according  to claim  10  wherein the aqueous  formaldehyde solution  comprises about 35  to about 85 weight  percent formaldehyde,  based on the total  weight of the aque› ous  formaldehyde solution,  the aqueous  formaldehyde  extract comprises  about 0.5 to about  10 weight percent,  based  on the total weight  of the aqueous  formaldehyde extract,  of  the alkyl sulfonic  acid catalyst, and  the weight ratio  of the  aqueous formaldehyde  solution to the organic  extract phase is  about 0.1: 1 to about  1:  1.  12.  The process according  to claim  11  wherein the aqueous  formaldehyde extract  is recycled to step  (A).  13.  A process for the  preparation  of glycolic acid, compris- ing contacting carbon  monoxide with  a reaction mixture  com› prising an aqueous  formaldehyde reactant  and  methanetrisul› fonic acid to produce  an aqueous glycolic  acid mixture.  14.  The process according  to claim  13,  wherein the molar  ratio of carbon monoxide  to  formaldehyde  is about 0.5: 1 to  about 100: 1, the  contacting  is at a pressure of  about 35 to  about 350 bar gauge  and a  temperature  of about 160 to about  220°  C., and the  concentration  of  methanetrisulfonic  acid in  the aqueous glycolic  acid mixture is about  0.2 to about 12  weight percent.  .  15.  A process for the  preparation  of glycolic acid, compris› mg  19.  The process according  to claim  15  wherein the aqueous  formaldehyde solution  of step (D) comprises  about 40 to  about 55 weight percent  formaldehyde  and the aqueous form› aldehyde extract  of step (D) is passed  to step (A).  *  *  *  *  *  18.  The process according  to claim  17,  wherein the tertiary  amine comprises  tris(2-ethylhexyl)amine;  the modifier com› prises  2-ethylhexanoic  acid; the diluent  comprises hexane,  heptane, decane, or  a  combination thereof;  the wash solvent  comprises hexane,  heptane, decane,  isoparaffinic mixed  hydrocarbons having  a boiling range between  90 and 325°  C.,  or a  combination thereof;  the wash modifier  comprises 2-eth› ylhexanoic acid,  n-hexanol, n-decanol,  or a  combination  thereof; and the  weight ratio of the  modifier to the tertiary  amine is about 2:  1 to about 4: 1.  or a  combination thereof,  wherein the weight  ratio of  the modifier to the  tertiary amine is about  1: 1 to about  5:1; and  (C)  separating the aqueous  raffinate and organic  extract  phases; and  (D)  extracting the organic  extract phase from  step  (C)  with  an aqueous  formaldehyde solution  to form an aqueous  formaldehyde extract  comprising  a major amount of  the  acid catalyst contained  in the organic extract  phase from  st~p  (C)  and an organic raffinate  phase comprising  a  mmor amount of  the acid catalyst  contained in the  organic extract phase.  (A) contacting carbon  monoxide with an  aqueous formal› de~~de reactant in  the presence of an  acid catalyst com› pnsmg  methanesulfonic  acid,  methanedisulfonic  acid  methanetrisulfonic  acid,  bis(methylsulfonyl)methane~  sulfonic acid, or  a  combination thereof  to produce an  aqueous glycolic  acid mixture comprising  about 70 to  about 90 weight percent  glycolic acid, based  on the total  weight of the aqueous  glycolic acid mixture,  and about 1  to about 10 weight  percent of the acid  catalyst;  17.  The process according  to claim  15,  wherein the acid  catalyst comprises  methanetrisulfonic  acid.  (B) extracting the  aqueous glycolic  acid mixture with  an  extraction solvent,  comprising  (i) about 5 to about  45 weight percent,  based on the total  weight of the extraction  solvent, of a tertiary  amine  comprising  tris(2-ethylhexyl)amine,  tris(2-ethylbu› tyl)amine, trioctylamine,  triisooctylamine,  triisode- cyl amine,  tridodecylamine,  tridecylamine, dioctyl› decylamine, didecyloctylamine,  or a  combination  thereof;  (ii) about 5 to about  45 weight percent,  based on the total  weight of the extraction  solvent, of a modifier  com› prising  2-ethylhexanoic  acid, !auric acid,  bis(2-ethyl› hexyl)hydrogen  phosphate, perfluorooctanoic  acid,  (G) combining the  organic wash extract  phase with the  extraction solvent  of step (B) or with  the organic extract  phase of step  (C).  (F) separating the  washed aqueous  raffinate and organic  wash extract phases;  and  (E) ’:ontacting the  aqueous raffinate  phase from step  (C)  with a wash solvent  comprising about  80 to about 100  weight percent, based  on the total weight  of the wash  solvent, of a wash  diluent comprising  hexane, heptane,  decane,  methylcyclohexane,  benzene, toluene,  xylene,  isoparaffinic mixed  hydrocarbons having  a boiling range  between 90 and 325°  C., or a  combination thereof- and  about  O  to about 20 weight  percent of a wash  modifier  comprising 2-ethylhexanoic  acid, !auric acid,  bis(2-eth› ylhexyl)hydrogen  phosphate, 2-ethylhexanol,  2-eth› ylbutanol, n-hexanol,  n-octanol, n-decanol,  or a combi› nation thereof, to  form a washed aqueous  raffinate phase  an~ an organic wash  extract phase, wherein  the weight  rat10 of the wash solvent  to the aqueous raffinate  phase is  about 0.1:1 to about  1:1;  16.  The process according  to claim  15,  further comprising  (D) extracting the  organic extract phase  from step  (C)  with  an aqueous  formaldehyde solution,  comprising about  35  to about 85 weight  percent formaldehyde,  based on the  total weight of the  aqueous formaldehyde  solution, to  fo~ an aqueous  formaldehyde extract  comprising  a  maJor amount of  the acid catalyst  contained in the  organic extract phase  from step  (C)  and an organic raf› finate phase comprising  a minor amount  of the acid  catalyst contained  in the organic extract  phase.  (C)  separating the aqueous  raffinate and organic  extract  phases; and  to form an aqueous  raffinate phase comprising  a major  amount of the glycolic  acid contained in  the aqueous  glycolic acid mixture  and an organic extract  phase  comprising  a major amount of  the acid catalyst  con› tained in the aqueous  glycolic acid mixture;  (iii) about 10 to  about 90 weight  percent of a diluent,  based on the total  weight of the extraction  solvent,  comprising hexane,  heptane, decane,  methylcyclo› hexane, benzene,  toluene, xylene, isoparaffinic  mixed  hydrocarbons having  a boiling range between  90 and  325°  C., or a  combination thereof; 