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 

(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. 

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 

(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; 

(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, 

or a combination thereof, wherein the weight ratio of the modifier to the tertiary amine is about 1: 1 to about 5:1; and 

(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; 

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; 

(C) separating the aqueous raffinate and organic extract phases; and 

(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. 

16. The process according to claim 15, further comprising 

(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; 

(F) separating the washed aqueous raffinate and organic wash extract phases; and 

(G) combining the organic wash extract phase with the extraction solvent of step (B) or with the organic extract phase of step (C). 

17. The process according to claim 15, wherein the acid catalyst comprises methanetrisulfonic acid. 

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. 

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). 

* * * * * 

