from 5 to 16 carbon atoms, an organophosphorus acid con› taining from 5 to 16 carbon atoms, an alkanol containing 6 to 12 carbon atoms, or a combination thereof, to form a washed aqueous raffinate phase and a organic wash extract phase, wherein the weight ratio of the wash solvent to the aqueous raffinate phase is about 0.1:1 to about 1:1; 

separating the washed aqueous raffinate and organic wash extract phases, and 

combining the organic wash extract phase with the extrac› tion solvent of step (A) or with the organic extract phase of step (B). 

13. The process according to claim 12 wherein the wash solvent comprises propane, butane, hexane, heptane, decane, ~ethylcyclohexane, methylene chloride, chlorobenzene, d1chlorobenzene, 1,2-dichloroethane, benzene, toluene, xylene, isoparaffinic mixed hydrocarbons having a boiling range between 90 and 325° C., or a combination thereof- and the ~ash _modifier comprises n-pentanoic acid, 2-meth;lbu› tanmc acid, 3-methylbutanoic acid, hexanoic acid, perfluo› rooctanoic acid, 2-ethylbutanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, pelargonic acid, nonanoic acid, decanoic acid, !auric acid, palmitic acid, bis (2-ethylhexyl)hydrogen phosphate, n-hexanol, 2-ethylhex› anol, 2-ethylbutanol, n-octanol, isooctanol, n-decanol, isode› canol, or a combination thereof. 

14. A process for recovering an acid catalyst from aqueous glycolic acid, comprising 

(A! extracting an aqueous glycolic acid mixture, compris› mg 

(i) about 70 to about 90 weight percent glycolic acid, based on the total weight of the aqueous glycolic acid mixture, and 

(ii) about 1 to about 10 weight percent of an acid catalyst comprising sulfuric acid, methanesulfonic acid methanedisulfonic acid, methanedisulfonic acid bi~ (methylsulfonyl)methanesulfonic acid, trifluo› romethanesulfonic acid, 1, 1,2,2-tetrafluoroethane› sulfonic acid, or a combination thereof- 

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 of a modifier comprising 2-ethylhexanoic acid, !auric acid, bis(2- ethylhexyl)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 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 

glycol!c. acid mi:-ture and an organic extract phase c~mpn_smg a maJor amount of the acid catalyst con› tamed m the aqueous glycolic acid mixture• 

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

(C) extracting the organic extract phase from step (B) 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 fon_n an aqueous formaldehyde extract comprising a maJor amount of the acid catalyst contained in the organic extract phase from step (B) and an organic raf› finate phase comprising a minor amount of the acid catalyst contained in the organic extract phase; 

(D) ~ontacting the aqueous raffinate phase from step (B) 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; 

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

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

15. The process according to claim 14 wherein the aqueous glycoli~ acid mixture is prepared by process comprising car› bonylat10n of formaldehyde in the presence of a sulfuric acid catalyst. 

16. The process according to claim 15 wherein the aqueous formaldehyde solution of step (C) comprises about 40 to about 55 weight percent formaldehyde and the aqueous form› aldehyde extract of step (C) is passed to the glycolic acid process. 

17. The process according to claim 16 wherein the acid catalyst comp~ses sulfuric acid; the amine comprises tris(2- ethylhexyl)amme; the modifier comprises 2-ethylhexanoic acid; the diluent comprises hexane, heptane, decane, or a combination thereof; the wash solvent comprises hexane, he~~ane, decane, isoparaffinic mixed hydrocarbons having a b01lmg range between 90 and 325° C., or a combination thereof; the wash modifier comprises 2-ethylhexanoic 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. 

18. The process according to claim 17 wherein the aqueous formaldehyde extract comprises about 0.5 to about 1 0 weight percent sulfuric acid, based on the total weight of the aqueous formaldehyde extract. 

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