organic extract phase comprising a major amount of the acid catalyst contained in the aqueous glycolic acid mix› ture. 

Embodiment 17 is a process that includes the features of embodiment 16, in which the molar ratio of carbon monoxide to formaldehyde is about 0.5: 1 to about 100: 1, and the con› tacting is at a pressure of about 35 to about 350 bar gauge and a temperature of about 160 to about 220° C. 

Embodiment 18 is a process that includes the features of any one of embodiments 16 and 17, in which the aqueous glycolic acid mixture comprises about 50 to about 95 weight percent glycolic acid and about 0.2 to about 12 weight percent of the alkyl sulfonic acid catalyst, each based on the total weight of the aqueous glycolic acid mixture. 

Embodiment 19 is a process that includes the features of any one of embodiments 16-18, in which the alkyl sulfonic acid catalyst comprises methanesulfonic acid, methanedisul› fonic acid, methanetrisulfonic acid, bis(methylsulfonyl) methanesulfonic acid, methylsulfonylmethanesulfonic acid, or combinations thereof. 

Embodiment 20 is a process that includes the features of any one of embodiments 16-19, in which the alkyl sulfonic acid catalyst comprises methanesulfonic acid, methanedisul› fonic acid, methanetrisulfonic acid, bis(methylsulfonyl) methanesulfonic acid, or combinations thereof. 

Embodiment 21 is a process that includes the features of any one of embodiments 16-20, in which the alkyl sulfonic acid catalyst comprises methanetrisulfonic acid. 

Embodiment 22 is a process that includes the features of any one of embodiments 16-21, in which the tertiary amine 30 comprises tris(2-ethylhexyl)amine, tris(2-ethylbutyl)amine, trioctylamine, triisooctylamine, triisodecyl amine, tridodecy› lamine, tridecylamine, dioctyldecylamine, didecylocty› lamine, or a combination thereof. 

Embodiment 23 is a process that includes the features of any one of embodiments 16-22, in which the modifier com› prises n-pentanoic acid, 2-methylbutanoic acid, 3-methylbu› tanoic acid, hexanoic 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, perfluorooctanoic acid, or a combination thereof. 

Embodiment 24 is a process that includes the features of any one of embodiments 16-23, in which the diluent com› prises pentane, hexane, heptane, decane, methylcyclohexane, methylene chloride, chlorobenzene, dichlorobenzene, 1,2- dichloroethane, benzene, toluene, xylene, isoparaffinic mixed hydrocarbons having a boiling range between 90 and 325° C., or a combination thereof. 

Embodiment 25 is a process that includes the features of any one of embodiments 16-24 and further comprises 

(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 form› aldehyde extract comprising a major amount of the acid catalyst contained in the organic extract phase from step (C) and an organic raffinate phase comprising a minor amount of the acid catalyst contained in the organic extract phase. 

Embodiment 26 is a process that includes the features of embodiment 25, in which the aqueous formaldehyde solution comprises about 35 to about 85 weight percent formaldehyde, based on the total weight of the aqueous formaldehyde solu› tion, 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 cata- 

lyst, and the weight ratio of the aqueous formaldehyde solu› tion to the organic extract phase is about 0.1: 1 to about 1: 1. 

Embodiment 27 is a process that includes the features of any one of embodiments 25-26, in which the aqueous form- aldehyde extract is recycled to step (A). 

Embodiment 28 is a process for the preparation of glycolic acid, comprising contacting carbon monoxide with a reaction mixture comprising an aqueous formaldehyde reactant and methanetrisulfonic acid to produce to produce an aqueous glycolic acid mixture. 

Embodiment 29 is a process that includes the features of embodiment 28, in which 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 concen› tration of methanetrisulfonic acid in the aqueous glycolic acid mixture is about 0.2 to about 12 weight percent. 

Embodiment 30 is a process for the preparation of glycolic acid, comprising (A) contacting carbon monoxide with an aqueous formaldehyde reactant in the presence of an acid catalyst comprising methanesulfonic acid, methanedisul› fonic acid, methanetrisulfonic acid, bis(methylsulfonyl) methanesulfonic 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-ethylbutyl) amine, trioctylamine, triisooctylamine, triisodecyl amine, tridodecylamine, tridecylamine, dioctyldecy- lamine, 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 compris› ing 2-ethylhexanoic acid, !auric acid, bis(2-ethylhexyl) hydrogen phosphate, perfluorooctanoic acid, or a com- bination 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, methylcyclohexane, benzene, toluene, xylene, isoparaffinic mixed hydrocarbons hav› ing a boiling range between 90 and 325° C., or a com- bination 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 com› prising a major amount of the acid catalyst contained 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 form an aqueous formaldehyde extract comprising a major amount of the acid catalyst contained in the organic extract phase from step (C) and an organic raffinate phase comprising a minor amount of the acid catalyst contained in the organic extract phase. 

Embodiment 31 is a process that includes the features of embodiment 30 and further comprises 

(E) contacting the aqueous raffinate phase from step (C) with a wash solvent comprising about 80 to about 100 weight 

