# US 8,785,686 B2 · Process for recovering and recycling an acid catalyst > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,686 B2 - Document ID: US8785686B2 - Status: Granted - Kind: B2 - Application number: 13/431,335 - Filed: 2012-03-27 - Published: 2012-08-23 - Granted: 2014-07-22 - Earliest claimed: 2010-09-23 - Assignees: Eastman Chemical Company - Applicants: Scott Donald Barnicki; Stephen Neal Falling; Jeffrey Scott Kanel; Robert Sterling Kline; Peter Borden Mackenzie; Andrew James Vetter - Inventors: Scott Donald Barnicki; Stephen Neal Falling; Jeffrey Scott Kanel; Robert Sterling Kline; Peter Borden Mackenzie; Andrew James Vetter - Web page: https://patentgrep.com/patent/US8785686B2 ## CPC - B01D 11/0492: {Applications, solvents used} - B01J 31/0225: {comprising sulfonic acid groups or the corresponding salts} - B01J 31/0227: {being perfluorinated, i.e. comprising at least one perfluorinated moiety as substructure in case of polyfunctional compounds} - B01J 31/40: Regeneration or reactivation - C07C 51/12: on an oxygen-containing group in organic compounds, e.g. alcohols - C07C 51/48: by liquid-liquid treatment - B01J 2231/321: Hydroformylation, metalformylation, carbonylation or hydroaminomethylation - Y02P 20/584: Recycling of catalysts - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract Disclosed is a process for the extractive recovery of an acid catalyst from an aqueous mixture of glycolic acid with an extraction solvent comprising a tertiary amine or an onium carboxylate compound, a modifier, and a diluent. The acid catalyst, which can comprise strong acids such as sulfuric acid, alkyl sulfonic acids, and fluoroalkyl sulfonic acids, can be recovered by back extraction with aqueous formaldehyde and recycled to a process for the preparation of glycolic acid by the acid-catalyzed carbonylation of formaldehyde. Also disclosed is a process for the preparation of glycolic acid by the acid-catalyzed hydrocarboxylation of formaldehyde. ## Claims ### Claim 1 A process for the preparation of glycolic acid, comprising (A) contacting carbon monoxide with an aqueous formaldehyde reactant in the presence of an alkyl sulfonic acid catalyst containing from 1 to 5 carbon atoms to produce an aqueous glycolic acid mixture; and (B) recovering the alkyl sulfonic acid from the aqueous glycolic acid mixture by extracting the aqueous glycolic acid mixture with an extraction solvent comprising at least one tertiary amine, at least one onium carboxylate compound or a combination thereof; at least one modifier comprising an aliphatic carboxylic acid, an organophosphorus acid, or a combination thereof; and at least one diluent comprising carbon dioxide, an aliphatic hydrocarbon, a halogenated hydrocarbon, 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 contained in the aqueous glycolic acid mixture. ### Claim 2 (depends on 1) The process according to claim 1, wherein the molar ratio of carbon monoxide to formaldehyde is about 0.5:1 to about 100:1, and the contacting is at a pressure of about 35 to about 350 bars gauge and a temperature of about 160 to about 220° C. ### Claim 3 (depends on 1) The process according to claim 1, wherein 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. ### Claim 4 (depends on 1) The process according to claim 1, wherein the alkyl sulfonic acid catalyst comprises methanesulfonic acid, methanedisulfonic acid, methanetrisulfonic acid, bis(methylsulfonyl)methanesulfonic acid, methylsulfonylmethanesulfonic acid, or combinations thereof. ### Claim 5 (depends on 1) The process according to claim 1, wherein the alkyl sulfonic acid catalyst comprises methanesulfonic acid, methanedisulfonic acid, methanetrisulfonic acid, bis(methylsulfonyl)methanesulfonic acid, or combinations thereof. ### Claim 6 (depends on 1) The process according to claim 1, wherein the alkyl sulfonic acid catalyst comprises methanetrisulfonic acid. ### Claim 7 (depends on 1) The process according to claim 1, wherein the tertiary amine comprises tris(2-ethylhexyl)amine, tris(2-ethylbutyl)amine, trioctylamine, triisooctylamine, triisodecyl amine, tridodecylamine, tridecylamine, dioctyldecylamine, didecyloctylamine, or a combination thereof. ### Claim 8 (depends on 1) The process according to claim 1 wherein the modifier comprises n-pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, 2-ethylbutanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, pelargonic acid, nonanoic acid, decanoic acid, lauric acid, palmitic acid, bis(2-ethylhexyl)hydrogen phosphate, perfluorooctanoic acid, or a combination thereof. ### Claim 9 (depends on 1) The process according to claim 1 wherein the diluent comprises 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. ### Claim 10 (depends on 1) 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 step (C) and an organic raffinate phase comprising a minor amount of the acid catalyst contained in the organic extract phase. ### Claim 11 (depends on 10) 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 aqueous 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. ### Claim 12 (depends on 11) The process according to claim 11 wherein the aqueous formaldehyde extract is recycled to step (A). ### Claim 13 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 an aqueous glycolic acid mixture. ### Claim 14 (depends on 13) 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. ### Claim 15 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, methanedisulfonic 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, dioctyldecylamine, 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 comprising 2-ethylhexanoic acid, lauric 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, based on the total weight of the extraction solvent, comprising hexane, heptane, decane, methylcyclohexane, 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 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. ### Claim 16 (depends on 15) The process according to claim 15, further comprising (E) contacting 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 0 to about 20 weight percent of a wash modifier comprising 2-ethylhexanoic acid, lauric acid, bis(2-ethylhexyl)hydrogen phosphate, 2-ethylhexanol, 2-ethylbutanol, n-hexanol, n-octanol, n-decanol, or a combination thereof, to form a washed aqueous raffinate phase and an 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; (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). ### Claim 17 (depends on 15) The process according to claim 15, wherein the acid catalyst comprises methanetrisulfonic acid. ### Claim 18 (depends on 17) The process according to claim 17, wherein the tertiary amine comprises tris(2-ethylhexyl)amine; the modifier comprises 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-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. ### Claim 19 (depends on 15) 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 formaldehyde extract of step (D) is passed to step (A).