HYDROCARBOXYLATION OF FORMALDEHYDE IN THE PRESENCE OF A HIGHER ORDER CARBOXYLIC ACID AND A HOMOGENEOUS CATALYST
First Claim
1. A process for the preparation of glycolic acid, comprising(A) feeding carbon monoxide, aqueous formaldehyde, a homogeneous acid catalyst, and a carboxylic acid comprising 3-6 carbon atoms to a hydrocarboxylation reaction zone to produce an effluent comprising said homogeneous acid catalyst and esters of glycolic and carboxylic acids;
- (B) recovering said homogeneous acid catalyst from said effluent by extracting said effluent with a first hydrophilic solvent to form a first aqueous extract phase comprising a major amount of said homogeneous acid catalyst contained in said effluent and a first organic raffinate phase comprising a major amount of said esters of glycolic and carboxylic acids contained in said effluent;
(C) separating said first organic raffinate phase and said first aqueous extract phase; and
(D) recycling said first aqueous extract phase to step (A).
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Abstract
Disclosed is a process for the production and purification of glycolic acid or glycolic acid derivatives by the carbonylation of formaldehyde in the presence of a homogeneous acid catalyst and a carboxylic acid. This invention discloses hydrocarboxylations and corresponding homogeneous acid catalyst and glycolic acid separations. The homogeneous acid catalyst is readily separated from the hydrocarboxylation reaction effluent and recycled and the carboxylic acid is readily removed from the glycolic acid and the carboxylic acid is recycled.
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Citations
32 Claims
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1. A process for the preparation of glycolic acid, comprising
(A) feeding carbon monoxide, aqueous formaldehyde, a homogeneous acid catalyst, and a carboxylic acid comprising 3-6 carbon atoms to a hydrocarboxylation reaction zone to produce an effluent comprising said homogeneous acid catalyst and esters of glycolic and carboxylic acids; -
(B) recovering said homogeneous acid catalyst from said effluent by extracting said effluent with a first hydrophilic solvent to form a first aqueous extract phase comprising a major amount of said homogeneous acid catalyst contained in said effluent and a first organic raffinate phase comprising a major amount of said esters of glycolic and carboxylic acids contained in said effluent; (C) separating said first organic raffinate phase and said first aqueous extract phase; and (D) recycling said first aqueous extract phase to step (A). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A process for the preparation of glycolic acid, comprising
(A) feeding carbon monoxide, aqueous formaldehyde, a homogeneous acid catalyst, and carboxylic acid selected from at least one of the group consisting of propionic acid, n-butyric acid, i-butyric acid, 2-methyl butyric acid, n-valeric acid, and i-valeric acid to a hydrocarboxylation reaction zone to produce an effluent comprising said homogeneous acid catalyst and esters of glycolic and carboxylic acids; -
(B) recovering said homogeneous acid catalyst from said effluent by extracting said effluent with a first hydrophilic solvent comprising 15 weight percent to 100 weight percent water and 0 weight percent to 85 weight percent of glycolic acid, each on a total first hydrophilic solvent weight basis, and optionally with a first hydrophobic solvent selected from at least one of the group consisting of hexane, cyclohexane, heptane, octane, decane, benzene, toluene, xylene, isoparaffinic mixed hydrocarbons having a boiling range between 90 and 325°
C., methyl naphthalene, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, methyl tertiary-butyl ether, and methyl tertiary-amyl ether to form a first aqueous extract phase comprising a major amount of said homogeneous acid catalyst contained in said effluent and a first organic raffinate phase comprising a major amount of said esters of glycolic and carboxylic acids contained in said effluent;(C) separating said first organic raffinate phase and said first aqueous extract phase; and (D) recycling said first aqueous extract phase to step (A). - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification