Process for the preparation of 1,4-cyclohexanedimethanol from terephthalic acid
AssigneeEastman Chemical Company
InventorsBenjamin Frederick Barton, Steven Leroy Cook, Jeff Scott Howell, Noah Glenn McMillan, Damon Bryan Shackelford, Brent Alan Tennant, Phillip Wayne Turner
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Abstract
Disclosed is a process for the preparation of 1,4-cyclohexanedimethanol from terephthalic acid. Terephthalic acid is esterified with (4-methylcyclohexyl)methanol and the terephthalate ester hydrogenated to 1,4-cyclohexanedimethanol in a 2-stage process. The (4-methylcyclohexyl)methanol that is formed during the hydrogenation step is recycled to the esterification reaction. Also disclosed is a method for purifying and recovering the 1,4-cyclohexanedimethanol product.
Claims25
A process for the preparation of a 1,4-cyclohexanedimethanol from terephthalic acid, comprising
- (i). contacting terephthalic acid and (4-methylcyclohexyl)methanol in a reaction zone at a temperature of about 200° C. to about 300° C. under super atmospheric pressure, while removing water from the reaction zone, to form an esterification product mixture comprising bis(4-methylcyclohexylmethyl) terephthalate;
- (ii). contacting the esterification product mixture with hydrogen in a first hydrogenation zone in the presence of a catalyst effective for hydrogenation of an aromatic ring to produce a liquid effluent comprising bis(4-methylcyclohexylmethyl) cyclohexane-1,4-dicarboxylate;
- (iii). contacting the effluent from the first hydrogenation zone with hydrogen in the presence of an ester hydrogenation catalyst in a second hydrogenation zone to produce a hydrogenation product comprising 1,4-cyclohexanedimethanol, 4,4′-oxybis(methylene)bis(methylcyclohexane), and (4-methylcyclohexyl)methanol and;
- (iv). recycling at least a portion of the (4-methylcyclohexyl)methanol from step (iii) to step (i).
A process for the preparation of 1,4-cyclohexanedimethanol from terephthalic acid, comprising
- (i). contacting terephthalic acid and (4-methylcyclohexyl)methanol in a mole ratio of alcohol to acid of about 2:1 to about 5:1, in a reaction zone at a temperature of about 220° C. to about 280° C. in the absence of a exogenous catalyst under superatmospheric pressure, while removing water from the reaction zone, to form an esterification product mixture comprising bis(4-methylcyclohexylmethyl)terephthalate and unreacted (4-methylcyclohexyl)methanol;
- (ii). contacting the esterification product mixture with hydrogen in a first hydrogenation zone in the presence of a palladium on alumina catalyst to produce a liquid effluent comprising bis(4-methylcyclohexylmethyl)cyclohexane-1,4-dicarboxylate;
- (iii). contacting the effluent from the first hydrogenation zone with hydrogen in the presence of a copper chromite catalyst in a second hydrogenation zone to produce a hydrogenation product comprising 1,4-cyclohexanedimethanol, 4,4′-oxybis(methylene)bis(methylcyclohexane), and (4-methylcyclohexyl)methanol;
- (iv). recovering the (4-methylcyclohexyl)methanol from the hydrogenation product by distillation;
- and
- (v). recycling at least a portion of the (4-methylcyclohexyl)methanol to step (i).
Dependencies are inferred from the claim text.