Tunable catalyst gas phase hydrogenation of carboxylic acids
AssigneeCelanese International Corporation
InventorsHeiko Weiner, Victor J. Johnston, John L. Potts, Radmila Jevtic
Life of this patent
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Abstract
A process for selective formation of ethanol from acetic acid includes contacting a feed stream containing acetic acid and hydrogen at an elevated temperature with catalyst comprising platinum and tin on a high surface area silica promoted with calcium metasilicate. Selectivities to ethanol of over 85% are achieved at 280° C. with catalyst life in the hundreds of hours.
Claims108
A process for production of ethanol by reduction of acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in the vapor phase in a mole ratio of hydrogen to acetic acid of at least about 4:1 at a temperature of between about 225° C. and 300° C. over a hydrogenation catalyst comprising platinum and tin dispersed on a silicaceous support wherein the amounts and oxidation states of the platinum and tin, as well as the ratio of platinum to tin, and the silicaceous support are selected, composed and controlled such that:
- (i) at least 80% of the acetic acid converted is converted to ethanol;
- (ii) less than 4% of the acetic acid is converted to compounds other than compounds chosen from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene and mixtures thereof;
- and the activity of the catalyst declines by less than 10% when exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10:1 at a pressure of 2 atm and a temperature of 275° C. and a GHSV of 2500 hr−1 for a period of 168 hours.
A process for production of ethanol by reduction of acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in the vapor phase in a mole ratio of hydrogen to acetic acid of at least about 4:1 at a temperature of between about 225° C. and 300° C. over a hydrogenation catalyst comprising platinum and tin dispersed on an oxidic support wherein the amounts and oxidation states of the platinum and tin, as well as the ratio of platinum to tin, and the oxidic support are selected, composed and controlled such that:
- (i) at least 80% of the acetic acid converted is converted to ethanol;
- (ii) less than 4% of the acetic acid is converted to compounds other than compounds chosen from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene and mixtures thereof;
- and the activity of the catalyst declines by less than 10% when exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10:1 at a pressure of 2 atm and a temperature of 275° C. and a GHSV of 2500 hr−1 for a period of 500 hours.
A process for production of ethanol by reduction of acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in the vapor phase in a mole ratio of hydrogen to acetic acid of at least about 4:1 at a temperature of between about 225° C. and 300° C. over a hydrogenation catalyst consisting essentially of platinum and tin dispersed on a modified stabilized silicaceous support, the modified stabilized silicaceous support comprising silica having a purity of at least about 95% by weight modified with an stabilizer-modifier chosen from the group consisting of (i) alkaline earth oxides, (ii) alkali metal oxides, (iii) alkaline earth metasilicates, (iv) alkali metal metasilicates, (v) zinc oxide, (vi) zinc metasilicate and (vii) precursors for (i)-(vi), and mixtures of (i)-(vii), wherein the amounts and oxidation states of the platinum and tin, the ratio of platinum to tin and the relative proportions of stabilizer-modifier to silica in the modified stabilized silicaceous support as well as the purity of the silica in the modified stabilized silicaceous support are controlled such that at least 80% of the acetic acid converted is converted to ethanol and less than 4% of the acetic acid is converted to compounds other than compounds chosen from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene and mixtures thereof.
A process for production of ethanol by reduction of acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in the vapor phase in a mole ratio of hydrogen to acetic acid of at least about 4:1 at a temperature of between about 225° C. and 300° C. over a hydrogenation catalyst consisting essentially of:
- a catalytic metal chosen from the group consisting of:
- Fe, Co, Cu, Ni, Ru, Rh, Pd, Ir, Pt, Sn, Re, Os, Ti, Zn, Cr, Mo and W as well as mixtures thereof in an amount of from about 0.1% to about 10% by weight;
- and an optional promoter, dispersed on a suitable support wherein the amounts and oxidation states of the catalytic metal(s) and the compositions of the support and optional promoter as well as reaction conditions are controlled such that:
- (i) at least 80% of the acetic acid converted is converted to ethanol;
- (ii) less than 4% of the acetic acid is converted to compounds other than compounds chosen from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, diethyl ether and mixtures thereof;
- and the activity of the catalyst declines by less than 10% when exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10:1 at a pressure of 2 atm and a temperature of 275° C. and a GHSV of 2500 hr−1 for a period of 500 hours.
Dependencies are inferred from the claim text.