Process for the production of cyclohexanedimethanol

A vapor phase process for the production of cyclohexanedimethanol by hydrogenation of dimethyl cyclohexanedicarboxylate which comprises:

• (a) providing a hydrogenation zone containing a charge of a granular heterogenous ester hydrogenation catalyst selected from reduced copper chromite catalysts wherein the Cu:Cr weight ratio is from about 0.1:1 to about 4:1;
• reduced, copper chromite catalysts wherein the Cu:Cr weight ratio is from about 0.1:1 to about 4:1 promoted with from about 0.1% by weight up to 15% by weight of barium, manganese or a mixture of barium and manganese;
• or reduced manganese promoted copper catalysts wherein the Cu:Mn weight ratio is from about 2:1 to about 10:1;
• (b) supplying to the hydrogenation zone a vaporous feed stream containing hydrogen and dimethyl cyclohexanedicarboxylate at an inlet temperature which is at or above the dew point of the mixture, wherein the dimethyl cyclohexanedicarboxylate is supplied to the hydrogenation zone at a rate corresponding to a liquid hourly space velocity of from 0.05 to about 4.0 h.sup.-1 ;
• (c) maintaining the hydrogenation zone at a combination of a temperature of from about 150.degree. C. to about 300.degree. C. and a pressure of from about 150 psia (about 10.34 bar) to about 2000 psia (about 137.90 bar) which maintains both the dimethyl cyclohexanedicarboxylate reactant and the cyclohexanedimethanol product in the vapour phase;
• and
• (d) recovering from the hydrogenation zone a vaporous cyclohexanedimethanol product wherein the trans-:cis-isomer ratio of the cyclohexanedimethanol product is in the range of from about 2:1 to about 3.8:1.

A vapor phase process for the production of 1,4-cyclohexanedimethanol by hydrogenation of dimethyl 1,4-cyclohexanedicarboxylate which comprises:

• (a) providing a hydrogenation zone containing a charge of a granular heterogenous ester hydrogenation catalyst selected from reduced copper chromite catalysts wherein the Cu:Cr weight ratio is from about 0.1:1 to about 4:1;
• reduced, copper chromite catalysts wherein the Cu:Cr weight ratio is from about 0.1:1 to about 4:1 promoted with from about 0.1% by weight up to 15% by weight of barium, manganese or a mixture of barium and manganese;
• or reduced manganese promoted copper catalysts wherein the Cu:Mn weight ratio is from about 2:1 to about 10:1;
• (b) supplying to the hydrogenation zone a vaporous feed stream containing hydrogen and dimethyl 1,4-cyclohexanedicarboxylate at an inlet temperature which is at or above the dew point of the mixture, wherein the dimethyl 1,4-cyclohexanedicarboxylate is supplied to the hydrogenation zone at a rate corresponding to a liquid hourly space velocity of from 0.2 to about 1.0 h.sup.-1 ;
• (c) maintaining the hydrogenation zone at a combination of a temperature of from about 210.degree. C. to about 260.degree. C. and a pressure of from about 450 psia (about 31.03 bar) to about 1000 psia (about 68.95 bar) which maintains both the dimethyl 1,4-cyclohexanedicarboxylate reactant and the 1,4-cyclohexanedimethanol product in the vapour phase;
• and
• (d) recovering from the hydrogenation zone a vaporous 1,4-cyclohexanedimethanol product wherein the trans-:cis-isomer ratio of the cyclohexanedimethanol product is in the range of from about 2.6:1 to about 3.8:1.