carbonate the hydrogenation reaction of the present invention may be conducted by introducing the starting material for the reaction the catalyst component and if necessary a solvent into the reactor and supplying hydrogen thereto it is preferred to conduct heat treatment of the catalyst prior to the introduction of the starting material by introducing the catalyst component if necessary together with a solvent into the reactor and heat treating it under a hydrogen or argon atmosphere whereby the formation of by products will be low and the selectivity will be improved such heat treatment is conducted usually at a temperature of from 100 u00b0 to 300 u00b0 c preferably from 150 u00b0 to 250 u00b0 c for at least 0 5 hour the hydrogen may be the one diluted with a gas inert to the reaction such as nitrogen or carbon dioxide the reaction is conducted usually at a temperature of from 50 u00b0 to 250 u00b0 c preferably from 100 u00b0 to 200 u00b0 c the hydrogen partial pressure in the reaction system is usually from 0 1 to 100 kg cm 2 preferably from 1 to 30 kg cm 2 it is of course possible to conduct the reaction at a lower or higher pressure but such is not advantageous from the industrial point of view the reaction may be conducted either in a batch system or in a continuous system in.