PRODUCTION OF DIMETHYL CARBONATE

Dimethyl carbonate (DMC) is prepared by continuous gas-phase reaction of carbon monoxide and methyl nitrite on a heterogeneous catalyst containing a platinum metal at 50 to 170 DEG C and 1 to 5 bar. The reaction product is subjected to a multi-stage work-up which contains the following steps: 1. The reaction product is separated into gaseous and liquid fractions in a scrubber/condenser; the gaseous fractions are fed back for the new formation of methyl nitrite and the liquid fractions are subjected to a distillative work-up. 2. In the first distillation stage carried out at 5 to 15 bar DMC is obtained as bottom effluent. The top product is subjected to a second distillation stage or a pervaporation or vapour permeation. 3.1 In the second distillation stage carried out at 0.2 to 1.5 bar methanol is obtained as bottom effluent which can be subjected to the new formation of methyl nitrite. The top product of the second distillation stage is again subjected to the first distillation stage. 3.2 Alternatively to 3.1, in the pervaporation or vapour permeation a permeate is obtained which essentially consists of methanol and can be subjected to the new formation of methyl nitrite, and a retentate which is fed back into the first distillation.