PROCESS FOR PREPARING ISOCYANATES

摘要

The invention relates to processes for preparing isocyanates by splitting urethane, said process comprising the following process steps: (i) provision of synthesis gas from natural gas, coal, heavy oil or biomass gasification and production of methanol from the synthesis gas, (ii) reaction of the methanol by oxidative carbonylation or with urea to give dimethyl carbonate (DMC), (iv) preparation of urethane by reacting amine with the dimethyl carbonate, (v) splitting of the urethane to give the isocyanate and methanol, (vi) recycling of the methanol to the preparation of the dimethyl carbonate.