Patent ID: 8759569
Filing Date: 2014-06-24
Classification: C07C

Abstract:
1. A process for the continuous preparation of producing an isocyanate, the process comprising: (a) preparing an isocyanate and solvent-containing reaction solution by reacting at least one amine with phosgene in a solvent, to obtain a reaction solution comprising an isocyanate and solvent; (b) separating crude isocyanate from the isocyanate and solvent-containing reaction solution at a pressure ≧ambient pressure, to obtain a crude isocyanate stream and a first solvent stream; (c) recycling at least a portion of the first solvent stream into the reacting (a); and (d) separating the crude isocyanate stream at a pressure ≦ambient pressure, to obtain a purified isocyanate stream and a second solvent stream at a pressure ≦ambient pressure, (e) optionally purifying at least a portion of the second solvent stream to obtain a second purified solvent stream having a water content of ≦100 ppm, based on the weight of the second purified solvent stream, and (f) recycling at least a portion of the second purified solvent stream into step (a).