| 摘要 |
In synthesis of dimethyl carbonate, acidic and salt impurities are removed from the condensed phase of the reaction effluent by partial evapn.. The condensed phase is fed to an evaporator which vaporises 80-99 (90-97) wt.% of the phase. Evapn. is at 1-3 bars abs. and 65-100 degrees C. The condensed phase may be pretreated with an acidic ion-exchange resin. Before being sent to the distn. section, the evaporated stream is contacted, in vapour phase, with a fixed bed of (modified) Al2O3 or of activated C, or is condensed and contacted with a basic macroporous polystyrene resin with amine or quat. ammonium gps.. The evaporator bottom residue is recycled to the synthesis, opt. after being sent to an exhaustion tower for recovering the organic components and concentrating the residual aq. HCl soln.. <IMAGE> |
