| 摘要 |
A process for preparing isocyanates comprising contacting carbon dioxide and a primary amine in the presence of an aprotic organic solvent and a base selected from the group consisting of a phosphazene compo und, an organic, nitrogenous base and mixtures thereof wherein the organic, nitrogenous base selected from the group consisting of guanidine compounds, amidine compounds, tertiary amines and mixtures thereof to produce the corresponding ammonium carbarnate salt, reacting the ammonium carbamate salt with an anhydride dehydrating agent to produce a product stream comprising the corresponding i socyanate, the aprotic organic solvent and the base salt derived from the anhydride, separating the base salt from the product stream, recove ring and recycling the base, and regenerating and recycl ing the anhydride dehydrating agent. |
