| 摘要 |
Continuous production is claimed of dialkyl carbonate (I) and diol (II) from a cyclic carbonate of formula (A) and an aliphatic monohydric alcohol of formula R2OH (B). The process comprises (1a) continuous feeding of a mixture of (A) and (B) containing 0-40 wt. % dialkyl carbonate into a continuous multi-stage distillation tower (a); (2) reacting (A) and (B) in the presence of a transesterification catalyst, in (a) and/or in a transesterification reactor (b) located outside (a), and connected to (a) by liquid-tight connections, so that liquid from (a) is fed to (b) continuously from side exits, and reacted material is recycled to (a); (3) removing dialkyl carbonate and low-boiling gas components from the top of (a); (4) removing high-boiling components containing diol and unreacted (A) from the bottom of (a); and (5) continuously feeding the high-boiling material from the bottom of the column to a hydrolysis reactor supplied with water, to hydrolyse unreacted (A) to diol and carbon dioxide, and withdrawing the liquid containing the diol. R1 = (CH2)m (optionally substituted by one or more of 1-10C alkyl and 6-10C aryl); R2 = 1-12C aliphatic hydrocarbon (optionally substituted as for R1); and m = 2-6. |
