| 摘要 |
Esterification is carried out in a column reactor (14) in which there is a plurality of esterification trays (15) each having predetermined liquid hold-up and containing a charge of a solid esterification catalyst thereon. e.g. an ion exchange resin containing a -SO3H and/or -COOH groups. A liquid phase containing the carboxylic acid component, e.g. a fatty acid mixture, flows down the column reactor from one esterification tray to the next downward one against an upflowing alcohol vapour stream, e.g. methanol vapour. Relatively dry alcohol vapour is injected (21) into the bottom of the column reactor. Water of esterification is removed from the top of the column reactor in the vapour stream (26), whilst ester product is recovered (23) from the sump of the reactor. As the liquid flows down the trays it encounters progressively drier alocohol and the esterification equilibrium reaction is driven further and further towards 100% ester formation. A polishing reactor (304) operated under liquid phase conditions may follow the column reactor, the ester-containing product from which is mixed with further alcohol before admission to the polishing reactor. |
