| 主权项 |
1. A process for preparing carboxylic esters by reacting a carboxylic acid or a carboxylic anhydride or a mixture thereof with an alcohol in the presence of an esterification catalyst selected from among alkoxides, carboxylates and chelate compounds of titanium, zirconium, tin, aluminum and zinc, in a reaction system comprising one or more reactors, with
a) water of reaction being distilled off as alcohol-water azeotrope with the vapor, b) the vapor being at least partly condensed, c) the condensate being separated into an aqueous phase and an organic phase, d) part of the organic phase being recirculated unchanged to the reaction system and 25 to 60% of the total organic phase being treated by evaporating and/or distilling off components having boiling points lower than that of the alcohol, wherein said evaporating and/or distilling off components having boiling points lower than that of the alcohol comprises depressurizing into a depressurization vessel, resulting in at least part of the components having boiling points lower than that of the alcohol evaporating, and e) the unvaporized liquid phase being at least partly recirculated to the reaction system, where the components having boiling points lower than that of the alcohol comprise olefins which are derived by elimination of water from the alcohol used. |
