| 摘要 |
<p>A continuous process for the preparation of carboxylic acid esters which an acid (mono-, di- or polycarboxylic acids, or anhydrides) and an alcohol (preferably ethanol) are passed countercurrently through a first and a second esterification zone optionally in the presence of a solid catalyst (acidic ion exchange resin containing SO3H and/or CO2H groups). The intermediate liquid product stream is passed from the first reaction zone to the upper section of a second reaction zone without passing through a distillation column. The second reaction zone is fed with a dry alcohol stream comprising less than about 1 weight % water; a first stream comprising unreacted alcohol and water is taken from the first reaction zone and treated to reduce the water content to form a wet alcohol stream which then recycled to the first reaction zone; and a second stream comprising unreacted alcohol and water and having a water content of from about 2-6 mole% is taken from the second reaction zone and supplied to the first reaction zone.</p> |
