| 摘要 |
<p>1. Process for continously esterifying methacrylic acid with a lower alkanol by introducing methacrylic acid and an at least equivalent quantity of the alkanol into a boiling esterification mixture at a temperature of from 70 to 170 degrees C which contains sulphuric acid or an organic sulphonic acid in a quantity corresponding to 50 to 500 g SO3 /l, distilling off a methacrylate/water azeotrope, stratifying the condensed distillate into an upper ester layer and a lower alkanol/water layer, recycling part of the ester layer as returned material into the distillation of the azeotrope, characterized in that aqueous methacrylic acid with a water content of from 5 to 60% by weight is introduced into the esterification mixture and the water thus added together with the water formed during the esterification is continuously distilled off in the form of the above mentioned azeotrope.</p> |
