| 摘要 |
<p>The invention relates to a method for the continuous production of unsaturated carboxylic acid anhydrides of formula (I) R-C(O)-O-C(O)-R (I), wherein R is an unsaturated organic group with 2 to 12 C atoms, by transanhydrization of an aliphatic carboxylic acid anhydride with a carboxylic acid of formula (II) R-COOH (II), wherein R is defined as above, in a rectification column having an upper, a middle and a lower zone. The method is characterized in that f) an inert boiling oil is present in the sump of the column, g) the feed-stock is fed to a reaction zone in stoichiometric ratios, h) the carboxylic acid formed as a by-product is removed at the top of the column, i) the non-reacted feed-stock is returned to the reaction zone, and j) the product of formula (I) is obtained via a lateral outlet, preferably between the middle and the lower column zone.</p> |
