| 摘要 |
Prodn. of 5-membered cyclic dicarboxylic acid anhydrides, esp. citraconic anhydride (I), is effected by contacting an aq. soln. of the corresp. dicarboxylic acid with a water-insoluble tert. amine (II), sepg. the resulting salt from the aq. phase, and either (a) adding an aromatic water-azeotroping agent (IIIa), distilling off the azeotrope, opt. sepg. phases, and sepg. the anhydride from (II) by distn., or (b) adding an aliphatic azeotroping agent (IIIb), distilling off a ternary azeotrope comprising hydrolysis-stable anhydride, H2O and (IIIb), sepg.-phases, and isolating the anhydride. |
