Cinnamic acid prodn.

摘要

Opt. substd. cinnamic acid is prepd. by reacting opt. substd. benzaldehyde (I) with ketene (II) in the presence of Zn salts of 6-18C aliphatic acids as catalyst in the absence of or in the presence of at most 0.1 wt.% water, carboxylic acids and carboxylic acid anhydrides (w.r.t. (I) + (II) + Zn salt), and subsequently heating the reaction prod. at 100-250 deg.C in the presence of acid or basic catalysts. Pref. the Zn salt catalyst is a Zn salt of a 6-12C aliphatic carboxylic acid, esp. Zn 2-ethylhexanoate or Zn laurate, used in an amt. of 0.1-10 wt.% w.r.t. (I).