A process for the preparation of a dihalogenovinyl-.gamma.-butyrolactone of the formula ##STR1## in which Hal each independently is F, Cl or Br, and R.sup.1 and R.sup.2 each independently is hydrogen or C.sub.1-4 -alkyl, or R.sup.1 and R.sup.2 together with the adjacent carbon atom form a cycloaliphatic ring with up to 7 carbon atoms, comprising hydrolyzing in acidic aqueous medium a compound of the formula ##STR2## in which R is hydrogen or C.sub.1-4 -alkyl, to form the corresponding acid and then, without isolation of the intermediate hydrolysis product, heating at 110.degree.-120.degree. C. to decarboxylate.
一种制备式为##STR1##的二卤代
乙烯基-
γ-丁内酯的方法,其中Hal各自独立地为F、Cl或Br,而R1和R2各自独立地为氢或C.sub.1-4-烷基,或者R1和R2与相邻的碳原子一起形成一个含有最多7个碳原子的环状脂肪族环。该方法包括在酸性
水介质中
水解式为##STR2##的化合物,其中R为氢或C.sub.1-4-烷基,以形成相应的酸,然后在不分离中间体
水解产物的情况下在110℃-120℃加热脱羧。