| abstract |
It is disclosed that citric acid or its salts are obtained by the hydrolysis of a 3-carbamoyl-3-hydroxy-4-cyanobutyric acid or salt, that a 3-carbamoyl-3-hydroxy-4-cyanobutyric acid or salt is obtained from a 3-carbamoyl-3,4-epoxybutyric acid or salt, that a 3-carbamoyl-3,4-epoxybutyric acid or salt is obtained from a 3-carbamoyl-3-hydroxy-4-halobutyric acid or salt, that a 3-carbamoyl-3-hydroxy-4-halobutyric acid is obtained from a 3-cyano-3-hydroxy-4-halobutyric acid or salt, that a 3-cyano-3-hydroxy-4-halobutyric acid or salt is obtained from a 3-oxo-4-halobutyric acid or salt, that a 3-oxo-4-halobutyric acid or salt is obtained from a 3-oxo-4-halobutyryl halide, and that a 3-oxo-4-halobutyryl halide is obtained from diketene. Preferred halide compounds are compounds of chlorine. |