| 摘要 |
Process for the preparation of di-n-propyl acetic acid of formula: <IMAGE> and its non-toxic alkali and alkaline earth metal salts whereby in a single stage, sodium n-propylate in n-propanol medium is added to a reaction medium formed of a cyanacetic ester of general formula: <IMAGE> in which R represents an alkyl radical having from 1 to 4 carbon atoms, and n-propyl bromide or iodide, the alkylation reaction taking place under reflux, the crude ester obtained is saponified with a 10 to 20% solution of sodium or potassium hydroxide, the salt thus obtained is acidified with a strong acid, to give the crude di-n-propyl cyanacetic acid, which is decarboxylated by heating at a temperature between 140 DEG and 190 DEG C, to provide the di-n-propyl acetonitrile, the di-n-propyl acetonitrile obtained is hydrolysed by means of an aqueous solution of 75 to 80% sulphuric acid at a temperature of 80 DEG -140 DEG C to give the crude di-n-propyl acetamide, which is hydrolyzed by means of an aqueous solution of 75-80% sulphuric acid at a temperature of 40 DEG -80 DEG C in the presence of sodium nitrite, to provide di-n-propyl acetic acid, which is caused to react, if so desired, with an alkali metal hydroxide or alkaline earth metal oxide in order to obtain the corresponding salt. |
