Method for preparing alpha-aminoisobutyric acid

The invention aims at the field of chemical industry and relates to a method for preparing alpha-aminoisobutyric acid. The method comprises the step of enabling acetone cyanohydrin and ammonium carbonate to be subjected to pressurized and heated reaction in an aqueous medium, thereby synthesizing alpha-aminoisobutyric acid, wherein ammonium carbonate can be replaced with ammonium bicarbonate or ammonia and carbon dioxide. The invention further relates to preparation using an alpha-aminoisobutyric acid production device, wherein a gas stripping device is especially used for recovering carbon dioxide and ammonia gas which are generated during synthesis reaction and are recycled for the synthesis of alpha-aminoisobutyric acid. According to the method disclosed by the invention, the yield is high, the purity of a product is high, and the equipment investment is small; in a whole process, carbon dioxide and ammonia are hardly consumed, no byproduct inorganic salt is produced, and inorganic base is not consumed, so that a very positive effect on the full and comprehensive utilization of resources and environmental protection is exerted; recovered carbon dioxide and ammonia and crystallized mother liquor are sufficiently utilized, so that the problem of pollution to environment caused by waste gases, waste water and waste residues can be excellently solved, and the environmental-friendly and clean production is really achieved.