METHOD FOR PRODUCTION OF ESTERS OF AMINOBENZOIC ACIDS Russian patent published in 1997 - IPC

FIELD: production of esters of aminobenzoic acids which are biologically active compounds and widely used in medicine. SUBSTANCE: method involves liquid phase hydrogenation of esters of nitrobenzoic acids. The process is carried out in the presence of supported palladium-containing catalysts, namely, nickel catalyst being modified by palladium and comprising ferrum or palladium catalyst comprising ferrum. Nickel catalyst comprises 0.07-0.25 % of nickel and 0.05-0.3 % of ferrum as calculated for mass of carrier; ratio of nickel and palladium in it is 1:1-0.5. Palladium catalyst comprises palladium and ferrum, their quantity is 0.07-0.6 % and 0.05-0.55 %, respectively, as calculated for mass of carrier. Palladium in catalyst is supported on carrier by adsorption of aqueous solution of its chlorohydroxo complexes which are prepared at mass ratio of hydroxide of alkaline metal and palladium 0.25-0.65: 1, respectively. EFFECT: improved efficiency of the method; decreased specific expense of precious metals; improved purity degree of desired product without additional purification. 4 cl, 1 tbl