| 摘要 |
1,259,968. Dicarboxylic acids. E.I. DU PONT DE NEMOURS & CO. 12 March, 1969 [12 March, 1968], No. 13136/69. Heading C2C. Straight chain dicarboxylic acids (8-12C) for example 1,12-dodecane-dioic acid, are prepared by oxidizing a cyclic alcohol and/or ketone (8-12C) in (1) a first vessel with aqueous nitric acid (40-60% concentration) at between 75‹ and 120‹ C. and pressure up to 7 atmospheres absolute and (2) in a second vessel maintaining the oxidate under oxidizing conditions at between 90‹ and 110‹ C. for 3 to 60 minutes, the reaction mixture being kept in a homogenous liquid state. An oxidation catalyst, e.g. copper and vanadium may be used and the first vessel may be a stirred reactor for step (1) and a plug flow reactor for step (2). The acid is recovered by cooling to precipitate and recrystallizing from aqueous nitric acid, preferably containing urea. |
