1. One-step oxidation of cyclohexane
Cyclohexane was used as a raw material, acetic acid as a solvent, and cobalt and bromide as catalysts at 2MP. And react at 90 °C for 10 ~ 13h. Yield 75%.
2. Cyclohexane step oxidation
(1) The preparation of KA oil can be directly air-oxidized at 1.0-2.5 MPa and 145-180°C, with a yield of 70%-75%. It is also possible to use metaborate as a catalyst, air oxidation at 1.0 ~ 2.0MPa and 165 °C, the yield can reach 90%, the ratio of alcohol to ketone is 10:1; the reactants are treated with hot water, the ester can be hydrolyzed, stratified, and water The layer recovers boric acid, which is dehydrated into metaborate for recycling; the organic layer is saponified with caustic soda, and the acid is removed, and cyclohexane is recovered by distillation to obtain an alcohol-ketone mixture.
(2) Oxidation of KA oil The KA oil was oxidized at 60 to 80°C and 0.1 to 0.4 MPa in a two-stage reactor with an excess of 50% to 60% nitric acid. The catalyst is a copper-vanadium system (0.1% to 0.5% copper and 0.1% to 0.2% vanadium) and the yield is 92% to 96% of the theoretical value. After the reactant is distilled out of nitric acid, high purity adipic acid can be obtained through two-time crystallization purification.