Method for preparing adipic acid through co-catalytic oxidation of six-carbon oxygenated compound and cyclohexane

Abstract

The invention discloses a method for preparing adipic acid through co-catalytic oxidation of a six-carbon oxygenated compound and cyclohexane. According to the method, cyclohexane is used as a raw material, a six-carbon oxygenated compound is used as a co-oxidant, and one of transitional metal salt or oxide, N-hydroxyphthalimide and analogues, metal phthalocyanine and metalloporphyrin, or a mixture of several ones thereof is used as a catalyst, the mass ratio of the six-carbon oxygenated compound to the cyclohexane is (0.003-9):1, and the dosage of the catalyst is 1-100,000ppm of the total weight of the cyclohexane; and under the conditions that an oxygen-containing gas is continuously introduced, the reaction temperature is 80-155 DEG C, the reaction pressure is 0.1-1.2MPa and the reaction time is 0.4-4 hours, the cyclohexane is oxidized into adipic acid in a solvent in one step. The method disclosed by the invention has the advantages of mild reaction conditions, high once through yield of product, good selectivity and environmental protection.

Description

technical field [0001] The invention relates to a method for preparing adipic acid, in particular to a method for preparing adipic acid by co-catalyzing oxidation of a six-carbon oxygen-containing compound and cyclohexane. Background technique [0002] Adipic acid is an important basic raw material for the nylon and polyurethane industries, as well as an intermediate for many lubricating oil additives. At present, the industrial production of adipic acid mainly uses cyclohexane as the starting material, and produces adipic acid through a two-step process. The first step uses air to oxidize cyclohexane to cyclohexanol and cyclohexanone (KA oil), and the second step uses nitric acid to oxidize KA oil to adipic acid. This route accounts for about 93% of the global total production capacity. Its reaction process is as follows: [0003] [0004] The first step process of the above route often uses a homogeneous cobalt-based catalyst or does not add a catalyst. During the rea...

AI Technical Summary

Problems solved by technology

Not only is the recovery of the catalyst difficult and the cost of the catalyst is high, but also a large amount of metals and additives crystallize out together with adipic acid, which makes the subsequent processing of the product complicated and difficult

[0011] In summary, although the prior art has solved the environmental pollution problem caused by nitric acid oxidation, it still faces the problems of harsh reaction conditions, low yield of adipic acid, high production cost, and complicated post-treatment.

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