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[Introduction] With the improvement of domestic R & D and process level, the production of cyclohexanone is no longer a technical problem for major manufacturers, and due to the good development of the downstream chemical fiber market, the production capacity and capacity of cyclohexanone are once again mentioned by more people. The following is a brief introduction to the current mainstream production process in China:
According to the raw materials, the production of cyclohexanone is divided into benzene method and phenol method, and the benzene method is divided into cyclohexane method and cyclohexene method. The phenol method is an early industrial production method. The method uses nickel as a catalyst to hydrogenate phenol to cyclohexanol, and then dehydrogenates under the action of zinc catalyst to obtain cyclohexanone. This route process is short, and the resulting product has high purity and good quality. However, the raw material phenol is more expensive, so this process is rarely used abroad to produce cyclohexanone. However, in recent years, there has been an overcapacity of phenol, and the phenol hydrogenation process has re-attracted attention.
The process of hydrogenation of benzene to cyclohexane also has two types: gas-phase method, the typical process is UOP method, Arco method, Houdry method, etc.; the typical process of liquid-phase benzene hydrogenation is IFP method, Arosat method and BP method, etc., with IFP as the leading position.
There are three different processes for the oxidation of cyclohexane to cyclohexanone, of which the cobalt oxidation method is the more commonly used process. Soluble cobalt is used as the catalyst to form a mixture of cyclohexanone and cyclohexanol, namely KA oil; non-catalytic oxidation, first chlorination of cyclohexane to cyclohexyl peroxide, and then catalytic decomposition to KA oil; boric acid oxidation method oxidizes cyclohexane to cyclohexyl boric acid, then hydrolyzes to cyclohexanol, and then dehydrogenates to obtain cyclohexanone.
The partial hydrogenation of benzene developed by Asahi Kasei Company in Japan is to hydrogenate benzene to cyclohexene, then hydrate cyclohexanol, and then dehydrogenate to cyclohexanone. The partial hydrogenation is mainly catalyzed by metal cobalt, usually P/SiO2 and Si2O3 as the carrier. Iron or zincide are co-catalysts, the one-way conversion rate of benzene is more than 50%, and the selectivity of cyclohexene is about 80%. The hydration reaction of cyclohexene uses zeolite as the catalyst, and the one-way conversion rate is 10% to 15%, and the selectivity is more than 99%. In previous years, this process was mainly used for the production of adipic acid. In recent years, more and more ca
