A New Process Of Caprolactam Be Prepared By Heterogeneous Ammoximation Reaction And Rearrangemented With Oleum In Cyclohexane Solvent

Caprolactam a white powder or crystalline substance is an important organic raw with oily feel.There are several problems of the exiting industrialized production not yet solved: process long,high investment,too many thiamine(a kind of by-products),serious environmental pollution.With the capacity of caprolactam is extending it is crucial for a company occupying favorable position in market competition to explore the new technology in order to reduce costs.The paper brought forward a new process in which caprolactam was prepared by cyclohexanone-oxime,which was synthesized by heterogeneous ammoximation reaction in cyclohexane,solvent rearrangement reacted with oleum.Prepared to the traditional process,the new one has these advantages: process short,low energy consumption,few by-products and so on.Firstly,the process of heterogeneous ammonia oximation to synthesize cyclohexanone-oxime was proved to be feasible by a lot of experiments.Then,the optimal conditions obtained by single-element experiments are as follows: reaction temperature 85 ℃,pressure 0.3MPa,molar ratio hydrogen peroxide to cyclohexanone-oxime 1.2:1,ammonia to cyclohexanone-oxime 1.15:1,cyclohexane to water 1:5,the feeding speed of cyclohexanone 20ml/min.Optimization experiments show that conversion of cyclohexanone reached 99.97%,selectivity of cyclohexanone oxime was more than 99.91% in two hours.Based on the rates of the light phase to the heavy phase determined by optimization experiments,our work preliminary studied on the separation of catalyst in the light phase and the extraction of cyclohexanone oxime to determined the proper ratio of extractant to the solvent in the heavy phase.Thes achievement provided references to the industrial production.Secondly,In the paper,the process of caprolactam with solvent rearrangement method based on the cyclohexanone oxime solvent.In the actual production,measures of reaction were the yield of caprolactam and the were studied titration value of rearrangement reaction solution.According to it,the paper studied on effects of the ratio of acid to oxime,the concentration of cyclohexanone oxime and reaction time on the the yield of caprolactam and the titration value of rearrangement reaction solution.Our results showed that in the condition of reaction time 2or 3 hours,temperature 70℃,the ratio of acid to oxime 1.4,the yield of caprolactam can reached 96% and the titration value of rearrangement reaction solution was 1.6.Besides,the concentration of cyclohexanone oxime had little effect on the reaction under consideration.In summary,based on the needs of industrial production,the paper explored a new process to prepare caprolactam which is shorter process,lower consumption of material and energy,saving investment costs and less by-products by connecting heterogeneous ammonia oximation and solvent rearrangement method.The achievement will provide new insights into the production of caprolactam with lower cost.