Research On The Hydrogenation Of3-chloro-4-methyl Nitrobenzene

3-chloro-4-methyl-nitrobenzene catalytic hydrogenation reaction is akey step in the production of2B oil. This reaction is a three-phase systemwith3-chloro-4-methyl-nitrobenzene, hydrogen as the raw materials andRaney-Ni as the catalyst.2B oil production in the modern enterprise ismainly by the method of sodium sulfide reduction. The process wasobsoleted because of high content of azo and lower purity of theproduct.With a large of the three wastes,the process of hydrogenation isphasing out. The use of3-chloro-4-methyl-nitrobenzene catalytichydrogenation process can effectively solve the above problem.Catalytic hydrogenation reduction of3-chloro-4-methyl-nitrobenzenehaven not yet published in the paper for the kinetics of catalytichydrogenation of halogenated aromatic nitro compounds.Owing to thecatalytic hydrogenation reduction, hydrogenation of the halogen in thebenzene ring, will reduce the selectivity and the device will be corrode.The hydrogenation process were studied in following three aspects:1.Agent hydrogenation performance of the test, and the bestoperating conditions tested. Selected catalytic hydrogenation of theoptimum conditions: reaction temperature70℃, pressure1.2MPa,Raney-Ni contents of5%can be obtained in high yield.2.With1L autoclave, kinetics of the Raney-Ni catalyst has beenselected. The effects of reaction temperature, pressure, amount of catalyst on the reaction. According to the study of the relevant mechanism, theintrinsic kinetics model of hydrogenation:The numerical methods nonlinear fitting of the availableexperimental data collected to be solving the model parameters.3.Kinetics on dehalogenation of3-chloro-4-methyl-nitrobenzenecatalytic was studied. Dehalogenation is mainly in two ways: First, rawmaterials direct to generate4-methyl nitrobenzene with hydrogen andcatalyst. Second,2B oil continues to restore, the formation ofdechlorination by p-toluidine. Choose of Raney-Ni catalyst, the proposeddechlorination mechanism, and assuming control steps to establish thedynamic model of the dechlorination. Use of numerical method tononlinear curve fitting to the available experimental data collected in thedechlorination model parameters to be solved.Estimated by nonlinear regression, the kinetics parameters were According to the study of3-chloro-4--methyl-nitrobenzene catalytichydrogenation, suggestions on production were given.Lastly,the authorgives the summary and outlook about the whole work.