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Adipic Acid Green Catalytic Synthesis Of - Homogeneous Catalyst System,

Posted on:2004-01-24Degree:MasterType:Thesis
Country:ChinaCandidate:Y X MiaoFull Text:PDF
GTID:2191360095450223Subject:Industrial Catalysis
Abstract/Summary:PDF Full Text Request
An environmentally benign and green process is highly desirable in the development of catalysis. One of the most important fields is to rebuild the conventional processes of petrochemical production, which measurably contribute to pollution. Currently, the industrial production of adipic acid still uses the oxidation of cyclohexanol /cyclohexanone mixture with nitric acid. The yield and selectivity are both high, but erosion is severe. Besides, the emission of N2O, NOx and the waste acid damage environment remarkably. Therefore, the development of the clean process for the adipic acid is an important subject in the chemical induatries.Cyclohexene can now be oxidized directly to adipic acid with 30 percent hydrogen peroxide in water solution. In the presence of tungsten catalyst and molybdenum catalyst, the effects of reaction condion (the amount of catalyst, ratio of H2O2/ cyclohexene, the adding method of H2O2, reaction temperature, reaction time, rotation rate and acidity of reaction system) on the green process of cyclohexene oxidation were studied.The efficiency of H2O2. during this catalytic process, the characteristic of the catalyst, the kinetic of this reaction were also studied.The results showed that the some type of tungsten compound is an effective catalyst. When W/cyclohexe = 2%, H2O2/ cyclohexene = 3 and pH value 0.5 is given, the isolated yield of adipic acid is 73.8% after the reaction mixture was stirred violently at air pressure from 73-95 for 8h. Under this condition, the efficiency of H2O2 can goes up to 98%.Mo was firstly used in the green synthesis of adipic acid. Its catalytic activity is inferior to W. The most isolated yield of adipic acid is 51.8%.Inorganic or organic acidic ligands play an important role in activity of the catalyst. Their proper acidity and chelated strength do favor to active structure of catalyst.Based on IR and the other chemical results, the active structure of catalyst is presumed to be:The kinetics of the reaction was preliminarily studied on the base of MS and GC. The results showed that the reaction is zero-order to cyclohexene in the preceding steps.
Keywords/Search Tags:green synthesis, catalytic oxidation, adipic acid, cyclohexene, hydrogen peroxide
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