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Catalytic Oxidation Of Cyclohexane To KA Oil By Molecular Oxygen And Catalytic Oxidation Of Cyclohexanone To Adipic Acid

Posted on:2018-06-06Degree:MasterType:Thesis
Country:ChinaCandidate:H X GaoFull Text:PDF
GTID:2321330518985955Subject:Chemical Engineering and Technology
Abstract/Summary:PDF Full Text Request
KA oil is a mixture of cyclohexanol and cyclohexanone,which is the major intermediate in the manufacture of caprolactam and adipic acid.Cyclohexanol is used as an industrial solvent,surface active agent,plasticizer and emulsifier;Cyclohexanone is also an important solvent and it has been widely used in the fields of pesticides,dyes,waxes,rubber,pharmaceutical intermediates and so on.Industrially,KA oil was mostly produced by oxidizing cyclohexane and the oxidants were oxygen or air.According to the difference of the catalytic system,the cyclohexane oxidation method can be divided into non-catalytic system,boric acid catalytic system,cobalt salt catalytic system and biomimetic catalytic system.However,the traditional KA oil production process has some disadvantages,such as low conversion,high investment in infrastructure,low utilization rate of atoms,easy deposition and coking of the production.Therefore,it is of great significance to develop an efficient and green process for the synthesis of KA oil.In this paper,we use molecular oxygen as oxidant and transition metal modified molecular sieve as catalyst,catalytic oxidation of cyclohexane to KA oil at lower temperature.This method has the advantages of the reaction conditions are mild,KA oil yield is high,and environmentally friendly.This paper employed SBA-15 as the carrier and different metal oxide modified catalysts were prepared by impregnation method.The catalytic performance of catalysts in oxidation of cyclohexane was investigated.The structure of the catalysts was characterized by XRD and BET.The results showed that CoOx/SBA-15 exhibited good catalytic performance,the conversion of cyclohexane was 14.2%,and the selectivity of KA was 51.3%.The 2%CoOx/SBA-15 catalysts were prepared at different calcination temperatures(450 ?,550 ?,650 ?),the catalytic performance of catalysts were investigated in oxidation of cyclohexane.The results showed that 550? is suitable calcination temperature.Then,the cobalt oxide modified catalysts with different cobalt content were prepared.The catalytic performance of the catalysts was also investigated and XRD,BET,H2-TPR,XPS,FT-IR,UV and SEM were used to characterize the catalysts.The results showed that the cobalt oxide can be highly dispersed on the carrier when the loading was 2%,and the catalyst exhibited good catalytic performance,the conversion of cyclohexane was 8.4%,and the selectivity of KA oil was 62.3%.Then,the influence of reaction conditions on cyclohexane oxidation was investigated catalyzed by 2%CoOx/SBA-15.The optimum reaction conditions were obtained: the reaction temperature was 135?,the reaction time was 2h,the oxygen pressure was 0.6MPa and the amount of catalyst was 0.08 g.The conversion of cyclohexane was up to 9.8% and the selectivity of KA oil was up to 63.1% under the optimized reaction condition.Then,the stability of the catalyst was investigated and the catalytic reaction mechanism was speculated.Finally,the oxidation of cyclohexanone to adipic acid was studied.The catalytic performance of different metal chlorides in cyclohexanone oxidation was compared.The results showed that the CuCl22H2O exhibited the best catalytic performance.Then,the effects of different solvents on the oxidation of cyclohexanone were investigated.It was found that the polar solvent was favorable to the reaction,and the n-butyl acetate was the best solvent.In the condition that CuCl22H2O as catalyst and n-butyl acetate as solvent,the effects of reaction temperature,reaction time,oxygen pressure and the amount of catalyst on the oxidation of cyclohexanone to adipic acid were investigated.Under the optimum reaction conditions,the conversion of cyclohexanone was up to 83.9% and adipic acid selectivity was up to 57.3%.This work provides a theoretical basis and technical evidences for the preparation of KA oil by oxidation of cyclohexane and catalytic oxidation of cyclohexanone to adipic acid by molecular oxygen.
Keywords/Search Tags:cyclohexane, molecular oxygen, KA oil, adipic acid, catalytic oxidation
PDF Full Text Request
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