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The Oxidation In The System Of TS-1/Urea/Hydrogen Peroxide

Posted on:2010-06-22Degree:MasterType:Thesis
Country:ChinaCandidate:D W LiFull Text:PDF
GTID:2121360275958157Subject:Energy and chemical
Abstract/Summary:PDF Full Text Request
Four TS-1 samples are prepared by classical synthesis,cheap template synthesis, TPAOH modification and vapor-phase transport,respectively.The samples are characterized by SEM,XRD,UV-Vis and Raman techniques.The catalytic performances of TS-1 samples are evaluated by the reaction of propylene epoxidation and cyclohexanone ammoximation. The result shows that nano-TS-1 prepared by classical method has the highest content of framework titanium and the smallest crystal size among the four samples.Compared with micro-TS-1,nano-scale TS-1 exhibits higher catalytic performance on PO selectivity and H2O2 utilization in propylene epoxidation,also shows higher yield of cyclohexanone oxime in cyclohexanone ammoximation.Propylene oxide(PO) is synthesized in the system of TS-1/urea/hydrogen peroxide.The micro-TS-1 samples with tetrapropylammonium bromide(TPABr) as the template is modified by TPAOH.The effect of modification conditions on propylene epoxidation are investigated, including concentration of TPAOH,the ratio of micro-TS-1 and modification agent, modification time and modification temperature.The result shows that the modification agent has great effect on the micro-TS-1 for propylene epoxidation.The optimal modification conditions of TS-1 are as follows:TS-1 is 5 g,TPAOH aqueous solution(0.15 mol) is 70 ml, modification time is 48 h,modification temperature is 170℃.As the molar ratio of urea to H2O2 is 1,74.79%H2O2 conversion is obtained with 92.16%PO selectivity and 77.34%H2O2 utilization.Ammoximation of cyclohexanone to cyclohexanone oxime with BSTR as reactor and nano-scale TS-1 sample as catalyst is carried out in the system of TS-1/urea/hydrogen peroxide,and the effect of temperature,NH3/UHP,UHP/CH,reaction time,solvent,and catalyst mass are investigated.The result shows that using mixed liquor of deionized water and tert.-butyl alcohol(v:v=4:9) as solvent,reacting at 80℃,NH3/UHP(molar ratio)4.2, UHP/CH(molar ratio) 1.5,reaction time 3 h,yield of cyclohexanone oxime is 87.26%and selectivity to cyclohexanone oxime is 98.23%.
Keywords/Search Tags:TS-1, Urea, Epoxidation of Propylene, Ammoximation of Cyclohexanone
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