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Study On Synthesis Of Cyclohexene From H2o2 And Cyclohexene With Heteropolyphosphatotungstate Or Heteropolyphosphatomolybdate As Catalyst

Posted on:2009-01-30Degree:MasterType:Thesis
Country:ChinaCandidate:K K SunFull Text:PDF
GTID:2191360302477276Subject:Chemical processes
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In this work, we used hydrogen peroxide and cyclohexene which were rich in HenanProvince as the main raw materials to carry the study on synthesis of cyclohexene oxide withhydrogen peroxide as oxidant. The main works and results as follow:A series of heteropolyphosphatotungstates or heteropolyphosphatomolybdates catalystswithQ3PX4O16[Q=(CH3)2(CnH2n+1)(CH2Ph)N,n=12,14,16,18;X=W,Mo] structures weresynthesized and then characterized by FTIR, atomic emission spectrum and elementalanalysis. These catalysts were used in the catalytic epoxidation of cyclohexene oxidized byhydrogen peroxide to study their catalytic properties with the same mole active components.It showed that the activity of W series is higher than Mo series with the same structures.Using [(CH3)2(C12H25)(CH2Ph)N]3PW4O16 as catalyst, the effects of many factors, suchas amount of catalyst, amount of cocatalyst, the volum of solvent, mole ratio of cyclohexeneto hydrogen peroxide, reaction time on epoxidation process were studied. On the base oforthogonal experiment, the uniform experiment was used. SPSS methods were used tooptimize the results of uniform experiment of [(CH3)2(C12H25)(CH2Ph)N]3PW4O16 catalyst.The equation is y=4.197+1.572X3+98.14X1X2-4.5X1X4+0.106X1X5-1252.023X22+39.827X2X4-0.007X3X5+3.41X42+9.49×10-5X52 The best reaction conditions: the catalyst about0.52mmol, mass of cocatalyst about 90 mg, volume of solvent CH2Cl2 about 35 mL,n(cyclohexene):n(H2O2)=3.75, reaction temperature 40℃, reation time 105 min.Under theseconditions, yield of cyclohexane oxide was 90.72%-97.74% with W series catalysts,[(CH3)2(C14H29)(CH2Ph)N]3PW4O16 has the highest acitivity and selectivity . Preliminarykinetic studies of [(CH3)2(C14H29)(CH2Ph)N]3PW4O16 catalyst was studied. After datahandling, the reaction obeys the rule of the first-order kinetic equation . The first-orderkinetic equation is (?)Activity of catalyst, yield and selectivity of cyclohexane oxide were improved by usinginorganic salt as cocatalyst. Relationships between yield of cyclohexane oxide and differenteffective C atoms with different catalysts were studied. Using solvent to separate catalyst outthe water phase or the organic phase. Catalyst was recoveryed by solvent which dielectric constant is about 20-33 in the organic phase.Using alcohol as solvent,V(C2H5OH):V(solution)=4, the recovery efficiency of catalyst was about 48%. Usingrecoveryed catalyst, yield of cyclohexane oxide was 91.23%.
Keywords/Search Tags:quaternary ammonium salts of heteropolyacids, cyclohexene, hydrogen peroxide, cyclohexane oxide
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