Study On Chemical Engineering Of Cyclohexene Oxidized By Dioxygen

Oxidation of olefins with molecular oxygen is one of the most important functionalgroup transformations in organic synthesis which is recognized as green oxidation.Especially, catalytic oxidation of cyclohexene (CY) using dioxygen has drawn moreattention as well. There are two aspects of research for this system. One is to explorethe feasibility of catalytic oxidation for specific active components and optimizereaction conditions in presence of selected catalysts. Another is to acquire the basicengineering data for oxidation products separation, purification and industrial design.So, vapor-liquid equilibrium (VLE) of relevant components in cyclohexene oxidationsystem was studied and other work was done in this dissertation shown as below:(1) The right analytic method of gas chromatography was establishedcorresponding to cyclohexene catalytic oxidation system. The internal standard curvesof CY, epoxycyclohexane (CYO), 2-cyclohexen-1-ol (CYOL) and 2-cyclohexen-1-one (CYONE) were obtained with toluene internal standard. The catalyst namedâ…¢-3was selected by previous research from our group and the technological conditions forthe production of CYONE were optimized and were as follows: the flux of oxygen5mL/min, the catalyst weight 0.15g, cyclohexene 2mL, solvent 20mL, temperature60℃, time 8h. The conversion of cyclohexene was up to 60.4%, and the selectivity ofCYONE was 90.9% under optimum conditions. Further, the macrokinetics which CYwas oxidized to CYONE with dioxygen was studied and the kinetic equation wasshown below and the apparent activation energy was E_a= 25.6kJ.mol^-1.(2) The new Schiff Base catalyst was synthesized, which cobalt was used asreactive components and supported by resin D380, and used for catalytic oxidation ofcyclohexene to produce CYO. The structure and properties of the catalyst werecharacterized by IR, ICP and DTA-TGA analysis. The optimum conditions for CYoxidation using dioxygen as oxidant and isobutylaldehyde as sacrificial reagent wereobtained as follows: temperature 60℃, the catalyst weigh 0.3g, CY 2mL, time 9h,n(isobutylaldehyde): n(cyclohexene)=2.5, acetyl nitrile 20mL. Under theseconditions, the conversion of CY was up to 93.42% and the selectivity of epoxy was80.93%.(3) Without any solvent and sacrifice reducer, a new green oxidation route of CYwith dioxygen was developed and studied systematically in a differential-reactor,which greatly alleviates problems caused by gas-liquid-solid triphase catalytic reaction. The catalystâ…¢-3 was selected in our previous research from our group.Under the optimum conditions, the amount of catalyst 1.5g, the fluxes of CY anddioxygen 0.04mL·min^-1 and 10mL·min^-1 respectively, reaction temperature 110℃, theconversion of CY was 20% in a single run and the selectivity of 2-cyclohexen-1-ol(CYOLE) and CYONE were 60%. The research revealed a new way to catalyticoxidation of olefins.(4) Vapor-liquid equilibrium data are necessary for industrial design when relevantsubstances need to be separated and purified. However, VLE data for cyclohexeneoxidization system with dioxygen were little reported. Three series of VLE data ofbinary system for CY, CYO and CYONE under ambient pressure and differenttemperatures were obtained by using an improved EC-2 still. All experimental datapassed the thermodynamic consistency test of Herrington. Each series of experimentalVLE data were correlated with the Wilson thermodynamic model and thecorresponding binary interaction parameters of the model were obtained. For CY (1)-CYO (2) binary system,Λ₁₂=1.1985 andΛ₂₁=0.3544. For CYO (1)-CYONE (2),Λ₁₂=1.2772 andΛ₂₁=0.3373. For CY (1)-CYONE (2),Λ₁₂=1.2973 andΛ₂₁=0.3270.Each series of experimental data were compared with the calculation values fromWilson equation and the mean deviations for each series were 0.0070, 0.0019 and0.0007.(5) The VLE data of ternary system for CY (1)-CYO (2)-CYONE (3) under normalpressure and different temperatures were obtained by using an improved EC-2 still.The experimental data were compared with calculation results from Wilsonparameters of binary systems. It was showed that the relative deviation of CY was0.0035 and CYO, CYONE was 0.0036,0.0026 respectively.