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Study On Epoxidation Of Alkenes

Posted on:2010-04-07Degree:MasterType:Thesis
Country:ChinaCandidate:J MengFull Text:PDF
GTID:2121360275993960Subject:Inorganic Chemistry
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Epoxidation of alkenes is an important class of reaction in view of its industrial applications.However,epoxidation of olefins is usually conducted under expensive catalyzer,oxidant and large amounts of industrial waste.Therefore,many epoxidation technique cannot be used in industry.In this thesis,epoxidation of 4-vinyl-cyclohexene(4-VCH) with sodium hypochlorite,peroxyacetic acid,30%(mass fraction) hydrogen peroxide as oxidant was studied.1.Sodium hypochlorite was used as oxidant.Sulphuric acid was added to a dispersion of 4-vinyl-cyclohexene in an aqueous solution of sodium hypochlorite,thus liberating hypochlorous acid which then reacted with the 4-vinyl-cyclohexene can form the dichlorohydrins.Then a solution of sodium hydroxide was added to form the 4-vinyl-cyclohexene dioxide.Effects of factors,such as reaction time,reaction temperature and the ratio of reactants etc.on yield of 4-vinyl-cyclohexene dioxide were also studied.Under optimum reaction conditions:4-vinyl-cyclohexene 2ml,0.3mol/L sodium hypochlorite 120ml,the grade of stirring was 7,0.5mol/L sulphuric acid 40ml was added in 20min,the yield and purity of 4-vinyl-cyclohexene dioxide can reach 76%(based on 4-VCH) and 96%, respectively.During the reaction process,sodium hypochlorite can dissolve in water,but 4-vinyl-cyclohexene cannot dissolve.We solved the problem by increasing the grade of stirring instead of using phase-transfer catalyzer.This method can reduce the cost and predigest the process.Under optimum reaction conditions,we also studied to enlarge the reaction.The yield of 4-vinyl-cyclohexene dioxide can reach 50% (based on 4-VCH).2.Epoxidation of 4-vinyl-cyclohexene to 1,2-epoxide-4-vinyl-cyclohexane with 40%(mass fraction)peroxyacetic acid as oxidant was studied.First of all,we concentrated 30%hydrogen peroxide to. 90%.Secondly,90%hydrogen peroxide reacted with acetic acid to form 40% peroxyacetic acid.Finally epoxidated 4-vinyl-cyclohexene to 1, 2-epoxide-4-vinyl- cyclohexane with the peroxyacetic acid as oxidant.Effects of factors,such as reaction time,reaction temperature and the ratio of reactants etc.on yield of 1,2-epoxide-4-vinyl-cyclohexane were also studied.Under optimum reaction conditions:40%peroxyacetic acid 7mL,4-vinyl-cyclohexene 2ml,sodium carbonate 1.2g,reaction temperature 40℃and reaction time 2.5h,the yield and purity of 1,2 - epoxide-4-vinyl-cyclohexane can reach 94.4%(based on 4-VCH)and 97%,respectively.3.An efficient method for the epoxidation of 4-vinyl-cyclohexene with hydrogen peroxide catalyzed by 1-methyl-3-butylimidazolium-decatungstate[bmim]4[W10O32]in ionic liquid [bmim]BF4 was studied.Firstly,we synthesized the catalyzer[bmim]4[W10O32] and the ionic liquid[bmim]BF4,then epoxidated 4-vinyl-cyclohexene to 1, 2 - epoxide-4-vinyl-cyclohexane.Effects of factors,such as reaction time,reaction temperature and the ratio of reactants etc.on yield of 1,2-epoxide-4-vinyl-cyclohexane were also studied.Under optimum reaction conditions:30%hydrogen peroxide 2.1mL,4-vinyl-cyclohexene 1.3ml,[bmim]4[W10O32]0.8g,[bmim]BF41ml,reaction temperature 55℃and reaction time 2.0h,the yield and purity of 1,2 -epoxide-4-vinyl-cyclohexene can reach 99%(based on 4-VCH)and 99%, respectively.The mild reaction condition,excellent yield of epoxides,and easy separation along with recycling of the catalytic system are the advantages of this method.
Keywords/Search Tags:4-vinyl-cyclohexene, 4-vinyl-cyclohexene dioxide, 1, 2-epoxide-4-Vinyl-cyclohexane, sodium hypochlorite, peroxyacetic acid, hydrogen peroxide, epoxidation
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