Selective Oxidation Of Cyclopentene To Glutaraldehyde Catalyzed By Reaction Control Phase Transfer Catalyst

Glutaraldehyde can be used as sterilization disinfectant,tanning agent,wood preservative,food industrial processing auxiliaries,drugs and polymer synthetic raw materials,so it has important applications in medicine,chemical industry and other fields.The method of preparing glutaraldehyde by oxidation of cyclopentadiene has a wide range of industrial application prospects due to abundant raw materias and cheap oxidizer of hydrogen peroxide.At present,the homogeneous catalytic system has the shortcoming that the catalyst is difficult to be recovered,although the heterogeneous catalytic system overcomes the problem that the homogeneous catalysis is difficult to be recovered,but there are some disadvantages,such as easy loss of active components and large mass transfer resistance.Therefore,under the premise of maintaining the high selectivity of catalyst to glutaraldehyde,it is necessary to continue to explore new ways to effectively solve the problem of catalyst recovery.In this paper,new routes for the preparation of glutaraldehyde by reaction controlled phase transfer catalysis and non-homogeneous catalytic cyclopentene oxidation are designed,and the details are as follows:?1?Using acid functional polymeric ionic liquid and non-acid functional polymeric ionic liquid as cations and PW₁₂O₄₀^3- as anion,a series of polymeric ionic liquid hybrid catalysts were synthesized,and the catalytic activity of this kind of catalyst was investigated.The catalyst NDMAM-BVIM-PW,under the condition of no solvent,shows the phenomenon of reaction control phase transfer,and the intermediate process forming emulsion was for Interfacial catalysis.Under the optimization condition?0.12 g Cat,12 mmol H₂O₂,10 mmol CPE,65 ?,3 h?,the yield of glutaraldehyde was 54.3%.The catalyst is easier to recycle,and the catalytic activity is not significantly reduced after 5 times recycles.?2?With carboxyl functional alkyl imidazole,N,N-dimethylhexadecane-1-amine,N,N-dimethyloctadecyl-1-amine as cations,and PW₄O₁₆^3- and PW₄O₃₂^3- of Dawson structure as anions,a series of acid functional ionic liquid hybrid catalysts were synthesized.The catalytic activity of these catalysts to prepare glutaraldehyde by catalyticcyclopenteneoxidationisalsoinvestigated.Forthecatalyst[C₈H₁₇N₂C₃H₃CH₂COOH]₃PW₄O₁₆ in tributyl phosphate ester heterogeneous catalytic system,theyieldofglutaraldehydeis57.5%.Forthecatalyst[C₁₆H₃₃N?CH₃?₂?CH₂?₂COOH]₃PW₄O₁₆ in acetone heterogeneous catalysis system,59%glutaraldehydeyieldisobtained.Thecatalyst[C₁₆H₃₃N₂C₃H₃CH₂COOH]₃PW₄O₁₆ shows the phenomenon of reaction control phase transfer in ethyl acetate solvent,and the catalyst is characterized by ¹H NMR,FT-IR and other means,and the yield of glutaraldehyde was 60%after reaction.The effect of solvent types on the preparation of glutaraldehyde by catalytic cyclopentene oxidation by using PW₄O₃₂^3-series of hybrid catalysts are investigated,and when[C₈H₁₇N₂C₃H₃CH₂COOH]₃PW₄O₃₂ is used as catalyst,the yield of glutaraldehyde is49.87%.?3?Withalkylimidazole,N,N-dimethylhexadecane-1-amine,N,N-dimethyloctadecyl-1-amine,hexadecylpyridinium chloride as cations,and Keggin structure of PW₁₂O₄₀^3-or Dawson structure of PW₄O₁₆^3-,PW₄O₃₂^3-as anions,under solvent conditions and solvent-free conditions,the preparation of glutaraldehyde by catalytic cyclopentadiene oxidation is investigated,and the reaction process is optimized,and its reaction mechanism is discussed.For a series of PW₄O₁₆^3-ionic liquid catalysts,the best catalyst[?-C₅H₅NC₁₆H₃₃]₃PW₄O₁₆ is screened,and the catalytic process shows the phenomenon of reaction control phase transfer.The catalyst[?-C₅H₅NC₁₆H₃₃]₃PW₄O₁₆ is characterized by FT-IR,and the structural changes of the catalyst before and after the reaction is investigated.Under the optimized reaction conditions?n?Cat?:n?H₂O₂?:n?CPE?=0.05:1.5:1,t=8 h,t=35 ??,the conversion rate of cyclopentene is 98%,and the yield of glutaraldehyde reaches72%.The catalyst is recycled 5 times,and the yield is still more than 60%.The catalyst[C₁₆H₃₃NH?CH₃?₂]₃PW₄O₁₆ also shows a good catalytic effect under solvent-free conditions.Under the optimization conditions(n?Cat?:n?H₂O₂?:n?CPE?=0.03:2.6:2,t=4 h,t=35?,the yield of glutaraldehyde is obtained by 64%.In this paper,several new routes for the preparation of glutaraldehyde by reaction controlled phase transfer catalysis or heterogeneous catalytic cyclopentene oxidation are designed,which is of great significance to the production of glutaraldehyde.