磷钨杂多酸类离子液体催化环戊烯选择性氧化制备戊二醛

以H_2O_2为氧化剂,将一系列磷钨杂多酸类离子液体用于催化环戊烯(CPE)选择性氧化制备戊二醛(GA)反应,筛选出催化活性最高的催化剂为π-C_5H_5NC_(16)H_(33)]_3PW_4O_(16).分别探讨了溶剂种类、用量、催化剂用量、H_2O_2用量、反应温度和反应时间等因素对反应的影响.确定了优化的反应条件:5 mL乙酸乙酯,n(Cat.)∶n(H_2O_2)∶n(CPE)=0.03∶50∶33,35℃,18 h,环戊烯的转化率达100%,戊二醛的选择性达87%.催化剂π-C_5H_5NC_(16)H_(33)]_3PW_4O_(16)循环使用7次后,戊二醛的选择性仍保持在80%以上.

Selective Oxidation of Cyclopentene to Glutaraldehyde Catalyzed by Heteropolyphosphatotungstate Ionic Liquids

With H2O2 as oxidant, a series of heteropolyphosphatotungstate ionic liquids was used to catalyze the selective oxidation of cyclopentene ( CPE) to prepare glutaraldehyde ( GA). Among these catalysts, π-C5H5NC16H33 ] 3PW4O16 exhibited the best catalytic activity. PW4O3-16 easily combined with H2O2 to form W—O—O—W. Using π-C5H5NC16H33 ] 3 PW4O16 as catalyst, the effects of the amount of catalyst, molar ratio of H2O2 to CPE, type and dosage of solvent, reaction temperature and reaction time on the catalytic behavior were investigated and discussed, respectively. The results show the best reaction conditions as follows: 5 mL of ethyl acetate, n(Cat.) : n(H2O2 ) : n(CPE)= 0. 03 : 50 : 33, 35 ℃, 18 h. The conversion of cyclopentene could reach 100%, and the yield of glutaraldehyde was 87%. After the reaction, the catalyst could automatically precipitate from the reaction liquid. After the upper liquid was poured out, the remaining catalyst could be directly reused by the addition of fresh reactants. Under the optimal reaction conditions, the recycling efficiency of the catalyst π-C5H5NC16H33 ] 3 PW4O16 was investigated. Because the structure of the catalyst didn't change before and after reaction by the analysis of FTIR spectra, π-C5H5NC16H33 ] 3 PW4O16 has exhibited a good recyclability. After 7 recycles, the yield of glutaraldehyde was still above 80%.