H3PW12O40/H2O2/H2O体系催化氧化苯甲醇合成苯甲醛

合成一系列杂多酸(盐)并采用红外光谱对其进行表征,研究它们对苯甲醇氧化合成苯甲醛反应的催化性能.并以H3PW1 2O40为催化剂,分别考察溶剂类型、反应时间、反应温度、催化剂用量和H2O2用量对该反应的影响,并且初步探讨该反应的反应机理.实验结果表明:5种杂多酸(盐)均具有Keggin型结构,以水为溶剂时,5种杂多酸(盐)均具有催化活性,其中H3PW12O40催化活性最高.在催化剂用量0.04mmol、w(H2O2)=30%的H2O2用量0.015mol、反应时间3.5h、反应温度90℃、溶剂水用量10mL的优化反应条件下,苯甲醇的转化率为95.59%,苯甲醛的收率可达91.62%.由此可知,H3PW12O40/H2O2/H2O体系是环境友好的高效催化体系,具有工业化应用前景.

Study of catalytic oxidation of benzyl alcohol to benzaldehyde over the system of H3PW12O40/H2O2/H2O

A series of heteropoly acid(salt) were synthesized and characterized with infrared spectoscopy.Their catalytic performance in the oxidation reaction of benzyl alcohol to synthesize benzaldehyde was investigated.The effects of the solvent type,reaction temperature,reaction time,catalyst dosage,and H2O2 dosage on this reaction were examined,respectively and the reaction mechanism of this reaction was preliminarily expired,also.The result showed that all the five heteropoly acids(salts) possessed the Keggin-type structure and better catalytic activity with water as solvent,among them the phosphotungstic acid was the best.Under following optimized reaction conditions that the amount of catalyst was 0.04 mmol and the amount of H2O2 was 0.015 mol,reacting at 90 ℃ for 3.5 h,the conversion rate of benzyl alcohol was 95.59% and the yield of benzaldehyde could reach 91.62%.It could be seen then that the system of H3PW12O40/H2O2/H2O was an environment-friendly high efficient catalyst system with industrial application prospect.