多钒取代磷钼杂多酸的阻聚、催化性质研究

通过酯交换反应合成了甲基丙烯酸异丁酯,并对反应条件进行优化;通过差式扫描量热法测定了磷钼钒杂多酸对甲基丙烯酸甲酯的阻聚性能,结果表明,随着杂多酸结构中钒钼比例数的增大、杂多酸用量的增加以及升温速率的提高,杂多酸的阻聚性能增强,且Dawson型杂多酸的阻聚性能高于Keggin型。在合成甲基丙烯酸异丁酯的反应中,经正交试验得到的最优反应条件为:醇酯物质的量比为1.2∶1,Dawson型磷钼钒杂多酸-V6催化剂(Dawson-V6)用量为反应物总质量的8%,反应时间7.5 h,磷钼钒杂多酸对不饱和酯的合成具有催化作用和较好的阻聚效果。

Study on Inhibition and Catalysis Properties of Multi-Vanadium Substituted Phosphomolybdic Heteropoly Acid

The inhibition properties of multi-vanadium substituted phosphomolybdic heteropoly acid on the polymerization of methyl methacrylate were determined by differential scanning calorimetry,at the same time,isobutyl methacrylate was synthesized via trans-esterification catalyzed by heteropoly acid.The results showed that the inhibition properties were enhanced with the increasing of the vanadium molybdenum proportion in the structure of heteropoly acid,dosage of heteropoly acid and heating rate.The inhibition properties of Dawson heteropoly acid is better than that of Keggin type.Optimal reaction conditions for the synthesis of isobutyl methacrylate were obtained while mole ratio of alcohol and ester is 1.2∶1,dosage of catalyst is 8%of the total mass of reactants,reaction time is 7.5 h.Not only better catalytic effect but also better inhibition properties of phosphomolybdic vanadium heteropoly acid were found in the synthesis of unsaturated ester.