摘要
采用溶胶凝胶法将Dawson型磷钨酸负载于SiO2上,制备的负载型催化剂H6P2W18O62/SiO2,通过FTIR、XRD、SEM、TGA对其进行表征。结果表明,该Dawson型磷钨酸可以较均匀地分散在SiO2载体上,且在催化合成4-苯基-6-甲基-5-乙氧羰基-3,4-二氢嘧啶-2(H)-酮的Biginelli反应中表现出较高的催化活性。最佳反应条件为:在固定苯甲醛用量为0.04 mol条件下,n(苯甲醛)∶n(乙酰乙酸乙酯)∶n(尿素)=1∶1.5∶1.5,催化剂用量为反应物总质量的2.0%,反应温度为80℃,反应时间为75 min。在最优条件下,产品平均收率可达82.3%,催化剂重复利用10次后收率仍达57.2%。
Phosphotungstic acids with Dawson structure（ H6P2W18O62） supported on SiO2 were prepared by sol-gel method. The properties of the catalyst were characterized by means of TGA,FTIR,SEM and XRD. The results show that H6P2W18O62 had been well dispersed into the SiO2 support,and the immobilized catalyst exhibited high catalytic activity in the Biginelli reaction for the synthesis of 4-phenyl-6-methyl-5-ethoxycarbonyl-3,4-dihydropyrimidin-2（ H）-ketone. The optimized conditions were as follows： fixed benzaldehyde consumption was 0. 04 mol,n（ benzaldehyde） ∶ n（ ethylacetoacetate） ∶ n（ urea） =1∶1. 5∶1.5,the mass ratio of the catalyst to total reactant was 2.0%,the reaction temperature was 80 ℃,and the reaction time was 75 min. The yield of the product could reach 82. 3% under the optimum conditions. It also maintained satisfactory catalytic activity for the synthesis of Biginelli compound after 10 rounds of recycling,and the yield was still above 57. 2%.
出处
《精细化工》
EI
CAS
CSCD
北大核心
2014年第9期1091-1095,1114,共6页
Fine Chemicals
基金
2013年国家级大学生创新创业训练计划项目(201313256001)
湖北师范学院硕士研究生创新科研基金项目(1051320130216)
National Undergraduate Training Programs for Innovation and Entrepreneurship(201313256001)
Postgraduate Innovation Scientific Research Foundation of Hubei Normal University(1051320130216)
