微孔多金属氧酸H_3PW_(12)O_(40)/SiO_2催化合成丙烯酸正丁酯

Synthesis of n-butyl acrylate with microporous silica-supported polyoxometalate H_3PW_(12)O_(40)/SiO_2 as catalyst

通过溶胶-凝胶技术将Keggin型杂多酸H3PW12O40负载于SiO2基质上,在含氧极性溶剂中得到不溶脱、易分离、可重复使用的具有大表面积(350 5m2/g)的微孔催化材料(孔径为0 57nm).利用UV,ICP,TGA,BET吸附等手段对该催化剂进行了表征.以H3PW12O40/SiO2做催化剂用丙烯酸和正丁醇合成丙烯酸正丁酯,催化活性高于H3PW12O40和H2SO4,当酯化反应2 5h时,丙烯酸的转化率可达97 6%,催化剂重复使用3次,其催化活性依然很高.

Microporous Keggin-type polyoxometalate material was obtained by supporting H3PW12O40 into a silica matrix using a sol-gel technique.The silica-supported 12-tungstophosphoric acid (H3PW12O40/SiO2) obtained is insoluble and readily separable porous materials with uniform micropores (0.57 nm) and a high specific surface area(350.5 m2 /g)in oxygen-containing polar solvents.H3PW12O40/SiO2 was characterized by ultraviolet-visible spectrophotometer(UV-vis),inductively coupled plasma(ICP),thermogravimetric analysis(TGA) and Brunner-Emmett-Teller method (BET)measurements.H3PW12O40/SiO2 obtained catalyzed the esterification reaction of acrylic acid with n-butyl alcohol to produce n-butyl acrylate,catalysis activity of H3PW12O40/SiO2 is higher than H3PW12O40 or sulfuric acid.Conversion was 976% for acrylic acid during the reaction period of 2.5 h.H3PW12O40/SiO2 kept its initial activity during three times of reuse.