疏水性固体酸H3PW12O40/HZSM-5催化合成丙烯酸正丁酯

制备了负载型疏水性固体酸催化剂H₃PW₁₂O₄₀/HZSM-5，并将该疏水性固体酸催化剂用于丙烯酸（简称AA）与正丁醇的酯化反应中。结果表明，硅铝摩尔比为60的HZSM-5负载质量分数为40％的H₃PW₁₂O₄₀，180℃干燥2h，H₃PW₁₂O₄₀/HZS-5催化剂的活性最高，丙烯酸转化率可达96.44％。H₃PW₁₂O₄₀/HZSM-5催化剂循环使用4次，丙烯酸的转化率仍保持在71.98%。采用XRD、FTIR以及原位红外对催化剂的结构和酸性进行了表征，测试结果均表明H₃PW₁₂O₄₀较好的分散于HZSM的表面，在催化剂表面存在Lewis酸和Brnosted酸，且其负载型疏水性固体酸H₃PW₁₂O₄₀/HZSM-5的酸量、催化活性和疏水性能均高于单组分H₃PW₁₂O₄₀。

Preparation of butyl acrylate catalyzed by a hydrophobic solid acid catalyst-H3PW12O40 supported on HZSM-5

A novel solid acid catalyst, H₃PW₁₂O₄₀(HPW) supported on HZSM-5, has been prepared for use in the esterification of acrylic acid (AA) with n-butanol. The molar ratios of Si to Al in the support, HPW loading and calcination temperature were optimized. The activity of the catalyst was found to be maximized when a material with w(H₃PW₁₂O₄₀)=40% was calcined at 180℃ for 2h, with the conversion of AA being 96.44%. After being reused 4 times, the measured conversion of AA was still over 70%. The catalysts were characterized by FTIR and XRD and their acidity was measured by in situ FTIR. The results indicate that HPW was successfully supported on the HZSM-5 with a high degree of dispersion on the support surface. Bands at 1525cm^-1 and 1686cm^-1, characteristic of acid sites, were observed in the in situ FTIR spectra of HPW/HZSM-5 after adsorption of ammonia, indicating that HPW/HZSM-5 has both Lewis acid sites and Bronsted acid sites.