Highly Efficient Production of Acrylic Acid by Sequential Dehydration and Oxidation of Glycerol

详细信息    查看全文

• 作者：Rong Liu ; Tiefeng Wang ; Dali Cai ; Yong Jin
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：May 28, 2014
• 年：2014
• 卷：53
• 期：21
• 页码：8667-8674
• 全文大小：375K
• 年卷期：v.53,no.21(May 28, 2014)
• ISSN：1520-5045

文摘

The selective dehydration鈥搊xidation of glycerol to acrylic acid is a very attractive approach for glycerol utilization. In this work, we demonstrated an efficient two-bed system for this process. The dehydration catalyst was Cs_2.5H_0.5PW₁₂O₄₀ supported on Nb₂O₅ (CsPW-Nb), and the oxidation catalyst was vanadium鈥搈olybdenum mixed oxides supported on silicon carbide (VMo鈥揝iC). The experimental results showed that the optimum reaction temperature and oxygen ratio for these two catalysts were very similar. This made the two-bed system simple and efficient. Compared with the single-bed system, the two-bed system with the dehydration catalyst and oxidation catalyst loaded separately was more favorable to avoid the overoxidation reaction of glycerol. A high yield of acrylic acid was achieved at optimized conditions in the two-bed system. The Br酶nsted acid sites on the dehydration catalysts were the active sites for acrolein formation. The byproducts produced on Lewis acid sites in the dehydration step and the water in the glycerol feed did not show negative effects on the acrolein oxidation reaction. Both the CsPW-Nb and VMo-SiC catalysts were stable for at least 70 h and had very good thermal stability at the coke burning temperature of 500 掳C.