氧化硅负载的固体碱上乙醛的气相缩合反应

在氧化硅负载的含碱金属固体碱催化剂上乙醛能有效地缩合生成丁烯醛及丁烯醇,反应具有中等转化率、较好的选择性(约90％)和稳定性.考察了不同反应条件对催化性能的影响,并对可能的反应活性相进行了探讨.

Vapour Phase Condensation of Acetaldehyde over Silica Supported Solid Base Catalysts

Silica supported low loading alkali metal containing catalysts (Li, Na, K, Cs/SiO2) can effectively catalyze the vapor phase condensation of acetaldehyde with dehydration to produce crotonaldehyde with good selectivity (ca. 9O%) and stability and moderate conversion. The optimized reaction temperature was in the range of 623~648 K- The approximative order of the reactivity of these solid base catalysts is K/SiO2> Na/SiO2> Cs/SiO2>Li/SiO2. The silicate and carbonate are probably the active phases for the reaction. Increasing the matel loading altered the context and structure of the catalysts, enhanced the coke formation and in turn the production of crotyl alcohol. A similar trend was observed when a more basic alkali metal was used or a larger W/F ratio was adopted.