Abstract:

With Na₂CO₃ as active component and carbon foam (CF) as carrier, solid base catalyst of Na₂CO₃/CF was prepared by volume impregnation method. Then, its structure and properties were characterized by SEM, SEM-EDS, FTIR, XRD, and BET. The specific surface area of the Na₂CO₃/CF catalyst was 182m²/g and the loaded Na₂CO₃ was evenly deposited on the cell wall surface of CF as fine grains with an average particle size less than 350nm. Subsequently, the catalytic activity and reusability of Na₂CO₃/CF were studied in the transesterification of rapeseed oil with methanol, and the process conditions were optimized. The optimal conditions were Na₂CO₃/CF dosage 10% (of oil weight), reaction time 180min, mole ratio of alcohol to oil 27/1, reaction temperature 65℃, and the resulting conversion was 97.80%. Moreover, the conversion still maintained 94.48% with the catalyst used for five times. The study would provide a new idea for the development of carbon-based solid base catalyst with high efficiency using the salt formed by strong base and weak acid as active center.

Key words: biodiesel, methanolysis, carbon foam, solid base catalyst, deactivation, regeneration

摘要：

以Na₂CO₃为活性组分、泡沫炭（CF）为载体，本文借助等体积浸渍法制备了Na₂CO₃/CF非均相固体碱催化剂，通过SEM、SEM-EDS、FTIR、XRD、BET对其结构性能进行分析表征，结果显示：Na₂CO₃/CF的比表面积为182m²/g，负载的Na₂CO₃以细小颗粒的形式均匀分布于CF泡壁表面，平均粒径<350nm。以菜籽油-甲醇体系为对象，分析了Na₂CO₃/CF的催化活性及重复利用性，并对酯交换反应的工艺条件进行优化，结果显示，在Na₂CO₃/CF用量为油重10%、反应时间180min、醇油物质的量比为27∶1、反应温度65℃的条件下，反应转化率高达97.80%，该催化剂重复利用5次，转化率仍可达94.48%。研究结果对开发以强碱弱酸盐为活性中心的碳基固体碱高效催化剂提供了新思路。

关键词: 生物柴油, 醇解反应, 泡沫炭, 固体碱催化剂, 失活, 再生