SO_4^(2-)负载型固体酸催化制备生物柴油

Biodiesel Preparation by SO_4^(2-) Supported Solid Acid Catalysts

以浸渍法制备了不同载体的SO42-负载型固体酸催化剂,用于催化制备生物柴油。考察了不同载体及不同焙烧温度下的催化剂活性,并对催化剂的失活和再生进行了研究。结果表明,本实验制备的SO42-负载型固体酸催化剂催化制备生物柴油时具有较高活性,最佳实验条件下,100℃反应13h,脂肪酸甲酯收率达90%以上;SiO2为载体时催化剂在100℃的干燥温度下催化活性较高,SnO2为载体时催化剂在450℃的焙烧温度下催化活性较高,而催化剂SO42-/SnO2-SiO2在焙烧温度小于450℃时催化活性皆较高。使用过的催化剂部分失活,原因是催化剂表面的硫酸根被甲醇淋洗掉;催化剂表面的活性位被油和甲酯所覆盖。使用过的催化剂通过焙烧,重新浸渍硫酸溶液再焙烧后,其活性得以恢复。

In this experiment, SO4^2- supported solid acid catalysts with different carriers were prepared and used to prepare biodiesel. The activity of the catalysts prepared with different carriers and different calcination temperatures was investigated, the deactivation and regeneration of the catalysts were studied. It is found that SO4^2- supported solid acid catalysts exhibited high activity for biodiesel preparation. Under the optimal conditions, 100℃ for 13 h, the yield of methylesters was above 90%. In the case of SiO2 as carrier at drying temperature of 100℃, in the case of SnO2 as carrier at calcinations temperature of 450℃, and in the case of SO4^2-/SnO2-SiO2 as mixed carrier at the calcinations temperature less than 450 ℃, all catalysts exhibited high activity. However, the used catalyst was partly deactivated, because SO4^2- was slowly leached out from the catalyst surface by methanol and activity sites were covered by oil and methyl esters. After calcination, rempregnation with H2SO4 solution, and re-calcination, the catalyst＇s activity was resumed.