固体碱K_2CO_3/Mg-Al-O催化酯交换制备生物柴油

Preparation of Biodiesel by Transesterification over K_2CO_3/Mg-Al-O Solid Base Catalyst

以镁铝水滑石为前驱体,经焙烧后得到的镁铝复合氧化物为载体,制备了负载型K2CO3/Mg-Al-O固体碱催化剂,并用于大豆油酯交换合成生物柴油反应中。研究了活性组分K2CO3负载量对催化剂结构和性能的影响。结果表明,在K2CO3负载量为30%时,形成的钾铝氧化物种是催化剂强碱中心和活性提高的主要原因。考察了反应条件对催化剂性能的影响,在反应温度60℃、时间6 h、醇油摩尔比12∶1和催化剂用量2.0%的条件下,生物柴油收率最高为88.5%,催化剂具有较好的稳定性。

Catalyst precursor Mg-AI hydrotalcite was prepared by coprecipitation and then the Mg-Al-O carrier was prepared by calcination. A series of Mg-AI-O supported K2CO3 catalysts were prepared to catalyze the transesterification of soybean oil for producing biodiesel. It is shown that the increased basic property and catalytic activity of K2CO3/Mg-Al-O catalyst loaded with 30 % K2CO3 are attributed to the new K-O-Al species produced by the interaction between support and K2CO3. The yields of biodiesel can reach 88,5 % under the conditions of reaction temperature 60 ℃, time 6 h, methanol / oil molar ratio 12：1 and catalyst amount 2.0 %.