纳米固体碱催化酯交换反应动力学

Kinetics of Transesterification of Jatropha Oil with Nano Solid Hydrotalcite Catalyst

尿素为沉淀剂制备纳米Mg-Al水滑石,对其高温煅烧物进行X射线衍射、傅里叶变换红外光谱和扫描电子显微镜表征,以其煅烧物为催化剂催化制备生物柴油,并系统研究酯交换反应动力学。研究结果表明:纳米Mg-Al水滑石500℃煅烧6 h,水滑石特征衍射峰d(003)部分消失,柱撑阴离子碳酸根离子对称性降低,晶粒团聚成层状结构。纳米固体碱催化酯交换反应的表观反应级数为1.5,表观活化能Ea=25.92 kJ/mol,在最优条件下,生物柴油转化率高达95.4%。

Mg-Al hydrotaleite nanoparticles were synthesized by coprecipitation using urea as precipitating agent, and subsequently calcined. The calcined particles were characterized by XRD, FT-IR and SEM. They were further used as nanocatalyst to produce biodiesel,and its transesterification kinetics was studied. Results showed that the characteristic XRD diffraction peak d（003） partly disappeared,the symmetric degree of carbonate anions decreased and the particles were agglomerated to form layer structure after the fresh nanoparticles were calcined at 500 ℃ for 6 h. With the catalyst,the transesterlfication reaction order was 1.5 with apparent activation energy of 25.92 kJ/mol. At the optimized condition, biodiesel yield was 95.4%.