Zn(Ac)_2/超高比表面积活性炭催化剂上乙炔法合成醋酸乙烯宏观动力学

Macrokinetics of the vinyl acetate synthesis on the catalyst of super-high specific surface area activated carbon supported Zn(Ac)_2

在接近工业生产条件下研究了Zn(Ac)2/超高比表面积活性炭 (ABET=2713m2/g) 催化剂上,乙炔法合成醋酸乙烯 (VAc) 反应宏观动力学,并与Zn(Ac)2/日本普通椰壳炭 (ABET=1384 m2/g) 催化剂进行了比较.实验结果求得两种不同比表面积载体催化剂的宏观动力学方程分别为:υ1=28.22p1.00C2H2p-0.62VAc和υ2=25.03p1.01C2H2p-0.52VAc,即合成VAc的反应对乙炔是1级反应,对VAc是负的反应级数,载体的比表面积越高催化剂的催化反应活性越高.求得在160℃～175℃两种催化剂反应的平均表观活化能分别为:52.49(kJ·mol-1)和53.87(kJ·mol-1),均小于文献报道的反应真实活化能87.80(kJ·mol-1).

The macrokinetics of vinyl acetate synthesis from acetylene and acetic acid on the Zn(Ac)2/super-high specific surface area activated carbon (SBET = 2713 m2/g) catalyst has been studied under conditions approaching those of industrial operation, and compared with Zn(Ac)2/Japaniese coco-shell carbon (SBET = 1384 m2/g) catalyst. The macrokinetics equations are v1 = 28.22pC2H21.00 pVAC-0.62 and v2 = 25.03pC2H21.01 pVAC-0.52 for two kinds of catalysts, respectively. The average apparent activation energys are 52.49 (kJ·mol-1) and 53.87 (kJ·mol-1) for the catalysts at temperature range of 160°C - 175°C, respectively. The results indicated that the reaction order to acetylene was one, and the reaction order to vinyl acetate was negative. The activation energy was less than real activation energy 87.80 (kJ·mol-1), which indicated that the synthesis reaction was seriously affected by diffusion. The catalytic activity increased with the increment of the specific surface area of the catalysts support. At the same time, the catalytic activity was less affected by increasing in specific surface area of support at high temperature range of 185°C - 195°C.