m-β-羟乙基砜硝基苯催化加氢过程中Pd/C催化剂耐用性的研究

Study on durability of Pd/C catalyst for catalytic hydrogenation of m mononitrophenyl-β-hydroxyethyl sulfone

通过 SEM,TGA,BET比表面积测定 ,对影响 Pd/C催化剂耐用性诸因素进行了研究。表明芳硝基化合物加氢过程中 Pd/C催化剂活性衰退的主要原因是反应过程中原料中的杂质在催化剂表面的机械覆盖及高温引起的热衰退所致。改用经精制提纯后的原料 ,选择适宜的反应条件 ,可使催化剂的活性及耐用性得到较大改善。本研究以实验室制备的 2 % Pd/C为催化剂 ,经提纯的工厂中间体产品 m-β-羟乙基砜硝基苯为原料 ,在 65℃、3.5MPa、乙醇为溶剂、原料∶乙醇∶催化剂 =1∶ 1∶ 0 .0 5(wt)的条件下反应 2 h,加氢转化率可达 99.7%。催化剂经反复使用 5次后 ,在上述反应条件下反应 5h,加氢转化率仍保持 81 .5%。

The effect of raw material on activity of Pd/C catalyst for catalytic hydrogenation of m mononitrophenyl β hydroxyethyl sulfone was investigated by SEM,TGA and BET.It was found that impurities in raw material has unfavourable effect on activity and service life of the catalyst.With 2% Pd/C catalyst and purified feedstocks,and under 70℃,3 5MPa(H 2)and alcohol/raw material ratio of 1/1(wt),the conversion of m mononitrophenyl β hydroxyethyl sulfone was 99 7% with fresh catalyst and 81 5% after five times of repeated use.