碳载体对Pd/C催化剂上合成五甲基二乙烯三胺选择性的影响

摘要

Pd/AC and Pd/MC catalysts were prepared by impregnent method with using active carbon (AC) and mesoporous carbon (MC) as supports.Pd content was 15％.The physico-chemical properties of the samples were analyzed by specific sufrace area (BET),X ray diffraction (XRD),thermogravimetric analysis (TG),transmission electron microscopy (TEM) and H2 temperature programmed desorption of (H2-TPD).The catalytic performance of Pd/AC and Pd/MC catalystswas investigated for pentanethyldiethylenetriamine (PMDETA) synthesis by hydrogenation of ethyldiethylenetriamine and formaldehyde.The results showed Pd/MC had a larger specific surface area,larger pore size,richer mesoporous volume,smaller Pd particles size and higher hydrogenadsorption capacity.Pd/MC had higher catalytic activity.DETA conversion was 100％ and PMDETA selectivity was up to 97％ over Pd/MC catalysts.Because of the space restriction characteristic of MC,Pd particles were well dispersed on MC and highly stable after reusing 15 times.%以活性碳(AC)和介孔碳(MC)为载体,采用浸渍法分别制备了Pd负载量为15％的Pd/AC和Pd/MC催化剂,采用物理吸附(BET),X射线衍射(XRD),热重分析(TG),透射电镜分析(TEM)和H2程序升温脱附(H2-TPD)对试样的理化性质进行分析.考察了Pd/AC和Pd/MC催化剂上二乙烯三胺(DETA)与甲醛加氢合成五甲基二乙烯三胺(PMDETA)的催化性能.结果表明:与Pd/AC相比,Pd/MC具有更大的比表面积和孔径、丰富的中孔孔容和更小的Pd颗粒尺寸及更高的氢吸附能力;Pd/MC具有较高的催化性能,DETA转化率为100％,PMDETA选择性达到97％;中孔对Pd颗粒空间限制特性使得Pd在MC表面分散较高,15次重复使用后仍具有高稳定性.