酸碱性浸渍条件对钯炭催化剂加氢性能的影响

采用氢氧化钠和盐酸调节钯炭(Pd/C)催化剂制备过程中的浸渍液的pH,制备了相应的钯炭催化剂。对Pd/C催化剂的成分、形貌等性质进行表征分析,研究了不同浸渍条件下制备的Pd/C催化剂对苯甲醛和2-氰基吡啶加氢的催化性能。结果表明,酸/碱浸渍方法可有效控制钯颗粒的尺寸大小及分散度。在浸渍液的pH值为3的条件下制备出的Pd/C-1~#催化剂平均粒径为2.78 nm。当浸渍液的pH值为10时,制备的Pd/C-2~#催化剂平均粒径为3.75 nm。对于2-氰基吡啶加氢,采用酸性浸渍条件制备的Pd/C催化剂具有更好的催化效果;而采用碱性浸渍条件制备的Pd/C-2~#催化剂对苯甲醛加氢效果更好。

Effect of acid/base impregnation conditions on hydrogenation performance of palladium carbon catalysts

The pH of impregnation solutions was first adjusted by sodium hydroxide and hydrochloric solution, then prepared corresponding Pd/C catalysts. Their properties were characterized by XRD, BET and TEM. The hydrogenation performance of the Pd/C catalysts prepared under different immersion pH on benzaldehyde and 2-cyanopyridine was studied. The results showed that the acid/base impregnation condition could effectively control the size and dispersion of palladium particles. For the catalyst (Pd/C-1^#) prepared by using a pH3 impregnation solution, its average Pd particle size was 2.78 nm, while for the Pd/C-2^# catalyst prepared by using a pH10 immersion solution, its average particle size was 3.75 nm. The Pd/C-1^# catalyst impregnated under acidic condition possesses a better conversion rate and selectivity in the hydrogenation of 2-cyanopyridine, while the Pd/C-2^# catalyst impregnated under alkaline condition has high conversion rate and selectivity for the hydrogenation of benzaldehyde.