摘要
使用浸渍-还原法分别制备了3%Pd/C、3%Pt/C和3%Pt-Fe/C催化剂,通过ICP、TEM、XPS等方法对催化剂的金属含量、表面形态、电子状态进行了表征。将制备的催化剂用于以混合硝基氯苯氨解后产物邻、对硝基苯胺和间硝基氯苯为原料,催化加氢合成邻、对苯二胺和间氯苯胺反应。通过对比3种催化剂,得到3%Pt-Fe/C催化剂催化效果最好。以3%Pt-Fe/C为催化剂,考察了各因素对混合硝基氯苯氨解产物加氢反应的影响,确定了反应的最优条件:起始催化剂用量0.8%(以反应原料的质量分数计),m(甲醇)∶m(水)=50∶50为溶剂,温度85℃,压力2 MPa,搅拌转速600 r·min^(-1)。在此条件下,反应物转化率为100%,邻、对苯二胺和间氯苯胺的总收率可以达到99%以上,催化剂可重复使用19次。对新鲜和失活的Pt-Fe/C催化剂进行BET、CO化学吸附、TEM等表征,发现失活后催化剂的比表面积大幅下降,判定催化剂孔道堵塞是导致催化剂失活的主要原因。
The 3%Pd/C,3%Pt/C and 3%Pt-Fe/C catalysts were prepared by impregnation-reduction method.The metal content,surface morphology and electronic state of the cata-lysts were characterized by ICP,TEM and XPS.The prepared catalyst was used to catalyze the hydrogenation of o,p-nitroaniline and m-nitrochlorobenzene from the products of mixed nitrochlorobenzene ammoniolysis to synthesize o,p-phenylenediamine and m-chloroaniline.By comparing 3%Pd/C,3%Pt/C and 3%Pt-Fe/C catalysts,the 3%Pt-Fe/C catalyst has the best catalytic effect.Using 3%Pt-Fe/C as catalyst,the influences of various factors on the hydrogenation of mixed nitrochlorobenzene aminolysates were investigated.The optimal re-action conditions were determined as follows:the initial catalyst amount was 0.8%(based on the mass fraction of reactive materials),m(methanol)∶m(water)=50∶50 is solvent,the temperature is 85℃,the pressure is 2 MPa,and the stirring speed is 600 r·min^(-1).Un-der these conditions,the reactant conversion rate is 100%,the yield of o,p-phenylenedia-mine and m-chloroaniline can reach more than 99%,and the catalyst can be reused for 19 times.The fresh and deactivated Pt-Fe/C catalysts were characterized by BET,CO chemi-sorption and TEM.It was found that the specific surface area of the catalyst decreased sig-nificantly after deactivation,and it was determined that the blockage of catalyst pore was the main cause of catalyst deactivation.
作者
张健
丁军委
张效磊
ZHANG Jian;DING Junwei;ZHANG Xiaolei(College of Chemical Engineering,Qingdao University of Science and Technology,Qingdao 266042,China)
出处
《青岛科技大学学报（自然科学版）》
CAS
2024年第5期22-31,共10页
Journal of Qingdao University of Science and Technology:Natural Science Edition
基金
山东省重点研发计划项目(2019GSF109055)。
关键词
Pt-Fe/C
苯二胺
间氯苯胺
催化加氢
Pt-Fe/C
phenylenediamine
m-chloroaniline
catalytic hydrogenation
