摘要
采用蒸氨沉积沉淀法制备了不同铜负载量的铜硅催化剂,并考察了铜硅催化剂在环己醇脱氢反应中的催化性能;进一步研究了金属氧化物助剂(Na_(2)O,MgO,K_(2)O,CaO,ZnO)对铜硅催化剂催化活性的影响。利用N2吸附-脱附、H2-TPR和NH3-TPD方法对铜硅催化剂进行了表征。实验结果表明,铜负载量对于环己醇转化率的影响明显大于环己酮的选择性,且当n(Cu)∶n(Si)=0.32时,环己醇的转化率达到46.3%;引入K_(2)O助剂的铜硅催化剂表现出优异的催化活性、选择性及热稳定性。表征结果显示,K_(2)O助剂的添加改变了氧化态铜物种的形态和分布,促进了活性组分的分散,提高了催化剂的催化活性;K_(2)O助剂与活性组分之间存在着一定的相互作用,这阻碍了金属铜颗粒的聚集,增强了催化剂的抗烧结能力;同时降低了催化剂的表面酸性,减少了中等强度酸性中心和强酸中心的数量,提高了目标产物的选择性。
The silica supported copper catalysts with different Cu loading were fabricated by the ammonia-evaporation deposition-precipitation method and their catalytic performance in the dehydrogenation of cyclohexanol(OL)to cyclohexanone(ONE)was investigated.Furthermore,the effect of metal oxide promoters(Na_(2)O,MgO,K_(2)O,CaO,ZnO)on the catalytic activity of CuSi catalyst was further studied.The catalysts were characterized by N2 adsorption-desorption,H2-TPR and NH3-TPD methods.The experimental results showed that the Cu content was significantly more influential on OL conversion than the selectivity of ONE,while n(Cu)∶n(Si)0.32,the OL conversion the maximum value of 46.3%.The catalyst introduced with K_(2)O additives exhibits excellent catalytic activity,selectivity and long-term stability.The characterization results showed that the addition of K_(2)O promoter affect the distribution and status of copper oxide species,promote the dispersion of the active components and improve the catalytic activity of the catalyst.Meanwhile,the interaction between K_(2)O additives and the active components impede the aggregation of Cu particles and enhance the anti-sintering performance of the catalyst.At the same time,the surface acidity of the catalyst is reduced,the number of acid sites with medium strength and strong strength is reduced,and the selectivity of the target product is improved.
作者
程帅
国海光
孙兵
Cheng Shuai;Guo Haiguang;Sun Bing(Shanghai Xunkai New Material Technology Co.,Ltd.,Shanghai 201208,China)
出处
《石油化工》
CAS
CSCD
北大核心
2022年第12期1388-1393,共6页
Petrochemical Technology
关键词
环己醇
催化脱氢
环己酮
铜基催化剂
助剂
稳定性
cyclohexanol
catalytic dehydrogenation
cyclohexanone
copper-based catalyst
promoters
stability
