摘要
在釜式反应器中，考察了采用机械混合催化剂Ru—Zn／SiO2＋HZSM-5催化由苯一步合成环己醇的过程。结果发现，HZSM-5的加入并没有得到目的产物环己醇，但是苯的转化率显著增加，且大部分产物为环己烷。分析认为是溢流氢作用的结果。由于HZSM-5表面酸中心和Ru加氢中心的共同存在，使得苯加氢反应存在2条路径，因此反应速率增加，苯的转化率增加；由于HZSM-5表面酸中心有利于中间物环己烯的吸附，从而易发生深度加氢，得到产物大部分为环己烷。当HZSM-5加入量较少（或n（SiO2）／n（Al2O3）较大）时，由于酸中心数量较少，其促进苯加氢反应的能力有限，且稀释了Ru-Zn／SiO2催化剂，造成反应速率减慢，苯的转化率降低。
The one-pot synthesis of cyelohexanol from benzene over the mechanically mixed catalyst Ru-Zn/SiO2-4- HZSM-5 was investigated in an autoclave. It was found that the addition of HZSM-5 didn＇t result in the objective cyclohexanoh However, the benzene conversion increased obviously, and cyclohexane was the main product. It was thought to be the result of the effect of hydrogen spillover. For the coexistence of the acid sites on the surface of HZSM-5 and Ru hydrogenation sites in the reaction system, there were two routes for benzene hydrogenation, so that the reaction rate and benzene conversion increased. Furthermore, the acid sites existing on the surface of HZSM-5 was in favor of the adsorption of cyclohexene, which thereby was over-hydrogenated easily to form cyclohexane mainly. When the addition of HZSM-5 decreased, or HZSM-5 with larger molar ratio of SiO2/Al2O3 was used, the reaction rate and benzene conversion decreased, which was attributed to the decrease of acid site, not only for its limited hydrogenation ability for benzene, but also for its dilution to Ru-Zn/SiO2 catalyst.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2008年第B10期73-78,共6页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家自然科学基金项目（20636030,20706011）、天津市自然科学基金项目（07JCZDJC00100）资助
关键词
环己醇
苯
一步合成
HZSM-5
溢流氢
cyclohexanol
benzene
one-pot synthesis
HZSM-5
hydrogen spillover
