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2898118 
Journal Article 
Coking and deactivation of catalyst inhibited by silanization modification in oxidation of benzene to phenol with nitrous oxide 
Zhai, PM; Wang, LQ; Liu, CH; Zhang, SC 
2005 
Yes 
Chinese Journal of Chemical Engineering
ISSN: 1004-9541 
CHEMICAL INDUSTRY PRESS 
BEIJING 
13 
1 
37-42 
English 
WOS:000227861600007 
The main cause to the deactivation of ZSM-5 catalyst, used for oxidation of benzene to phenol (BTOP) by nitrous oxide, is that the carbon deposition on the catalyst surface blocks the mouth of pores of the catalyst. In the experiments, ZSM-5 catalyst was modified by chemical surface deposition of silicon, and then the effect of modification condition on the catalyst activation was studied. The catalyst samples were characterized by XRF, EPS, XRD, TEM, NZ adsorption at low temperature, pyridine adsorption-infrared technique and etc. All the above results show that the uniform SiO2 membrane can be formed on ZSM-5 crystal surface. The SiO2 membrane covers the acid centers on ZSM-5 surface to inhibit surface coking, to avoid or decrease the possibility of ZSM-5 pore blockage so that the catalyst activity and stability can be improved efficiently. The optimum siliconiting conditions determined by the experiments are as follows: 4% load of silanizing agent, volume (ml)/mass (g) ratio of hexane/ZSM-5=15/1, and 16 h of modification time. Compared with the samples without siliconiting treatment, the samples treated under the above optimum condition can increase the productivity of phenol by 14% for 3 h reaction time and by 41% for 6 h reaction time respectively. 
nitrous oxide; phenol; oxidation of benzene to phenol (BTOP) reaction; coking; deactivation; silanization; SiO2 membrane