| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
A large quantity of styrene monomer was produced in the world from ethylene and benzene to give ethylbenzene followed by dehydrogenation. 3 step processes were required in the current technology. This project was planned to develop a simple and energy saving chemical process. For this, ethane was used for the alkylation of benzene using various acid catalysts such as zeolite. However, yield of ethylbenzene was very small. Considering that formation of ethyl cation from ethane is difficult, loading of several metal species which are capable of dehydrogenation of alkane was examined.
Alkylation of benzene with ethane was carried out using various zeolite catalyst at temperature ranges of 400 to 550℃. Loading of platinum onto zeolite enhanced yield of ethylbenzene greatly. Among zeolite tested, H-ZSM5, H-AlMCM41, and H-MCM22 showed catalytic activities. However, mordenite did not give ethylbenzene. Moderate acid strength distribution is the key factor of zeolite catalyst. Optimum catalyst and conditions for this reaction is as follows :
Platinum-loaded H-ZSM5 catalyst containing 6.8 wt % Pt, at the reaction temperature of 500℃, afforded ethylbenzene and styrene formation rates of 14.2 and 0.8 mmol h^<-1>・g^<-1> of catalyst, respectively (benzene-based yields 7.3 and 0.4 %). In the alkylation of benzene with ethane over platinum-loaded H-ZSM5, ethene would be initially formed from ethane over the metallic platinum. Then the alkylation would proceed over the acid sites of H-ZSM5.
Dehydrogenation of ethylbenzene was investigated, and found that magnesium oxide-loaded vanadium oxide exhibited very high activity in the presence of carbon dioxide. Carbon dioxide promoted redox cycle of vanadium oxide during dehydrogenation reaction. Where lattice oxygen of vanadium oxide was gradually lost during dehydrogenation, then carbon dioxide reoxidized low valent vanadium oxide to higher valency state.
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