Isomerization And Oligomerization Of Dicy-clopentadiene Using Al-MCM-41Molecular Sieves

High density fuel can improve the flight range of aircrafts and serve as collant ofpassive thermal protection due to its high density and excellent thermal stability. Inthis thesis, the isomerization and oligomerization of endo-dicyclopentadiene werestudied using Al-MCM-41molecular sieves as catalysts, with the purpose ofsynthezing high density fuel.The catalytic performance of several molecular sieves on the isomerization andoligomerization of endo-Dicyclopentadie were evaluated, and Al-MCM-41showshighest activity for the isomerization. The optimal reaction conditions for commercialAl-MCM-41catalysis is as follows: temperature of140℃, catalyst dosage of15wt%,reactant concentration of25wt%, decahydronaphthalene as solvent, and reaction timeof5h. As a result, the yield and selectivity of exo-DCPD are50.54%and84%,respectively. As to the oligomerization, the main function of Al-MCM-41is toproduce more stereoisomers of TCPD. On the one hand, the exo-DCPD derived fromisomerization could participate in the oligomerization. On the other hand, Al-MCM-41could catalyze the isomerization of TCPD isomers. Ultimately, a two step strategywas desigined to synthesize TCPD.To enhance the catalytic activity of Al–MCM-41, a series of Al-grafted MCM-41were prepared by post-synthesis grafting method, and characterized by ICP, in-situpyridine adsorption, NH₃-TPD, XRD,27Al and²⁹Si MAS NMR, N2adsorption/desorption and TGA. The influences of structure and acidity on thecatalytic performances were discussed. The weak Lewis acid sites are believed to bethe active sites for the endo-to exo-isomerization, meanwhile the moderate onesaccount for the [2+2] cycloaddition of two DCDP molecules. Al-MCM-41with Si/Alratio of8is most active for isomerization, and the yield of exo-DCPD increases42%compare with the commercialAl-MCM-41.Hierarchical ZSM-5was prepared by alkali-treatment. Introducing mesostructure into ZSM-5can significantly increase the activity on the isomerization andoligomerization. Specifically, the hierarchical ZSM-5shows excellent activity onDiels-Alder oligomerization.