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Production of methyl-substituted aromatics via novel zeolite catalyst process routes

Thesis/Dissertation ·
OSTI ID:5536073

Shape selective zeolites with structures related to zeolites ZSM-5 and ZSM-48 were synthesized, characterized and evaluated for potential application to the production of methyl-substituted aromatic hydrocarbons whose hydrogenated analogs are in the aviation turbine fuel boiling range. Zeolite ZSM-5 with high crystallinity could be synthesized in the presence of organic bases such as 1,6-hexanediamine (C6DN) and tetrapropylammonium bromide (TPABr). Crystalline ZSM-48 could be synthesized only at initial molar silica-to-alumina ratios greater than 200. A non-intergrowth mixture of ZSM-5 and ZSM-48 was obtained at silica-to-alumina rations between 50 and 200. The cracking of normal-hexane was used to determine the acidity of synthesized zeolites. It was determined that pentanes were absent from the reaction product for the isomerization of isobutane over synthesized ZSM-5 and SZM-48 zeolites. The cut-off point in the hydrocarbon product distribution for the methanol conversion over synthesized ZSM-5 was found at C{sub 10} aromatics. A similar trend was observed with ZSM-48; however, aromatic selectivity was lower. A study of the catalytic conversion of methanol and the selectivity of the individual catalysts and of various combinations and sequences of the catalysts was conduced in a high pressure fixed bed reactor system. ZSM-48 was found to be highly selective for olefins at moderate opening conditions when converting methanol. The olefins produced from the conversion of methanol over ZSM-48 were converted to higher boiling hydrocarbons over ZSM-5 in a second reactor operated at 7 atm.

Research Organization:
Utah Univ., Salt Lake City, UT (USA)
OSTI ID:
5536073
Country of Publication:
United States
Language:
English