The production of methyl-substituted aromatics via novel zeolite atalyst process routes.

摘要

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). It was found that C6DN has the ability to promote the crystallization of ZSM-5 in the absence of sodium ions. 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 ratios between 50 and 200. Indium-type zeolites ZSM-5 and ZSM-48 were also synthesized. However, it was determined by SEM and ammonia-TPD that the method of preparation was not capable of achieving insertion of indium in the framework.;The cracking of normal-hexane was used to determine the acidity of synthesized zeolites. Attainable levels of superactivity of the order of magnitude of ;It was determined that pentanes were absent from the reaction product for the isomerization of isobutane over synthesized ZSM-5 and ZSM-48 zeolites. This suggests that there is not enough space for a bimolecular transition state in the pores of ZSM-5 or ZSM-48.;The cut-off point in the hydrocarbon product distribution for the methanol conversion over synthesized ZSM-5 was found at C;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 conducted 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. In particular, it was possible to produce methyl-substituted aromatic species.