ZSM-11 is a high silica zeolite, belonging to the pentasil type zeolites.zsm-11 zeolite It has a cubic crystal structure with a strong network of channels.zsm-11 zeolite It is an excellent shape-selective adsorbent and has been used in toluene-methanol alkylation, xylene isomerization, and toluene disproportionation reactions. It is also known as a good catalyst for paraffin cracking and aromatics alkylation.
The zeolite is prepared by hydrothermal treatment.zsm-11 zeolite Cerium ions are incorporated into the zeolite by the ion exchange method. The resulting cerium modified ZSM-11 has superior catalytic properties in the one-pot synthesis of 4H-pyran derivatives by cyclocondensation of aromatic aldehydes, malononitrile and ethyl acetoacetate. The modified zeolite was characterized by powder-X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. It is highly active in the toluene-methanol alkylation reaction, exhibiting a higher selectivity for the conversion of benzyl alcohol into 4-H-pyran-4-one and higher catalyst lifetime than the unmodified zeolite.
A crystalline form of the zeolite is obtained after ion exchange with NH4NO3.zsm-11 zeolite It is calcined at 1000deg F for 2 hours, contacted with an ammonium chloride solution to effect ammonium exchange for residual sodium and dried. The zeolite is sized to 60/80 mesh. It is contacted with a five-component feedstock comprising n-hexane, 3-methylpentane, 2,3-dimethylbutane, benzene and toluene under contact conditions of 800deg F, 200psig, hydrogen/hydrocarbon mole ratio of 3, and weight hourly space velocity (WHSV) of 3 hr-1. The zeolite is observed to exhibit simultaneous paraffin cracking, aromatics alkylation and interconversion activity in the feedstock.
To determine the effect of size and composition on the catalytic performance in methanol conversion, L-ZSM-11, M-ZSM-11 and S-ZSM-11 were synthesized with different pore volume and surface area.zsm-11 zeolite Their catalytic performance in methanol conversion was compared by GC-MS, 13C MAS NMR, transient 12C/13C methanol switching experiment and co-feeding experiments involving isotope labeling of 12C-propene, 12C-n-butene and 12C-benzene. The results showed that the smaller L-ZSM-11 zeolite has a better pore structure for enhancing the alkene-based cycle in methanol conversion, but its dehydrogenation ability suffers from this improvement.
The zeolite prepared in accordance with the present invention may be used in organic compound, i.zsm-11 zeolite e., hydrocarbon compound, conversion processes, such as alkylation of olefins with aromatics, transalkylation of low molecular weight paraffins and olefins, aromatization of normally gaseous or liquid low molecular weight paraffins and/or olefins, isomerization of aromatics, paraffins and olefins, disproportionation of aromatics, and the like. In addition to the use of the zeolite in such conversion reactions, it may be employed in intimate combination with a univalent or multivalent organic cation or an alkali metal form of the hydrogenating element, such as tungsten, vanadium, molybdenum, rhenium, nickel, cobalt, chromium and manganese. It is also useful in conjunction with noble metal catalysts, such as platinum or palladium. It can also be used in association with other materials such as metal oxides. The zeolite thus prepared can be admixed with a solid support or deposited thereon, and used in an organic compound or hydrocarbon compound conversion process in which the zeolite is exposed to an acid such as sulfuric or nitric acids.
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