The influence of the structural type and of the textural and acid properties of the zeolite on the catalyst selectivity in synthesis of a mixture of liquid hydrocarbons with increased content of isoalkanes from dimethyl ether was examined. The synthesis of liquid hydrocarbons enriched in triptane in the course of gasoline production from CO and H-2 via dimethyl ether in the presence of La-H-Y zeolite was performed for the first time. Excess hydrogen in the system and relatively short contact time of the catalyst with the feed favor an increase in the triptane yield. Additional modification with palladium leads to optimization of the acid properties of the La-H-Y zeolite and, as a consequence, to an increase in the triptane content of the gasoline from 2.0 to 9.4 wt %.

The effect of the method of introduction of zinc cations and the zinc content in a nanocrystalline zeolite of the ZSM-5 type on the physicochemical and catalytic properties of the material in DME conversion to a mixture of liquid synthetic hydrocarbons has been studied. Zinc is introduced into the catalysts both during the zeolite synthesis and the ion exchange (Zn n Al m NZ5 and ZnNZ5, respectively). The use of nanocrystalline Zn n Al m NZ5 zeolites provides the formation of a mixture of liquid hydrocarbons with a high selectivity of no less than 90%; the liquid hydrocarbons contain more than 70% of isoparaffins and a small amount of aromatic compounds. An increase in the zinc loading of the Zn n Al m NZ5 zeolite from 0.9 to ~3% leads to an increase in the methanol content in the aqueous phase of the liquid product, an increase in the selectivity for liquid hydrocarbons, and a slight increase in the concentration of aromatic and unsaturated hydrocarbons in the mixture. In the presence of the ZnNZ5/Al 2 O 3 catalyst with Zn introduced by ion exchange, the methanol content in the aqueous phase and the aromatics content in the liquid hydrocarbon mixture are significantly higher. The Zn n Al m NZ5 nanozeolites are characterized by a more developed external surface, a higher concentration of mesopores, and higher acidity.

Comparative data obtained by studying the synthesis of С5+ hydrocarbons from dimethyl ether (DME) on catalysts using MFI zeolites available from different manufacturers are presented. It has been shown that MFI zeolite samples substantially differ in their acidic properties and structural, morphological, and textural characteristics. The catalysts based on different MFI zeolites also noticeable differ in the yield and chemical composition of С5+ hydrocarbons. By switching from the stand-alone operation of a DME conversion reactor to the joint operation of two reactors for synthesis of oxygenates (DME and/or methanol) from synthesis gas and synthesis of hydrocarbons from oxygenates connected by a single circuit, high selectivity for hydrocarbons of the gasoline fraction is achieved with the catalyst based on the MFI zeolite, for which the bands characteristic of Н3О+ acid sites are observed in diffuse reflectance IR spectra.