N. V. Kolesnichenko

Manufacturing of lower olefins from natural gas through methanol and its derivatives (review)

State-of-the-art processes for the manufacturing of lower olefins (mainly ethylene and propylene) from natural gas through methanol, dimethyl ether, and ethanol are surveyed. The processes involving the synthesis of dimethyl ether via the dehydration of methanol and ethanol production via methanol homologation are discussed.

Synthesis of lower olefins from dimethyl ether in the presence of zeolite catalysts modified with rhodium compounds

The catalytic properties of zeolite catalysts modified with rhodium compounds in the synthesis of olefins from dimethyl ether (DME) and methanol (MeOH) have been studied. The optimum concentration of rhodium in the composition of a zeolite catalyst has been determined. It has been shown that one of the possible precursors of ethylene in the conversion of DME is ethanol, which, under reaction conditions, can be formed through both the DME isomerization and methanol homologation stages.

Glycerol carboxylation to glycerol carbonate in the presence of rhodium complexes with phosphine ligands

The carboxylation of glycerol to glycerol carbonate in the presence of rhodium complexes with phosphine ligands has been studied. It has been found that rhodium complexes are active in the presence of a quaternary or inorganic salt and mediate this reaction with 100% selectivity. The most effective catalyst has been obtained by promoting the {RhCl3 + PPh3} system with potassium iodide. The reaction has been run in a reducing environment in a methanol solution at a temperature of 140°C and a pressure of 50 atm (40 atm of CO2 and 10 atm of H2).

Study of magnesium-containing zeolite catalysts for the synthesis of lower olefins from dimethyl ether

The catalytic properties of magnesium-containing zeolite catalysts in the synthesis of olefins from dimethyl ether (DME) were studied. The optimal concentrations of magnesium in the zeolite catalyst were found, and a procedure for its introduction was developed. The effect of the operation conditions of DME conversion into lower olefins on the catalyst activity and selectivity was studied. The stability of the catalytic properties of the synthesized catalyst after oxidative regeneration was examined.

Conversion of dimethyl ether into lower olefins on a La-Zr-HZSM-5/Al2O3 zeolite catalyst

The catalytic properties of La-Zr-HZSM-5/Al2O3 in the synthesis of olefins from dimethyl ether (DME) were studied. It was shown by the method of temperature-programmed ammonia desorption that acid sites of medium strength are responsible for the high catalyst selectivity for lower olefins. It was found that the preliminary high-temperature treatment of zeolite or the replacement of nitrogen with steam increased not only the selectivity of the catalyst for lower olefins, but also its activity and stability. The effect of the operating parameters of the DME conversion into the lower olefins and the dependence of the catalyst activity on the number of regenerations were studied.

Catalytic conversion of rape oil into alkane-aromatic fraction in the presence of Pd-Zn/MFI

Results on the conversion of rape oil into the alkane-aromatic fraction in the presence of a prototype of a MFI-based industrial catalyst (Si/Al = 30) promoted with 0.6 wt % Pd and 1 wt % Zn are presented. It has been shown that an increase in the process temperature from 360 to 420°C leads to a significant increase in the yield of aromatic compounds, and an increase in the substrate space velocity leads to a three-fold increase in the yield of C4–C6 alkanes of primarily the iso-branched structure. The genesis of active Pd and Zn clusters is discussed on the basis of X-ray data.

Conversion of dimethyl ether into C2-C4 olefins on zeolite catalysts

The effect of the nature of the metal introduced into HZSM-5 on the properties of the catalysts for the synthesis of olefins from dimethyl ether was studied. By means of the ammonia temperature-programmed desorption technique, it was shown that a decrease in the total amount of acid sites increases the selectivity for lower olefins. As the ratio of the medium to strong acid sites increases, the yield of olefins increases. The effect of the nature of gaseous additives in the feedstock on the selectivity for lower olefins was studied at T = 340°C, p = 0.1 MPa, and ν0 = 2000 h−1.

Slurry technology in methanol synthesis (Review)

The review summarizes data published in the scientific and patent literature on the synthesis of methanol in slurry reactors using finely divided heterogeneous catalysts suspended in liquids. Variants of methyl alcohol production in inert liquid media and with the use of an active liquid phase have been considered. The advantages of the slurry technology over the conventional gas-phase process of methanol production are discussed.

Stability of La-Zr-HZSM-5/Al2O3 zeolite catalysts in the conversion of dimethyl ether to lower olefins

The stability of the zeolite component and a La-Zr-HZSM-5/Al2O3 catalyst synthesized on its basis in the synthesis of lower olefins from dimethyl ether (DME) has been studied. It has been shown that both the zeolite component and the catalyst based on it exhibit highly stable catalytic properties. A high-temperature treatment of the zeolite component and the finished La-Zr-HZSM-5/Al2O3 catalyst with air and steam, respectively, leads to a significant increase in the catalyst selectivity for olefins, particularly propylene, while the activity in the DME conversion slightly decreases as the steaming temperature increases from 500 to 750°C.

The effect of steam on the conversion of dimethyl ether to lower olefins and methanol over zeolite catalysts

The effect of steam on the catalytic properties of La-Zr-HZSM-5/Al2O3 and Mg-HZSM-5/Al2O3 in the synthesis of olefins from dimethyl ether (DME) has been studied. It has been found that the presence of steam has a significant effect on the ethylene-to-propylene ratio regardless of the nature of the modifier; the formation of methanol was observed only on Mg-HZSM-5/Al2O3. In situ high-temperature diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy has revealed that the formation of methanol on Mg-HZSM-5/Al2O3 occurs owing to the formation of methoxy groups on the surface of the zeolite during the interaction between DME and basic sites. The resulting methoxy groups can be easily converted to methanol in the presence of steam.