Yu. N. Kochkin

FEATURES OF FUNCTIONALIZATION OF MCM-41 SILICA MESOPOROUS MOLECULAR SIEVES DURING THEIR TEMPLATE SYNTHESIS

We have shown that functionalization of MCM-41 mesoporous molecular sieves during their template synthesis using the effect of solubilization of organic hydrophobic co-condensing compounds makes it possible to obtain highly ordered mesoporous molecular sieves, with concentrations of vinyl or allyl groups covalently bonded to the surface of the silica matrix of about 3.5 mmol/g, which after sulfonation have acidic properties and exhibit catalytic activity in the process of ethyl tert-butyl ether synthesis.

Effect of the Acidity of Ca,H-Bea Zeolites on Their Catalytic Characteristics in the Dimethyl Ether Production from Methanol

It was shown that Ca,H-BEA zeolites are active and highly selective catalysts for the dehydration of methanol. It was established that the catalytic activity of the zeolites in the synthesis of diethyl ether is determined by the ratio of the concentrations of weak and medium acid sites. The highest productivity is given by zeolites with a ratio of weak and medium acid sites close to 1.5.

Effect of the Component Ratio in ZrO2-SiO2 Catalysts on the Selectivity of Dimethyl Carbonate Formation from Methanol and Carbon Dioxide

The catalytic activity of ZrO2-SiO2 systems in the gas-phase carboxylation of methanol was studied. The formation of dimethyl carbonate proceeds on the catalysts with predominantly strong base sites. The concentration and strength of these sites is a function of the phase composition of the catalysts.

Adsorption—Desorption Dynamics of Alcohols on H-Beta and H-CMK Zeolites Nanocrystallites Studied by Quartz Crystal Microbalance Method

The quartz crystal microbalance (QCM) method was used to study the adsorption–desorption dynamics of alcohols on the zeolite nanocrystallites (diameter, 200 nm). The mass transfer of C1–C4 alcohols on zeolites H-Beta and H-CMK nanocrystallites in the pulse and steady-flow modes at 100 °C and p/ps < 0.04 was studied with the QCM method. Experimental results show that the adsorption–desorption dynamics of various alcohols on the nanocrystallites is governed by diffusion in micropores, which is characterized by effective diffusion coefficients Defmicro = 10−13 to 10−15 cm2 s−1. Slow mass transfer of alcohols in the micropores of zeolites indicates natural limitations on the rate of the acid–base heterogeneously catalytic reactions over these solids.

Effect of Spectrum of Acidity of Zeolites of Various Structural Types on Their Catalytic Characteristics in the Synthesis of Ethyl tert-Butyl Ether

The catalytic properties of zeolites of various structural types in the liquid phase synthesis of ethyl tert-butyl ether from isobutylene and ethanol have been studied. The activity and selectivity of the catalysts depend on the concentration and strength of the acid centers. A possible mechanism for the synthesis of ethyl tert-butyl ether is proposed, suggesting that isobutylene and ethanol are activated on the weak and strong acid centers respectively.

Catalytic Properties of Various Types of Sulfonated Cation-Exchange Resins in the Synthesis of Isopropyl Tert-Butyl Ether

The acidic and catalytic characteristics of various types of sulfonated cation-exchange resins, differing in the location of the active phase, in the synthesis of isopropyl tert-butyl ether (IPTBE) were studied. It was established that a sulfonated cation-exchange resin on a wide-pore silica gel support has the highest selectivity with respect to IPTBE (100%). It was shown that mineral–organic sulfonated cation-exchange resins have higher activity than bulk sulfonated cation-exchange resins due to the accessibility of their acid centers for the reagents.

Effect of the Morphology of Sulfo Cation Exchangers on their Catalytic Properties in the Preparation of Ethyl tert-Butyl Ether

It was shown that the morphology of sulfo cationic exchange catalysts described by fractal geometry determines their characteristics in the heterogeneous catalytic synthesis of ethyl tert-butyl ether. It was established that catalysts with partial coverage of the support by the sulfo cation exchanger have higher selectivity and greater productivity in the active phase than catalysts with more than monolayer coverage.

Effect of crystallinity in HZSM-5-amorphous alumosilica systems on their catalytic properties in the synthesis of dimethoxymethane

Granulated catalysts with 3–5% H-ZSM-5 phase were obtained from a highly dispersed alumosilica and were used for the synthesis of dimethoxymethane (DMM) from methanol and formaldehyde. The activity of these catalysts is greater than the activity of pure zeolite. A linear correlation was found between the yield of DMM and the content of Brönsted acid sites in the catalysts.

Effect of Acid Site Localization in Sulfonic Resin Amberlyst 15 on its Catalytic Properties in Ethyl tert-butyl Ether Synthesis

The role of the localization of acid sites in macroporous sulfonic resin Amberlyst 15 in the synthesis of ethyl tert-butyl ether was investigated. By partial blockage of the acid sites by Na+ cations it was established that internal acid sites are primarily active in the reaction while a side reaction with the formation of tert-butanol takes place at the external acid sites.

Etherification of Ethanol and iso -Propanol with iso -Butylene Over Sulfonic Resin Catalysts of Various Morphology

It was established that the “turnover frequency” of the etherification reactions of ethanol and iso-propanol with iso-butylene depends on the morphology of the sulfonic resin catalysts which determines the accessibility of the acid sites to the reagents. It was found that the morphology of the sulfonic resins has a stronger effect than ethanol on their activity in the etherification of iso-propanol. With improved accessibility of the acid site the predominant factors influencing the formation rate of the ethers are the basicity, polarity, and size of the reagent molecules.