A. L. Lapidus

Ethanol and diesel fuel from plant raw materials: A review

Data on various methods for the production of ethanol (bioethanol) and diesel fuel (biodiesel) from plant biomass and on the properties of raw materials in use are presented. Main trends in the development of processes for plant biomass conversion into bioethanol and biodiesel are considered.

Synthesis of liquid fuels from products of biomass gasification

Abstract Liquid hydrocarbons can be successfully produced from the product of air-biomass gasification by Fischer-Tropsch synthesis over cobalt catalysts. The presence of considerable concentrations of carbon dioxide and nitrogen in the reaction feed influences this process: carbon dioxide by reducing the probability of side reactions, and nitrogen by promoting the formation of diesel range hydrocarbons.

Conversion of Synthesis Gas into Alcohols on Supported Cobalt- Molybdenum Sulfide Catalysts Promoted with Potassium

The use of transition metal sulfides as catalysts for the synthesis of alcohols can solve the problem of catalyst resistance to sulfur. Catalysts based on molybdenum sulfide of different compositions (promoted with Co and K) were synthesized with the use of various supports (aluminum oxide, aluminum oxide modified with silicon oxide, Sibunit, and titanium silicate) and tested in the reactions of alcohol synthesis and the hydrofining of a mixture of thiophene with n-1-hexene. The dependence of catalyst activity in the synthesis of alcohols on support pore size was demonstrated. It was found that an increase in the potassium content of the active phase of a catalyst increased its activity in the synthesis of alcohols and decreased it in hydrodesulfurization and hydrogenation reactions. Transmission electron microscopy data made it possible to quantitatively evaluate the effect of a potassium additive on the morphology of the active phase; the hypothesis that potassium was intercalated between the layers of molybdenum sulfide was proposed.

Promotion of cobalt catalysts for the Fischer-Tropsch synthesis with alkali metals

The promotion of supported cobalt catalysts for the synthesis of hydrocarbons from CO and H2 with alkali metals was studied. The catalysts were characterized by X-ray diffraction analysis, oxygen titration, and the temperature-programmed desorption (TPD) of CO. Catalytic tests showed that the introduction of alkaline promoters increases selectivity for higher hydrocarbons, decreases selectivity for methane, and also increases the concentration of olefins in the gasoline fraction of products. The promoting effect depends on the catalyst preparation method. The TPD of CO was used to demonstrate that the greatest amount of CO was adsorbed on the surface of a catalyst promoted with potassium; in this case, the strength of CO binding on this catalyst reached a maximum. The data of the TPD of CO correspond to the highest selectivity of a cobalt-potassium catalyst for the formation of higher hydrocarbons.

Models for the calculation and prediction of the octane and cetane numbers of individual hydrocarbons

Based on an approach to finding structure-property relationships, we constructed models for calculating the octane and cetane numbers of individual hydrocarbons (alkanes and cycloalkanes). The models obtained for octane numbers are superior to well-known analogous models described in the literature in terms of the accuracy and predictive efficiency. This is the first attempt to develop a model of this kind for the cetane number. The results of the calculations of these characteristics for a number of unsynthesized and uncharacterized compounds are given.

Catalytic carbonylation in ionic liquids

Synthesis gas, which is formed upon the gasification of solid fossil fuels, is a source of carbon monoxide—a valuable reagent for chemical industry. In this review, studies performed in the last few years at the Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, on the catalytic carbonylation of olefins, alcohols, and halides in ionic liquids are considered. Catalytic systems containing no phosphine ligands were developed; these systems make it possible to recycle the homogeneous catalyst by the extraction of synthetic products from the reaction mass.

Kinetics and mechanism of the oxidative dehydrogenation of isobutane on cobalt, nickel, and manganese molybdates

The kinetics of oxidative dehydrogenation of isobutane in the presence of atmospheric oxygen on manganese molybdate has been studied. The experiments have been carried out in a circulation flow reactor at 470–530°C. The form of kinetic equations and the mechanism of the formation of isobutene, carbon oxides, and cracking products on manganese molybdate are similar to those found previously for the same reaction on cobalt and nickel molybdates. The highest yields of isobutene and propene (isobutane cracking products) are achieved on Co0.95MoO4. The mechanism of the process has been investigated by the unsteady-state response method. Manganese molybdate contains the largest amount of reactive oxygen, whereas nickel molybdate contains the smallest amount of reactive oxygen. The earlier conclusion that molybdate lattice oxygen and chemisorbed oxygen play the main role in the formation of iso-C4H8 and in deep oxidation processes, respectively, is confirmed.

Kinetics of benzene and toluene hydrogenation on a Pt/TiO2 catalyst

The kinetics and mechanism of benzene and toluene hydrogenation on a Pt/TiO2 catalyst were studied in steady-state and non-steady-state regimes in the presence or absence of strong metal–support interactions (SMSI). It was found that the kinetics and mechanism of the test reactions were independent of SMSI. The observed effect of a decrease in the catalytic activity in the SMSI state was due to structural changes in the active centers of the catalyst and to the presence of strongly bound hydrogen species on the surface; this was also supported by thermal-desorption data.

Kinetics of carbon monoxide methanation on nickel catalysts

The kinetics of CO methanation in excess H2 on CaO- and CeO2-doped nickel catalysts supported on Al2O3 and TiO2 was studied at atmospheric pressure in a temperature range of 180–240°C. It was found that the same rational fractional rate equation corresponding to the reaction taking place at high surface coverages, is valid for all of the catalysts. The activity of nickel catalysts in the methanation reaction and their adsorption capacity with respect to reaction mixture components depend on the nature of the support and dopants.

Influence of the porous structure of the support on the properties of cobalt catalysts for hydrocarbon synthesis from CO and H2

The dependence of the properties of supported cobalt catalysts for hydrocarbon synthesis from CO and H2 on the porous structure of the supports (aluminas and aluminosilicates) is reported. A correlation between the mean Co0 crystallite size and the pore diameter of the support is established. The specific CO conversion rate falls sharply as the size of Co0 particles decreases to 6 nm and below. The methane and C5+ hydrocarbon selectivities as a function of the Co0 crystallite size pass through an extremum.