Volume 2, Issue 1

The modeling of ethylbenzene dehydrogenation in a catalytic membrane reactor has been carried out for porous membrane by means of two-dimensional, non-isothermal stationary mathematical model. A mathematical model of the catalytic membrane reactor was applied, in order to study the effects of transport properties of the porous membrane on process performance. The performed modeling of the heat and mass transfer processes within the porous membrane, allowed us to estimate the efficiency of its use in membrane reactors, in comparison with a dense membrane (with additional oxidation of the hydrogen in shell side). The use of a porous ceramic membrane was found to cause an increase of the ethylbenzene conversion at 600°C, up to 93 %, while the conversion in the case of conventional reactor was 67%. In this work, we defined the key parameter values of porous membrane (pore diameter and thickness) for ethylbenzene dehydrogenation in catalytic membrane reactor, at which the highest conversion of ethylbenzene and styrene selectivity can be reached.

For two series of catalysts based on praseodymium ferrite, their structural and redox properties as well as performance in ethanol steam reforming have been studied. The first series was PrFe 1-x Ni(Co) x O 3 (x=0.3-0.4) perovskites prepared by modified Pechini route, and the second one was 5%wt.Ni(Co)/PrFeO 3 of different dispersion prepared by impregnation of PrFeO 3 , including samples modified by 5%wt. Mo. At temperatures above 700°C, for all catalysts, the main products were hydrogen and CO. At temperatures below 700°C, initial ethanol conversion and hydrogen yield were higher for supported catalysts as compared with ones derived from Ni(Co)-containing perovskites. While Ni-based catalysts derived from perovskite were more active as compared with Co-based samples, Co-supported PrFeO3 perovskite has shown a higher initial activity as compared with Ni-supported one. The long-term tests in the realistic feed and TEM studies of spent catalysts revealed that perovskite-derived catalysts have a higher coking stability than perovskite-supported ones due to formation of highly dispersed Ni-Fe alloy particles strongly interacting with disordered perovskite–like matrix. The method of Mo supporting only slightly affects the initial activity of Ni/PrFeO 3 –based catalysts but noticeably modifies their coking stability: 5%Mo/5%Ni/PrFeO 3 catalyst prepared by successive impregnation possesses the highest stability among perovskite-supported catalysts.

The analysis of the chemical nature of wood waste processing by fungus and bacteria was the starting point for innovative production of a new, relatively simple, colloidal catalytic system based on iron (III) oxides, combined with environmentally friendly oxidants - hydrogen peroxide and/or atmospheric oxygen. Colloidal iron(III) oxides, obtained by hydrolysis of Fe(III) salts in water in the presence of surfactants, catalyze the oxidative destruction of lignocellulosic biomass under atmospheric pressure, at a mild temperature range of 60-70 o C, under the influence of H 2 O 2 and O 2 . The oxidative destruction of biomass (wood sawdust, peat, olive press cake, oat straw) results in formation of light organic acids, esters and other low molecular oxidation products derived from lignin, hemicelluloses, cellulose, lipoproteins and sugars; the solid product constitutes mainly of cellulose and its derivatives. The yield of solid residue depends on biomass nature, reagents concentration ratio (biomass, catalyst, hydrogen peroxide), and oxidation process duration. Water solution of organic acids and esters can be used in agriculture for fodder processing.

The process of obtaining low molecular weight C 2 -C 4 olefins, as a result of thermal and thermocatalytic conversion of cottonseed oil was investigated. The total content of olefin gases obtained by the thermal conversion of cottonseed oil in the temperature range of 700-800°C is 57.2-65.2 wt. %. Thermocatalytic conversion of cottonseed oil on the natural halloysite nanotubes as a catalyst in the temperature range of 500-800 ° provides the total content of olefins 10.8-69.2 wt. with increased yield of propylene and butenes.

The activity and stability of niobia supported on silica catalyst have been tested in continuous micro-pilot reactors, for biodiesel production starting from acid vegetable oils. A catalyst was prepared by the impregnation of silica pellets with a loading of 12% of Nb and was extensively characterized. The activity of this catalyst in both esterification and transesterification was tested in a continuous micro-pilot laboratory plant in which acid oil was fed (FFA 10% w/w) at a temperature of 220°C and at a pressure of 60 bar. The niobia based catalyst resulted in a very active catalyst in both esterification (FFA conversion = 95-90%) and transesterification reactions (FAME yield = 80-90%), and the activity remained quite constant for more than 100 h on stream. Notwithstanding this stability, a non-negligible leaching phenomena has been detected, in the case of long-time continuous runs, as the Nb concentration on the spent catalyst resulted lower than that on the fresh one. The obtained result confirms that the leaching of the active specie is one of the most strong problem in heterogeneous catalysis for biodiesel production.

The problems of synthesis of Ni-Mo, Ni-Mo Co and Co-Mo oxide catalysts for hydrodesulfurization and hydrogenation of aromatic hydrocarbons in the composition of kerosene, diesel and oil fractions are discussed. The influence of spent adsorbent and kaolin as the additives on the physical-chemical and catalytic properties of bimetallic and trimetallic catalysts is established.

The main aspects of the cathode materials morphology for Intermediate Temperature Solid Oxide Fuel Cells (IT SOFC) are considered in this paper. The approaches for estimation of their basic properties, e.g. oxygen mobility and surface reactivity, are described and the results of different techniques (e.g. weight and conductivity relaxation, oxygen isotope exchange) application for studies of powders and dense ceramic materials are compared. The Ruddlesden-Popper type phases (e.g. Pr2NiO4) provide enhanced oxygen mobility due to cooperative mechanism of oxygen interstitial migration. For perovskites, the oxygen mobility is increased by doping, which generates oxygen vacancies or decreases metal-oxygen bond strength. Nonadditive increasing of the oxygen diffusion coefficients found that for perovskite-fluorite nanocomposites, it can be explained by the fast oxygen migration along perovskitefluorite interfaces. Functionally graded nanocomposite cathodes provide the highest power density, the lowest area specific polarization resistance, and the best stability to degradation caused by the surface layer carbonization/ hydroxylation, thus being the most promising for thin film IT SOFC design.

Production of hydrogen, being an environmentally friendly energy source, has gained a lot of attention in the recent years. In this article, iron-based catalysts, with different active metal loadings, supported over magnesia and titania are investigated for hydrogen production via catalytic decomposition of methane. The catalytic activity and stability results revealed that magnesia supported catalysts performed better than titania supported catalysts. Hydrogen reduction temperature of 500°C was obtained suitable for catalyst activation. For magnesia supported catalysts, only higher loadings i.e., 30% and 40% Fe-Mg catalysts showed reasonable activity, while all titania supported catalysts presented less activity as well as deactivation. Among all the catalysts, 30% Fe/MgO catalyst displayed better activity. The formation of carbon nanofibers was evidenced from morphological analysis. FESEM and TEM images showed the generation of nonuniform carbon nanofibers with broader diameter. The catalysts were characterized using different techniques such as BET, H2-TPR, O2-TPO, XRD, TGA, FESEM and TEM.

In this paper, we have shown modification of high-silicon zeolite ZSM-5 by zirconium, and the results of ethanol conversion on this catalyst. Effect of process parameters on the selectivity of ethanol dehydration products was analyzed. In addition, a mechanism of aromatic hydrocarbons formation including reactions of dehydrogenation, dehydrocyclization and alkylation of intermediates was discussed. It was found that with increasing temperature a selectivity decreased for reactions of isomerization and increased selectivity for aromatic products and products of cracking reactions. The data also confirms that hexene-1 is an intermediate in the conversion process of ethanol and the catalyst system with 1% Zr-ZSM-5 has a bi-functionality. Catalytic properties of the system in the conversion of hydrocarbons are determined by the presence on their surface of both Broensted and Lewis acid sites.

This work is focused on the characterization of a novel vanadium pentoxide catalysts on a glass-fiber support. The catalyst support consists of a non-porous glass-fiber fabric covered with an additional external surface layer of porous secondary support of SiO 2 . The vanadia active component is synthesized from vanadyl oxalate precursor by means of an impulse surface thermo-synthesis method. Such catalysts demonstrate high activity and appropriate selectivity in the reaction of H2S oxidation by oxygen into sulfur in the practically important temperature range below 200°C. According to the characterization data, the freshly prepared vanadia catalyst partially consists of mostly the amorphous and badly ordered vanadia with some part of the wellcrystallized V 2 O5 phase. Under the reaction conditions the main part of vanadia in the catalyst remains in the amorphous V 2 O 5 form, while the less part becomes reduces into of VO 2 and other vanadium oxides (such as VO, V 2 O 3 V 3 O 7 and V 4 O 9 ). Most probably, the crystallized V 2 O 5 in course of reaction is responsible for the deep oxidation of hydrogen sulphide into SO 2 , while the lower vanadium oxides promote the selective H2S oxidation into elemental sulfur.

In this paper, theoxidation process of 2 -methylnaphthalene to vitamin K3, using a gold catalyst systems will be discussed. This catalysis process is based on the hypercrosslinked polystyrene, synthesized by the impregnation with solutions of precursors − HAuCl4·2H2O and Ph3PAuCl. The use of gold catalyst system, which has been synthesized using Ph3PAuCl, allows to obtain the main product − 2-methyl-1,4-naphthoquinone − with 72% yield.

Several described in literature crosslinking methods to obtain heterocyclic moieties were discussed in this review. Selected important properties of polyamides and their synthesis reactions were briefly presented. The heterocyclic moieties displayed a wide range of applications in medicine and industry. New heterocyclic derivatives obtained by linking heterocyclic moiety to amic acids and imides found diverse applications: as surfactants, antimicrobial agents, or corrosion inhibitors. The present article describes the state-of-the art synthesis methods of the heterocyclic compounds and their application.