The article describes some variants of mechanisms of nitro compounds reduction, offered by authors in the scientific literature. The focus is on the description of the work of Kazakh and Russian chemists working in the field of catalysis. In most of the works, the classical scheme of the mechanism of the hydrogenation of Haber-Lukashevich nitrobenzene is confirmed and detailed by experimental methods. One of the interesting aspect of the article is description the mechanism of Ya.A. Dorfman which used the orbital theory of catalysis. The orbital approach of the Ya.A. Dorfman mechanism is constructed in the light of modern orbital representations and is valid for the hydrogenation of the nitro group on various catalysts. Among the discussed mechanisms are ideas of Haber, Debus, Jungers, V.P. Shmonina, Lukashevich, M. Geirovsky, Yu. B. Vasilyev, M.V. Klyuev, E.F. Weinstein, E. Gelder, Ya.A. Dorfman and others.
Catalysts on the metal block carriers for decrease exhaust gases of motor transport were synthesized and tested. Stability of the carrier and the active phase of the catalysts to poisons SO 2 and oxygen in the processes of cleaning of exhaust gases was studied. In the presence of 3% oxygen, the catalyst activity was considerably increased, especially for Co+Mn and Ni+Mn, but increase in content of oxygen to 10% reduced effectiveness of catalysts. Nickel-manganese catalyst promoted with 0.1 wt.% Pt was the most stable against oxygen influence. The activity of catalysts based on Pt, Pt+Pd, Pd in presence of SO 2 decreased at low test temperatures, but after calcination at 500°C with air blowing for 2 h activity of Pt catalyst was almost returned and reached 80%. After the tests of the catalysts at the stand on the basis of the diesel generator (5GF-LDE with power of 5 kVA) degree of conversion of CO was 99.6%, hydrocarbons-80.7 %, nitrogen oxides -60-61.9%.
The work aim was preparation of catalysts with various active phase on metal block carriers and test their effectiveness on exhaust gases of the stationary diesel generator at various loadings. The active phase was prepared on the basis of the platinum group metals, oxides of nickel, manganese. The catalyst on the basis of 0.1% of Pt kept the activity during 100 h. test on the diesel generator. The most effective catalyst at all engine operating conditions was the sample containing 5% of nickel oxide and manganese and activated of 0.1% Pt. The catalytic samples on the basis of Ni and Mn promoted by Pd (0.1%, 0.25%) and Pt (0.1%), provide high degree of conversion of CO to CO 2 , C x H y to CO 2 and H 2 O, NO to N 2 .
In present work the paths for obtaining the road oil bitumen are presented from the wastes of coal oil of the Karazhyra field. For the improvement of the quality of obtained bitumen the modification was carried out of elementary sulfur. The processes of modification by elementary sulfur allow to obtain the viscous road oil bitumen of high quality.
The constantly increasing growth in the number of cars is one of the reasons for the deterioration of the ecological situation in cities and large settlements. In Kazakhstan, on a national scale, the share of motor vehicles in total emissions of pollutants into the atmosphere by all technogenic sources reaches on average 40%, in the mass of industrial waste - 2%. The content of toxic substances in the exhaust of diesel and gasoline engines varies and depends on the type of engine and mode of operation, as well as on the quality of the fuel, the composition of the combustible mixture in the engine cylinders, speed and driving conditions, ignition system and fuel control. The number of all toxic components in the exhaust gas exceeds the maximum permissible standards by tens and hundreds of times. One of the most reliable ways to reduce the toxicity of vehicle exhaust gases and remove harmful substances is the complete oxidation of exhaust components using catalytic compositions on metal or ceramic block carriers. The article accumulates data from the scientific literature about toxicity of different components of exhaust gases and catalytic neutralization of vehicle exhaust gases by various scientific schools.
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