Carbon reaction with oxides

Step one is, oxygen diffusion in the porous system of the particle inwards to the char combustion front and the reaction site, (2) adsorption of oxygen to the active sites on the intraparticle char phase, (3) oxidation reaction with carbon, and (4) desorption of... 

The SR process involves two reactions, the conversion of hydrocarbon with steam to form hydrogen and carbon oxides [reaction (9.1)] and the WGS reaction for the conversion of carbon monoxide into carbon dioxide [reaction (9.2)] ... 

J. L. Gay Lussac and L. J. Thenard 5 showed in 1811 that if many of the metallic oxides be intimately mixed with carbon the reaction with chlorine proceeds more readily than with the oxide alone the metal chloride and carbon monoxide or dioxide are the products of the reaction. M. le Quesneville and F. Wohler used this process for aluminium chloride, chromic chloride, silicon tetrachloride, etc., and C. Baskerville for thorium tetrachloride. 

Coke, deposited on a catalyst, may be removed by one of several reactions oxidation, reaction with water to form carbon monoxide and hydrogen methanation, and the Boudouart reactions. 

The ratio of steam to oxygen (air) in the gasifier controls the peak temperature in the combustion zone. If a nonslagging operation is desired, sufficient steam is added to offset exothermic oxidation reactions with endothermic steam-carbon reactions to stay safely below the ash-fusion temperature. Slagging gasifiers operate at a higher temperature, and ash is removed in a molten state and then quenched in a water bath. 

Hydrogen cyanide is metabolized through several pathways. In the major metabolic pathway (60-80% of absorbed cyanide), cyanide is converted to thiocyanate in a reaction that is catalyzed by rhodanase or 3-mercaptopyruvate sulfur transferase (Baumann et al. 1934 Himwich and Saunders 1948 Wood and Cooley 1956 Singh et al. 1989). Minor pathways include the oxidation of hydrogen cyanide or thiocyanate to carbon dioxide, reaction with cystine to form 2-aminothiazoline-4-carboxylic acid and 2-imnothizolidine-4-carboxylic acid, reaction with hydroxocobalamine to form cyanocobalamin, and conversion of hydrogen cyanide to formic acid, which enters one-carbon metabolism in the body (Wood and Cooley 1956 Boxer and Rickards 1952 Ansell and Lewis 1970 Baumeister et al. 1975). 

The JANAF thermochemical tables deal with the two forward solid carbon oxidation reactions producing CO and CO2. The CO oxidation is a matter of subtraction for the equilibrium constant. 

In contrast to polymerisates, polycondensates can not be depolymerized under inert conditions. Decomposition usually leads to the destruction of the chemical structure and the monomers. The thermal decomposition of PET starts at about 300°C in an inert atmosphere [25]. Between 320 and 380°C the main products are acetaldehyde, terephthalic acid, and carbon oxides under liquefaction conditions. The amounts of benzene, benzoic acid, acetophenone, C1-C4 hydrocarbons, and carbon oxides increase with the temperature. This led to the conclusion that a P-CH hydrogen transfer takes place as shown in Eigure 25.8 [26]. Today the P-CH-hydrogen transfer is replaced as a main reaction in PET degradation by several analytic methods to be described in the following sections. The most important are thermogravimetry (TG) and differential scanning calorimetry (DSC) coupled with mass spectroscopy and infrared spectroscopy. 

Dimethylsulfoxonium methylide. 14,152 15,147 16,146 17,126-127 18,148 19,139 Polyhomologation. The ylide provides the methylene unit in chain extension of triorganoboranes. Besides oxidative workup to generate alkanols, the replacement of the boron atom by a hydroxylated carbon on reaction with dichloromethyl methyl ether gives compounds with trident carbon chains. 

There are mass transfer tasks in the G/L systems, which require special reactor designs. Such tasks include absorption processes, in which strongly diluted gases necessarily participate and the liquid phase consists of liquids which are inmiscible or contain an readily precipitating solid. Examples are oxidation reactions with an ozone-air (3 vol.-% O3) or an ozone-oxygen mixture (6 vol.-% O3), flue gas scrubbing of 6-8 vol.-% CO2 with waste caustic soda, whereupon sodium carbonate is formed and upon exceeding its solubUity precipitates out, etc. 

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