Compound decomposition

While the rate of azo-compound decomposition shows only a small dependence on solvent viscosity, the amount of cage reaction (and hence f) varies dramatically with the viscosity of the reaction medium and hence with factors that determine the viscosity (conversion, temperature, solvent, etc.) 1... 

Hofer et al. [671] observed that the decompositions of Ni3C and Co2C (the iron compounds melt) obeyed the zero-order equation for 0.3 < a < 0.9 (596-628 K and E = 255 kJ mole-1) and 0.2 < a < 0.75 (573-623 K and E = 227 kJ mole-1), respectively. The magnitudes of the rate coefficients for the two reactions were closely similar but the nickel compound exhibited a long induction period and an acceleratory process which was not characteristic of the reaction of the cobalt compound. Decomposition mechanisms were not discussed. 

Volume 4 Volume 5 Decomposition of Inorganic and Organometallic Compounds Decomposition and Isomerisation of Organic Compounds Section 3. INORGANIC REACTIONS... 

This section is mainly concerned with reactions that involve nitric acid, of which behaviour is even more difficult to interpret. Indeed, nitric acid is not only a strong oxidant but also a nitrating agent,especially when it is combined with sulphuric acid. With nitrated derivatives it can also be destabilising due to its acidic property, which faciiitates the compounds decomposition. Since most reactions give rise to a detonation it is even more difficult to interpret the accidents. 

These results can be interpreted in terms of competition between recombination of the diradical intermediate and conformational equilibration, which would destroy the stereochemical relationships present in the azo compound. The main synthetic application of azo compound decomposition is in the synthesis of cyclopropanes and other strained-ring systems. Some of the required azo compounds can be made by 1,3-dipolar cycloadditions of diazo compounds (see Section 6.2). 

Carbenes from Diazo Compounds. Decomposition of diazo compounds to form carbenes is a quite general reaction that is applicable to diazomethane and other diazoalkanes, diazoalkenes, and diazo compounds with aryl and acyl substituents. The main restrictions on this method are the limitations on synthesis and limited stability of the diazo compounds. The smaller diazoalkanes are toxic and potentially explosive, and they are usually prepared immediately before use. The most general synthetic routes involve base-catalyzed decomposition of V-nitroso derivatives of amides, ureas, or sulfonamides, as illustrated by several reactions used for the preparation of diazomethane. 

Thermogravimetry (TG) is a measure of the thermally induced weight loss of a material as a function of the applied temperature [45]. Thermogravimetric analysis is restricted to studies that involve either a mass gain or loss, and it is most commonly used to study desolvation processes and compound decomposition. The major use of TG analysis is in the quantitative determination of the total volatile content of a solid. When a solid can decompose by means of several... 

When a solid is capable of decomposing by means of several discrete, sequential reactions, the magnitude of each step can be separately evaluated. Thermogravimetric analysis of compound decomposition can also be used to compare the stability of similar compounds. The higher the decomposition temperature of a given compound, the more positive would be the DG value and the greater would be its stability. 

Two mechanisms of azo-compound decomposition were discussed intensively in the literature concerted decomposition with simultaneous dissociation of two C—N bonds... 

Decomposition The breakdown of a chemical or substance into different parts or simpler compounds. Decomposition can occur due to heat, chemical reaction, decay, etc. 

Animals and plants, especially roots and microorganisms, provide biochemical, bioorganic, and organic compounds to soil. These may be in the form of cellular components, such as cell walls, membranes, enzymes, and complex and simple organic compounds. Decomposition of complex cellular material and... 

The availability of contaminating organic compounds is also often described by their partition coefficient between water and a solvent, most often octanol. The more soluble a compound is in water, the more available for decomposition. By describing the solubility ratio, the relative rates of organic compound decomposition in soil can be estimated [3],... 

The metal-catalyzed decomposition of diazo compounds has broad applications in organic synthesis [1-8]. Transient metal carbenoids provide important reactive intermediates that are capable of a wide variety of useful transformations, in which the catalyst dramatically influences the product distribution [5]. Indeed, the whole field of diazo compound decomposition was revolutionized in the early 1970s with the discovery that dirhodium tetracarboxylates 1 are effective catalysts for this process [9]. Many of the reactions that were previously low-yielding using conventional copper catalysts were found to proceed with unparalleled efficiency using this particular rhodium catalysis. The field has progressed extensively and there are some excellent reviews describing the breadth of this chemistry [5, 7, 10-17]. 

Cohalt and nitrogen form three nitrides, CoiNi. Co N. and CoN, products of nu tal/ammonia reaction and compound decomposition. All are gray-black or black in color. 

Azo compound decomposition is much less susceptible to polar substituent effects, and so probably has less charge separation in the transition state,75 but is more sensitive to geometrical restrictions. Bridgehead azo compounds decompose at rates lower than expected on the basis of their tertiary nature, whereas peresters are much less strongly affected.70 The difference can be rationalized by the proposal that the transition state comes farther along the reaction coordinate in azo decomposition, so that the nonplanarity forced on the incipient radical by the ring system is felt more strongly there. 

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