Activation of decomposition

Triethanolamine and urea are very strong activators of decomposition of OBSH. The activator reduces the temperature at which optimum gas generation occurs. DPG is also a strong activator of decomposition of OBSH. Stearic acid and calcium oxide are also moderate activators of OBSH. 

Instead of introducing substituent groups into a molecule we may dissolve a reactant in a solvent and the energy of activation of decomposition of the complex reactant-solvent will vary in a similar manner as we alter the solvent as exemplified by the data of von Halban (Zeit. Phys. Ohem. lxxvii. 129, 1909) on the decomposition of triethylsulphine bromide, the energies of activation being calculated without correction for the possible alterations with the temperature of the concentration of the complex undergoing reaction. 

Any discussion of the energies of activation of decomposition of the paraffin components of feeds is complicated by the complex mechanisms of these reactions. In every case, the decomposition reaction is highly product-inhibited, so that, at any reaction temperature, calculated first order rate constants fall off rapidly with time. The inhibition is so severe, that it is necessary to assume kinetic orders far above second to fit the decomposition-time curves (if one can fit them with any simple order at all). An example, from some work by K. D. Williamson (2) is shown in Figure 1. As a result, if we compare rates at different temperatures at constant residence time we calculate relatively low activation energies (of the order of 45,000 cal/Mol) (3). This is because at the higher conversions of the higher temperatures, product inhibition is greater than at the lower temperatures. 

The molecule decomposes by elimination of CF, which should occur with equal probabilities from each ring when energy is randomized. However, at pressures in excess of 100 Torr there is a measurable increase in the fraction of decomposition in the ring that was initially excited. From an analysis of the relative product yield versus pressure, it was deduced that energy flows between the two cyclopropyl rings with a rate of only 3x10 s In a related set of experiments Rabinovitch et al [116] studied the series of chemically activated fliioroalkyl cyclopropanes ... 

Nitrocellulose is among the least stable of common explosives. At 125°C it decomposes autocatalyticaHy to CO, CO2, H2O, N2, and NO, primarily as a result of hydrolysis of the ester and intermolecular oxidation of the anhydroglucose rings. At 50°C the rate of decomposition of purified nitrocellulose is about 4.5 x 10 %/h, increasing by a factor of about 3.5 for each 10°C rise in temperature. Many values have been reported for the activation energy, E, and Arrhenius frequency factor, Z, of nitrocellulose. Typical values foiE and Z are 205 kj/mol (49 kcal/mol) and 10.21, respectively. The addition of... 

Studies on the kinetics of formation of S2F2Q and reviews of appHcable Hterature have been reported (124—126). Other work has concentrated on the use of cell culture evaluation methods for assessing cytotoxic activity of SF decomposition products (127,128). Several laboratories seek to provide methods for accurately determining S2F2Q in operating electrical units (57). 

Depending on the peroxide class, the rates of decomposition of organic peroxides can be enhanced by specific promoters or activators, which significantly decrease the energy necessary to break the oxygen—oxygen bond. Such accelerated decompositions occur well below the peroxides normal appHcation temperatures and usually result in generation of only one usehil radical, instead of two. An example is the decomposition of hydroperoxides with multivalent metals (M), commonly iron, cobalt, or vanadium ... 

Alkyl hydroperoxides can be Hquids or soHds. Those having low molecular weight are soluble in water and are explosive in the pure state. As the molecular weight increases, ie, as the active oxygen content is reduced, water solubiUty and the violence of decomposition decrease. Alkyl hydroperoxides are stronger acids than the corresponding alcohols and have acidities similar to those of phenols, Alkyl hydroperoxides can be purified through their alkali metal salts (28). 

Conventional triorganophosphite ligands, such as triphenylphosphite, form highly active hydroformylation catalysts (95—99) however, they suffer from poor durabiUty because of decomposition. Diorganophosphite-modified rhodium catalysts (94,100,101), have overcome this stabiUty deficiency and provide a low pressure, rhodium catalyzed process for the hydroformylation of low reactivity olefins, thus making lower cost amyl alcohols from butenes readily accessible. The new diorganophosphite-modified rhodium catalysts increase hydroformylation rates by more than 100 times and provide selectivities not available with standard phosphine catalysts. For example, hydroformylation of 2-butene with l,l -biphenyl-2,2 -diyl... 

Cesium forms simple alkyl and aryl compounds that are similar to those of the other alkah metals (6). They are colorless, sohd, amorphous, nonvolatile, and insoluble, except by decomposition, in most solvents except diethylzinc. As a result of exceptional reactivity, cesium aryls should be effective in alkylations wherever other alkaline alkyls or Grignard reagents have failed (see Grignard reactions). Cesium reacts with hydrocarbons in which the activity of a C—H link is increased by attachment to the carbon atom of doubly linked or aromatic radicals. A brown, sohd addition product is formed when cesium reacts with ethylene, and a very reactive dark red powder, triphenylmethylcesium [76-83-5] (C H )2CCs, is formed by the reaction of cesium amalgam and a solution of triphenylmethyl chloride in anhydrous ether. 

First order decomposition was established for dimethyldiazirine (215) and ethylmethyl-diazirine (216). The activation energy is 139 kJ moF for (215) the half life at 100 °C is 97 h. On decomposition of (216) the products formed and their respective yields are as indicated. The products correspond qualitatively and quantitatively with the results of thermal decomposition of 2-diazobutane formed in situ in aprotic solvents. Analogous comparisons of decomposition products of diethyldiazirine, isopropylmethyldiazirine, n-butyl- and t-butyl-diazirine agree equally well 66TL1733). 

If the decomposition reaction follows the general rate law, the activation energy, heat of decomposition, rate constant and half-life for any given temperature can be obtained on a few milligrams using the ASTM method. Hazard indicators include heats of decomposition in excess of 0.3 kcal/g, short half-lives, low activation energies and low exotherm onset temperatures, especially if heat of decomposition is considerable. 

Composting is the process of aerobic thermophilic decomposition of organic wastes to a relatively stable humus. Decomposition results from the biological activity of microorganisms which exist in the waste. 

The manner and rate of decomposition of hypohalous acids (and hypohalite ions) in solution are much influenced by the concentration, pH and temperature of the solutions, by the presence or absence of salts which can act as catalysts, promotors or activators, and by light quanta. The main competing modes of decomposition are ... 

The decomposition of chlorous acid depends sensitively on its concentration, pH and the presence of catalytically active ions such as Cl which is itself produced during the decomposition. The main mode of decomposition (particularly if Cl is present) is to form CIO2 ... 

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