Bimolecular decomposition

The heat of decomposition (238.4 kJ/mol, 3.92 kJ/g) has been calculated to give an adiabatic product temperature of 2150°C accompanied by a 24-fold pressure increase in a closed vessel [9], Dining research into the Friedel-Crafts acylation reaction of aromatic compounds (components unspecified) in nitrobenzene as solvent, it was decided to use nitromethane in place of nitrobenzene because of the lower toxicity of the former. However, because of the lower boiling point of nitromethane (101°C, against 210°C for nitrobenzene), the reactions were run in an autoclave so that the same maximum reaction temperature of 155°C could be used, but at a maximum pressure of 10 bar. The reaction mixture was heated to 150°C and maintained there for 10 minutes, when a rapidly accelerating increase in temperature was noticed, and at 160°C the lid of the autoclave was blown off as decomposition accelerated to explosion [10], Impurities present in the commercial solvent are listed, and a recommended purification procedure is described [11]. The thermal decomposition of nitromethane under supercritical conditions has been studied [12], The effects of very high pressure and of temperature on the physical properties, chemical reactivity and thermal decomposition of nitromethane have been studied, and a mechanism for the bimolecular decomposition (to ammonium formate and water) identified [13], Solid nitromethane apparently has different susceptibility to detonation according to the orientation of the crystal, a theoretical model is advanced [14], Nitromethane actually finds employment as an explosive [15],... 

The decompositions of hydroperoxides (reactions 4 and 5) that occur as a uni-or bimolecular process are the most important reactions leading to the oxidative degradation (reactions 4 and 5). The bimolecular reaction (reaction 5) takes place some time after the unimolecular initiation (reaction 4) provided that a sufficiently high concentration of hydroperoxides accumulates. In the case of oxidation in a condensed system of a solid polymer with restricted diffusional mobility of respective segments, where hydroperoxides are spread around the initial initiation site, the predominating mode of initiation of free radical oxidation is bimolecular decomposition of hydroperoxides. 

The rate constant k, which involves the rate constant of bimolecular decomposition of hydroperoxides khi from the Scheme 2 may thus be determined, so that we find the value of [d(f/Imax)/df], which is the slope of chemiluminescence-time record at its inflexion point. This ratio is function of k as follows ... 

Kinetics based on the idea of spreading is formally based on the model of development of an infectious disease among human population [59,60]. The formalism of chemical kinetics, however, should be treated with a care as a similar equation can be derived from the homogeneous model assuming bimolecular decomposition of hydroperoxides as an initiating event. 

In addition to hydroperoxide decomposition by the reaction of the first-order bimolecular decomposition was observed in cyclohexanol at [H202] > 1 M [60], The bimolecular radical generation occurs with the rate constant k 6.8 x 108 exp(—121.7/R7) L mol-1 s-1. The following mechanism was suggested as the most probable. 

The rapid decomposition of adjacent POOH groups is the result of decomposition similar to the bimolecular decomposition of two ROOH (see Chapter 4). 

The primary reason for attempting to synthesize imido alkylidene complexes, e.g., W(NR)(CH-f-Bu)(0-f-Bu)2, was the belief that the appropriate imido ligand will block bimolecular decomposition reactions more effectively than an oxo... 

Bimolecular decomposition of a non-metal hydride organometallic complex, such as metal formyl complexes, which may involve metal hydride precursors MC( = 0)H + H20 <-> M(CO)+ + OH + H2 N/A 36... 

Observed stoichiometry of the cerium-alkoxyhydroperoxide reaction was a little more than 1 mole of peroxide per equivalent of Ce. This agrees well with Reaction 4s predominating over a bimolecular decomposition analogous to Reaction 3. Because the observed stoichiometry was so close to 1 1, chain reaction decomposition initiated by metal ions appears of little importance in this case. 

Compared to the time scale of their formation, the carbonyl oxides are quite long lived (10 -10 s), and so their subsequent reactions can be monitored kinetically. For most of the carbonyl oxides, the decay is best fit to a second-order rate law, indicating a bimolecular decomposition pathway. For benzophenone oxide, the ketone is the major product at room temperature, and no dimer can be detected. A bimolecular process involving O2 extrusion from two molecules of the oxides is suggested under these conditions. 

Bimolecular Decomposition of the Transient Complexes Methyl Transfer Reactions Rearrangement of the Carbon-Skeleton of R (H20)sCrCH02+ as a Hydride Transfer Reducing Agent Alkene Complexes... 

Assuming a random distribution of the catalyst in a matrix, the bimolecular decomposition distance was estimated to be almost contact distance between molecules. 

When two catalyst molecules are needed for the 4-electron water oxidation, the catalytic activity shows an optimum catalyst concentration in the matrix since bimolecular decomposition still takes place, and cooperative distance between catalyst can be determined also by assuming a random distribution. 

Bimolecular decomposition of the catalyst takes place at its high oxidation state,... 

Compounds containing 02 cation 340 are colorless with the exception of 02+PtF6, which is red due to the PtF6 ion. The compound 02+PF6 decomposes slowly at 80°C862 and rapidly at room temperature, giving oxygen, fluorine, and phosphorous pentafluoride. 18F tracer studies on 02+BF4 have led to the conclusion that the mechanism of the decomposition involves the equilibrium [Eq. (4.216)] followed by a bimolecular decomposition of 02F.863... 

The robust, well-shielded cavity found in hemicarcerands offers tremendous scope for the use of these hosts as micro-reaction vessels in order to protect reactive species from bimolecular decomposition by isolating them from the outside medium. Furthermore, the unique intracavity environment with its fluid-like properties in which guest species are, formally, in a very condensed state at very high pressures, may well result in unique inclusion reactivity. Indeed, the inner volume of carcerands and hemicarcerands has been described as a new phase of matter distinct from solid, liquid and gas. A number of elegant demonstrations have been made of the potential of inclusion reactions, and there is clearly a great deal of scope for their use as molecular reaction vessels. 

Even though theoretical studies have identified a number of potentially metastable structures [1, 2], the experimentally observed nitrogen compounds are still few. The azide anion, N3, wai. first synthesized in 1890 by Curtius [3]. Christie and coworkers have since 1999 reported the preparation and isolation of Ns"1" together with several different counter ions [4, 5]. A few other species, such as N3, Ns+, N4+, and N6, have been observed only as gaseous or matrix-isolated ions or radicals [6-12], We recently reported the detection of cyclic N5 in a mass spectrometry experiment [13], This observation has later been verified by Christie et. al. in a more elaborate study [14], The experimental preparation and detection of an open-chain N4 molecule was reported in 2002 by Cacace et al [15]. This species is expected to be unstable towards bimolecular decomposition and also too low in energy to be of any greater interest as a HEDM. 

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