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Abstract: The molecular mechanism of the Hoffmann elimination involving (N-Cl),N-methylethanolamine and HO− to yield 2-methyleneamino-ethanol has been theoretically characterized by using DFT at the B3LYP/6-31++G∗∗ computing level. The role of water as a solvent was analyzed by using both discrete and hybrid discrete-continuum models. The rearrangement proceeds along a water-assisted asynchronous concerted mechanism. The Gibbs free energy reaction barrier decreases when two water molecules are included in the reaction, one of them acting simultaneously as H+ donor/acceptor to/from the nitrogen/oxygen atom of (N-Cl),N-methylethanolamine, although not involved in a proton relay mechanism, it favours the elimination. [Copyright &y& Elsevier]

Abstract: The formation and fragmentation of the indene dication is studied using synchrotron radiation. The double-ionization energy of indene amounts to 21.8±0.1eV. The appearance energies of the fragments and are 25.8±0.1eV and 25.7±0.2eV, respectively. Although the appearance energies are almost the same, the dicationic fragment is formed in a higher yield than . It is suggested that the elimination of atomic hydrogen is associated with a considerable energy barrier, whereas the H2 elimination proceeds via very small barrier or is barrier-less process with respect to the reaction endothermicity. [Copyright &y& Elsevier]

Abstract: For an important class of organic reactions in which a fragment of the reactants, the leaving group (LG) or nucleofuge (Z), is detached of the substrate bearing the bonding electron pair, the global electrophilicity index of the CH3LG system is proposed as a reliable descriptor of the intrinsic nucleofugality of the LG. The model is illustrated by ranking within a unique relative scale, the LG ability of 28 functional groups commonly involved in substitution and elimination reactions in organic chemistry. [Copyright &y& Elsevier]

Abstract: The dynamics of initial decomposition of gas phase 1,3,3-trinitroazetidine (TNAZ) is investigated by using B3LYP/6-31+G(d,p) method and microcanonical variational transition state theory. Three initial decomposition pathways, NO2 fission, HONO elimination, and direct ring-opening reaction are considered. The calculated rate constants indicate that the rate constants of NO2 fission reaction are larger than those of both HONO elimination and ring-opening reaction in gas phase. However, HONO elimination and ring-opening channels may be important for the decomposition reaction of TNAZ in solid state. These results provide new understanding of the dynamics of the initial decomposition steps of TNAZ. [Copyright &y& Elsevier]

Abstract: The reaction of N-methyl-2-pyrrolidinone with CS2 has been found to take place at elevated temperatures (>200°C) in high yields, but the theoretical study for this reaction revealed the activation energy to be as high as 140kcalmol−1, which made this reaction an impermissible process. Conflicts between the theoretical study and experimental finding made us reinvestigate the mechanism of this reaction in detail, using density functional theory at the B3LYP/6-31G(d) level. Our research suggested a simple addition–elimination mechanism, in which the activation energy was calculated to be only 36kcalmol−1; this result corresponds well with the experimental finding. [Copyright &y& Elsevier]

Abstract: Non-adiabatic direct dynamics calculations were carried out to investigate the radical and molecular decomposition channels of formic acid. The calculations show, in agreement with experiment, that the HCO+OH dissociation channel accounts for ∼70% of the product yields. In addition, the molecular eliminations of CO and CO2 are minor channels, with a CO/CO2 branching ratio that depends on what isomer is initially excited to the S1 state. This result is also in qualitative agreement with experimental results in an Ar matrix environment. [Copyright &y& Elsevier]

The transition state energy for Cl2 molecular elimination from 1,2-dichloroethane is computed at compostite CBS-Q (based on B3LYP/6-31++G(d) optimized structure) and G3MP2 (based on MP2/6-31++G(d) optimized structure) levels of theory. Forward rate constants are calculated as 4.25E11 T0.826·exp(−93.4 kcal mol−1/RT) and 7.62E10 T0.892·exp(−98.5 kcal mol−1/RT) s−1, respectively for these two methods. Intrinsic reaction coordinate (IRC) analysis is performed to verify the transition state structures. While the overall, elimination of Cl2 plus olefin formation has a relative low ΔHrxn; the reaction with these barriers is evaluated to be not important in thermal reactions of chlorocarbons. [Copyright &y& Elsevier]