The CH_3OH+Cl Hydrogen Abstraction Reactions: An ab initio Study

The two channels of the CH(3)OH+Cl hydrogen abstraction reaction, leading to the final products CH(2)OH+HCl (i) and CH(3)O+HCl (ii), have been studied by performing ab initio MP2 calculations with the triplet split-valence polarization basis sets. For each of the two channels the following simple reaction path is predicted: reactants --> transition state --> intermediate --> products. The previously reported complicated paths(2) calculated without using the IRC technique are criticized. Our calculations indicate that channel (i) is exothermic and has a negligible energy barrier while channel (ii) is endothermic and has a substantial energy barrier. These results imply that channel (i) is favorable, which is in line with experiment.

Product Vibrational State Distributions of F+CH_(3)OH Reaction on Full-Dimensional Accurate Potential Energy Surface

The hydrogen abstraction reaction of methanol with fluorine atoms can produce HF and CH_(3)O or CH_(2)OH radicals,which are important in the environment,combustion,radiation,and interstellar chemistry.In this work,the dynamics of this typical reaction is investigated by the quasi-classical trajectory method based on a recently developed globally accurate full-dimensional potential energy surface.Particularly,the vibrational state distributions of the polyatomic products CH_(3)O and CH_(2)OH are determined by using the normal mode analysis method.It is found that CH_(3)O and CH_(2)OH are dominantly populated in the ground state when the reactants are at the ground ro-vibrational state.The OH stretching mode,torsional mode,H_(2)CO out-of-plane bending mode and their combination bands in the CH_(2)OH product can be effectively excited once the OH stretching mode of the reactant CH_(3)OH is excited to the first vibrationally excited state.Most of the available energy flows into the HF vibrational energy and the translational energy in both channels,while the radical products,CH_(3)O or CH_(2)OH,receive a small amount of energy,consistent with experiment,which is an indication of its spectator nature.

Kinetics of the Reaction of Abstracting Hydrogen from Ethylene by Hydrogen Atom

Hydrogen abstraction reaction, H+C2H4 --H2+C2H2 was studied by using A initio SCF method. Ge-ometries were fully optimized at SCF level and energies were computed at STO-3G basis set for reactants and transition state. Vibrational analysis was performed thereupon. Finally, the rate constant calculations were carried out at different temperatures for all range of reaction temperature according to Eyring's sbwlute reaction rate theory. The calculated activation energy is 12. 68 kcal/mol, lower than observed value (H. S kcal/mol) by 1. 82 kcal/mol only. The agreement of the calculated rate constants with the experiments is satisfactory.

Density Functional Theory Studies on the Mechanism of Activation Formic Acid Catalyzed by Transition Metal Oxide MoO

This paper systematically studies the reaction mechanisms of formic acid catalyzed by transition metal oxide MoO. Three different reaction pathways of Routes I, Ⅱ and Ⅲ were found through studying the reaction mechanism of transition metal oxide MoO catalyzing the formic acid. The transition metal oxide MoO interacts with the C=O double bond to form chiral chain compounds（Routes I and Ⅱ） and metallic compound MoOH2（Route Ⅲ）. In this paper, we have studied the mechanisms of two addition reaction pathways and hydrogen abstraction reaction pathway. Routes I and Ⅱ are both addition reactions, and their products are two different chiral compounds MoO3CH2, which are enantiomeric to each other. In Route Ⅲ, metal compounds MoOH2 and CO2 are obtained from the hydrogen abstraction reaction. Among them, the hydrogen abstraction reaction occurring in Route Ⅲ is more likely to occur than the others. By comparing the results of previous studies on the reaction of MxOy-＋ ROH（M= Mo,W; R = Me, Et）, we found that the hydrogen abstraction mechanism is completely different from the mechanism of oxygen-containing organic compound catalyzed by MxOy.

PERFORMANCE AND INITIATION MECHANISM OF ISOPROPYLTHIOXANTHONE IN SURFACE PHOTOGRAFTING

In a polymerization model with low density polyethylene (LDPE) as the substrate and acrylic acid (AA) as the monomer, the performance of isopropylthioxanthone (ITX) in initiating surface photografting polymerization was evaluated. The results show that the reactivity of photopolymerization and photografting of ITX locate between benzophenone (BP) and benzildimethylketal (BDK) for polymerization, BDK > ITX > BP; for surface grafting polymerization, BP > ITX > BDK. These results can be explained by a reaction mechanism of the inter-molecular or intra-molecular hydrogen abstraction reaction of ITX.

Ab initio Calculation and Kinetic Study for the Abstraction Reaction of H with SiHCl_3

The mechanism of the reaction of H with SiHCl_3 has been investigated at highlevel of ab initio molecular orbital theory. Theoretical analysis provides a conclusive evidencethat the main process occurring in this reaction is the hydrogen abstraction from the Si―H bond,the abstraction of Cl has higher barrier and is difficult to react. The kinetics has been studiedusing canonical variational transition-state theory (CVT) with small curvature tunneling effect(SCT) correction. The rate constants have been calculated over a wide temperature range of 200―3000K. The CVT/SCT rate constants exhibit typical non-Arrhenius behavior, a three-parameterrate-temperature formula is fitted as follows; k( T) = (3.24 x 10^(-19)) T^(2.30) exp( - 250/T) [inunit of mL/(molecule·s). The calculated CVT/SCT rate constants match well with the experimentalvalues.

Ab Initio Study of the Oxygen Atom Abstracting Hydrogen from Difluoromethane and Dichloromethane

The three potential surfaces for reactions of the O atom to abstract H atoms from CH2F2 and CH2Cl2 were studied using the ab initio method. The frequencies, geometries and energies of all species are calculated. The best estimates of the heat of reactions are 30.92 KJ/mol and 13.01 KJ/mol, and, the best potential barrier heights for both reactions are calculated to be 74.50 KJ/mol and 67.22 KJ/mol, respectively. the second-order rate coefficients calculated are 2.8721x10(-21) and 4.2522x10(-20) cm(3)/molecule-s at 298 K, respectively.

DFT Study of VOC Pollutants Catalyzed by Optimal MoxOy:Exploration of Reaction Mechanism of CH3COOH + MoO2

We propose the complicated catalytic mechanisms for the acetic acid molecule catalyzed by transition metal oxide MoO2 based on density functional theory calculations.The geometries and energetic values of all stationaries and transition states involved in the three different reaction pathways(ChannelsⅠ,ⅡandⅢ)are reported and analyzed.All reaction mechanisms are fully different from that of MoxOy catalyzing volatile organic compounds(VOCs)in previous studies.The completely new mechanisms catalyzed by MoO2 for acetic acid have been discovered for the first time.ChannelsⅠ(ⅠA andⅠB)andⅡare both addition reactions and channelⅢis hydrogen abstraction reaction by producing a leaving group.The barrier energies of reaction are also compared with other catalytic reactions,showing that MoO2 catalyst expresses a lower barrier energy(8.22 kcal/mol)by addition reaction,which represents MoO2 tends to absorb acetic acid pollution gas via addition reaction rather than release toxic substances.This also means that MoO2 is a more effective and representative catalyst and is suitable for further study of catalytic carboxylic acids,so the reaction mechanisms may provide a useful theoretical guidance and solution for the catalysis of carboxylic acids.

Quantum superchemistry of de Broglie waves： New wonderland at ultracold temperature

The experimental realization of atomic Bose-Einstein condensation at ultracold temperature has led to rapid advances in creating and manipulating cold molecules, and which has given birth to a new research field of quantum matter-wave superchemistry. Contrary to the classical Arrhenius law, the tunnelingdominated ultracold reactions can be realized through the highly-controlled magneto-optical technique. Novel quantum effects have been identified in these cold reactions, such as the super-selectivity rule in dissociating triatomic molecules, and the quantum size （vessel-shape） effect. In this review, we focus on a variety of new achievements in this fascinating matter-wave wonderland, including the quantum finitenumber effect and double-slit interference in assembling cold molecules, the quantum noise in triggering collective abstraction reaction, and the magnetic phase transition in a laser-catalyzed quantum spin-mixing gas. The practical applications of matter-wave superchemistry are also introduced, such as the optical information storage via quantum photo-association, and the laser-enhanced creation of spinor or even chiral molecules.