Baojun Wang

Application of computational chemistry in understanding the mechanisms of mercury removal technologies: a review

The control of mercury in flue gas is challenging, and many investigators have focused on different mercury removal technologies. The application of computational chemistry in understanding mercury removal mechanisms will help to modify and design mercury removal materials, thereby improving the efficiency of the removal of mercury in flue gas. Therefore, a review of theoretical studies on the adsorption and oxidation of mercury has been undertaken in the current study. In this contribution, the homogeneous oxidation mechanisms of Hg0 as well as heterogeneous interactions including adsorption of mercury species and oxidation of Hg0 on activated carbon, metals, metal oxides and other materials have been summarized. In addition, possible future directions of theoretical calculations on understanding the removal of mercury are outlined.

Pyrolysis Mechanisms of Quinoline and Isoquinoline with Density Functional Theory

Abstract The pyrolysis mechanisms of quinoline and isoquinoline were investigated using the density functional theory of quantum chemistry, including eight reaction paths and a common tautomeric intermediate 1-indene imine. It is concluded that the conformational tautomerism of the intermediate decides the pyrolysis products (C 6 H 6 HC≡C—C≡N, C 6 H 5 C≡N and HC≡CH) to be the same, and also decides the total disappearance rates of the reactants to be the same, for both original reactants quinoline and isoquinoline during the pyrolysis reaction. The results indicate that the intramolecular hydrogen migration is an important reaction step, which often appears in the paths of the pyrolysis mechanism. The activation energies of the rate determining steps are obtained. The calculated results are in good agreement with the experimental results.

Theoretical studies on reaction mechanism of H2 with COS

The reaction mechanisms of H2 with OCS have been investigated theoretically by using density function theory method. Three possible pathways leading to major products CO and H2S, as well as two possible pathways leading to by-product CH4 have been proposed and discussed. For these reaction pathways, the structure parameters, vibrational frequencies and energies for each stationary point have been calculated, and the corresponding reaction mechanism has been given by the potential energy surface, which is drawn according to the relative energies. The calculated results show that the corresponding major products CO and H2S as well as by-product CH4 are in agreement with experimental findings, which provided a new illustration and guidance for the reaction of H2 with OCS.

The Dehydration of Methanol to Dimethyl Ether over a Novel Solid Acid-base Catalyst

A novel polymer solid acid-base catalyst Cat-AAA (Al + aminoacetic acid) with aluminum and nitrogen was prepared from aminoacetic acid and Al by using triblock copolymer Pluronic F127 as a template via evaporation induced organic–organic assembly method. Cat-AAA was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectra. The acid-base properties of the catalysts were determined by temperature programmed desorption using CO2 and NH3 as probe molecules. The dehydration of methanol to dimethyl ether over Cat-AAA had been studied; the results showed that the conversion of methanol and selectivity of dimethyl ether is higher at a high reaction temperature. The key requirements for a good catalyst for dehydration of methanol to dimethyl ether are: (i) weak acid-sites activate O in a methanol molecule; (ii) at the same time, weak base-sites activate H of hydroxy group in another methanol molecule.

Quantum Chemistry Studies on the Free-radical Growth Mechanism of Polycyclic Arenes from Benzene Precursors

The free-radical growth mechanisms for the formation of polycyclic arenes (PCAs) were constructed based on the block unit of benzene, and were calculated by the quantum chemistry PM3 method. Two kinds of reaction paths are proposed and discussed. The calculation results show that the formation of PCAs is only controlled by the elimination of H atom from benzene, and the corresponding activation energy is 307.60 kJ.mol(-1). H(2) is only the effluent gas in our proposed reaction mechanism, and the calculation results are in accord with the experimental facts.

Formation of carbon deposits from coal in an arc plasma

Abstract The issue of deposited carbon (DC) on a reactor wall during the producing of acetylene by the coal/arc plasma process is a potential obstacle for the industrialization process. The formation mechanism of DC is very difficult to reveal because the high complexity of coals and the volatile matter. Combining with quenching technique, the methane, liquid petroleum gas and benzene were employed as the model materials to roughly act as the light gas, chain and aromatic subcomponents of volatile matter, and then the reasonable formation mechanism of DC was subtly speculated accordingly.

Styrene from Toluene by Side Chain Alkylation over a Novel Solid Acid-base Catalyst

Abstract A novel solid acid-base catalyst with aluminum and nitrogen was prepared from aluminum and amine by using triblock copolymer Pluronic F127 as a template and resol as a framework via evaporation-induced organic–organic assembly method. The catalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectra. The acid-base properties of the catalyst were determined by temperature-programmed desorption using CO2 and NH3 as probe molecules, and the side chain alkylation of toluene with methanol over the catalyst has been investigated. The results show that the catalyst demonstrates the higher activity and selectivity.

Side-chain Alkylation of Toluene With Methanol over a Novel Solid Acid-base Catalyst

Abstract A novel solid acid-base catalyst Cat-NH(CH3)2 with aluminum and nitrogen was prepared from phenol and formaldehyde by using the triblock copolymer Pluronic F127 as a template and resol as a catalyst precursor via evaporation induced by the organic–organic assembly method. The catalyst was characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The base properties of the catalyst were determined by temperature programmed desorption using CO2 as a probe molecule. The side chain alkylation of toluene with methanol over the catalyst had been studied, the results showed that Cat-NH(CH3)2 has demonstrated a higher activity and selectivity than the alkali exchanged zeolites. This may be because the strength of the specific surface base sites of this catalyst is favored to bimolecular side-chain alkylation reaction.