Spectroscopic analysis and DFT calculations of a food additive Carmoisine

The spectroscopic (FT-IR, FT-IR gas phase, FT-Raman and UV) and NBO analysis of 4-Hydroxypiperidine by density functional method.

Application of common duckweed (Lemna minor) in phytoremediation of chemicals in the environment: State and future perspective.

Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, 13C, 1H, UV) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 4-[(4-aminobenzene) sulfonyl] aniline by ab initio HF and density functional method

The molecular structure of 1-azanapthalene-8-ol was calculated by the B3LYP density functional model with 6-31G(d,p) basis set by Gaussian program. The results from natural bond orbital analysis have been analyzed in terms of the hybridization of atoms and the electronic structure of the title molecule. The stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital analysis. The electron density based local reactivity descriptors such as the Fukui functions were calculated. The dipole moment (μ) and polarizability (α), anisotropy polarizability (∆α) and rst order hyperpolarizability (βtot) of the molecule have been reported.

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Natural Bond Orbital (NBO) Population Analysis of 1-Azanapthalene-8-ol

The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWF π-π=−8.1537+6.5638BL N-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules’ orbital geometry indicates that their visible absorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).

Study on the prediction of visible absorption maxima of azobenzene compounds

The liquid–solid multiphase flow in Oslo crystallizer was simulated by computational fluid dynamics (CFD) and described by Euler–Euler model and k-ε turbulence model. The velocity field and solid phase concentration field in Oslo crystallizer with different structural elements were systematically studied. The results show that, within the range of 0–82.5°, the fluid velocity and axial mixing in the evaporation chamber are significantly affected by the inlet pipe structure, and the length of the central downcomer also has distinct impact on the crystal classification ability of the crystallizer. As the angle between the axis of the inlet pipe and the tangent line at the inlet point increases, the tangential velocity in the evaporation chamber decreases, the axial velocity near the wall increases, and the volume fraction of solid particles decreases. As the length of the central downcomer increases, the position of the vortex center gradually goes up and moves towards the wall. In order to obtain high-quality products and extend the continuous operation cycle of the device, the angle between the axis of the inlet pipe and the tangent line at the inlet point should be 60–75°, and the distance between the central downcomer and the bottom of the crystallizer should be .8 m. 

Influence of Oslo crystallizer structure characteristics on crystallization process

Critical Temperatures, Critical Pressures and Densities of Acetone-Water Solution

Study on the Reactive Extraction Process for Heptaldehyde–Undecane–Sodium Bisulfite Aqueous Solution System

Abstract The substitutions of the chlorine atoms in p-dichlorobenzene (DCB) or the chlorine end-groups of polyphenylene sulfide (PPS) by sodium N-methyl-4-aminobutyrate (SMAB) are important reactions in the polymerization of PPS. The reaction process of DCB with SMAB was studied under conditions similar to the polymerization of PPS. The molecular structures of the products were analyzed through high-performance liquid chromatography, liquid chromatography-mass spectroscopy, gas chromatography-mass spectrometry, and other methods. Several pairs of para- and meta-isomer products were found, which indicates the coexistence of both nucleophilic addition–elimination (SN2Ar) mechanism and aryne intermediate mechanism. Based on mechanism analysis, the networks of reactions of DCB with SMAB were proposed and the effects of the ratio of SMAB to DCB, water content, and temperature on the reaction process were studied.

Shen-feng Yuan

Papers

Study on the prediction of visible absorption maxima of azobenzene compounds

Influence of Oslo crystallizer structure characteristics on crystallization process

Critical Temperatures, Critical Pressures and Densities of Acetone-Water Solution

Study on the Reactive Extraction Process for Heptaldehyde–Undecane–Sodium Bisulfite Aqueous Solution System

A new insight into the reaction mechanism in preparation of poly(phenylene sulfide)