Advanced Materials Research Vols. 750-752

Abstract: Mixtures of phenol and m-cresol in 1-propanol were first reacted with phosphoric acid and then with furfural to form gels, which were dried under ambient pressure and pyrolyzed under nitrogen atmosphere to form monolithic macroporous carbon xerogels. The molar ratio of m-cresol to phenol (m-C/P), phenol and m-cresol to furfural ((m-C+P)/F), phenol and m-cresol to phosphoric acid ((m-C+P)/H₃PO4) was fixed at 1:5, 1:2 and 4.0 respectively while the m-C+P+F in 1-propanol was changed from 18 to 30 g/100ml to investigate the effect of the m-C+P+F concentrations on the porous properties of the monolithic carbon xerogels. It is found that the surface areas of the monolithic carbon xerogels are mainly contributed by micropores and their mesopore volumes are negligible. The monolithic carbon xerogels are rich in macropores whose sizes decrease from 4 to 0.22μm with increasing m-C+P+F concentrations. Moreover, the yields of the monolithic carbon xerogels are around 60%, which is higher than previous ones without phosphoric acid.

Abstract: The Pt/γ-Al₂O₃ catalyst was prepared by the method of impregnated with chloroplatinic acid (H₂PtCl₆) under different conditions. The acid-base of the carrier, the pH of impregnate liquid were systemic studied. Only when the pH value in 3.5, the loading of Pt on the carriers is the highest degree of dispersion.Various competitive adsorbents were added to impregnation liquid to improve the dispersion of the Pt. The effect of strong electrostatic adsorption on the dispersion of Pt/γ-Al₂O₃ catalyst. The characterization of Pt/γ-Al₂O₃ catalysts were investigated.

Abstract: Two novel gadolinium sandwich-type complexes containing tetrabenzoporphyrin (TBP) ligands-Gd (TBP)₂ and Gd (TBP)₃ were prepared from porphyrin 1 and Gd (acac)₃. nH₂O under Ar by boiling 1, 2, 4-Tcb for 15~17h and 45~48 h respectively. Their structures are characterized by Uv-Vis, HR-MS and IR. The spectroscopic studies show that their longest-wavelength visible and near-IR absorption bands are obviously red-shifted due to the extension of the π conjugated systems in the TBP ring. The magnetic studies indicate that the observed value of χ_MT for Gd (TBP)₂ is close to the combined value of Gd (III) and porphyrin radical anion at room temperature and that antiferromagnetic interaction possibly results from the intramolecular spin exchange between the porphyrin π-radical electron and that the gadolinium f unpaired electrons dominates its magnetic properties over the whole temperature range while there is no magnetic interactions between two Gd (III) ions in Gd (TBP)₃ in the range from room temperature down to 20K and very weak antiferromagnetic coupling exsits between two Gd (III) ions below 20K.

Abstract: Manganese oxide (Mn₃O₄) catalyst was prepared by decomposition method and characterized by X-ray powder diffraction (XRD) and fourier transform infrared spectrum (FTIR). Catalytic activity of Mn₃O₄ was tested by the oxidation of toluene to benzoic acid with molecular oxygen in liquid-phase and solvent free conditions. As a result, 45% conversion of toluene and 91% selectivity of benzoic acid was achieved. It is proved that Mn₃O₄ catalyst can use several runs without decrease of activity.

Abstract: Methanol dehydrogenation to formaldehyde was conducted in a fixed-bed flow reactor under the atmospheric pressure with sodium carbonate modified by metal oxides. The effects of catalyst composition, reaction temperature, weight hourly space velocity (WHSV) on the reaction were investigated. The catalysts were characterized by XRD, TG and nitrogen adsorption. The results indicated that ZnO/Na₂CO₃ containing 2wt% ZnO prepared by mechanical grinding method had higher catalytic activity for methanol dehydrogenation to formaldehyde. The conversion of methanol and the selectivity of formaldehyde were respectively 57.62% and 77.84% under the condition of w_methanol/w_feed =0.19, reaction temperature 650°C and WHSV (methanol) 7h^-1.

Abstract: In order to prepare special alcohol-soluble polyvinyl butyral (PVB), the reaction condition was explored in this paper after analyzing the molecular structure of PVB. Under a simple and economical condition, PVB with 14.2% of butyraldehyde group and good alcohol-solubility were prepared, the PVB film forms quickly after the volatilization of ethyl alcohol, and it has good diaphaneity, high tensile strength, and excellent mechanical properties. The highest tensile strength of the PVB film reaches 50.9MPa, which can meet some requirements of many applications.

Abstract: The nanocomposite films with different ZnO:Fe₂O₃ ratio was prepared by Sol-Gel method on slides glass, Its structure performance was characterized by XRD, SEM, and the photocatalytic performance of different ZnO: Fe₂O₃ ratio films was investigated. The results showed that: the three layers film that with Zn: Fe ratio was 1:2, had the best photocatalytic effect.

Abstract: A new uranium-containing silicotungstate A-β-Na₁₄[Na₂(UO₂)₂(SiW₉O₃₄)₂]·43H₂O (1) was synthesized in an aqueous solution. The compound was characterized by elemental analysis and infrared spectra analysis. A single-crystal X-ray analysis was carried out on crystal (1) which crystallizes in triclinic system, space group p ī, with a = 13.386 Å, b = 13.506 Å, c = 16.183 Å, α = 85.337o, β = 73.608o γ = 64.833o and Z = 1. Polyanion (1) consists of two A-β-SiW₉ units which sandwich two uranium and two sodium ions, leading to a Keggin-type sandwich structure. The photoluminescent spectrum of (1) shows typical emission features of uranyl compounds.

Abstract: In the present paper, a bubbling reactor is employed to investigate the macroscopical kinetics of magnesium sulfite oxidation in presence of the solid catalysts. A synthesized solid metal catalyst M was selected by performance comparison, which had significant catalytic effect on the oxidation rate of magnesium sulfite. The experimental results indicated that the reaction orders are 0 and 0.61 with respect to magnesium sulfite concentration and oxygen partial pressure. Moreover the apparent activation energy of the reaction is 10.66 KJ/mol. Thus a useful reference is provided for recycle of byproduct by catalyzed oxidation in magnesia desulphurization.

Abstract: The density functional method of wB97xD in combination of 6-31+G** basis set was applied to the study of the heterodimers between hexahydro-1,3,5-trinitro-1,3,5-triazine and water. Three stable dimers were located. The binding energies have been corrected for the zero-point vibrational and basis set superposition errors. The largest corrected binding energy is 26.21 kJ/mol. Natural bond orbital analyses and frequency calculations were performed on each optimized structure. The thermodynamic properties of enthalpies, entropies and Gibbs free energies in the dimerization process were presented.