Advanced Materials Research Vols. 560-561

Abstract: Al2O3 supported platinum catalysts prepared by using different impregnation methods have been tested for the dehydrogenation of propane to propylene. The effect of promoter type and amounts of promoters has been investigated in a detail. The results indicated that the best catalytic performance was achieved on the catalyst prepared under the following conditions: sequential impregnation method, Sn and K as promoter, Pt loading 0.5%, Sn loading 1.0%, K loading 2.1%.

Abstract: A novel one-pot catalytic synthesis of 1-benzoylpyrene through acylation of pyrene with benzoyl chloride catalyzed by various Keggin type heteropoly acids (salts) was investigated. Pure 1-benzoylpyrene was obtained and the structure of 1-benzoylpyrene was identified by GC/MS, FT-IR and 1H NMR spectra. H3PW12O40 (PW) was found to be the most active catalyst in the acylation. The yield and the selectivity of 1-benzoylpyrene were up to 97.6 % and 100 %, respectively. The effects of experimental parameters on the catalytic acylation reaction and the recycling performance of PW catalyst were studied. PW catalyst shows well catalytic activity after running for 5 times. The facile product separation and the recycling performance of PW catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 1-benzoylpyrene.

Abstract: Znic-containing mesoporous HMS (Zn-HMS) with various znic contents were synthesized by using netural dodecylamine(DDA) as template at ambient temperature and characterized by means of XRD, FT-IR and TEM. The catalytic performance of Zn-HMS was evaluated by the oxidation of thiophene, and the influences of the zinc content and zinc source on the catalytic performances of the samples were studied. It was observed that a limited content of zinc can be incorporated into the siliciate framework of HMS and appropriate amount of zinc incorporated would promote the formation of the typical wormhole-like structure of HMS and exhibited high catalytic properties while excessive zinc incorporated would destroy the structure. Besides, for all the zinc sources, the samples synthesized from Zn(NO3) 2 have better catalytic effect, and it is benefical for zinc incorporating.

Abstract: The hydrolysis of p-nitrophenyl picolinate (PNPP) catalyzed by two nickel (II) complexes (bis(O,O’-di(2-phenylmethyl) dithiophosphate) nickel(II) (NiR1) and bis(O,O’-di(2-phenylethyl) dithiophosphate) nickel(II) (NiR2)) was investigated kinetically in this work. The results indicate that both metal complexes accelerate the hydrolysis of PNPP dramatically and the NiR1 exhibits higher catalytic function on PNPP hydrolysis in the buffered solution with relatively low pH values, while NiR2 shows slightly more efficacy on hydrolysis of PNPP in relatively high pH buffered solutions. This variance is ascribed to the synergism effect of space hindrance of the complexes and the nucleophilic attack of metal-hydroxy species generated by the complexes.

Abstract: A metallic Ni catalyst was prepared with nickel sponge, followed by acid treatment. The reaction scheme of partial oxidation of methane to synthesis gas over the metallic Ni catalyst had been suggested and researched. For defining the logical kinetic regime, the effects of operational variables on mass and heat transport resistances were investigated. In the absence of significant mass and heat transfer resistances, high selectivities to syngas were obtained on the metallic Ni catalyst even in the low methane conversion range. With the increase of CH4/O2 ratios, the selectivities to H2 and CO on the metallic Ni catalyst also increased.

Abstract: Corncob powder was hydrolyzed with formic acid under the catalyzation of hydrochloric acid. Sugar contents in hydrolysis liquor at different reaction time and temperature were determined. The chemical compositions in hydrolysis residue were also analyzed. Results showed that the formic acid could hydrolyze the polysaccharides in corncob and the degradation products were dissolved in hydrolysis liquor. The addition of catalytic hydrochloric acid accelerated the hydrolysis of polyose. The proper hydrolysis condition was 80°C for 3h. Lignin might undergo hydrolysis at higher temperature.

Abstract: Low density printing paper was widely used in printing best-seller at present. Besides of high bulk, good stiffness, soft color, it also had some advantages, such as reducing user’s load, protecting eyes, extending the storage time etc. Quality index of domestic low density printing paper was lower than foreign index. The gap mainly expressed on tensile index specially. This study used Aspen BECMP as main pulp, as a result of its higher strength, lower cost and other advantages comparing with PRC-APMP. Here we discussed three pulps ratio to make low density printing paper. The results of experiment indicated that using Aspen BECMP was able to make low density printing paper by adding certain amount chemistry pulp. Moreover, the best bulk value can up to 2.45cm3/g, and the tensile index was 36.08Nm/g.

Abstract: Ethyl (R)-2-hydroxy-4-phenylbutyrate was prepared by enzyme resolution of racemic ethyl- 2-hydroxy-4-phenylbutyrate. The optimal resolution conditions were 0.074 mol/L ethyl-2-hydroxy-4-phenylbutyrate, 20 mg lipase AK in 2.0 ml ethenylethanoate, 30 0C, 100 rpm. Enantiomeric excess of ethyl (R)-2-hydroxy-4-phenylbutyrate was up to 99%. Kinetic resolution model of ethyl- 2-hydroxy-4-phenylbutyrate by lipase AK was described by double substrate ping-pong mechanism. Model data agreed well with experimental data.

Abstract: The mechanics of contact interaction of rigid spherical indenter with two-layer elastic - plastic half-space, simulating a surface of a solid body with a thin surface layer is considered. Analytical dependences of critical indentation and bearing capacity on mechanical characteristics of materials of a base and a coating, and as well as that for thickness of top layer (coating) in all region of possible thickness are received and analyzed. Existence of regions of the abnormal structural strength allowing the surface layered material to identify unequivocally as a topocomposite is shown. Theoretical dependences were verified by a final elements method.

Abstract: The effect of aging treatment on mechanical properties and electrical conductivity of Cu-5.7%Cr in situ composite produced by equal channel angular pressing (ECAP) was investigated here. The rotation and spreading of Cr particles was observed in Cu-5.7%Cr alloy during the ECAP, resulting in long thin in situ filaments. The equiaxed grains of the Cu phase with an average size of 200 nm were developed after eight passes of ECAP. When aging at 400~450 °C for 1 h, Cu-5.7%Cr composite after ECAP shows the maximum microhardness, and the electrical conductivity is larger than 70% of IACS. At 400 °C, the peak aging time appears for 0.5~2 h, dependent on the pre-strain for all ECAP samples. With the increase of ECAP passes, the enhancement of tensile strength due to the aging treatment declines, and even shows negative after eight passes of ECAP. The combination of ECAP and aging treatment would be a promising process to balance mechanical properties and electrical conductivity of Cu-5.7%Cr composite.