Advanced Materials Research Vols. 634-638

Abstract: The lead(II) Complex constructed with 5-hydroxyisophthalic acid, [Pb3(5-hipa)2]n•4H2O(1), (5-hipa = 5-hydro- xyisophthalic acid) has been synthesized by hydrothermal methods and structurally characterized by elemental analysis, IR and X-ray single crystal diffraction. In trinuclear symmetrical complex 1, Pb1 is four-coordinated, Pb2 and Pb3 are three-coordinated by 5-nitroisophthalic acid groups, respectively, which is further connected through intermolecular hydrogen bonds resulting in a three-dimensional (3D) network.

Abstract: Rosin-modified lignosulfonates were prepared according to the following procedure: firstly, sulfomethylation of kraft lignin; secondly, preparation of 2,3-epoxypropyl ester of rosin; thirdly, preparation of modified-rosin lignosulfonates via etherification of sulfomethylated lignin with 2,3-epoxy propyl ester of rosin. Experimental results show that the optimum conditions for synthesis of 2,3-epoxy propyl ester of rosin are as follows: molar ratio for n(rosin): n (epichlorohydrin): n (NaOH) is1:6:1, reaction temperature is 100 °C(for rosin ester) and 75 °C(for 2,3-epoxypropyl ester of rosin, the same below), reaction time is 5.5 h and 3 h respectively. When molar ratio of lignosulfonate to 2,3-epoxypropylester of rosin is 1/5, rosin-modified lignosulfonates were prepared at 55 °Cfor 4.5 h with pH 11.5. Hydrophilic sulfonic group and the lipophilic adbietic group were incorporated into the molecular structure of kraft lignin via corresponding reactions. The surface tension of 10 g/L aqueous solution of rosin-modified lignosulfonate is 49.3 mN/m.

Abstract: Maize starches and hydrogen-peroxide were used as major raw materials to synthesize oxidized starch by microwave radiation in a few minutes. Its crystal structure was analyzed respectively by X-ray diffraction (XRD), infrared spectroscopy (FT-IR), differential scanning calorimetry(DSC) and the apparent morphology was observed by scanning electron microscope (SEM). The XRD results show that the samples’ crystallinity has declined obviously after microwave radiation for 3.0 min and 6.0 min, and the later sample formes new crystal; The FT-IR results indicate that when microwave radiation time increases, the proportion of the native crystalline structure in the sample declines; The DSC results demonstrate that in microwave radiation, some spiral structure in internal starch granule is destroyed, while the starch-starch crystal structure subjects to a certain degree of destruction; The SEM results show that with the microwave radiation time increasing, the degree of erosion on the sample particle surface increases and expands gradually into the inside.

Abstract: Making use of the amphoteric characteristic of zinc oxide and the weak acidity of hydrolyzed ammonium heptamolybdate, we synthesized high-purity zinc molybdate through chemical reactions. At optimum reaction temperature of 70°C, 1 hour of reaction time and reuse of mother liquor, the molybdenum yield exceed 98%. This process has no wastewater discharge, and the products can be easily filtered. The productivity is significantly increased.

Abstract: Titanium Silicalite-1 (TS-1) was successfully synthesized from amorphous silica and titania powders by using a ball-milling method. In this method, amorphous fumed silica and anatase titania powders were ground in a planetary ball mill to produce a silica-titania precursor. The obtained precursor was then hydrothermally treated where TPABr was used as a template to obtain titanium silicalite-1 (TS-1). The XRD and UV-vis spectra indicate that the titanium in anatase with octahedral coordination is incorporated into the silica-titania precursor and the final TS-1 framework with a tetrahedral coordination. SEM image shows that TS-1 synthesized in this work appears in a shape of elongated prism with a dimension of about 3μm×1μm×0.2μm. This method gives a simple new approach to the synthesis of TS-1 using inexpensive silicon source, titanium source and template.

Abstract: Biomass gasification was separated from catalytic pyrolysis in a two-stage fixed bed reactor with precalcined copper slag catalysts placed in a secondary reactor. The effects of gasification temperature (720-950°C), steam to biomass (S/B) mass ratio (0-2g/g), precalcined copper slag to biomass (C/B) mass ratio (0-2g/g) and copper slag precalcined at different temperatures (800-1000°C) on characteristics of biomass gasification were investigated. The experimental results show that the increase of gasification temperature, S/B mass ratio, C/B mass ratio and precalcination temperature are all favorable for raising gasification efficiency and enhancing the H₂ production. With copper slag precalcined at 1000°C for 5 hours as catalyst under the experimental conditions examined, the H₂ content, the hydrogen yield, the gas yield and the gasification efficiency reach the maximum of 59.16%, 0.72 Nm³/kg, 1.22 Nm³/kg and 77.56%,respectively.

Abstract: A series of metal oxides were employed as catalysts for the synthesis of dimethylhexane -1,6-dicarbamate(HDC) from 1,6-hexamethylenediamine(HDA) and methyl carbonate(MC). Lead dioxide showed excellent catalytic activity, 100% HDA conversion and 93% HDC yield could be achieved at 463K for 6h. The effects of reaction temperature, reaction time and catalyst amount on the yield of HDC were investigated in details.

Abstract: Catalytic decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over a series of solid base that have different ZrO2 content using a fixed-bed reactor. CO2 and CClF3 were the main-products and no CO was detected as by-product. The decomposition activity depended on the calcination temperature and the Zr:Na. Calcined at 600 °C and Zr:Na=1:0.35 were the best catalyst preparation conditions. Adopting low concentration of oxygen and CCl2F2 and high concentration of water vapor is preferable to the achievement of high conversion of CCl2F2 and selectivity for CO2. The catalytic activity of Na2O/ZrO2 remained steady for 120 h on stream.

Abstract: Catalytic degradation of azo dye Congo red in aqueous solution by spinel LiMn2O4 was studied. Degradation conditions were also optimized by orthogonal experiment. The results showe that the optimal degradation experimental conditions are: The initial pH is 3.0; The amount of catalyst is 10.0 mg; The amount of 30% H2O2 is 2.00 mL. The decolourization ratio of 20 mL 20 mg/L Congo red solution is 85.95%.

Abstract: Coaled carbon-based solid acid (CCBSAC) is reported as a new, efficient and recyclable catalyst for the regioselective multicomponent synthesis of dihydropyrimidin-2(1H)-ones from aldehydes, β-ketoesters and urea or thiourea under solvent-free conditions. The structure and thermal stability of CCBSAC which resulted from ultra-clean coal resources mainly were characterized by IR, XRD, and TG. Nineteen dihydropyrimidin-2(1H)-ones examples were prepared and this catalyst could recycle up to 4 consecutive runs without losing its efficiency. The high yields of products, short reaction times, ease of work-up and clean procedure will make the present method a useful and important addition to the previous methodologies for the synthesis of dihydropyrimidin-2(1H)-ones.