Advanced Materials Research Vols. 233-235

Abstract: Fuel ethanol converted from biomass is a reliable substitute for fossil fuels, and lays people’s hope on the sustainable development in the fields of energy and climate. The limitation in source of raw materials and production cost are bottlenecks which restrain the wide use of fuel ethanol. This article makes an overview of the current research progress in the new technologies from the directions in the exploiting of raw materials and energy saving and polluted water emission reduction in the production process of fuel ethanol, and analyzes the potential application prospects and advantages of various new technologies.

Abstract: Solvent-free N-alkylation of phthalimide with alkyl halides catalyzed by basic ionic liquids was developed in this conmmunication. With a comparative study, [Bmim]OH (1-butyl-3-methyl imidazolium hydroxide) exhibited the highest catalytic activity among the selected basic ionic liquids, which afforded a convenient, efficient and general protocol for N-alkyl phthalimides exclusively.

Abstract: This paper evaluates the catalytic effectiveness of CuZnO_x/γ-Al₂O₃ catalyst for the degradation of an azo dye, acid red GR, using H₂O₂ as an oxidant, under very mild conditions (atmospheric pressure and t = 40 ). In the catalytic wet peroxide oxidation (CWPO) process, the results show that it is possible to remove 80% of COD during the initial 30 h. But a considerable drop of catalytic activity is found after prolonged run. As characterization datas shown, the deactivation of the catalyst is caused by the depositon of intermediates on the surface and serious coverage of the active sites. However, calcination method which is possible to burn the organic species that trapped in the catalyst reaches complete restoration of the spent catalyst.

Abstract: With ion implantation, a high xylanase-producing strain Aspergillus niger BU99 was selected. Different late acting carbon sources (wheat bran, wheat straw, corncob and bagasse) had an effect on enzymatic production. Additionally, it was found that fast acting carbon sources (lactose, galactose, sucrose, glucose and maltose) put into the media affected on xylanase production too. Severe catabolic repression was observed in the media with lactose, but other sugars (galactose, sucrose, glucose and maltose) could increase the production of xylanase compared with the control. The production of xylanase was improved too when corncob flour was hydrolyzed by α-amylase, cellulase or/and glucoamylase. Additionally, it was found that the production of xylanase would be almost higher at 60h when the media contained glucose or were hydrolyzed by enzymes.

Abstract: Through the benzene alkylation experiments with long chain olefin over solid acid catalysts activated at different temperature in the fixed-bed reactor, the kinetics of alkylation reaction and the deactivation kinetics of catalyst were established. The results showed that the activity and stability of catalyst decreased with increasing the activation temperature of catalysts. The reaction rate constant (k) and the deactivation rate constant (k_d) of catalyst in kinetic models were also estimated through the optimization method, respectively. The acidity of catalyst was characterized by ammonia (NH₃)-temperature programmed desorption (TPD), and the desorption kinetics of NH₃ was obtained. The characterization results showed that the acid amount or the acid density gradually decreased, while the desorption activation energy or the acid strength increased, as the activation temperature of catalyst increased. In addition, the relationships between the acidity and catalytic performance of catalysts were correlated. It was found that the catalyst with higher acid amount and the lower acid strength on the surface exhibited the better catalytic performance and stability.

Abstract: Mesoporous V-MCM-41 materials with good hydrothermal stability had been synthesized by microwave-assisted hydrothermal method. The samples by microwave-assisted hydrothermal synthesis and conventional heating remain the same mesoporous structure by XRD and N₂ adsorption analysis. The V-MCM-41 materials by microwave-assisted hydrothermal synthesis show the good hydrothermal stability, close to that of the materials by conventional heating. The high surface area of the sample by 720 W microwave treatment for 8 min was the same as that of the sample by conventional heating (110 °C for 12 h).

Abstract: The benzene alkylation with long chain olefin over solid acid catalyst in the fixed-bed reactor was carried out under near critical conditions. The kinetic model of alkylation correlated with external diffusion and yield model of products were determined, and the model parameters, such as, the external diffusion factor, olefin conversion rate constant and the rate constant forming three products, were estimated. The statistical analysis showed the kinetic model had the higher simulation precision. Compared with the catalyst with 12~16 mesh (Cat-2), the activity and selectivity of linear alkyl benzene (LAB) of catalyst with 20~40 mesh (Cat-1) was higher.

Abstract: Nanoscale supported tungsten oxide catalysts were synthesized by hydrothermal method using γ-Al₂O₃, Nb₂O₅, TiO₂, ZrO₂ and CeO₂ as supports with a loading of 5~20% WO₃ on each supports, respectively. The physical properties and structural information were characterized by BET, XRD, ICP-AES and in situ Raman spectroscopy. Raman results confirm that the desired molecular arrangements of the active surface WO_x species have been achieved without the presence of the crystalline WO₃ phase. The reactivity/selectivity of the supported WO_x catalysts are chemically probed with steady-state methanol oxidation reaction. The catalytic results of methanol oxidation reaction have revealed that the acid sites are present on the surface of WO_x/Al₂O₃, WO_x/Nb₂O₅, WO_x/TiO₂ and WO_x/ZrO₂ catalysts for the mainly production of dimethylether (DME), and redox sites have only present on the surface of the WO_x/CeO₂ catalysts for the oxidation production of formaldehyde (HCHO). In addition, the WO_x/CeO₂ catalysts possesses the high redox reactivity and the WO_x/Al₂O₃ catalyst possesses the highest acid reactivity.

Abstract: The effects of PW/SiO₂ activation temperature on MPA (p-methoxyacetophenone) synthesis from toluene and acetic anhydride were carefully studied, and catalysts were carefully characterized by BET and XRD. The charactrerized results displayed that the interaction between PW and SiO₂ promoted the loss of acidic protons from PW to form the weak acid PW₁₂O_38.5 over PW/SiO₂. The weak acid site PW₁₂O_38.5 over PW/SiO₂ came into being when activation temperature increased to 300 °C, and the appearance of PW₁₂O_38.5 over PW/SiO₂ resulted in MPA yield decline.

Abstract: A Ni metal form was used to carry the Ru catalyst to induce the hydrogen gas from the NaBH₄ solution. Results show the Ni material was replaced by Ru material. Ru has been coating twice or more to cover all the Ni metal form surface as possible. About 4% of the Ru catalyst plate shows higher hydrogen generation efficiency. Relative to the concentration of NaBH₄ solution, the 20 wt.% is consisted with the 4% of Ru catalyst plate. Additional thermal treatment between every coating process, the Ru material can be adhered tightly. Furthermore, adding a layer of plastic film on the Ru catalyst plate can maintain 79% of the generation efficiency after 17 cycles of generation.