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April 15,2012
Volume 5,Issue 7
Pages -
Subject Area:Basic Subject of Chemical Engineering,Coal Chemical Engineering,Biochemical Engineering,Catalytic Chemistry

Title: Application of Aspen Plus in design of chemical engineering

Authors: YAO Wenjin, WU Huashuai, CAO Junya
PP: 688-693
Abstract: In this paper, the functions and application methods of Aspen Plus and its simulation for some kinds of models are introduced, which are used to discuss Aspen Plus applied in design of chemical engineering. The research shows that Aspen Plus is applied widely in research, development, design, process control, optimization and technical transformation in chemical engineering, which improves the efficiency and level of design of chemical process.
Keywords: fundamental discipline of chemical engineering; process simulation; Aspen Plus; chemical engineering design

Title: Numerical simulation study on cold flow state in rotary kiln

Authors: LU Chao, LI Yanan, WANG Ping, SHI Haiyan, ZHANG Hong
PP: 683-687
Abstract: In this paper, computational fluid dynamics (CFD) technology was used to study the cold flow field in the rotary kiln. The results showed that there were central reflux zone, internal reflux zone and external reflux zone in the rotary kiln, and was consistent with predecessor’s research, which accounted for the rationality of the grid, the reliability of numerical method and the advantages of the burner. The performance of four-channel coal burner was helpful to improve quality and efficiency cement calcination.
Keywords: coal chemical engineering; rotary kiln; numerical simulation; reflux zone

Title: Study on long-distance and dynamic characteristics of plasma based on polymer membranes

Authors: ZHAO Zhiping, LI Ning, LI Meisheng, ZHANG Yue, LIU Wenfang
PP: 677-682
Abstract: In the present investigation, the long-distance and dynamic characteristics of plasma were explored. The glow distance of low-temperature plasma as a function of plasma parameters was discussed. Field emission scanning electron microscopy (FESEM) and accurate weight loss were used to characterize the etching effect occurred on the plasma treated polytetrafluoroethylene (PTFE) membranes. The peroxide radicals on the plasma irradiated polypropylene (PP) fibril membrane were detected by 1,1-Diphenyl-2-picrylhydrazyl (DPPH) method after the sample exposed to air for few mintunes. The effect of plasma parameters on the content of peroxide radicals was investigated. Results show that the membrane samples set in their proper places, where are more than about 20 cm far away from the discharge center in this study range, could be able to avoid the etching and degradation of membrane bulk greatly. The peroxides also can be detected on the membrane irradiated even at a long distance of 40 cm downstream from the center of the inductor coil. Not only that, more peroxides and a longer glow distance can be obtained by long-distance and dynamic plasma flow treatment. The dynamic plasma flow can be led through membrane pores. And the penetrated active species carried by flowing plasma can penetrate the first layer of the PP fibril membrane, but even treat the second membrane layer.
Keywords: membrane separation; plasma; long-distance and dynamic characteristics; peroxide radicals; glow distance

Title: Development of research on lignocellulose pretreatment

Authors: LUO Fang, ZHANG Hong, GUAN Dongming
PP: 666-676
Abstract: Ethanol and other biofuels produced from lignocellulosic biomass represent a renewable, more carbon-balanced alternative to both fossil fuels and corn-derived or sugarcane derived ethanol. Unfortunately, the presence of lignin in plant cell walls impedes the breakdown of cell wall polysaccharides to simple sugars and the subsequent conversion of these sugars to usable fuel. The pretreatment of lignocellulose could largely destroy the structure of cell walls and released the cellulose, then improved the accessibility between cellulase and cellulose, what’s more, the hemicellulose released could be used in many ways. This paper explicitly introduces different pretreatment technologies of lignocellulosic materials in recent years, and evaluated their advantages and disadvantages. Some valuable technologies with low power consumption, high efficiency and low pollution were recommended to guide the industrial application of ethanol production fromlignocellulose.
Keywords: biochemical engineering; lignocellulose; reviews; pretreatment; ethanol

Title: Effect of citric acid on Co-Mo hydrodesulfurization catalysts of coking benzol

Authors: QU Zhongwei, DU Xiaodi, ZENG Kai, LEI Jiaheng
PP: 661-665
Abstract: Coking benzol hydrodesulfurization catalysts were prepared by the isovolumic impregnation method using cobalt and molybdenum as active metals. The properties of the catalyst modified by citric acid in the impregnation solution and the catalytic performance and the structure of hydrodesulfurization were examined. The physical and chemical properties of the catalysts were investigated with BET, X-ray diffraction (XRD) and thermogravimetric-differential scanning calorimeter (TG-DSC), it was revealed that the BET specific surface area and pore volume of Co-Mo catalyst were increased by adding CA in the impregnation solution, and also more pores were made. The interaction between Co and carrier was reduced when Co2+ chelated with CA. The increase of CA concentration leaded to the Mo sulfide phase tended to form Mo3S4 phase, Co sulfide phase tended to form CoS phase. The sulfuration of Co phase was delayed by adding CA, leading to cover the sides and edges of MoS2 phase, and form more active centers.
Keywords: catalytic chemistry; chelating agent; hydrodesulfurization; coking benzol

Title: RAFT emulsion polymerization of styrene

Authors: HU Chengjie, YANG Hai, CHEN Li, YANG Lei
PP: 654-660
Abstract: Living polystyrene chains with higher molecular weight were synthesized via emulsion polymerization process mediated by amphiphilic reversible addition-fragmentation chain transfer (RAFT) agent. As indicated by the kinetic curves, the whole reaction period was divided into three stages: nucleation, constant rate and deceleration, which were similar to those in conventional emulsion polymerization. During reaction, experimental molecular weights agreed well with the theoretical ones, demonstrating the living characters of the polymerization. Influenced by the nucleation process, the molecular weight distributions were high initially, but they decreased afterwards. The polydispersity index (PDI) was only 1.21 when the average molecular weight Mn of the product grew to 70 000 g/mol finally. Meanwhile, the latex was of monodispersed particle size. These properties were all far superior to those of products from RAFT miniemulsion polymerization.
Keywords: textile chemistry and dyeing and finishing engineering; living radical polymerization; reversible addition-fragmentation chain transfer; emulsion polymerization; amphiphilic reversible addition-fragmentation chain transfer agent

Title: Application of nonlinear optical single-molecular image technique on studying nanostructure of starch chain

Authors: WANG Xiaoming
PP: 650-653
Abstract: Objective: To distinguish the nano structures of crude starch and gelatinized starch. Methods: The nonlinear optical single molecular image technique was used to study the nanostructure of starch molecular chains. Results: The experiment showed that the main structure of crude starch is α-helix structure of glucose and more α-helix structure tangled together. The structure of gelatinized starch is line structure tangled together. Conclusion: The experiment demostrated that nonlinear optical single molecular image technique is a very useful tool in macromolecular nanostructure research.
Keywords: polymeric chemistry and physics; nonlinear optical molecular image; starch chain nanostructure; gelatinized starch nanostructure

Title: Synthesis and characterization of 3-aminopropyltriethoxysilane modified uv-curable waterborne polyurethane emulsions

Authors: LUO Jiahe, GUO Jinshan
PP: 642-649
Abstract: In this work, a series of 3-aminopropyltriethoxysilane (APTES, KH550) modified UV-curable waterborne polyurethane emulsions (Si-PUs) were synthesized by incorporating the pentatry thritol triacrylate (PETA) and the APTES into the end of the polyurethane chains. Structural and morphological features of coatings were assessed using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Results showed that the coating is uniform and homogeneous. Thermal property of the coatings was also examined by thermogravimetric analysis (TGA). It was found that grater thermal property was obtained with incorporation of APTES. In addition, study on effect of water resistance of Si-PUs films showed that improving water resistance with hydrophobicity of Si—O—Si linkage. Results from the mechanical measurements showed that the APTES improved various mechanical properties such as pencil hardness, gloss, adhesion and flexibility but decreased the impact resistance of the films.
Keywords: polymer chemistry; UV-curable; waterborne; polyurethane; KH550

Title: Synthesis and characterization of one-dimensional CdS nanostructure

Authors: WU Zhipei, ZHANG Yanbin, LI Dan, FU Xiuli
PP: 636-641
Abstract: Chemical vapor deposition method was developed to fabricate various one-dimensional (1D) CdS nanostructures including CdS nanoribbons, CdS nanowires with different rough surface and CdS nanowires wreathed with irregular CdS particles. The controllable synthesis of the 1D nanostructures was realized by determining the deposition temperature and the flow of carrier gas. And then by use of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and other characterization methods, the synthesized CdS nanowires were further observed and analyzed. Through the experimental method and control requirements, the different CdS nanowires light structure was compared and analyzed .Growth mechanism of the nanostructure was investigated in detail. The 1D CdS nanowires follow a typical vapor-liquid-solid (VLS) growth mechanism and the growth of CdS nanoribbons contains the VLS and vapor-solid (VS) mechanism.
Keywords: inorganic synthetic chemistry; chemical vapor deposition; CdS nanostructures; nanowire

Title: Hydro(solvo)thermal synthesis and characterization of durian-shaped dodecahedral rutile microparticles

Authors: GAO Qiong, LIU Jia, YANG Xianfeng, WEN Yuping, ZHOU Qiang, WU Mingmei
PP: 630-635
Abstract: In this paper, aqueous complex titanyl oxalate acid was synthesized through hydrothermal approach in the oxalic acid solution, and it can be further transformed into rutile micro-polyhedral under hydrothermal situation. The products were characterized in detail by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED) techniques. Furthermore, with varying reaction time , a series of TiO2 nanocrystals with different phase and complex morphologies were performed. And an interesting phenomenon that the crystal phase composition of product can to-and-fro transform with the change of experimental parameters was found. The effect of different parameters on the crystal phase composition and morphology of the product was also investigated. The photocatalytic degradation results of methyl orange clearly demonstrate that the photocatalytic performance of TiO2 nanomaterials is related to their structure.
Keywords: inorganic synthetic chemistry; oxalic acid; TiO2; nanocomposites; hydrothermal synthesis; controlled growth

Title: Low temperature synthesis and catalytic activity studies of titanium-containing mesoporous SiO2 catalyst Ti-MCM-41

Authors: YANG Mu, WANG Ge, WANG Yingying
PP: 623-629
Abstract: Titanium-containing mesoporous SiO2 catalyst Ti-MCM-41 has been successfully synthesized by post synthesis approach at room temperature. The material has been characterized by small-angle X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution electronic microscope (HRTEM), nitrogen adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis) and inductively coupled plasma (ICP). The results demonstrate the existence of an ordered mesoporous structure. Mesoporous molecular sieve has good catalytic activity in the epoxidation of cyclooctene with aqueous H2O2 as an oxidant. The paper also investigates the influence of different Si/Ti ratio on the structure and performance of the mesoporous titanium silicalite catalyst and the influence of surface modification on the performance of the catalyst, and the results show that the appropriate increase of titanium content of the catalyst can enhance the catalytic efficiency. With diphenyldimethoxysilane modified the surface of mesoporous molecular sieves, the catalytic properties are also improved.
Keywords: material chemistry; MCM-41; titanium silicalite catalyst; epoxidation; surface modification

Title: Study of Cu/ZrO2 catalyst for oxidation dehydrogenation from diethanolamine to iminodiacetic acid

Authors: LI Yanni
PP: 615-622
Abstract: Cu-zirconia catalyst was prepared by coprecipitation and tested for oxidation dehydrogenation from diethanolamine to iminodiacetic acid (IDA). The results showed that the catalytic activity was influenced by the reaction conditions. Techniques of X-ray Zdiffraction (XRD), scanning electron microscope-energy dispres spectroscopy (SEM-EDS) and N2 adsorption-desorption were used to characterize the structure and surface properties of the catalyst. The results showed that the structural change of the catalyst was the major factor of deactivation in the reaction process. The sodium hydroxide accelerated the crystallization of catalyst and weakened the interaction between copper and zirconia, which brought about copper particles growing up rapidly and being lost.
Keywords: catalytic chemistry; iminodiacetic acid; Cu-zirconia catalyst; sodium hydroxide; crystallization

Title: Reduction of CeO2(111) film by low energy Ar+ sputtering

Authors: WANG Guodong, KONG Dandan, PAN Yonghe, PAN Haibin, ZHU Junfa
PP: 607-614
Abstract: The structure and electronic properties of epitaxial grown CeO2(111) thin films before and after Ar+ bombardment have been systematically studied in situ with synchrotron radiation photoemission spectroscopy (SRPES). Under the condition of the energy of Ar ions being 1 keV and a constant current density of 0.5 μA/cm2, Ar+ bombardment of the surface causes a new emission appearing at 1.6 eV above the Fermi edge, which is related to the localized Ce 4f1 orbital in the reduced oxidation state Ce3+. With increasing time of sputtering, the intensity of the reduced state Ce3+ increases and reaches a constant value after 15 min sputtering, which corresponds to the surface being exposed to 2.8×1015 ions/cm2. The reduction of CeO2 is attributed to a preferential sputtering of oxygen from the surface. Ar+ bombardment leads to a gradual buildup of an, approximately 0.74 nm thick, sputtering altered layer after 15 min sputtering. These studies have demonstrated that Ar+ bombardment is an effective method for reducing CeO2 to CeO2-x and the degree of the reduction is related to the energy and amount of Ar ions been exposed to the CeO2 surface.
Keywords: physical chemistry; Ar+ sputtering; synchrotron radiation; cerium oxide; preferential sputtering

Title: IR investigation of Pt nanothorn assembles

Authors: TIAN Na, ZHOU Zhiyou, SUN Shigang
PP: 602-606
Abstract: This paper investigated the in situ infrared (IR) spectra CO adsorbed on Pt nanothorn assembles, which are electrodeposited on glassy carbon substrate. The shape of IR spectra of CO adsorbed on Pt nanothorn assembles is bipolar, different from that on bulk Pt electrode (downward peak), which may due to the spctial structure of the Pt nanothorn assembles. Pt nanothorn assembles show significantly enhanced IR absorption, yielding an IR enhancement factor of 17.
Keywords: physical chemistry; platinum; electrodeposition; in situ IR spectroscopy

Title: Reactions of ketenes and imines with alkenyl substituent(s)

Authors: WANG Zhixin, XU Jiaxi
PP: 591-601
Abstract: Reactions of ketenes and imines with alkenyl substituent(s) have been reviewed. Reactions of alkenylketenes and imines or ketenes and alkenylimine produce 3-or 4-alkenyl-β-lactams, and 5,6-or 2,3-dihydro-1H-pyridine-2-ones. In the reactions, imines attack the ketenes to generated zwitterionic intermediates. The formed intermidates with conjugative double bonds can undergo either conrotatory four-membered ring closure to give rise to β-lactams, or disrotatory six-membered ring closure to produce six-membered heterocyclic compounds dihydro-1H-pyridine-2-ones. The selectivity in the ring closure is controlled by both steric hindrance and the electronic effect. Reactions of alkenylketenes and alkenylimines give rise to unstable 3,4-dialkenyl-β-lactams, which further undergo the Cope rearrangement to afford unsaturated eight-membered lactams.
Keywords: physical organic chemistry; β-lactam; reviews; alkenylketene; alkenylimine; imine; ketene

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