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April 15,2011
Volume 4,Issue 7
Pages -
Subject Area:Coal Chemical Engineering,Chemical Process Control and Simulation,Catalytic Reaction Engineering,Analytical Chemistry,Computational Chemistry,Electrochemical Analysis,Electrochemistry,Applied Chemistry (Specifically Applied to the Relevant Disciplines)

Title: Study on preparation and analysis of carbamazepine-saccharin cocrystal

Authors: LI Runyan, CONG Haifeng, MAO Huilin, GONG Junbo
PP: 667-672
Abstract: Carbamazepine-saccharin (CBZ-SAC) cocrystal was prepared using different crystallization technologies, and characterized by single crystal diffraction, powder X-ray diffraction（PXRD）, differential scanning calorimeter （DSC）and Fourier transform infrared spectrometry （FT-IR）. Crystal habits of CBZ, SAC and CBZ-SAC in different solvents were investigated, the cocrystal habit was simulated by the Materials Studio software. It is showed that solvents affected CBZ and SAC crystal habits than that of CBZ-SAC, the simulated cocrystal habit fitted well with the experimental one.
Keywords: pharmaceutical engineering; carbamazepine-saccharin cocrystal; preparation; simulation; crystal habit

Title: Effects of different catalysts on yield of products of Huolinhe lignite pyrolysis

Authors: TIAN Jing, WU Jianjun, HU Chang’e, LIU Qiong
PP: 661-666
Abstract: In this paper, the effect of the addition of catalysts CaO, MgO, K2CO3 and Na2CO3 in different rations on the yield of catalytic pyrolysis products of Huolinhe lignite were estimated by Gray-King (G-K) low temperature experimental oven and the Fourier transform infrared spectroscopy (FTIR) analysis of char with the addition of CaO, K2CO3 was separately carried out. The results show that the addition of CaO and MgO can increase the char yield and reduce the tar yield, while K2CO3 and Na2CO3 can increase the gas yield and reduce the tar and semi-coke yield. The FTIR analysis of the char indicates that CaO may remain in the semi-coke in the form of carbonate.
Keywords: coal chemical engineering; catalytic; lignite; pyrolysis

Title: Model control applied to split heat-exchanger network

Authors: YU Qiaoxin, CUI Guomin, ZHOU Yanjun
PP: 656-660
Abstract: A method called model control was presented, and it was used in chemical process control and simulation. First of all, an accurate mathematical model of split heat exchanger networks was established, which can calculate both the outlet parameters of fluids and the energy recovery of the heat exchanger networks. Then, the optimal mathematical model of the split heat exchanger networks was established in order to reach the target of the maximum energy recovery. Through optimizing, the optimal flow split parameters in different operating conditions can be obtained. Case study shows that, using the mathematical model of the split heat exchanger networks and optimization strategies in the control of heat exchanger networks, adjusting the parameter of model in real time can always reach the best energy recovery, and overcome the control lag effectively.
Keywords: chemical process control and simulation; model control; split heat exchanger networks; energy recovery

Title: Catalytic synthesis of ethyl acetate by an acidic ionic liquid N-methylpyrrolidone hydrosulfate

Authors: GAO Nannan, LI Wenchun, TANG Xiaoxue, CUI Wei, TANG Shengwei
PP: 648-655
Abstract: An acidic ionic liquid N-methylpyrrolidone hydrosulfate (［Hnmp］HSO4) was used as catalyst to synthesize ethyl acetate. The effects of different reaction parameters, such as reaction temperature, reaction time and catalyst dosage were investigated. The results showed that N-methylpyrrolidone hydrosulfate exhibited excellent catalytic activity. The yield of ethyl acetate was about 65% (mass fraction) when the reaction was conducted at optimum reaction conditions: the molar ratio of ethanol and acetic acid is 1.4∶1.0, the dosage of catalyst based on alcohol is 2.5% (molar fraction), the reaction temperature is 120℃ and reaction time is 135 min. After separation with the product and dry at high vacuum, the acidic ionic liquids recycled 6 times without significant yield decrease.
Keywords: chemical reaction engineering; ionic liquid; ethyl acetate; acetic acid; ethanol; esterification

Title: Preparation and performance testing of polyoxometalate isomers/polyaniline materials

Authors: DU Dongdong
PP: 641-647
Abstract: Polyoxometalate isomers/polyaniline (SiW11Co/PANI) was prepared by various methods. The products were characterized by means of ultraviolet (UV) spectrum, and the photocatalyst properties of the products were studied. In the experiments, the removal efficiencies to methylene blue under different conditions, such as illumination time, catalyst content, initial concentration of the solution, light sources and pH values were studied, the best catalyzing condition was determined, the best preparation method was analyzed, and the decomposition of the dye was researched. The results showed that the SiW11Co/PANI synthesized under solid method with acid had good photocatalytic properties.
Keywords: analytical chemistry; polyoxometalates; photocatalysis; dye

Title: FI-ICPMS coupling technique for highly selective determination of four heavy metals in complex matrices

Authors: LI Yan, JIANG Yan
PP: 635-640
Abstract: An online displacement solid-phase extraction via magnetic immobilization of mercapto-functionalized magnetite microspheres onto the inner walls of a knotted reactor coupled with ICPMS was developed for highly selective preconcentration and interference-free determination of trace heavy metals (Hg, Cu, Pb and Cd) in complex matrices. Online displacement solid-phase extraction of 2.7 mL aqueous solution gave the enhancement factors of 45-56 for the four noble metals in comparison with direct nebulization of aqueous sample solution, and the detection limits (3s) of 2.2-5.5 ng/L for the four noble metals. The sample throughput of the developed method was about 20 samples/h, and the relative standard deviation for eleven replicate determinations of the noble metals at the 50 ng/L level ranged from 1.4% to 2.5%. The developed method was successfully applied to selective determination of trace Hg, Cu, Pb and Cd in onion and garlic.
Keywords: analytical chemistry; flowing injection; magnetically immobilization; on-line displacement solid phase extraction; inductively coupled plasma mass spectrometry; heavy metal

Title: Algorithm of 3D rotation based on OpenGL and its application in computational chemistry

Authors: ZHU Tiemin, HOU Jin, WANG Fenying, GAO Yajun, ZHAO Jianwei
PP: 627-634
Abstract: This paper presents several 3D graph rotation schemes in the OpenGL display, including imitating 3D tracking ball with virtual ball, representing rotations via quaternions and rotating viewpoint. Combined with the characteristic of molecular dynamics simulations, a novel 3D graph rotation algorithm based on viewpoint is implemented. The model controls the quantity and direction of rotation by the mouse and the viewpoint is set as the reference center. The position of viewpoint is adjusted to the rotation immediately. According to the new position, the rotation accuracy is modified to adapt to it at the same time. The model can be investigated from all directions, and it is more convenient to study the crystal structure and small changes of the structure. The results demonstrates that this method is preferable real-time and shows high efficient in the molecular dynamics simulations.
Keywords: computational chemistry; OpenGL; molecular dynamics; viewpoint; 3D rotation

Title: Influence of pH of testing solutions on electrochemical activity of {HECE/AA}n-Mb films

Authors: HU Yang, HU Naifei, LIU Hongyun
PP: 619-626
Abstract: The {HECE/AA}n-Mb films was fabricated by loading heme protein myoglobin (Mb) into {HECE/AA}n layer-by-layer films, where HECE is quaternized hydroxyethyl cellulose ethoxylate and AA is sodium alginate. The fraction of electroactive Mb among the total Mb loaded into the {HECE/AA}n-Mb films decreases remarkably as the pH of testing solution increases. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments with small electroactive probe demonstrates that the permeability of {HECE/AA}n-Mb films toward small counterions in solution decreases remarkably as the pH of testing solution increases. The transportation of counterions from external solution phase into film phase and/or from film phase to solution phase may become a limiting factor for Mb exchanging electrons with the underlying PG electrodes since the Mb molecules in the films take electron-hopping or electron self-exchange mechanism in electron transfer. The pH of testing solution would influence the porosity or permeability of the films, and the mobility of counterions with the film phase depends on the porosity or permeability of the films, so the pH of testing solution would greatly influence the electrochemical activity of Mb in the films.
Keywords: electrochemical analysis; myoglobin; absorption; layer-by-layer assembly; direct electrochemistry; pH value

Title: Fabrication of multi-responsive interpolymer complex micelles based on reversible covalent bond formation among phenylboronic acid and glucose moieties

Authors: WANG Di, LIU Shiyong
PP: 610-618
Abstract: Two types of diblock copolymers containing phenylboronic acid and glucose moieties, respectively, poly(N-isopropylacrylamide)-b-poly(N-acryloyl-3-aminophenylboronic acid) (PNIPAM-b-PAPBA) and poly(N-isopropylacrylamide)-b-poly(acryloyl glucosamine) (PNIPAM-b-PAGA) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Due to the formation of borate ester functionalities between phenylboronic acid and glucose moieties under slightly alkaline conditions (pH=9.3), mixed solution of PNIPAM-b-PAPBA and PNIPAM-b-PAGA diblock copolymers can spontaneously form interpolymer complex micelles consisting of PAPBA/PAGA complex cores and PNIPAM coronas. Since the formation/cleavage of borate ester linkages is highly reversible upon the variation of solution pH and glucose concentrations, interpolymer complex micelles fabricated via reversible covalent bond formation between PAPBA and PAGA blocks exhibit multi-responsiveness to pH and glucose.
Keywords: polymer chemistry; complex micelles; scientific experiment method; reversible covalent bond; multi-responsiveness

Title: Preparation of PtAu/MWCNTs nanocomposites for electrocatalytic oxidation of methanol

Authors: XU Bin, MA Jianchun, BAI Yancui, ZHANG Weide
PP: 601-609
Abstract: In this paper, a series of catalysts named PtAu/mulit-walled carbon nanotubes (PtAu/MWCNTs) with different Pt/Au molar ratio were prepared by reduction of H2PtCl6·6H2O and HAuCl4·3H2O with ethylene glycol as a reducing reagent and sodium citrate as a stabilizing reagent. By changing the deposition order of metals, Au@Pt/MWCNTs ［PtAu=20% (mass fraction), and Pt/Au molar ratio was 4∶1］ nanocomposites were prepared by successive reduction of HAuCl4·3H2O and H2PtCl6·6H2O. XRD (X-ray diffrattion) and TEM (transmission electron microscope) were adopted to characterize the nanocomposites. The result indicates that the PtAu nanoparticles with an average diameter of about 4.0 nm are supported on MWCNTs successfully. In addition, these nanocomposites show excellent catalytic activity for the oxidation of methanol, especially for the PtAu/MWCNTs nanocomposite with Pt/Au molar ratio of 4∶1, which could be concluded that incorporation of an appropriate amount of Au with Pt nanoparticles can greatly enhance the activity of the catalyst. Meanwhile, it was also observed that the activity of the Au@Pt(1∶4)/MWCNTs was better than that of PtAu(4∶1)/MWCNTs, which may illustrate that the structure of the catalysts has a great influence on their catalytic activity.
Keywords: physical chemistry; nanotubes; platinum and gold nanoparticles; methanol; electrocatalytic oxidation

Title: Study on selective oxidation of ethane over SBA-15 supported catalyst with ultra-low loading amount of transitional metal

Authors: LIU Jian, ZHANG Peng, ZHAO Zhen, ZHANG Zhe, DUAN Aijun, JIANG Guiyuan
PP: 596-600
Abstract: A series of SBA-15 mesoporous zeolite-supported transitional metal oxide catalysts with low loading amount of additives were prepared by the method of incipient-wet impregnation. The structures of the catalysts were characterized by using the techniques of N2 adsorption, low angle X-ray diffraction (XRD) and UV-Raman spectroscopy, and their catalytic performances for the selective oxidation of ethane were investigated. The results demonstrated that for the Zn/SBA-15, Fe/SBA-15 and V/SBA-15 catalysts, the stable ion configuration structures with d-orbitals fully occupied or half occupied or empty are good for the selective oxidation of ethane to aldehydes.
Keywords: physical chemistry; ethane; selective oxidation; catalyst; SBA-15; supported oxide

Title: Synthesis of 3-［1-(2,4,6-trimethyl)phenyl］indenyl-dicyclohexylphosphoium tetrafluoroborate

Authors: ZHANG Bei, YU Guang’ao, XIA Jianlong, HAO Xiaowei, LIU Shenghua
PP: 593-595
Abstract: Synthesis of 3-［1-(2,4,6-trimethyl)phenyl］indenyl-dicyclohexylphosphoium tetrafluoroborate deprotonation of 1-(2,4,6-trimethyl)phenyl indene by BuLi and trapping of the lithiated intermediate by Cy2PCl afforded regiospecific 3-［1-(2,4,6-trimethyl)phenyl］indenyl-dicyclohexylphosphine as the product, this phosphineligand react with tetrafluoroborate acid give the air stable 3-［1-(2,4,6-trimethyl)phenyl］indenyl-dicyclohexylphosphoium tetrafluoroborate. The product has been fully characterized by 1H NMR, 13C NMR 31P NMR spectroscopy, and X-ray crystal diffraction techniques.
Keywords: organic chemistry; positional specificity; phosphine; tetrafluoroborate; synthesis

Title: Synthesis of solution processable photovoltaic materials based on diketopyrrolopyrrole

Authors: YING Weijiang, HUA Jianli
PP: 587-592
Abstract: A new type of D-A-D type triphenylamine-diketopyrrolopyrrole-triphenylamine derivates was synthesized via Suzuki coupling reaction, in which the structure and the performance were characterized by nuclear magnetic resonance (NMR), mass spectra (MS), ultraviolet-visible (UV-Vis) absorption and steady-state photoluminescence spectra, respectively. The compound has a good solubility, wide absorption spectrum and fine film-forming properties. The steady-state photoluminescence of DPPE and PCBM blends shows the donor of DPPE is strongly quenched, the initial results suggest that the compound is a promising candidate for solution processable photovoltaic materials.
Keywords: applied chemistry; diketopyrrolopyrrole; triphenylamine; synthesis; bulk heterojunction; photovoltaic materials

Title: Recent development on catalytic asymmetric Pictet-Spengler reaction

Authors: ZHAO Jiannan, LIN Lili, LIU Xiaohua, FENG Xiaoming
PP: 580-586
Abstract: The Pictet-Spengler reaction is one of the most direct, efficient and prevailing method to construct optically active tetrahydroisoquinoline and tetrahydro-β-carboline. In this paper, the recent progress on the catalytic asymmetric Pictet-Spengler reaction between tryptamine and aldehyde or ketone was briefly described. Combined with the possible catalytic reaction mechanism, the catalytic outcomes of catalysts such as chiral borane, thiourea, phosphoric acid and chlorosilane were compared. The strategy to improve the enantioselectivity and yield of the corresponding tetrahydro-β-carboline was also discussed through the modification of the substrate. At last, the outlook of the catalytic asymmetric Pictet-Spengler reaction was summarized.
Keywords: organic chemistry; tetrahydro-β-carboline; reviews; asymmetric catalysis; Pictet-Spengler reaction

Title: The research progress on cathode material Li2MnSiO4 of lithium ion battery

Authors: TANG Zhiyuan, WEI Yi
PP: 576-579
Abstract: Li2MnSiO4, as a novel lithium ion battery cathode material, is promising due to its wide source, low cost, environmental benign and high specific capacity. In this paper the crystal structure, electrochemical performance and the synthesizing methods of Li2MnSiO4 were presented. Aiming at the defects, such as low electronic conductivity and unstable crystal stability, some improvements were proposed, such as carbon coating and metal doping. Finally the prospect of application tendency was depicted.
Keywords: applied chemistry; cathode material of lithium ion battery; reviews; Li2MnSiO4

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