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September 15,2010
Volume 3,Issue 17
Pages -
Subject Area:Chemical Engineering Thermodynamics,Chemical Reaction Engineering,Coal Chemical Engineering,Biochemical Engineering,Evaporation and Crystallization,Chemical Separation Engineering,Applied Chemistry (Specifically Applied to the Relevant Disciplines),Analytical Chemistry,Electrochemical Analysis,Environmental Radiochemistry

Title: Applications of Mathematica in fluid flow

Authors: ZHANG Yaqi, DU Yingchun, DU Chunhui
PP: 1820-1826
Abstract: The results of calculation examples show that: mathematical software Mathematica is used for processing some calculations about fluid flow, such as deriving flat wall falling film flow velocity distribution function by symbol calculation, curve fitting approach to fluid flow experimental data, solving differential equation from non-steady-state flow by NDSolve function, solving sets of nonlinear equations in simple and complex pipe-line calculations by FindRoot function, etc. By the application of Mathematica, the complex, cumbersome, time-consuming manual calculation can be removed from, and student s capacity using computer to solve fluid flow problems will improve greatly.
Keywords: chemical engineering thermodynamics; Mathematica; mathematical software; chemical engineering; fluid flow

Title: Determination and correlation of cefazolin sodium solubility

Authors: JIN Haihong, LI Yu, REN Baozeng
PP: 1813-1819
Abstract: Using a laser monitoring observation technique, the solubility values of cefazolin sodium in dimethyl sulfoxide and ethanol mixtures were measured at temperatures from 293.15 to 317.15 K at atmospheric pressure with the solvent mole fraction composition ranged from 0 to 0.9. The solubility of cefazolin sodium is increases with an increase of temperature in dimethyl sulfoxide and ethanol binary solvent mixture. Simultaneously, the solubility decreases with an increase of concentration of ethanol in the solvent mixture. The experimental data were correlated with the modified Apelbat equation and CNIBS/Redlich-Kister equation, respectively. For the ten group solubility data studied, the CNIBS/Redlich-Kister equation was found to provide a more accurate mathematical representation of the experimental data. The experimental solutility data and the correlation equation can be used as the basis of thermodynamic data and the model applied in the crystallization process of cefazolin sodium.
Keywords: chemical thermodynamics; cefazolin sodium; laser monitoring observation technique; solubility

Title: Experimental study on premixed laminar combustion of combustible gas mixture

Authors: LV Xiaohui
PP: 1807-1812
Abstract: The laminar combustion characteristics of combustible gas mixture (H2, H2+CO, 75% aqueous alcohol, 85% aqueous alcohol, 95% aqueous alcohol, 75% aqueous alcohol mixing different proportions of H2) were studied at different excess air ratio by using high-speed schlieren photography technique in a constant volume combustion bomb. The results show that laminar glow velocity decreases with the increase of excess air ratio. Increasing of hydrogen fraction will increase laminar burning velocity. Markstein length of aqueous alcohol increases with the increase of excess air ratio and decreases with the increase of hydrogen fraction.
Keywords: energy chemistry; aqueous alcohol; laminar glow velocity; Markstein length

Title: Conversion kinetics of D-xylose into furfural catalyzed by SO42-/ZrO2-TiO2

Authors: ZHANG Junhua, LIN Lu
PP: 1800-1806
Abstract: SO42-/ZrO2-TiO2 catalysts were synthesized by co-precipitation method, and the solid catalysts were characterized by powder X-ray diffraction (XRD). The catalysts were used in the catalytic conversion of D-xylose to furfural. An optimized furfural yield of 54% was achieved in 240 min at the temperature of 463 K over SO42-/ZrO2-TiO2 with Zr/Ti mole ratio of 7∶3. With the assumption of first order kinetics equation, the decomposition kinetics of D-xylose was attended, and the evaluated activation energy (E) and pre-exponential factor (A) of D-xylose decomposition was 116.65 kJ·mol-1 and 2.5×1011 min-1, respectively.
Keywords: chemical reaction engineering; biomass fuel; D-xylose; furfural; solid acid; kinetics

Title: Technology of injecting inhibitor liquor to prevent coal spontaneous combustion of sulfur-coal full-mechanized caving face

Authors: GUO Xin'an, GAO Qingcong, SU Shilong, YIN Xiaodan, LI Jinshuai
PP: 1795-1799
Abstract: The paper proposed a technology injecting inhibitor liquor into coal. The inhibitor liquor injected into coal with high pressure may permeate evenly into coal pores. No matter how cracked the coal is, it can be evenly surrounded by the inhibitor liquor. The inhibitor liquor isolates coal from air, thus it can prevent oxygenation and prolong time of spontaneous combustion, which provide assurance for safety mining. The technology was applied to S1105 work surface of Xinyang mine, and the experiment results showed that the technology had good fireproofing effect.
Keywords: coal chemistry engineering; spontaneous combustion of coal; sulfur-coal; Na2CO3 inhibitor; inhibitor liquor

Title: Study on the preparation capability of coal water slurry with different rank coals

Authors: ZHANG Yuliang, WU Guoguang, MA Shaolian, MENG Xianliang, LI Ping
PP: 1790-1794
Abstract: In this paper, the promoter action of different dispersants on coal s slurry ability has been studied by using 3 kinds of coals in different ranks, to study the influence of coal rank on character of coal s slurry. The experiment uses sodium-lignosulphonate(SLS) and naphthalenesulfonic acid-formaldehyde condensate (NSF) as additives. The synergistic effects of SLS and NSF and their compound dispersants have been researched yet. The results show that: the SLS dispersant has lower slurry property than the NSF to the three coal samples with different ranks; the low-rank coal has low slurry property, which can not be obviously increased by recomposing dispersants; and the high-rank coal has high slurry proerty, which can be obviously increased by recomposing dispersants.
Keywords: coal chemistry engineering; compound dispersant; slurry ability; rank of coal; fluidity; stability

Title: Cloning and sequence analysis of Deoxyribose aldolases from Bacillus strains

Authors: CHEN Liwei, YANG Lirong, CHEN Xiong, XU Gang, WU Jianping
PP: 1782-1789
Abstract: Four Bacillus strains were chosen via genome mining, and the putative deoxyribose aldolases (DERA) origined from the chromosome of these microorganisms were individually cloned via Polymerase chain reaction (PCR), and over-expressed in E.coli. It was found that these Bacillus DERAs had similar cleavage activity for their natural substrate 2-deoxy-D-ribose-5-phosphate (DRP), compared with E.coli DERA(EcoDERA), while they exhibited higher catalysis ability over EcoDERA in the retroaldol reaction of nonphosphorylated substrate 2-deoxyribose (DR). The ratio of specifcity constants for DR compared to DRP (［Kcat/Km(DR)］/［Kcat/Km(DRP)］) of four Bacillus strains DERA were all two or three orders of magnitude higher than EcoDERA. On the other hand, they had high tolerance towards heat, considering 40%~65% of the activity could be retained when they were heated at 70℃. It showed similar structure characters in the alignment of five DERA amino acid sequences, that Lys172, Phe200, Val206, and Ser239 in EcoDERA were all or partly replaced by Phe, Val, Ile and Ala in BsuDERA, BliDERA and BamDERA, and BthDERA, respectively. The differences might affect the electrostatic environment in substrate-binding pocket and the hydrophobic interaction around the scaffold of the two key Lys residues, herein were responsible for the differences in substrate specificities.
Keywords: biochemical engineering; deoxyriboaldolase; genome mining; substrate specificity

Title: On-line monitoring of zinc lactate concentration during cooling crystallization process

Authors: ZHANG Xiangyang, QIAN Gang, ZHONG Liang, ZHOU Xinggui, YUAN Weikang
PP: 1776-1781
Abstract: A method concerning on-line monitoring of solution concentration during cooling crystallization process by using conductivity meter was proposed in this paper. That is, solute concentration in slurry under different temperatures can be estimated by investigating the effect of temperature on conductivity of homogeneous solution and the contribution of solid concentration to slurry conductivity, respectively. Furthermore, four cooling crystallization processes of zinc lactate were performed, and the variations of concentration were measured on-line based on this method. And the accuracy was verified by comparing with the experimental results measured off-line by high performance liquid chromatography (HPLC).
Keywords: chemical separation technology; conductivity; crystallization; concentration; online measurement

Title: Study of fluorine removal by nanofiltration

Authors: LIU Xundong, GONG Jingwen, YANG Hongwei
PP: 1771-1775
Abstract: The effects of pressure, temperature and concentration on the removal of fluorine from synthetic high-fluorine water by nanofiltration (NF) membranes (NF90 and NF270) were investigated. The results show that there is a corresponding increase of the fluorine retention rate with the increasing of pressure. But, when the pressure reaches a certain value, the fluorine retention rate changes flattening. The membrane flux increases with the increasing of the pressure. For NF270 membrane, the fluorine retention rate has a slight decline with the increasing of temperature; nevertheless, there is an insignificant effect for NF90 membrane. In high-fluorine water, the effects of fluorine concentrations on the fluorine retention rate and membrane flux are little.
Keywords: chemical separation engineering; nanofiltration; membrane separation; drinking water; fluorine

Title: Effect of short branched structure and branching degree on the rheological, crystallization properties and environmental stress cracking resistance of high density polyethylene

Authors: ZHANG Jie, WU Jian, LI Yao, DUAN Hongyi, GUO Jinshan
PP: 1763-1770
Abstract: In this study, three kinds of short-branched-chain high-density polyethylene (HDPE) which could compared very well were selected by high temperature liquid nuclear magnetic resonance (NMR). Those HDPE was not modified by any physical or chemical methods. A series of experiments were carried out to focus on the influence of the branching density and branched-chain type on the performance of HDPE. The research results show that the effect of branching density on the rheological properties mainly lies on temperature and the effect of branched-chain length lies more on the shear rate; while the impact of branching type is more significant for the crystalline properties and resistance to environmental stress cracking properties.
Keywords: polymer chemistry; short-branching high-density polyethylene; rheology; crystallization; environmental stress cracking resistance

Title: Research on measuration of the sudan I by using fluorenscence quenching Processing method

Authors: WU Tianli, WANG Xingmin
PP: 1757-1762
Abstract: After using fluorescence spectrophotometer to measure Sudan I, the reseults show that: when the tryptophan is combined with the Sudan I, the fluorenscence in the tryptophan will be quenched. Within a certain range of 0.001 4-0.009 5 mg/L（R=0.998 4）, the fluorenscence quenching effects has a linear character of relationship with the thickness of Sudan I-acetonitrile, based on this situation a method of determining the Sudan I content quickly in the chili with the adoption of using the tryptophan fluorenscence quenching process has been established. The detection limit of this method is 0.000 7 mg/L, while the method of using the fluorenscence queching process to determine the Sudan I is original, fast, simple, with high delicacy and selectivity, and requires less resource. It is used to determine the Sudan I content in the Tine chili, the Gangu chili and their products, and the results are satisfying.
Keywords: inorganic chemistry; Sudan I; fluorescence quenching; chili; acetonitrile; tryptophan

Title: Study on purification methods of removing impurity from quartz

Authors: WU Huating, XIE Lishan, XU Yafang, Chen Jiannan, LIN Gucheng, ZHENG Xiaoan, YAN Guiyang
PP: 1752-1756
Abstract: Based on oxalic acid purification method, quartz offered by Shaxian Jingcheng Company was treated with different methods (i.e. acid leaching, magnetic separation and ultrasound). In order to compare the purifying effect of various methods, the concentration of iron and aluminum, the characterization of X-ray diffraction （XRD）, X-ray fluorescence （XRF） and whiteness were analyzed. The primary experimental results show that the effect of ultrasonic treatment is better. Sample A, the iron content decreased rate gets to 4.368 mg Fe/（g Quartz·L H2C2O4·h）. Sample B, the aluminum ion content decreased rate gets to 9.486 4 mg Al/（g Quartz·L H2C2O4·h）. The whiteness of sample improved obviously without destroying the crystal structure of quartz.
Keywords: inorganic chemistry; quartz; removing iron; removing aluminum; ultrasound; purification

Title: Determination of chlorogenic acid in tobacco by using near infrared spectroscopy

Authors: HAO Yong, CAI Wensheng, SHAO Xueguang
PP: 1747-1751
Abstract: A method for quantitative analysis of chlorogenic acid in tobacco extracts was developed by using near infrared (NIR) spectroscopy and partial least squares (PLS) regression. Effects of the coexistence solutes on PLS model were discussed by constructing different models with standard solutions and real tobacco extracts. Results show that standard samples can be used as a part of the calibration samples when there are not enough real samples, and the interference of the coexistence solutes can be eliminated by selection of suitable wavelength regions. With the optimized model, the root mean square error of calibration set (RMSEC) of the model and the root mean square error of prediction (RMSEP) of the external validation set are found to be 0.007 7 and 0.010 8, respectively, and a good correlation between reference concentrations and predicted values 0.983 was obtained.
Keywords: analytical chemistry; near infrared spectroscopy; chlorogenic acid; wavelength selection; interval partial least squares

Title: Direct electrochemistry of hemoglobin based on Au-GE modified carbon ceramic electrode

Authors: HE Yaping, ZHENG Jianbin, LI Kuangtian, SHENG Qinglin
PP: 1742-1746
Abstract: A new electrochemical biosensor based on the hemoglobin (Hb)/room temperature ionic liquid (IL)/Gold-graphene nano composite material（Au-GE）/carbon ceramic electrode (CCE) modified electrode was structured for the determination of hydrogen peroxide (H2O2). The direct electrochemistry and electrocatalytic of hemoglobin was studied and a new cyclic voltammetry method for the determination of H2O2 was formed. The resulting Au-GE composite film and the immobilization of Hb was characterized by Raman spectra, UV-vis, and electrochemical methods. Hb/IL/Au-GE/CCE showed a pair of well-defined, quasi-reversible redox peaks. It also showed good electrocatalytic ability to the reduction of H2O2 with the linear 2.7×10-7-2.5×10-4 mol/L and the detection limit was 1.1×10-7 mol/L (S/N=3). The apparent Michaelis-Menten constant (KappM) was estimated to be 16.6 μmol/L.
Keywords: direct electrochemistry; electrocatalytic; biosensor of hydrogen peroxide; homoglobin; gold-graphene nano composite material

Title: Primary investigation on selective identification of Cu2+ by pyrene-appended cyclen

Authors: HUANG Yu, CHEN Shanyong, ZHANG Ji, TAN Xinyu, LU Qiaosen, ZHANG Yu, YU Xiaoqi
PP: 1737-1741
Abstract: A new macrocyclic polyamine (1,4,7,10-tetrazacyclododecane) derivative 4 was prepared. The macrocyclic polyamine moiety was bridged by L-glutamic acid via amino bond and pyrene. Fluorescence quench experiments were carried out to compare the fluorescence selectivity ability of different metal ions in methanol/water mixture. The results indicated that compound 4 exhibited excellent selectivity and binding ability towards Cu2+. The association constant (Kassoc) of 4 for Cu2+ was 2.0 06 mol/L.
Keywords: applied chemistry; cyclen; copper ion; fluorescent probe

Title: Progress on the conversion of cellulose in ionic liquids

Authors: LUO Jia, ZHANG Jiaxi, HU Changwei
PP: 1730-1736
Abstract: As the most abundant biorenewable resource, the conversion of cellulose into fuels and chemicals has attracted increasing attention. In this paper, the research background and the recent developments concerning the conversion of cellulose in ionic liquids are reviewed. The characteristics and existing problems are discussed. Especially the significance of using ionic liquids as cellulose solvent is demonstrated in details，for the design and synthesis of specific ionic liquids for the activation of cellulose molecules and the efficient transformation of cellulose is important. The prospect of the use of ionic liquid as cellulose solvent is discussed.
Keywords: physical chemistry; cellulose conversion; reviews; ionic liquids; design and synthesis

Title: Chemistry problems in high level radioactive waste disposal project

Authors: LIU Chunli
PP: 1725-1729
Abstract: China plans to construct a geologic repository in the middle of this century to safely and effectively dispose the high-level radioactive waste produced from military activities, nuclear power plants and nuclear technology application processes. The role of chemistry in high level radioactive wastes disposal project is discussed and the radiochemistry, analytical chemistry and inorganic chemistry in helping scientists to insight the processes of reactions of key radionuclides with the host rock and backfilling materials are discussed in terms of safety assessment of a geologic repository for high level radioactive waste.
Keywords: environmental radiation chemistry; high level radioactive waste; reviews; geologic disposal; safety assessment

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