Table of Content

30 August 2012, Volume 32 Issue 4 Previous Issue    Next Issue

研究报告

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Blends of Poly(L-lactic Acid) and Wheat Straw Fiber GAO Qin-wei;XU Chen;XU Zhe;ZHAO Li-fang 2012, 32 (4):  1-4.  Abstract ( 697 )   PDF (1188KB) ( 883 )   Save The blend solutions of poly(L-lactic acid) (PLLA) and wheat straw fiber (WSF) were prepared in the solvent of N-methyl morpholine-N-oxide. Then the blends of PLLA and WSF were also prepared. Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffraction were performed to determine PLLA/WSF blends. The compatibility and crystalline of PLLA and WSF in blends were investigated. The results show that PLLA and WSF can form a homogeneous mixture solution in N-methyl morpholine-N-oxide. Strong interaction between PLLA and WSF can be detected, which suggests good compatibility between the two components in PLLA/WSF blends. The morphology and properties of PLLA/WSF blends vary with the ratios of PLLA to WSF. With increasing PLLA contents, the glass transition temperatures of PLLA/WSF blends gradually reduce to that of PLLA. Both PLLA and WSF are crystalline, while PLLA/WSF blends are amorphous when the ratio of PLLA to WSF is less than 6:4. When the ratio of PLLA/WSF is more than 6:4, the blend is crystalline and their melting points increase with increasing PLLA contents. Thus biodegradable polymeric materials with different properties can be prepared through changing ratios of PLLA to WSF. Related Articles | Metrics

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Enhancement Effect of Exogenous Additives on Enzymatic Conversion of Moderate Temperature Alkali-treated Corn Stover Residue OUYANG Jia;LI Xin;CHEN Mu;LIAN Zhi-na 2012, 32 (4):  5-9.  Abstract ( 804 )   PDF (1159KB) ( 690 )   Save Moderate temperature alkali-extracted corn stover was used as a substrate for enzymatic hydrolysis. The effects of diffe-rent additives on enzyme hydrolysis were investigated and their possible mechanisms were studied.The results indicated that polyethylene glycol 6000 (PEG6000) was the most effective additive. The moderate temperature alkali pretreatment resulted in decreased lignin (50.02% removal). When 40 g/L cellulose was treated by 15 FPIU/g Celluclast 1.5 L and 30 BU/g Novozyme 188 for 48 h, the sample with 73.51% glucose yield and 84.51% hydrolysis yield was obtained as 4.0 g/L PEG6000 was added, which increased 26.2% and 27.1% in contrast to the sample without PEG6000, respectively. Addition of PEG6000 reduced the adsorption of enzyme protein on alkali-extracted corn stover. On the other hand, the enzyme distribution in liquid phase, enzyme activity and stability were promoted. The cellulase activity of celluclast 1.5 L increased by 34.1% and its stability increased by 57.3% in presence of PEG. Related Articles | Metrics

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Effect of Press on Reconstituted Tobacco Paper-base Properties ZENG Jian;CHEN Ke-fu;XIE Jian-ping;XU Guang;LI Jun;RAO Guo-hua;YANG Fei;GAO Wen-hua 2012, 32 (4):  10-14.  Abstract ( 691 )   PDF (1776KB) ( 736 )   Save Tobacco stem and tobacco dust were used to prepare tobacco paper-base in this study. The effect of pressure in press section on the properties of tobacco paper-base was studied. The results indicated that tensile index gradually increased from 17.27N·m/g to 23.69N·m/g; tear index decreased from 2.00mN·m2/g to 1.69mN·m2/g, bulk decreased from 2.43cm3/g to 1.80cm3/g and density increased from 0.41g/cm3 to 0.56g/cm3 when the pressure increased from 0MPa to 0.4MPa. Meanwhile, the air permeability decreased from 1.20μm/(Pa·s) to 0.04μm/(Pa·s), and filling value gradually declined from 7.23cm3/g to 6.08cm3/g. Similar trends of max wettability value tW,max and t95 eigenvalue were observed with the increase of pressure. The lowest tW,max 0.097s and t95(t95 with characterizes the time point, paper is permeated by liquid and signal intensity of 95% after the maximum)0.442s were obtained as the pressure was 0MPa, and the tobacco paper-base showed better liquid permeability and surface structure. The SEM results revealed that the lower pressure (<0.2MPa) was beneficial for the improvement of the tobacco paper-base porosity, which was positive to enhance the filling value and air permeability, as well as the liquid permeability of tobacco paper-base. Related Articles | Metrics

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Catalytic Pyrolysis Kinetics Analysis of Soybean Oil LIN Xiao-yu;ZHOU Yong-hong;XU Jun-ming 2012, 32 (4):  15-20.  Abstract ( 643 )   PDF (1418KB) ( 900 )   Save Thermo gravimetry (TG) and differential scanning calorimetry (DSC) analysis of soybean oil pyrolysis was performed from room temperature to 600℃. It indicated the decomposition mechanism was changed by adding sodium carbonate and alumina as catalysts. Vyazovkin approach is applied to calculate the activation energy by TG curves with different heating rates (5, 10, 20K/min). The tendency of the calculated results is consistent with DTG and DSC curves. The required reaction time for isothermal condition is estimated based on the activation energy. It suggested that the reaction rates of the violent pyrolysis might be decreased with sodium carbonate and γ-alumina catalysts. Related Articles | Metrics

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Crosslinking Reaction and Kinetics of Aminated Polyols from Lignin Model Compounds NIE Ming-cai;KONG Zhen-wu;HUO Shu-ping;WU Guo-min;CHEN Jian 2012, 32 (4):  21-27.  Abstract ( 703 )   PDF (1396KB) ( 832 )   Save The guaiacol and vanillin lignin model compounds with aminated polyols were dissolved by butanone to prepare the solution with solid content 30%, and then mixed with MDI-50 as the molar ratio of —NCO to —OH is 1:1. The characterization of crosslinking reaction of these two aminated polyols with MDI-50 at ambient temperature was investigated by DEA, and the crosslinking reaction kinetics was investigated by FT-IR in this study. The kinetic equations of these two crosslinking reaction systems were obtained. The results indicated that the crosslinking reactions between these two aminated polyols and MDI-50 were similar in reactivity, and the reactions followed the n-order reaction kinetic model. Related Articles | Metrics

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Preparation of 2,3-Butanediol by Enzymatic-hydrolysis and Fermentation of Liquefied Straw JIANG Yang;ZHANG Yu-cang;HE Lian-fang;JIN Feng-xie 2012, 32 (4):  28-38.  Abstract ( 647 )   PDF (1285KB) ( 782 )   Save In this paper, the straw was liquefied using glycol as solvent and enzymatically pretreated firstly. Then it was fermented by Klebsiella pneumoniae CICC 10011 to prepare 2,3-butanediol. The influence factors such as temperature, pH, inoculum, rotation speed,reaction time, substrate concentration on the liquefied products fermentation for 2,3-butanediol were studied. After double-membrane concentration of hydrolysate, the total sugar concentration of liquefied straw could be controlled between 85 and 95g/L after liquefaction and enzymolysis. This procedure not only provided enough carbon sources, but also achieved the automation of process control, increase product concentration, and reduce the cost of separation. The optimum fermentation conditions were described as follows: initial total sugar concentration was 94.3g/L; temperature was set at 37℃; pH value was 5.5; inoculation amount of strain was 10%; rotation speed was 170 r/min; fermentation was carried out for 72h. Under this condition, 36.47g/L of 2,3-butanediol was obtained with the yield of 42.5% relative to the total sugar. The efficiency was 0.51g/(L·h), and the highest yield of liquefied products which were converted to 2,3-butanediol was 33.4%. Related Articles | Metrics

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Physicochemical Properties of Lacquer Oils DONG Yan-he;WANG Cheng-zhang;YE Jian-zhong;YUAN Jiao-jiao;ZHOU Yan;HE Yuan-feng 2012, 32 (4):  28-32.  Abstract ( 576 )   PDF (1573KB) ( 848 )   Save The physicochemical properties of lacquer oils from Shanxi under different pretreatments were studied in this paper. Chemical constituents of lacquer oils of Rhus Succedanea L., seeding and grafting Rhus Succedanea L. from Jianxi were studied too. The results showed that lacquer oils after aqueous wash or soaked by petroleum ether are light and clarify in color, and its yield improves from 9.61% to 14.87% accordingly. Meanwhile, their acid value are 9.79 and 6.95, respectively. This result is clearly lower than the lacquer oils without any pretreatment. The saponification value and peroxide value are lower, too. That the content of linoleic acid in lacquer oils from Shanxi is higher than 72% results in a high application value. The skin and kernels of the introduced lacquer berries from Jiangxi are easier to be separated. Their relative contents of the linoleic acid are 56.222%. Related Articles | Metrics

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Effect of Spacer Chain Character on Surface Activities of Rosin-based Quaternary Ammonium Gemini Surfactants HAN Shi-yan;LI Shu-jun;ZHAO Yan-yan;SONG Zhan-qian;FANG Gui-zhen 2012, 32 (4):  39-42.  Abstract ( 668 )   PDF (1145KB) ( 916 )   Save Two types of rosin-based quaternary ammonium gemini surfactants(Ⅰand Ⅱ) were successfully prepared with tetramethylethylenediamine and triethylenediamine as spacer groups. The results of the surface activity analysis showed that: the critical micelle concentrations (CMC) of Ⅰ and Ⅱ are 1.42×10-4 and 9.7×10-4mol/L, respectively. The γCMC of Ⅰ and Ⅱ is 36.69, 43.41mN/m, respectively. The emulsifying times of these two gemini surfactants is 16 and 10min, respectively. The calculated values of pc20 are 4.2 and 3.2, respectively. The calculated value of hydrophile lipophile balance (HLB) of both these two gemini surfactants is 14.45. Ⅰ has good compatibility with anion surfactants, whereas Ⅱ has bad compatibility with anion surfactants. And the effects of the spacer groups' character on surface activities of quaternary ammonium gemini surfactants were explored. The results showed that rosin-based quaternary ammonium gemini surfactants by flexible chain spacer groups Ⅰ has higher activity than that by rigid chain spacer groups Ⅱ. Related Articles | Metrics

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Effect of Steam Explosion and Organosolv Pretreatment on the Hydrolysis of Poplar Substrate KANG Neng;LIU Zhong;HUI Lan-feng;LU Xiu-juan;MIAO Hong 2012, 32 (4):  43-46.  Abstract ( 886 )   PDF (1140KB) ( 1163 )   Save The influences of steam explosion and organosolv pretreatments on the cellulose content, crystallinity index, lignin content and hydrolysis of the triploid populous tomentosa under the optimal conditions were investigated in present study. Their impacts on hydrolysis characterizations of poplar substrate were studied, too. The results indicated that lignin could partly be removed by steam explosion pretreatment. In contrast, organosolv pretreatment can removed more lignin than that by steam explosion. The lignin was 63.34% lower than that of untreated one. The crystallinity index increased to 1.962 after steam explosion and to 1.712 after organosolv pretreatment compared to the raw material. The conversion rate of glucose was 81.36% after organosolv pretreatment and up to 91.29% after steam explosion. Related Articles | Metrics

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Ultrasound-assisted Enzymatic Hydrolysis of Furfural Residues after Alkaline Peroxide Pretreatment XING Yang;BU Ling-xi;ZHU Li-wei;JIANG Jian-xin 2012, 32 (4):  47-52.  Abstract ( 640 )   PDF (1149KB) ( 705 )   Save Ultrasound-assisted enzymatic hydrolysis of furfural residues after alkaline peroxide pretreatment was studied. The glucose yields and remaining enzyme activity after enzymatic hydrolysis in different modes were analyzed and compared. The results showed that ultrasound-assisted enzymatic hydrolysis after 2 h of saccharification was the optimized condition and glucose yield in this procedure was enhanced from 55.01% to 73.35% in comparison with traditional procedure. The mechanical effect of ultrasound-assisted affected enzyme adsorption and desorption and was beneficial to enzyme combination with the substrate. The diffe-rent ultrasonic assisted enzymatic hydrolysis were believed to affect the glucose yield and the U-C mode was better than other modes. The yields of enzyme addition after ultrasonic treatment were 46.35% higher than those of enzyme addition before ultrasonic treatment. It is clear that ultrasound-assisted enzymatic hydrolysis of furfural residues after alkaline peroxide pretreatment with low energy consumption and low pollution will provide a good development direction for the industrial production of ethanol. Related Articles | Metrics

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Preliminary Study on Pyrolysis of Wood Tar in Molten Salt Media LÜHong-yun;YU Feng-wen;TANG Qiang;JI Jian-bing 2012, 32 (4):  53-57.  Abstract ( 806 )   PDF (1186KB) ( 1186 )   Save Catalytic cracking reactions was performed using wood tar as raw material under the catlysis of molten salt in fixed-bed cracking reactor. The influence of cracking temperature on the components of product was investigated. The chemical components of wood tar and secondary cracking products were analyzed using gas chromatograph with mass selective detector (GC-MS). It was found that the wood tar is mainly compsed of guaiacol, 4-ethyl guaiacol, 4-methyl guaiacol, 3-methyl phenol, diacetone alcohol etc. Combination of high cracking temperature and low feed rate are beneficial to the cracking reaction of tar. The secondary cracking of tar yield could reach 16.47% under the reaction conditions of temperature 500℃ and the feeding rate 1 g/min. Under the effect of molten salt, the amount of acids, ketones, esters and phenanthrene was significantly reduced. The conversion of phenol is lower than other fractions, and other fractions can be converted phenolic fractions. Related Articles | Metrics

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Thermal Stability of Gallic Acid GUO Man-man;XIAO Zhuo-bing;PENG Mi-jun;YU Hua-zhong;GUO Rui-ke 2012, 32 (4):  58-62.  Abstract ( 1953 )   PDF (1074KB) ( 1753 )   Save Thermal decomposing curves of gallic acid in different heating speeds were obtained in the nitrogen atmosphere by TG-DTG techniques. Two analysis methods of Achar and Coats-Redfern were used to speculate the probable mechanism of thermal decomposing reaction and the kinetic parameters. The shelf life of gallic acid at room temperature was calculated by the kinetic parameters of the first stage. With the increasing of the heating rate, thermal decomposing tempreture of gallic acid rose. The most probable kinetic mechanisms of the three-stage thermal decomposition were all chemical reactions, and the corresponding mechanisms followed on reaction order. In accordance with the data of TG and Gaussian, one molecule of gallic acid lost 0.5 atom O at the fisrt-stage, and lost another 0.5 atom O and a molecule CO2 at the second stage. The shelf life of gallic acid at room temperature was about 1.5-2 years. Related Articles | Metrics

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Synthesis of Mesoporous Molecular Sieves MCM-41 Using Rice Straw and Rice Straw Ash and Its Property Analysis TANG Xiao-hong;LI Bao-jun;LI Cheng-wei 2012, 32 (4):  72-76.  Abstract ( 665 )   PDF (1572KB) ( 1097 )   Save The mesoporous molecular sieves RS-MCM-41 and RSA-MCM-41 were synthesized using rice straw (RS) or rice straw ash (RSA) as silica source. The differences between these two catalysts and SDS-MCM-41 catalyst synthesized from sodium silicate (SDS) were compared. The acidity of RSA-Al40/MCM-41 and RSA-Al10/MCM-41 were promoted by grafting Al with 40 and 10 of Si/Al mole ratio. After that, they were used as solid acid catalyst for synthesis of geranyl propionate (GP). The structures of the synthesized molecular sieves were characterized by XRD, FT-IR, NH3-TPD, and N2 adsorption-desorption. The structure of RS-MCM-41, RSA-MCM-41 and SDS-MCM-41 are shown in similar hexagonal mesoporous structure, good long-range order and crystallinity. However, all the catalysts showed low catalytic activities in synthesis of GP. Aluminum can be introduced into the framework of molecular sieves by grafting method as aluminum oxygen tetrahedron. After grafting, aluminium has negative influence on the crystallization of mesoporous molecular sieves, but it has positive influence on the amount of Brnsted acid sites on MCM-41 surface. The more of aluminium grafted, the stronger catalytic activity of molecular sieves is. The conversion of 54.47% and selectivity of 74.82% in synthesis of GP can be achieved with RSA-Al10/MCM-441 catalyst. Related Articles | Metrics

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Kinetics and Model Building of Extraction of Siberian Cocklour Fruit Oil ZHAO Wen-ying;ZHU Qing-shu;YUE Li;HUANG Qiao-yan;ZHANG Dan-dan 2012, 32 (4):  63-66.  Abstract ( 740 )   PDF (1109KB) ( 751 )   Save The extraction kinetics of Siberian cocklour fruit oil was investigated. An extraction model, based on the assumption of a second-order mechanism for extraction, was developed to predict the rate constant of leaching, the saturated leaching capacity, and the initial extraction rate with various extraction temperatures. The rate constant is a function of the temperature, and the relation of yield with extect time and temperature was deduced:Ct=t/(1.99×10-5exp(3065/T)+t/(0.003T-0.748)). This study provided a reference for industrial production. Related Articles | Metrics

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Antioxidant Activity of Camellia Oil Extracted by the Sub-critical Fluid MIAO Jian-yin;CHE Ke;CHEN Xue-xiang;LV Hong-cai;HUANG Yi-cheng;GUAN Xiao-sheng;CHEN Hong-zhang;ZHUANG Xue-ying;CAO Yong 2012, 32 (4):  67-71.  Abstract ( 668 )   PDF (1179KB) ( 878 )   Save In this paper, the polyphenol contents, DPPH-scavenging ability and effects of inhibition of the peroxide value and thiobarbituric acid value of sunflower oils during storage were analyzed for sub-critical camellia oil, commercial refined camellia oil and pressed crude camellia oil. It was shown from the results that the polyphenol contents of of sub-critical camellia oil,commercial refined camellia oil and pressed crude camellia oil were 6.26mg/g, 1.70mg/g and 8.33mg/g, respectively. The DPPH radical scavenging IC50 of sub-critical camellia oil was 15.39g/L (equivalent to 0.02g/L of VE), which was approximate to pressed crude camellia oil, but significantly lower than the commercially available refined camellia oil (21.66g/L). There were much more polyphenols contained in both sub-critical camellia oil and pressed crude camellia oil. The sub-critical camellia oil had a better performance in inhibiting the peroxide value and thiobarbituric acid value of sunflower oils during storage than that of commercial refined camellia oil and pressed crude camellia oil. Sub-critical camellia oil had the capacity to keep the antioxidant activity of oil products. In the process of producing camellia oil, sub-critical fluid extraction was a superior technology. Related Articles | Metrics

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Enzyme Treatment before and after Oxygen Delignification of Acacia EMCC Kraft Pulp WANG Yu-xiu;TONG Guo-lin;YOU Ji-xue 2012, 32 (4):  77-82.  Abstract ( 767 )   PDF (1495KB) ( 762 )   Save The effect of enzyme treatment on oxygen delignification of Acacia EMCC kraft pulp was investigated. The results indicated that the optimum dosage of laccase/xylanase system (LXS), which produced by white-rot fungus, was 7IU/g in the pretreatment process. For LXS pretreated pulp, high quality pulp was obtained when fibers were treated by 2.5 alkali dosage for 60 min at 100℃ in oxygen delignification. The optimum treatment time and enzyme dosage was 2h and 5IU/g when LXS was used for pulp posttreatment after oxygen delignification. The SEM indicated that the fibers with rough surface and many tiny holes and cracks in the cross section of the cell wall were obtained after enzyme treatment. It clearly showed that LXS could be used as posttreatment following oxygen delignification. Related Articles | Metrics

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Chemical Constituents of Ziziphus jujuba Mill var. spinosa Roots CHE Yong CHE Yong;LI Song-tao;ZHANG Yong-qing 2012, 32 (4):  83-86.  Abstract ( 901 )   PDF (1079KB) ( 2145 )   Save Chemical constituents in the roots of Ziziphus jujuba Mill var.spinosa were studied. The consti-tuents were separated and purified by repeated column chromatagraphy with silica gel and Sephadex LH-20. Their structures were elucidated based on the chemical and spectral analysis. Seven compounds were iso-lated from petroleum,EtOA fractions. Their structures were identified as lupeol(Ⅰ), betulinic acid(Ⅱ), ceanothic acid(Ⅲ), isoceanothic acid(Ⅳ), stigmasterol(Ⅴ), 3-O-β-D-glucopyranosyl-stigmasterol(Ⅵ), adouetine X(Ⅶ). Compounds Ⅳ, Ⅵ, Ⅶ were obtained from the plant for the first time. Related Articles | Metrics

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Mechanism of Diluted Acid Pretreatment to Improve Enzymatic Hydrolysis of Corn Stover YAO Lan;ZHAO Jian;XIE Yi-min;YANG Hai-tao;YANG Wu-feng;QU Yin-bo 2012, 32 (4):  87-92.  Abstract ( 626 )   PDF (1430KB) ( 955 )   Save In order to study the mechanism of diluted acid pretreatment on enhancing cellulose conversion during cellulase hydro-lysis process, microscopic structure and physical/chemical characteristics of corn stover before and after diluted acid pretreatment were investigated. The cellulose conversion ratio increased from 31.88% to 95.74% when the corn stover was pretreated by 1.875% acid solution as a 1:15 liquid ratio at 170℃ for 60min. The XRD analysis showed that the crystallinity of cellulose increased from 31.88% to 58.7% after acid pretreatment. But only slight change of cellulose crystalline was observed when the corn stover was treated to some level. The rough fiber surface with more holes was detected after dilute acid pretreatment. This was beneficial for the connection between cellulose and corn stover. The specific surface area significantly increased from 0.329m2/g to 2.878m2/g after dilute acid pretreatment. It was also beneficial for enzymatic hydrolysis of corn stover cellulose. Related Articles | Metrics

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Synthetic Process of 2-(3,4,5-Trimethoxyphenyl)-1,3-dithiolane WANG Yan;JIANG Ping; 2012, 32 (4):  93-96.  Abstract ( 671 )   PDF (1063KB) ( 671 )   Save 2-(3,4,5-trimethoxyphenyl)-1,3-dithiolane was prepared by thioacetalization using 3,4,5-trimethoxybenzaldehyde and 1,2-ethanedithiol. The product structure was characterized by FT-IR, GC-MS, etc. The process conditions of the product were optimized by single factor experiment. The yield of product was more than 98% under the optimal process condition. Related Articles | Metrics

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Synthesis of 6-(4-Methyl-pent-3-enyl)-5,8-dihydro-naphth- alene-1,4-diol GAO Fei-fei;LUO Jin-yue;KAN Chen-xi 2012, 32 (4):  102-106.  Abstract ( 788 )   PDF (1152KB) ( 800 )   Save The myrcene and 1,4-benzoquinone are used as raw materials to synthesize naphthalene catechol derivatives naphthalene-1,4-diol. Using GC-MS, melting point determination, FT-IR, 1HNMR as detection means, the structure of the product is identified as 6-(4-methyl-pent-3-enyl)-5,8-dihydronaphthalene-1,4-diol. Diels-Alder reaction is affected by different type of catalysts, catalyst amount, reaction solvent, reaction temperature, the ratio of raw materials and reaction time. It is concluded that the suitable molar ratio of myrcene to 1,4-benzoquinone is 1:1,while the fittest catalyst is ZnCl2, the dosage is 15% of 1,4-benzoquinone. Ethyl acetate is chosen as solvent and the reaction temperature is 80℃, reaction time is 10 h. Under this condition, the selectivity and yield of product reached 81.0% separately. Related Articles | Metrics

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Synthesis and Characterization of Zincum Maleopimarate YANG Zhong-zhi;HUANG Qi-liang;LEI Fu-hou 2012, 32 (4):  97-101.  Abstract ( 858 )   PDF (1361KB) ( 980 )   Save Zincum maleopimarate (MPAZn) has been synthesized from maleopimaric acid and zinc acetate with solvent method. The influence of reaction conditions such as amount of raw material, reaction time, reaction temperature on product were discussed respectively. Zinc content in the products was determined by complexometric titration. The target product was analyzed and characterized by Fourier transform infrared spectrometer (FT-IR), Scanning electron microscope (SEM), Energy dispersive X-ray microanalysis (EDAX) analysis and X-ray diffraction (XRD). The optimum reaction conditions were ascertained as follows: n(zinc acetate):n(maleopimaric acid)=3:1,at 328K for 5h,the yield of MPAZn could reach 94%. It was found that MPAZn was three-dimensional reticulation compound and chemical bonding occurs between the —COO- and Zn2+. Related Articles | Metrics

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Microwave-assisted Alkali Pretreatment and Cyanoethylation of Secondary Fiber ZHANG Chun-hong;SUN Ke-wei;CHEN Qiu-ling;SUN Pei-shi 2012, 32 (4):  107-112.  Abstract ( 650 )   PDF (1279KB) ( 788 )   Save Microwave was applied to enhance alkali pretreatment and its impact on cyanoethyl modification of secondary fiber (SF) was studied in this paper. The structures, properties and thermoplastic mechanism of cyanoethylated SF (CSF) were also investigated. The results indicated that the microwave radiation power e.g., 200、400 and 600 W, could improve the reaction degree of CSF and reduce the reaction time of cyanoethylation. The continuous microwave radiation was more effective than batch one. Decrystallization of cellulose was observed as SF was cyanoethylated. The crystallinity degree of CSF decreased with the increasing reaction degree of cyanoethylation, but meanwhile, the interplanar distance of CSF increased. CSF was thermoplastic and thermo-compressed substrate. The CSF with higher degree of cyanoethylation showed better mechanical and thermoplastic properties. The thermoplastic property of CSF should be attributed to the introduction of —CH2CH2CN groups onto cellulose, which destroyed the structure of cellulose crystalline, and promoted the movement of cellulose macromolecule and/or chain segment. Related Articles | Metrics

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Simultanous Determination of Quercetin and Kaempferol in Melaleuca alternifolia (Maiden et Betehe) Chee 1 by HPLC LIN Xiao;DONG Xiao-min;CHEN Ming-sheng;HUANG Yan;LIU Bu-ming; 2012, 32 (4):  113-116.  Abstract ( 855 )   PDF (1273KB) ( 1156 )   Save A high-performance liquid chromatography (HPLC) method was developed for simultaneous determination of quercetin and kaempferol in Melaleuca alternifolia (Maiden et Betehe) Chee 1.The sample was extractd by HCl-MeOH solution (volume ratio 5:100) in water bath, then separated by a C18 column with CH3OH-C2H3N-0.4% phosphoric acid solution (volume ratio 21:21:58) as the mobile phase solution under 370 nm wavelength. The HPLC experiment was performed at room temperature with flow rate 1.0mL/min. Quercetin and kaempferol contents in M.alternifolia from different area were determined. The result showed that quercetin and kaempferol content in Nanxiao town of Yongning was the highest and that in Yongning was the lowest. Related Articles | Metrics

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Hydrolysis Kinetics of Microcrystalline Cellulose Catalyzed by Fe3+ and Dilute Hydrochloric Acid REN Ling-bing;CAO Qing;XIE Xiao-ling 2012, 32 (4):  117-122.  Abstract ( 782 )   PDF (1118KB) ( 1978 )   Save The microcrystalline cellulose was hydrolyzed in the presence of 1g/L FeCl3 and 2% hydrochloric and the hydrolysis kinetics was investigated in this study. According to the principle of minimum of residue error S between actual yields of glucose and calculated value from the established function, the objective function is selected. The results indicated that the activation energy of the hydrolysis reaction for microcrystalline cellulose and glucose can be significantly reduced due to the presence of H+ and Fe3+. For the hydrolysis reaction of microcrystalline cellulose and glucose, the activation energy is 81.70kJ/mol and 43.85kJ/mol, respectively. The hydrolysis constant rate of microcrystalline cellulose is 0.0414, 0.0732 and 0.1153h-1 at the temperature of 130, 140 and 150℃, respectively. For glucose, it is 0.2053, 0.2424 and 0.3565 h-1 at the corresponding temperatures. Related Articles | Metrics

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Chemical Constituents of Volatile Oil from Leaves of Sabina vulgaris Ant. TIAN Xu-ping;GAO Li 2012, 32 (4):  123-127.  Abstract ( 747 )   PDF (1081KB) ( 1536 )   Save The volatile composition from fresh leaves and dry leaves of Juniperus sabina L. storaged for one year were analyzed by steam distillation and gas chromatography-mass spectrometry (GC-MS). 31 compounds from fresh leaves were indentified, and 23 compounds from dry leaves were indentified. The same composition between fresh leaves and dried leaves were 15 kinds. The compounds of contents decreased were (E) 2,7-dimethy1-3-octen-5-yne (51.88%, 15.29%), limonene(1.65%, 1.13%), α-terpinolene(0.92%, 0.58%), 3,7-dimethyl-2,6-octadienoicacid methyl ester(2.88%, 0.50%), α-longipinene (1.91%, 1.46%), α-cedrol(12.69%,10.81%).The compounds of contents increased were β-thujone (1.01%, 1.98%), 4-methyl-1-(1-methyl ethyl)-3-cyclohexen-1-ol (0.22%, 2.83%), β-citronellol(0.22%,10.83%), sabinyl acetate(4.37%, 39.83%).The difference of heterogeneous were significantly. The difference of volatile composition from the fresh leaves and dry leaves of Juniperus sabina L. were distinct, but characteristic compounds were the same. The compound kinds and contents of volatile oil gradually decrease with storage time extended. Related Articles | Metrics

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Advances on Properties and Analysis Method of Tannase WANG Hui;LI Ying-hong;YAN hong;LI Zhong-hai 2012, 32 (4):  128-134.  Abstract ( 679 )   PDF (1168KB) ( 1439 )   Save This article reviews tannase-producing strains, physicochemical properties difference of tannase from different sources. The enzymology properties, molecular biological characteristics, catalytic reaction mechanism of tannase, and its analysis method, et al. are also introduced. Related Articles | Metrics