Table of Content

30 June 2002, Volume 22 Issue 2 Previous Issue    Next Issue

研究报告

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STUDY ON INTRINSIC KINETICS OF CATALYTIC HYDROGENATION OF ROSIN DUAN Wen-gui;CHEN Xiao-peng;WANG Lin-lin 2002, 22 (2):  1-6.  Abstract ( 582 )   PDF (1124KB) ( 637 )   Save Investigations were undertaken on the intrinsic kinetics of catalytic hydrogenation of rosin on Raney nickel at 150- 180℃ and 4-7 MPa using gum rosin as raw material and 200# gasoline as solvent.Based on the experimental result,a suitable reaction model was selected to show the reaction between molecules of abietic-type resin acids and hydrogen adsorbed on the catalyst surface,while desorption of the product dihydroabietic acid could be the rate controlling step.Intrinsic kinetic equation was given. Related Articles | Metrics

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PREPARATION OF HIGN PERFORMANCE MESOPOROUS GRANULAR ACTIVATED CARBON HU Fu-chang;PAN Mei-xing;CHEN Shun-wei 2002, 22 (2):  7-11.  Abstract ( 552 )   PDF (608KB) ( 635 )   Save High performance mesoporous granular activated carbon was prepared from drupe stones by activation with phosphoric acid.85% H3PO4 was added to drupe stones,then heated and stirred on time to impregnate the material swelling until viscidity vanished and loose,then carbonized,activated,extracted with water and dried.Effects of temperature and time on impregnation-swelling,carbonization and activation on properties of the product were studied by orthogonal test.Also,comparative tests by different treatment methods on the raw materials were carried out.Property tests of the product show the results of maximum carbon tetrachloride adsorption 160%,decolorization of caramel A 130%,abrasion resistance 94%,total pore volume 1.7 mL/g,proportion of the mesopore 40%-50%. Related Articles | Metrics

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STUDY ON PREPARATION AND ADSORPTION CHARACTERISTICS OF CHEMICALLY MODIFIED BARKS WANG Ge-hui;SONG Zhan-qian;WANG Lian-sheng 2002, 22 (2):  12-16.  Abstract ( 576 )   PDF (964KB) ( 1005 )   Save Two kinds of chemically modified barks(FMB and EMB)were made by cross-linking bark with formaldehyde and epichlorohydrin,respectively.Study on yields of modified bark was conducted at different concentrations of HCl and NaOH,and various reaction temperature.Adsorption characteristics of FMB and EMB to basic pink dye and Cu2+ were also studied.Experiment results show that:(1)chemical stabilities of FMB and EMB were improved through cross linking reactions,which prevented the effluence of color substances from the bark;(2)Compared to the unmodified bark,adsorption capacities of FMB and EMB were increased over 70% to basic pink dye(95 mg·g-1)and over 40% to Cu2+(78 mg·g-1). Related Articles | Metrics

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PREPARATION AND PROPERTIES OF ROSIN-ACRYLICS HYBRID POLYMER LATEXES LIN Ming-tao;JIANG Yu;CHU Fu-xiang 2002, 22 (2):  17-20.  Abstract ( 686 )   PDF (564KB) ( 691 )   Save Rosin-acrylics hybrid latexes were prepared by semi-continuous emulsion polymerization with a rosin emulsion as seed.The hybrid fine-particle rosin emulsion was prepared by inverse emulsification.The hybrid polymer latexes were characterized with dynamic light scattering,SEM,DSC and GPC.Effects of the structure of rosin and rosin derivatives on polymerization as well as the 180° and T-peel strength of latexes obtained were investigated.Results shows that introduction of rosin derivatives improves remarkably the bonding properties of acrylic polymers. Related Articles | Metrics

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ELECTROCHEMICAL DEGRADATION OF SODIUM LIGNOSULFONATE TU Bin;LU Zhuo-min;CHEN Fan-geng 2002, 22 (2):  21-25.  Abstract ( 598 )   PDF (660KB) ( 547 )   Save Sodium lignosulfonate was degraded into substances with relatively low molecular weights by anodic degradation.The reaction was conducted in an electrolytic cell equipped with PbO2 membrane electrode as anode and stainless steel gauze as cathode.Effects of voltage,time,temperature,and pH are discussed.Products were characterized by chemical and instrumental means.Some condensed products were formed during the reaction.Ring cleavage was proved to occur when the voltage was above 3.0 V.Therefore,the voltage should be restricted to avoid excessive ring cleavage.Surface tension and oil-water interfacial tension of lignosulfonate was reduced after the reaction.Improved surface activity of the degradation product was achieved when used with petroleum sulfonate. Related Articles | Metrics

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STUDIES ON XYLITOL FERMENTATION OF CORN COBS HYDROLYSATE BY CANDIDA SP. SUN Kun-shan;XIA Li-ming 2002, 22 (2):  26-30.  Abstract ( 557 )   PDF (731KB) ( 532 )   Save The adaptation of Candida sp.can effectively enhance its resistance to the inhibitors in the hydrolysate of corn cobs,and therefore improves the xylose utilization efficiency and xylitol yield.At 30℃,hydrolysate produced by dilute acid pretreatment can be directly fermented after simply treated by Ca(OH)2 using the adapted yeast strain.The optimum fermentation conditions were as follows:inoculum size 10%(volume ratio),inoculum age 17 h,nitrogen source 1.5 g/L Bacto-yeast extract and 2.5 g/L Bacto-tryptone,volume charge 120 mL in 250 mL flasks,intitial pH value 5.5.Xylose utilization efficiency over 79.8% and xylitol yield higher than 62.4% were obtained respectively.This process can effectively reduce the pretreatment costs,showing broad prospects of applications. Related Articles | Metrics

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STUDIES ON SYNTHESIS AND FIRE RETARDANCE OF TETRABROMOBISPHENOL A HU Yun-chu 2002, 22 (2):  31-34.  Abstract ( 578 )   PDF (600KB) ( 649 )   Save The synthetic conditions of tetrabromobisphenol A were studied.Char yield and thermokinetic parameters during pyrolysis of wood treated with tetrabromobisphenol A were studied by TG-DTA method.Results showed that tetrabromobisphenol A yield increased from 70.7% to 85.6%,and bromine content increased from 54.1% to 55.4% as the condition was converted from room temperature to ice-water bath.The yield increased from 85.6% to 93.4% as benzene was used as a solvent to replace alcohol.The yield increased from 93.4% to 94.2%,bromine content increased from 56.1% to 58.8% and melting point reached 179.0-181.3℃ as the dosage of raw materials changed from 1:2 to 1:2.4.The char yield increased from 31.2% to 45.4%, after Cunninghamia lanceolata wood was treated with tetrabromobisphenol A.By elution experiment,char yield loss of wood treated by ammonium phosphate is 26.7%,compared to 4.27% by tetrabromobisphenol A.Optimum synthetic condition of tetrabromobisphenol A is in ice-water bath with benzene as solvent by raw material ratio 1:2.2-2.4.The pyrolysis process of wood can be changed by tetrabromobisphenol A during fire-retarding process.Tetrabromobisphenol A possesses not only strong fire-retarding ability on wood but also strong resistance against leaching. Related Articles | Metrics

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STUDY ON ALKOXYLATION OF α-PINENE CATALYZED BY DEALUMINATED USY ZEOLITE MOLECULAR SIEVE LIU Han-wen;YIN Du-lin 2002, 22 (2):  35-38.  Abstract ( 456 )   PDF (935KB) ( 630 )   Save Experiments on alkoxylation of α-pinene with C1～C4 alcohols catalyzed by dealuminated USY(SiO2/Al2O3=10.99)zeolite molecular sieve were conducted.Main adducts in the reaction were α-terpinyl ether and bornyl ether,while main isomeric product was dipentene. Alcohol structure and reaction time have definite influence to selectivity of alkoxylation.Effects of solvent and temperature were also remarkable to methoxylation. Related Articles | Metrics

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STUDY ON PREPARATION AND PROPERTIES OF LOW FORMALDEHYDE EMISSION UF RESINS JIANG Yu;WANG Chun-peng;LIU Yi;LIN Ming-tao;ZHAO Lin-wu 2002, 22 (2):  39-42.  Abstract ( 644 )   PDF (739KB) ( 933 )   Save Parameters in resin manufacture to produce formaldehyde-urea(UF)resins capable of producing low formaldehyde emission particleboards and plywoods were presented and discussed.UF resins were produced through four stages of different reaction pH values(1.5,9.0,4.5,8.0).Free formaldehyde contents of UF resins were affected most significantly by the amount of the added urea in the last stage.During the weak acid stage,methylene linkages in the polymeric resin increased and dimethylene ether linkages decreased as formaldehyde/urea molar ratio and pH decreased.While in the alkaline pH stage,under similar formaldehyde/urea ratio,free formaldehyde content and formaldehyde emission decreased with increase of reaction pH.Addition of 2%-5%(mass ratio)crosslinking agent improved wood adhesion of UF resin of low molar ratio.Formaldehyde emission reached E1(<10 mg/100 g)standard requirement when particleboard and plywood were made with UF resin when formaldehyde/urea molar ratio was lowered to 1:1. Related Articles | Metrics

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STUDY ON ETHANOL FERMENTATION BY IMMOBILIZED CELLS OF ALUMINIUM ALGINATE SONG Xiang-yang;MAO Lian-shan;YANG Fu-guo;YONG Qiang;YU Shi-yuan 2002, 22 (2):  43-46.  Abstract ( 541 )   PDF (520KB) ( 600 )   Save Life time of immobilized Pichia stipitis yeast cells was prolonged significantly when the gel was formed with aluminium alginate instead of calcium alginate.Endurance against phosphate of aluminium alginate gel was increased 3 times than that of calcium alginate gel.Glucose-xylose mixture could be co-fermented to ethanol by immobilized Pichia stipitis yeast cells of aluminium alginate.The concentration of ethanol in final broth was enhanced from 26.0 g/L to 27.3 g/L,and utilization ratio of total sugar was 93.7%. Related Articles | Metrics

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STUDY ON CATALYTIC SYNTHESIS OF 2,3,4- TRIHYDROXYBENZOPHENONE HU Xian-ming;HU Quan-yuan;SU Jiang-tao;ZHOU Xiao-bo;HE Jian-she 2002, 22 (2):  47-50.  Abstract ( 644 )   PDF (499KB) ( 587 )   Save A new method for catalytic synthesis of 2,3,4-trihydroxybenzophenone is described.Pyrogallol was used as starting material,which is commercially available.By using a mixture of aromatic hydrocarbon and water as a binary solvent,reaction of pyrogallol with PhCCl3 was carried out in the presence of a catalyst(ZnCl2、AlCl3 or SOCl2).2,3,4-Trihydroxybenzophenone was obtained in yields of 80%-87% with the advantages of easy control,stable yield,high product quality and low cost.Influences of reaction temperature,time,catalysts,solvents,etc.to yields of the product are discussed. Related Articles | Metrics

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STUDY ON ELECTROCHEMICAL DEGRADATION OF PULP ALKALINE TREATMENT EFFLUENT LIU Le-wen;OU YI-fang;HUANG Qiu-lian 2002, 22 (2):  51-53.  Abstract ( 534 )   PDF (371KB) ( 691 )   Save Electrochemical degradation of effluent from pulp alkaline treatment was studied with SiC anode and stainless steel gauze cathode.The result showed:pH value of the effluent increased at first,then decreased;electroconductivity decreased at first,then increased;COD and chroma of effluent decreased significantly in the early stage.UV spectra also showed the effectiveness of electrochemical degradation on the effluent. Related Articles | Metrics

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STUDY ON ELECTROCONDUCTIVITY OF BAMBOO CHARCOAL AND TECHNOLOGY OF PREPARING HIGH ELECTROCONDUCTIVIVE BAMBOO CHARCOAL SHAO Qian-jun;XU Qun-fang;FAN Zhi-wei;ZHANG Wen-biao 2002, 22 (2):  54-56.  Abstract ( 671 )   PDF (532KB) ( 1456 )   Save Through the study on carbonization of bamboo at several stages,it is found that carbonization temperature and time are the main factors affecting graphite proportion and electric properties.Volume electroresistivity,moisture and yield were measured at different carbonization temperature and time in the experiments.This study provides technology to prepare high electrocon-ductive bamboo charcoal through pyrolysis followed by secondary treatment. Related Articles | Metrics

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STUDY ON ENZYMATIC HYDROLYSIS OF XYLAN INTO XYLO-OLIGOSACCHARIDE XU Yong;CHEN Mu;YU Shi-yuan;YONG Qiang;YAO Chun-cai 2002, 22 (2):  57-60.  Abstract ( 741 )   PDF (689KB) ( 956 )   Save In the preparation of xylo-oligosaccharide by enzymatic hydrolysis of xylan,effects of xylanase and cellulase were compared,the effect of agitation rate and time dependence were studied in 10-litter tank.Results showed that the optimum hydrolytic conditions were:xylan concentration 30 g/L,xylanase loading 1%(volume ratio)and agitation rate 180 r/min,under which yields of xylo-oligosaccharide and total sugar after 2 hours were 35.2% and 41.9% respectively,and oligomeric xylan of DP 2-5 constituted 25.9% of solid in the substrate product. Related Articles | Metrics

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COMPARISON ON DECAY-AND LEACH-RESISTANCES AMONG THREE QUATERNARY AMMONIUM SALTS AS WOOD PRESERVATIVES FANG Gui-zhen;REN Shi-xue 2002, 22 (2):  61-64.  Abstract ( 591 )   PDF (535KB) ( 684 )   Save Comparison on decay- and leach-resistances among 3 quaternary ammonium salts,namely:didecyl dimethyl ammonium chloride,didecyl dimethyl ammonium acetate and didecyl dimethyl ammonium propionate,as wood preservatives were conducted by applying them to Populus ussuriensis,wood specimen,using Coriolus versicolor(L.ex Fr.)Quel as test fungus.At the retention of 3.8, 3.8, 3.9 kg/m3,testing results showed the mass loss to be 7.2%, 7.9%, 7.6%,respectively.Didecyl dimethyl ammonium acetate in wood showed stability against neutral and alkaline solutions,whereas the propionate showed stability against acidic solution. Related Articles | Metrics

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STUDIES ON SEASONAL VARIATION OF FLAVONOIDS AND LACTONES IN BAMBOO LEAVES ZHANG Ying;WU Xiao-qin;YU Zuo-yu 2002, 22 (2):  65-69.  Abstract ( 524 )   PDF (1047KB) ( 753 )   Save Seasonal variations of total flavonoids(TF)and total lactones(TL)in bamboo leaves of Phyllostachys nigra(Lodd.ex.Lindl.)Munro(as example of Phyllostachys genus),and their anti-free radical activity were investigated using spectrophotometric and chemiluminescent analyses,respectively.Results showed that TF,on dry basis of leaves,varied in a range of 0.67%- 1.71% throughout a year,kept at a much higher level from November through next April.During the same period,TL varied between 0.44%- 1.02%.The IC 50 of dry leaves on O2·- and ·OH were 2.94-33.05 μg/mL and 3.47-8.78 mg/mL, respectively.The scavenging activity on O2·- was the strongest in February and the weakest in June,and generally much stronger from November through early May.However,the scavenging activity on ·OH was rather stable throughout the year.Optimum time for leaf picking is the period from November through next March. Related Articles | Metrics

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STUDY ON GELATION PROPERTIES OF MIXED GEL OF CHITOSAN AND CARBOXYL METHYL KONJAC GLUCOMANNAN GUM HE Dong-bao;SHI Xiao-ming;SHI Yi;ZHAN Dong-feng 2002, 22 (2):  70-74.  Abstract ( 658 )   PDF (1017KB) ( 710 )   Save Mixed gels of chitosan and carboxyl methyl konjac glucomannan gum were prepared by varying the ratio of constituents.Mixed gel at 4% of total polysaccharide concentration showed a synergistic maximum when the ratio of carboxyl methyl konjac glucomannan gum to chitosan was 20/80.Effects of preparation temperature(Tp),incubation time,salt ion concentration,Mη and DD of chitosan on gelation have been studied.It has been observed that there was a gel strength maximum when incubation time was 30 min,salt ionic concentration was 1.6 mol·L-1.Mη and DD of chitosan was 8.0×105 and 85%,respectively.Mechanism of gelation was investigated by FT-IR spectrometry. Related Articles | Metrics

综述评论

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PROSPECT ON RESEARCH AND DEVELOPMENT OF BIOMASS ENERGY UTILIZATION JIANG Jian-chun 2002, 22 (2):  75-80.  Abstract ( 1420 )   PDF (619KB) ( 5104 )   Save Biomass energy is an important part of renewable energy.High effective utilization and development of biomass energy has positive effects on solving energy and environment problems.Since 1970's,in countries worldwide,especially in advanced countries,extra attentions have been paid to conduct researches on the application technique of biomass energy and a lot of research progress have been achieved,some of which have been used in industrial scale.In this paper,the progress of research and development in domestic and abroad,concerning biomass solidification,liquefaction,gasification and direct combustion technique,are summarized.According to our country's situation,proposals on research and development prospect are put forward. Related Articles | Metrics

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PROGRESS ON PREPARATION OF SUPERABSORBENTS FROM CELLULOSE LI Jian-fa;SONG Zhan-qian 2002, 22 (2):  81-85.  Abstract ( 801 )   PDF (461KB) ( 2256 )   Save This paper reviews the progress of research and development on superabsorbents from cellulose.With different chemical modification methods such as etherification and graft copolymerization,cellulose derivatives have various water absorbence of 10-3 000 times difference,while graft copolymerization is the most effective method.Recent trends on preparing cellulose-based superabsorbents were evaluated,such as cationic superabsorbent and bacteria cellulose.Applications of superabsorbents in agriculture and forestry were also summarized. Related Articles | Metrics

研究快报

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STUDIES ON SYNTHESIS OF NOPYL PROPANOATE AND ITS 13C CHEMICAL SHIFT CHARACTERISTICS WANG Zong-de;XIAO Zhuan-quan;AN Xin-nan 2002, 22 (2):  86-88.  Abstract ( 572 )   PDF (609KB) ( 653 )   Save Nopyl propanoate was synthesized by the reaction of nopol with propionic anhydride,and its structure was identified by MS,IR, 1H NMR and 13C NMR.Conformational analysis was performed by comparing 13C chemical shift of C-6,C-7 with those of α-pinene.Result suggests that C-1-C-2-C-3-C-4-C-5 fragment is planar,and the 6,6-dimethylbicyclo[3.1.1]hept-2-ene fragment is Y-shaped.Nopyl propanoate can be assigned as derivative of apopinene with a substituent at C-2,and the substituent has effect on chemical shift mainly at C-2,C-1 and C-3,while interaction between the substituent and other carbons is insignificant. Related Articles | Metrics

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HIGH-SPEED ESTERIFICATION OF ROSIN WITH ETHANOL UNDER MICROWAVE IRRADIATION LIN Zhong-xiang 2002, 22 (2):  89-91.  Abstract ( 674 )   PDF (345KB) ( 1086 )   Save Esterification of rosin with ethanol under microwave irradiation was studied.Acid value of ethyl rosinate was 3.88 mgKOH/g by reacting rosin with ethanol in the presence of p-toluenesulfonic acid under microwave irradiation for 24 min.Dosage of catalyst is 12%-16% and ethanol is 2-3 times(on the basis of rosin mass). Related Articles | Metrics