Showing papers in "Chemical Research and Application in 2002"

Fast and convenient determination of HOMO energy level of organic eletroluminescent material using electrochemistry method

Abstract: It is very important to obtain an accurate determination of HOMO energy level of organic electroluminescent materialUsually cyclic voltammetry is used to determine itIn this paper,linear scanning voltammetry was instead utilized to attain a reault of oxidation potential(or HOMO energy level) due to the film of organic electroluminescent material on the working electrodeLess amount of materials was consumed in this methodThe proposed method was faster and more convenient

Studies on the thermal decomposition of ammonium sulfate

Abstract: In this paper,on the basis of chemical analysis and IR analysis,the mechanism of the thermal decomposition for ammonium sulfate was put forward.The thermal decomposition process consists of three steps:ammonium bisulfate was produced firstly,ammonium pyrosulfate secondly,and broken down into NH 3,SO 2,and others lastly.The relation between the rate of decomposition and the atmosphere was discussed.

The improvement and influence of ultrasonic and microwave irradiation on the extraction of traditional Chinese medicine

Abstract: The cavitation,mechanical action and thermal action of ultrasonic wave and microwave to the extraction of active components from Traditional Chinese Medicine (TCM) have been discussed.The Ultrasonic and microwave properties such as frequency,stregnth,action time and the ratio of the action "on to off" have different influence to the extraction of components.In some conditions,ultrasound gives a positively improved action to the extraction,but in other condition or to other TCM it may give a negative influence on extraction ratio and change the composition of extracted components.Generally,their positive actions are represented on increasing the extraction efficiency,and increasing the extraction time in large scale and leading to the operation more easily.43 articles are reviewed.

Analysis of IR spectrum and crystal morphology of polyalumina-silica chlorid(PASC) prepared by various method

Abstract: With the technology of IR spectrum and crystal morphology,studying the effect on interatomic bonding action and molecular shape of coagulating agent PASC when it is prepared by various methodsIt shows that as PASC is produced by basifying polymerization,comparing to that by others way,the IR spectrum of PASC shows,965cm -1 peak proportion reflecting Si O Al bond accrete 118%,266%,875cm -1 peak proportion reflecting Al O Al bond accrete 23%,30%It may be caused by multinuclear hydroxy aluminum's content and Zeta electric potential increases in the process hydrolyze concrete with PASCIt disappear in crystal morphology,molecular chain is longer and branching further,so that PASC have better potentiality of arching and charge neutralization

Chemical constituents of angelica dahurica

Abstract: From dried roots of angelica dahurica,nine compounds including eight liner furancoumarins were extracted,separated,and characterized by spectroscopic methods.

Progress in studies on rare earth schiff base complexes in our country

Abstract: The last two decades progress in the studies on types,synthetic method,crystal structure,spectra properties of rare earth Schiff base complexes,as well as application of these complexes in catalysis,biology and medicine aspects were briefly reviewed.

Comparison of determination methods for proanthocyanidin from grape-seed extracts

Abstract: Three methods,n butyl alcohol hydrochloric acid,vanillin hydrochloric acid and vanillin sulfuric acid,were used to determine the proanthocyanidin from grape seed extractsThe different methods were compared according to the choice of standard samples and the reaction theoryAs a result,the vanillin hydrochloric acid method was shown to be the best for the determination of proanthocyanidin wherein catechin was used as the standard sample,the test wavelength was 500nm,the linearity range was 10～150μg/ml,the reaction was finished at 20±1℃ for 15h,the relative standard deviation being 079% and the recovery was 981%

The synthesis of melamine resin tanning agent

Abstract: By using ethanolamine as etherifying agent and proper hydrophilic auxiliary,a new melamine resin tanning agent was synthesized.It was shown that the stability and water solubility of the new product had been greatly improved in comparison with ones prepared by conventional methods.The conditions and mechanisms for synthesis of the product were described in detail.

Influence of pH and small molecule organic compound on the aqueous two-phase system formed by SDS/CTAB/H_2O mixture

Abstract: This study was about the effect of pH and small molecule organic compound on the phase behavior of SDS/CTAB/H 2O mixture.The ATPS regions and LC regions were mainly discussed.It was shown that when the pH of the system was not neutral LC regions enlarged but ATPS regions reduced.In the condition of strong acid,the ATPS a region in which anionic surfactant in excess would extend to the SDS-H 2O axis of the pseudo phase diagram of SDS/CTAB/H 2O system.Small molecule organic compound that was not ionized in aqueous solution combined with water in the form of hydrogen bond.For this reason,the hydration of surfactant decrease and cationic surfactant and anionic surfactant integrate to form precipitate.So the surfactant-rich phase of ATPS showed milky white and the polarizing appearance was not clear.

Progress in cyclopeptides research

Abstract: The synthesis of cyclopeptides,and their properties and applications in recent years were reviewed.

Advances in polymer nanomaterials II.polymer/inorganic nanocomposites

Abstract: Polymer nanomaterials include nanoscale polymers and polymer/inorganic nanocomposites.This paper reviewed the advance inpolymer/inorganic nanocomposites.The sol gel,encapsulating,in situ synthesis,template,intercalation,deposition,mechanical pulverization,assembly,and solution or melt mixing were mainly looked over.

Preparation,characterization and eletrochemical performance of cobalt-substituted nickel hydroxide

Abstract: Nanophase Co substituted nickel hydroxide samples were synthesized by solid state reaction and characterized by XRD,TEM,and TG DTA techniques.The results showed that the products were nanosized(40nm),globe shaped β Ni(OH) 2 materials.TG DTA curves showed that β Ni(OH) 2 began to decompose when temperature was above 200℃.The electrochemical behaviors of various cobalt substituted nanophase nickel hydroxide were studied by charge discharge,cyclic voltammetry and Tafel curve experiments.The results indicated that the internal resistance of nickel electrode was lowered because of the presence of Co,and the reversity and the oxygen evolution potential of the nickel electrode were increased.As a result,the charging efficiency,discharge capacity and the cyclic life of cobalt substituted nanophase nickel hydroxide were improved.

Separation of alkaloids from swertia mileensis by high-speed countercurrent chromatography

Abstract: Alkaloids from swertia mileensis were isolated successfully by high speed countercurrent chromatography with a two phase solvent system, CHCl 3∶CH 3OH∶NaH 2PO 4(pH=5.3)=4∶3∶1,to obtain 6 components,in which 3 components exhibited orange red colour with bismuth potassium iodide reagent.The results were verified by TLC and six pure components were isolated.One was characterized as gentianine(28.5%) by spectroscopic method.

Application of ELISA in the detection of plant virus

Abstract: A review was presented on the improved methods of Enzyme Linked Immunosorbent Assay(ELISA) in the detection of plant viruses with 29 referencesThe research progress in this field was also discussed

A study on technology of extracting pectin from mango peel

Abstract: Mango peel scrap was used as raw material in this experiment to extract pection. The method of producing pectin that extracted by acid solution and precipitated by ethanol was applied. The influence of pH value, time of ex-traction and temperature on the production was studied. The optimun condition was that mango peel scrap was trans-ferred into acid solution of pH2, and the solution was stirred at 85℃～90℃ for 90min~100min.

Progress in studies on organosilicon surfactant for agrochemical

Abstract: Organosilicon surfactant is a novel adjuvants for agrochemical.Its application and advancement were reviewed and special properties were emphasized,such as excellent wetting?supper spreading?stomatal infiltration?rainfastening abilities etc.

Studies on phase diagram of nonionic surfactant Tween 80

Abstract: The microstructure of Tween 80/n alcohol/n hydrocarbon/water fits for petroleum bacteria to grow.The effect of n alcohol,n hydrocarbon,content of n octadecane and NaCl concentration on Tween 80/n alcohol/n hydrocarbon/water system has been studied at 50℃.The results indicated that the effect of NaCl concentration on the system is small.The area of O/W microemulsion increases,the area of O/W microemulsion decreases,and the total area of microemulsion increases with the increase of carbon number of alcohol.The order of the total area of the microemulsion increasing with different kind of hydrocarbon is n cetane≈n tetradecanen dodecanen decanen octadecaneoctane.The total area of the microemulsion decreases when the content of n octadecane increases in the system.The growth power time curves of petroleum bacterial strain B 2 have been determined by using a 2277 Thermal Activity Monitor at 50.0℃.The growth medium of the microemulsion promotes the growth of B 2 and the O/W microemulsion is more fitted for B 2 to grow.

Studies on thermodynamics and kinetics of the direct polycondensation of lactic acid

Abstract: Through the direct synthesis of polylactic acid(PLA)from lactic acid under atmospheric pressure without catalyst,the thermodynamics and kinetics of the direct polycondensation of lactic acid were studied.The key factors to synthesize high molecular weight of PLA were dehydrating under higher vacuum,controlling appropriate reaction temperature,and choosing optimal catalyst.This provided a theoretical basis for further studies on the direct synthetic conditions of PLA.

Inhibition of elastase by forsythiaside from fructus forsythiae

Abstract: Forsythiaside was obtained by using macro reticular resin D 101 and vaccum liquid chromatography.Using the method of agarose diffusion,the inhibition of porcine pancreatic elastase by forsythiaside was studied.The results shown that forsythiaside could inhibit the activity of porcine pancreatic elastase.

Determination of chemical constituents of vanilla by supercritical CO_2 fluid extraction

Abstract: The flavor components were extracted by supercritical CO 2 fluid from vanilla beans at the extracting pressure 35MPa and 30MPa,and analyzed by GC/MS.Twenty eight and thirty two kinds of known compounds in the two vanilla extracts were identified by NIST107LIB and NIST21LIB data base,respectively.

Chemical components of aloe and their separation and measurements

Abstract: The application of aloe is broad in the fields of medicine,beautification,health protection and chymorrhea.We reviewed the chemical components of aloe and their separation,purification and measurements to promote the investigation and application of aloe.

Studies on SiO_2/Al_2O_3 and catalytic performance of dealuminated usy catalyst

Abstract: The effective B acid amount of dealuminated USY(DUSY) zeolites with different silica/alumina ratios were measured by UV spectrometry with 2,6 dimethyl pyridine as adsorbentes in the presence of cyclohexane or anhydrous ethanol or tetrahydrofuranThe isomerization of α pinene was used to check the acidic catalytic properties of these zeolitesThe results indicate that effective B acid amount of DUSY measured in polar anhydrous ethanol or tetrahydrofuran is lower than that of non polar cyclohexaneThe effect of solution concentration of effective B acid amount of DUSY zeolites is smallAs the silica/alumina ratio of catalyst increases,effective B acid amount and conversion of isomerization of α pinene all raise

Advance in the synthesis of p-aminophenol with the catalytic hydrogenation of nitrobenzene

Abstract: p Aminophenol(PAP)is an important chemical raw material and very useful intermediate for the prepation of certain medicineThe mechanism of the reactions for its preparation by one step hydrogenation and re arrangement of nitrobenzene in acid medium was discussedBased on the study of references,several methods were suggested for controlling side reactions;the possible routes for improving the yield and purity of PAP were described

Electrochemical behavior of zinc(II) ion at a self-assembled monolayer of L-cysteine and its application in analysis

Abstract: The electrochemical behavior of zinc(Ⅱ) ion at self assembled modified gold electrodes with L cysteine was investigated.Cys/SAM/Au showed excellent electrocatalytic activity for the reduction of zinc(Ⅱ) ion.In a B R buffer solution(pH 7.45),a sensitive reduction peak of zinc(Ⅱ) ion was observed with Cys/SAM/Au.The peak potential was 0.02V(vs.SCE).The peak current of zinc(Ⅱ) ion on Cys/SAM/Au was proportional to the concentration of zinc(Ⅱ) ion between 1.5×10 -9 and 1.5×10 -6 mol·L -1 .The detection limit was 1.5×10 -10 mol·L -1 .This method was used to analyze human hair samples with satisfied results.

Determination of the iron in water using the method of primary-secondary wavelengths

Abstract: A mathematical model of the determination of the iron in water using the method of primary secondary wavelengths was proposed.According to the relation between absorbance (A) and the wavelength of the irradiation light(λ) and the iron(x) in water,a way with high accuracy to determine the iron in water was investigated.The calculation curve is stable and hardly affected by environmental conditions.Experiments with water samples have shown that the detection limit was 0.015μg·ml -1 ,RSD≤3.5%,and the recovery rate was 95.4%～101.6%.

Investigation on corrosion kinetics behavior of dacromet coating

Abstract: The corrosion kinetics behavior of Dacromet coating was studied by potentiodynamic scan,galvanostatic charge and fast triangular voltage methods.The corrosion kinetics parameters were calculated and the semiconductor conductivity of the coating was investigated.The superior anticorrosive effect of the coating can be attributed to the multilayer inactivation that greatly increases the breakthrough potential and prolongs the breakdown time.On the other hand,the conductivity of the coating could allow the metal powder within the coating displaying sacrificial protection effect at the expense of anade controllably for steel substrate in salt water environments.The coating formed by substituting boric acid for a part of chromic anhydride in the coating solution,contained more charge carriers and showed more negative corrosion potential,so that the coating still effectively displayd such protection effect even in fresh water.

Determination of disodium ferrate by spectrophotometry

Abstract: The disodium ferrate is very unstable,but its decomposition can be constrained by a strong oxidative agent,sodium hypochlorite.The concentration of disodium ferrate was determined by spectrophotometry directly with pH=12～14 and one percent sodium hypochlorite as a solvent.The accuracy and precision of this method was also discussed in this article.

Decomposition of high concentrated ozone under high humidity condition

Abstract: Four ozone decomposition catalysts were prepared and their catalytic reactivity were investigatedThe ozone decomposition efficiency showed that even under a high humidity condition at relative humidity of 95%,the four variety of catalysts maintained high ozone decomposing performance for a long period of timeEspecially,the RP catalyst had the best reactivity,the ozone decomposition efficiency after starting the reaction 20 hours still remained at 996%

Recover copper from spent ammoniacal etchant by extraction using Lix 54-100

Abstract: Facts affect recovering copper from spent ammoniacal etchant by extraction using Lix 54-100 were analysised.Copper amount in spent etchant whose copper concentration reached 150g/l could decrease to the level of fresh etchant in one or two stage,when phase ratio(O/A)was 2/1,and 80% Lix 54-100 was used as organic phase.

Spreading of aqueous mixtures of fluorocarbon hydrocarbon surfactants on oil

Abstract: Spreading on oil of cationic anionic fluorocarbon hydrocarbon surfactants R fCONH(CDH 2) 3N(C 2H 5) 2CH 3I/C nH 2n+1 COONa and R fCOONa/C mH 2m+1 N(CH 3) 3Br (R f=F[CF(CF 3)CF 2O] 2CF(CF 3);n=7,9,11,13;m=8,10,12) was studied.It showed that counter charged hydrocarbon surfactants decrease spreading concentration of fluorocarbon surfactants and make fluorocarbon surfactants that have high surface tension spread on oil.The sealing capability of aqueous film on oil is enhanced by both counter charged hydrocarbon surfactants and xanthan gum.