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2008 Volume 25 Issue 1
2008, 25(1): 1-4
Abstract:
The adsorption of lead(Ⅱ) on the extracellular polymer of superiority bacteria in natural water and its main components such as the exopolysaccharides and extracellular proteins were investigated.The main components were separated from the extracellular polymers of natural surface coatings cultivated in Changchun Nanhu Lake.The results show that three adsorbents' maximum adsorptive capacities are 23.64,15.8,3.48 mg/g respectively when the solution original pH is 6.Both Langmuir and Freundlich isotherm equations could describe the thermodynamics adsorption processes of Pb on the extracellular polymers,exopolysaccha-rides and extracellular proteins.The existence of Cd affected the adsorption of Pb.The pH value also affected the adsorption processes.The mechanisms of adsorption of Pb were studied by infrared spectroscopy and the functional groups participated in the adsorption were identified,such as acetylamino group(-NHCOCH3) and amino-group(-NH2) of protein,hydroxyl group(-OH) of exopolysaccharide,etc.The results show that the biosorption ability of the exopolysaccharides is much higher than that of the extracellular proteins in the extracellular polymers.
The adsorption of lead(Ⅱ) on the extracellular polymer of superiority bacteria in natural water and its main components such as the exopolysaccharides and extracellular proteins were investigated.The main components were separated from the extracellular polymers of natural surface coatings cultivated in Changchun Nanhu Lake.The results show that three adsorbents' maximum adsorptive capacities are 23.64,15.8,3.48 mg/g respectively when the solution original pH is 6.Both Langmuir and Freundlich isotherm equations could describe the thermodynamics adsorption processes of Pb on the extracellular polymers,exopolysaccha-rides and extracellular proteins.The existence of Cd affected the adsorption of Pb.The pH value also affected the adsorption processes.The mechanisms of adsorption of Pb were studied by infrared spectroscopy and the functional groups participated in the adsorption were identified,such as acetylamino group(-NHCOCH3) and amino-group(-NH2) of protein,hydroxyl group(-OH) of exopolysaccharide,etc.The results show that the biosorption ability of the exopolysaccharides is much higher than that of the extracellular proteins in the extracellular polymers.
2008, 25(1): 5-8
Abstract:
NH4+/molybdenum disulfide intercalated material was prepared by the exfoliation and restacking process.It could be used to store the single-layered molybdenum disulfide for a long time.It could be also used as a precursor to be inserted with other guest molecules to prepare new intercalated materials.The intercalated material was characterized by XRD and TGA.The results indicated that the interlayer spacing in the MoS2 was increased from 0.615 nm to 0.954 nm.The content of the inserted NH4+ was determined by elemental analysis and TGA,which showed that the as-prepared NH4+/molybdenum disulfides were(NH4+)3.1MoS2 and(NH4+)2.9MoS2 respectively.According to the results of XRD and TGA,no change of the intercalation compound was found after it had been saved in air for one month.The degree of intercalation was found to be dependent on the concentration of NH4Cl,the reaction temperature and time.The NH4+/molybdenum disulfide with the biggest interlayer spacing was obtained when the concentration of NH4Cl was 1.0%,reaction tempe-rature 30℃ and the reaction time 12 h.
NH4+/molybdenum disulfide intercalated material was prepared by the exfoliation and restacking process.It could be used to store the single-layered molybdenum disulfide for a long time.It could be also used as a precursor to be inserted with other guest molecules to prepare new intercalated materials.The intercalated material was characterized by XRD and TGA.The results indicated that the interlayer spacing in the MoS2 was increased from 0.615 nm to 0.954 nm.The content of the inserted NH4+ was determined by elemental analysis and TGA,which showed that the as-prepared NH4+/molybdenum disulfides were(NH4+)3.1MoS2 and(NH4+)2.9MoS2 respectively.According to the results of XRD and TGA,no change of the intercalation compound was found after it had been saved in air for one month.The degree of intercalation was found to be dependent on the concentration of NH4Cl,the reaction temperature and time.The NH4+/molybdenum disulfide with the biggest interlayer spacing was obtained when the concentration of NH4Cl was 1.0%,reaction tempe-rature 30℃ and the reaction time 12 h.
2008, 25(1): 9-12
Abstract:
The effect of temperature(293~313 K) on chromatographic separation of mandelic acid over a C18 column was investigated with L-phenylalanine-CuSO4 aqueous solution and methanol as the chiral ligand mobile phase.Higher column temperature was found to be disadvantageous to the enantiomer separation.The retention time,resolution and selectivity of the chiral separation were decreased with temperature increase.The Van't Hoff plots of the ln k' versus 1/T of the enantiomers have a good linearity with a correlation coefficient of 0.99.The thermodynamic functions(ΔH0,ΔS,RΔH0,ΔS,RΔS0) were calculated,and in the examined temperature range,the enthalpy contribution to the enantiomer transfer energy was found to be more significant than the entropy one.Therefore,the enantiomeric separation is a enthalpy controlling process.
The effect of temperature(293~313 K) on chromatographic separation of mandelic acid over a C18 column was investigated with L-phenylalanine-CuSO4 aqueous solution and methanol as the chiral ligand mobile phase.Higher column temperature was found to be disadvantageous to the enantiomer separation.The retention time,resolution and selectivity of the chiral separation were decreased with temperature increase.The Van't Hoff plots of the ln k' versus 1/T of the enantiomers have a good linearity with a correlation coefficient of 0.99.The thermodynamic functions(ΔH0,ΔS,RΔH0,ΔS,RΔS0) were calculated,and in the examined temperature range,the enthalpy contribution to the enantiomer transfer energy was found to be more significant than the entropy one.Therefore,the enantiomeric separation is a enthalpy controlling process.
2008, 25(1): 13-16
Abstract:
α-and β-MnO2 nanorods were successfully prepared by a hydrothermal method based on the redox reaction of KMnO4 and ascorbic acid(AA).XRD,TEM techniques were used to characterize the as-prepared MnO2 samples.The results indicated that reaction temperature and reaction time were the key factors to determine the crystallographic forms of the final products from the hydrothermal system,in which the molar ratio of AA to KMnO4 was 1:5.α-MnO2 nanorods were obtained when the reaction was conducted at 150~160℃ for 12 h,while β-MnO2 nanorods were prepared at 170℃ for 24 h.The catalytic activities of the as-prepared MnO2 nanorods and commercial MnO2 were evaluated by minitoring the degradation of fuchsin acid in the presence of H2O2.Both α-and β-MnO2 nanorods exhibited higher catalytic activity on the degradation of fuchsin acid than bulk MnO2.β-MnO2 had the highest activity among the three,resulting in 97.6% decoloration of the fuchsin acid solution within 60 minutes.
α-and β-MnO2 nanorods were successfully prepared by a hydrothermal method based on the redox reaction of KMnO4 and ascorbic acid(AA).XRD,TEM techniques were used to characterize the as-prepared MnO2 samples.The results indicated that reaction temperature and reaction time were the key factors to determine the crystallographic forms of the final products from the hydrothermal system,in which the molar ratio of AA to KMnO4 was 1:5.α-MnO2 nanorods were obtained when the reaction was conducted at 150~160℃ for 12 h,while β-MnO2 nanorods were prepared at 170℃ for 24 h.The catalytic activities of the as-prepared MnO2 nanorods and commercial MnO2 were evaluated by minitoring the degradation of fuchsin acid in the presence of H2O2.Both α-and β-MnO2 nanorods exhibited higher catalytic activity on the degradation of fuchsin acid than bulk MnO2.β-MnO2 had the highest activity among the three,resulting in 97.6% decoloration of the fuchsin acid solution within 60 minutes.
2008, 25(1): 17-21
Abstract:
Seven novel N,N-nitrophenyl urea compounds were synthesized in yields of 74%~88% via non-phosgene method,and their structures were confirmed by IR,GC-MS,1H NMR and elemental analysis.Their primary double-function activity was screened on Oryza sativa and Echinochloa crusgalli L.The seven compounds exhibited certain plant growth regulating activity and herbicidal activity.Among those compounds,compound C exhibited 6.66%,0.89%,3.18%,and 0.3% growth regulating activities to living,stem length,root length,and fresh weight of Oryza sativa and 55%,and 42.56% inhibitory rates against living and fresh weight of Echinochloa crusgalli L,showing the potential of double-function.In addition,the correlations between biological activities and molecular structures of the compounds were discussed.
Seven novel N,N-nitrophenyl urea compounds were synthesized in yields of 74%~88% via non-phosgene method,and their structures were confirmed by IR,GC-MS,1H NMR and elemental analysis.Their primary double-function activity was screened on Oryza sativa and Echinochloa crusgalli L.The seven compounds exhibited certain plant growth regulating activity and herbicidal activity.Among those compounds,compound C exhibited 6.66%,0.89%,3.18%,and 0.3% growth regulating activities to living,stem length,root length,and fresh weight of Oryza sativa and 55%,and 42.56% inhibitory rates against living and fresh weight of Echinochloa crusgalli L,showing the potential of double-function.In addition,the correlations between biological activities and molecular structures of the compounds were discussed.
2008, 25(1): 22-26
Abstract:
In this paper,the damage of deoxyribonucleic acid(DNA) under the action of photosensitive compound,hematoporphyrin(HP),activated by ultrasonic irradiation has been investigated by means of UV-Vis and fluorescence(FL) spectra.Under the cooperative action of ultrasonic irradiation and HP,the UV-Vis absorbence of the DNA solution showed obvious hyperchromic effect,while the fluorescence intensity of the DNA-EB solution exhibited evident quenching phenomenon.The influence of ultrasonic irradiation time,HP concentration and solution acidity on the damage of the DNA under ultrasonic irradiation in the presence of HP was also studied.The results showed that,under certain conditions,the damage of the DNA would be enhanced with the increase of ultrasonic irradiation time and HP concentration.However,the influence of solution acidity on the damage of the DNA was more complicated.In weak acidic or neutral solutions,the damage of the DNA was obvious,but the trend decreased for basic solutions.In addition,the HP concentration also decreased,which indicated that the HP was destroyed,too.The possible mechanism on the damage of the DNA under ultrasonic irradiation in the presence of HP was also discussed,which explained such damage of the DNA by the theories of sonoluminescence and "hot spot".These results may provide some guidances for the sonodynamic treatment(SDT) of various cancers in clinic in the future.
In this paper,the damage of deoxyribonucleic acid(DNA) under the action of photosensitive compound,hematoporphyrin(HP),activated by ultrasonic irradiation has been investigated by means of UV-Vis and fluorescence(FL) spectra.Under the cooperative action of ultrasonic irradiation and HP,the UV-Vis absorbence of the DNA solution showed obvious hyperchromic effect,while the fluorescence intensity of the DNA-EB solution exhibited evident quenching phenomenon.The influence of ultrasonic irradiation time,HP concentration and solution acidity on the damage of the DNA under ultrasonic irradiation in the presence of HP was also studied.The results showed that,under certain conditions,the damage of the DNA would be enhanced with the increase of ultrasonic irradiation time and HP concentration.However,the influence of solution acidity on the damage of the DNA was more complicated.In weak acidic or neutral solutions,the damage of the DNA was obvious,but the trend decreased for basic solutions.In addition,the HP concentration also decreased,which indicated that the HP was destroyed,too.The possible mechanism on the damage of the DNA under ultrasonic irradiation in the presence of HP was also discussed,which explained such damage of the DNA by the theories of sonoluminescence and "hot spot".These results may provide some guidances for the sonodynamic treatment(SDT) of various cancers in clinic in the future.
2008, 25(1): 27-32
Abstract:
Wheat gluten,a kind of cheap and reproducible agricultural by-products,was modified to produce a new paper strength agent similar to polyamide polyamine epichlorohydrin(PPE) synthesized from petroleum resources.The modification reaction included hydroxymethylation of gluten and cationic activation with epichlorohydrin.The modified wheat gluten contains three kinds of functional groups,hydroxy-azetidinium,Chlorohydrin and epoxy groups.Those groups can bond with the fibers of pulp to form three-dimensional networks around the fibers,improving paper strength.The hydroxymethylation of gluten was carried on in the suspension of 5% gluten with 1% formic acid and 0.7% formaldehyde under 70℃,and then cationic activation with 8% epichlorohydrin under 60℃.The modified gluten carries cationic charges,which can increase the Zeta potential and retention of pulp slurry,and improve the physical properties of hand sheets.The gains of dry strength and wet strength of hand sheet were 35% and 20% respectively when 5% modified gluten was used in the pulp slurry.
Wheat gluten,a kind of cheap and reproducible agricultural by-products,was modified to produce a new paper strength agent similar to polyamide polyamine epichlorohydrin(PPE) synthesized from petroleum resources.The modification reaction included hydroxymethylation of gluten and cationic activation with epichlorohydrin.The modified wheat gluten contains three kinds of functional groups,hydroxy-azetidinium,Chlorohydrin and epoxy groups.Those groups can bond with the fibers of pulp to form three-dimensional networks around the fibers,improving paper strength.The hydroxymethylation of gluten was carried on in the suspension of 5% gluten with 1% formic acid and 0.7% formaldehyde under 70℃,and then cationic activation with 8% epichlorohydrin under 60℃.The modified gluten carries cationic charges,which can increase the Zeta potential and retention of pulp slurry,and improve the physical properties of hand sheets.The gains of dry strength and wet strength of hand sheet were 35% and 20% respectively when 5% modified gluten was used in the pulp slurry.
2008, 25(1): 33-37
Abstract:
A new TiO2/polyfurfurylamine(CPFA) nanocomposite was successfully prepared via a process,known as in-situ two-step method(in-situ TSM),from monomer furfurylamine(FA) and TiO2 and used as catalyst to degrade dye MB molecules.The effects of the factors,such as the heat treatment and TiO2 content,on the catalytic property were investigated.Catalytic experiments indicated that under natural light and room temperature conditions,the MB solution was fully decolorized on TiO2/CPFA nanocomposite particles within 2 min.And TiO2/CPFA nanocomposite particles with 42.48% of TiO2,treated at 460℃,exhibited much higher catalytic activity and could keep very high activity on MB decolorization reaction when it was repeatedly used 3 times.TEM results show that in-situ TSM was successful for preparing TiO2-conjugated polymer nanomaterial and the size of TiO2/CPFA particles was about 26 nm and the size distribution was very narrow.XRD results show that TiO2 of the composite material was a mixture of rutile and the content of rutile was about 79%.
A new TiO2/polyfurfurylamine(CPFA) nanocomposite was successfully prepared via a process,known as in-situ two-step method(in-situ TSM),from monomer furfurylamine(FA) and TiO2 and used as catalyst to degrade dye MB molecules.The effects of the factors,such as the heat treatment and TiO2 content,on the catalytic property were investigated.Catalytic experiments indicated that under natural light and room temperature conditions,the MB solution was fully decolorized on TiO2/CPFA nanocomposite particles within 2 min.And TiO2/CPFA nanocomposite particles with 42.48% of TiO2,treated at 460℃,exhibited much higher catalytic activity and could keep very high activity on MB decolorization reaction when it was repeatedly used 3 times.TEM results show that in-situ TSM was successful for preparing TiO2-conjugated polymer nanomaterial and the size of TiO2/CPFA particles was about 26 nm and the size distribution was very narrow.XRD results show that TiO2 of the composite material was a mixture of rutile and the content of rutile was about 79%.
2008, 25(1): 38-42
Abstract:
Six aryl nitrogen mustard derivatives were designed and synthesized with N,N-di(2-chloroethyl)-1,4-phenylene diamine(4) as the pharmacophore,terpineols and linear saturated alcohols as the carrier,and carbamate as the linker.The yields for the target compounds were between 66%~90%.The structures of the compounds were confirmed by 1H NMR,13C NMR,MS and elemental analysis.The in vitro anti-tumor activities of these compounds were tested preliminarily on B16,K562,and CHO cells.The results demonstrate that some compounds possessed higher activity than reference compound 4,and were similar to the commercial drug Melphalan in certain range of concentrations.The in vitro inhibition of farnesyl modified compound 6e against B16 was even better than that of Melphalan at a concentration of 0.1~10 μmol/L.
Six aryl nitrogen mustard derivatives were designed and synthesized with N,N-di(2-chloroethyl)-1,4-phenylene diamine(4) as the pharmacophore,terpineols and linear saturated alcohols as the carrier,and carbamate as the linker.The yields for the target compounds were between 66%~90%.The structures of the compounds were confirmed by 1H NMR,13C NMR,MS and elemental analysis.The in vitro anti-tumor activities of these compounds were tested preliminarily on B16,K562,and CHO cells.The results demonstrate that some compounds possessed higher activity than reference compound 4,and were similar to the commercial drug Melphalan in certain range of concentrations.The in vitro inhibition of farnesyl modified compound 6e against B16 was even better than that of Melphalan at a concentration of 0.1~10 μmol/L.
2008, 25(1): 43-47
Abstract:
With enoxacin as template molecule,methacrylic acid and 4-rinylpyridine as functional monomers,a molecularly imprinted polymer was prepared via a molecular imprinting technique.The molecularly imprinted polymer was investigated in equilibrium binding experiment to evaluate its adsorption property and selective recognition.Scatchard analysis showed that two classes of binding sites were formed in the enoxacin imprinted polymer under the studied concentrations.The dissociation constant(Kd1) and the apparent maximum binding capacity(Qmax) were Kd1=0.22 mmol/L,Qmax1=52.2 μmol/g for high affinity binding sites and Kd2=1.23 mmol/L,Qmax2=150.5 μmol/g for low affinity binding sites,respectively.The experiments of binding different substrates indicated that the imprinted polymer possessed a high selectivity and a high recognition ability for enoxacin.When it was used as a solid phase extraction sorbent,the imprined polymer effectively completed the clean-up and enrichment of the sample in the analysis of enoxacin from human serum.
With enoxacin as template molecule,methacrylic acid and 4-rinylpyridine as functional monomers,a molecularly imprinted polymer was prepared via a molecular imprinting technique.The molecularly imprinted polymer was investigated in equilibrium binding experiment to evaluate its adsorption property and selective recognition.Scatchard analysis showed that two classes of binding sites were formed in the enoxacin imprinted polymer under the studied concentrations.The dissociation constant(Kd1) and the apparent maximum binding capacity(Qmax) were Kd1=0.22 mmol/L,Qmax1=52.2 μmol/g for high affinity binding sites and Kd2=1.23 mmol/L,Qmax2=150.5 μmol/g for low affinity binding sites,respectively.The experiments of binding different substrates indicated that the imprinted polymer possessed a high selectivity and a high recognition ability for enoxacin.When it was used as a solid phase extraction sorbent,the imprined polymer effectively completed the clean-up and enrichment of the sample in the analysis of enoxacin from human serum.
2008, 25(1): 48-52
Abstract:
The title complex was synthesized from the reaction of pyridine-4-carbaldehyde thiosemicarbazone with zinc acetate and characterized by elemental analysis,IR,UV and X-ray crystal diffraction.The X-ray diffraction revealed that title complex 1 contains one four-coordinated zinc ion connected by two thiosemicarbazone ligands via the pyridyl nitrogen atom of one thiosemicarbazone ligand,the sulfur atom,two oxygen atoms of two acetate anions coordinating through the other thiosemicarbazone ligand,forming a distorted tetrahedron of Zn(Ⅱ) ion.Each ligand adopting the head-to-end coordination mode coordinates to two zinc ion via the pyridine nitrogen and sulphur atoms,respectively.Thus zinc ions are bridge-linked to form an pseudo-helical chain framework.Between the chains,three-dimensional network framework is formed by hydrogen bonding and π-π interactions.It is novel that the pyridine nitrogen atom and sulphur atom of a potential NNS tridentate thiosemicarbazone without using its imine nitrogen adopt the head-to-end NS coordination mode.
The title complex was synthesized from the reaction of pyridine-4-carbaldehyde thiosemicarbazone with zinc acetate and characterized by elemental analysis,IR,UV and X-ray crystal diffraction.The X-ray diffraction revealed that title complex 1 contains one four-coordinated zinc ion connected by two thiosemicarbazone ligands via the pyridyl nitrogen atom of one thiosemicarbazone ligand,the sulfur atom,two oxygen atoms of two acetate anions coordinating through the other thiosemicarbazone ligand,forming a distorted tetrahedron of Zn(Ⅱ) ion.Each ligand adopting the head-to-end coordination mode coordinates to two zinc ion via the pyridine nitrogen and sulphur atoms,respectively.Thus zinc ions are bridge-linked to form an pseudo-helical chain framework.Between the chains,three-dimensional network framework is formed by hydrogen bonding and π-π interactions.It is novel that the pyridine nitrogen atom and sulphur atom of a potential NNS tridentate thiosemicarbazone without using its imine nitrogen adopt the head-to-end NS coordination mode.
2008, 25(1): 53-57
Abstract:
A novel organic compound substituted with hole transporting arylamine and electron transporting 1,3,4-oxadiazole moieties was designed and synthesized via facile multistep reactions with a high yield.The compound is N-phengyl-N-(4-(5-(4-biphenyl)-1,3,4-oxadiazol-2-yl)phenyl)benzenamine,PBPOPB).The compound emits intensive blue light with a high fluorescence quantum yield of 87% under~365 nm light excitation.Cyclic voltammetry results imply the compound has good hole-transporting and electro-transporting properties.TG analysis shows a high heat-stability of the compound.Preliminary study on the electroluminescence of the fluorescent dye prepared via vacuum evaporation indicates that the compound has potential for the production of organic light emitting diodes(OLED).The maximum luminance for the blue light emitting OLEDs with single layered homojunction reached 2 800 cd/m2,whereas for double layered heterojunction OLEDs,the best result was more than 16,750 cd/m2.All the results indicate that the synthesized compound with electron-transporting/hole-transporting unit is a good blue light-emitting material and hole-transporting material for fabrication of organic light-emitting diodes.
A novel organic compound substituted with hole transporting arylamine and electron transporting 1,3,4-oxadiazole moieties was designed and synthesized via facile multistep reactions with a high yield.The compound is N-phengyl-N-(4-(5-(4-biphenyl)-1,3,4-oxadiazol-2-yl)phenyl)benzenamine,PBPOPB).The compound emits intensive blue light with a high fluorescence quantum yield of 87% under~365 nm light excitation.Cyclic voltammetry results imply the compound has good hole-transporting and electro-transporting properties.TG analysis shows a high heat-stability of the compound.Preliminary study on the electroluminescence of the fluorescent dye prepared via vacuum evaporation indicates that the compound has potential for the production of organic light emitting diodes(OLED).The maximum luminance for the blue light emitting OLEDs with single layered homojunction reached 2 800 cd/m2,whereas for double layered heterojunction OLEDs,the best result was more than 16,750 cd/m2.All the results indicate that the synthesized compound with electron-transporting/hole-transporting unit is a good blue light-emitting material and hole-transporting material for fabrication of organic light-emitting diodes.
2008, 25(1): 58-62
Abstract:
Electrochemical behavior of pseudoephedrine hydrochloride(PSE) on multi-wall carbon nanotube modified glassy carbon electrode(MWCNT/GCE) was investigated by cyclic voltammetry(CV).The experimental results showed that the direct electrochemical oxidation of PSE was sluggish on GCE,with no oxidation peaks appearing,indicating that PSE has a high overpotential and can not be directly oxidized.However,on MWCNT/GCE,its oxidation current increased with the potential shifting positive,and an irreversible oxidation peak appeared at 0.902 V,which indicated that MWCNT/GCE can catalyze the electrochemical oxidation of PSE very well.The influence of experimental conditions on the electrochemical behavior of PSE was also studied.No oxidation peaks appeared for PSE at pH<7.0;whereas at pH>7.0,an anodic oxidation peak appeared,which was a diffusion-limited electrode reaction process;at the same time the diffusion coefficient D,electron transfer coefficient α,and the electrode reaction rate constant kf were determined to be 3.10×10-6 cm2/s,0.94,and 1.48×10-3/s,respectively.The experimental results of the amperometric response to time showed that current signal of the MWCNT/GCE was proportional to the PSE concentration,and the response time was less than 5 seconds,and the response concentration limit was 1×10-5 mol/L.The method can be used in PSE electrochemical quantitative determination with low detection limit and high sensitivity.
Electrochemical behavior of pseudoephedrine hydrochloride(PSE) on multi-wall carbon nanotube modified glassy carbon electrode(MWCNT/GCE) was investigated by cyclic voltammetry(CV).The experimental results showed that the direct electrochemical oxidation of PSE was sluggish on GCE,with no oxidation peaks appearing,indicating that PSE has a high overpotential and can not be directly oxidized.However,on MWCNT/GCE,its oxidation current increased with the potential shifting positive,and an irreversible oxidation peak appeared at 0.902 V,which indicated that MWCNT/GCE can catalyze the electrochemical oxidation of PSE very well.The influence of experimental conditions on the electrochemical behavior of PSE was also studied.No oxidation peaks appeared for PSE at pH<7.0;whereas at pH>7.0,an anodic oxidation peak appeared,which was a diffusion-limited electrode reaction process;at the same time the diffusion coefficient D,electron transfer coefficient α,and the electrode reaction rate constant kf were determined to be 3.10×10-6 cm2/s,0.94,and 1.48×10-3/s,respectively.The experimental results of the amperometric response to time showed that current signal of the MWCNT/GCE was proportional to the PSE concentration,and the response time was less than 5 seconds,and the response concentration limit was 1×10-5 mol/L.The method can be used in PSE electrochemical quantitative determination with low detection limit and high sensitivity.
2008, 25(1): 63-66
Abstract:
A method of accelerated solvent extraction and reverse-phase high performance liquid chromato-graphy(ASE-RP-HPLC) was developed to determine the concentration of phthalates in plastics.The plasticpieces were extracted with dicholoride methane by accelarated solvent extraction(ASE),and then the extractant was concentrated,filtered,and prepared for HPLC analysis.The analysis was performed on a Diamond column(250 mm×4.6 mm i.d.,5 μm) with acetonitrile-water(95:5,volume ratio) as the mobile phase at a flow rate of 1.0 mL/min,and it was detected at 254 nm using a UV detector.Quantitative analysis was carried out with external standard method.The calibration curves were linear in the range of 0.1~100 mg/L and the correlation coefficients were above 0.999 for both compounds.The relative standard deviations were below 5.20%.The recoveries of both phthalates added were 87%~108%.The detection limit of the method was 10 mg/L.The method is a fast and simple one to detect the concentration of phthalates in plastics.
A method of accelerated solvent extraction and reverse-phase high performance liquid chromato-graphy(ASE-RP-HPLC) was developed to determine the concentration of phthalates in plastics.The plasticpieces were extracted with dicholoride methane by accelarated solvent extraction(ASE),and then the extractant was concentrated,filtered,and prepared for HPLC analysis.The analysis was performed on a Diamond column(250 mm×4.6 mm i.d.,5 μm) with acetonitrile-water(95:5,volume ratio) as the mobile phase at a flow rate of 1.0 mL/min,and it was detected at 254 nm using a UV detector.Quantitative analysis was carried out with external standard method.The calibration curves were linear in the range of 0.1~100 mg/L and the correlation coefficients were above 0.999 for both compounds.The relative standard deviations were below 5.20%.The recoveries of both phthalates added were 87%~108%.The detection limit of the method was 10 mg/L.The method is a fast and simple one to detect the concentration of phthalates in plastics.
2008, 25(1): 67-72
Abstract:
The nucleating agent 1,3;2,4-di-p-chlorinbenzylidene sorbitol(CDBS) and nano-calcium carbonate(nano-CaCO3) were added in polypropylene(PP).The results of DSC indicate that the crystallization rate and the crystallization temperature of PP increased with the addition of nano-calcium carbonate particles,while the crystallinity of PP did not change obviously.The crystallization temperature of PP with nucleating agent CDBS was higher than that of non-nucleated PP by about 20℃.The crystallization rate and the crystallinity of PP increased with the addition of CDBS,with the crystallinity of PP reaching 38%.The results of XRD and PLM show that the nucleating density increased obviously when CDBS was added into the samples.But the crystal structure of the α-form of polypropylene was essentially unaffected by the nucleating agent.CDBS was an effective nucleating agent for PP.The haziness of the sample decreased from 56% to 12% with the addition of CDBS and CDBS was a good transparent agent for PP.The nucleating agent and the nanoparticles could increase the tensile strength and impact strength of PP.The impact strength of PP increased from 33 J/m to about 44 J/m.But CDBS reduced the ultimate strain of the sample by about 26%.
The nucleating agent 1,3;2,4-di-p-chlorinbenzylidene sorbitol(CDBS) and nano-calcium carbonate(nano-CaCO3) were added in polypropylene(PP).The results of DSC indicate that the crystallization rate and the crystallization temperature of PP increased with the addition of nano-calcium carbonate particles,while the crystallinity of PP did not change obviously.The crystallization temperature of PP with nucleating agent CDBS was higher than that of non-nucleated PP by about 20℃.The crystallization rate and the crystallinity of PP increased with the addition of CDBS,with the crystallinity of PP reaching 38%.The results of XRD and PLM show that the nucleating density increased obviously when CDBS was added into the samples.But the crystal structure of the α-form of polypropylene was essentially unaffected by the nucleating agent.CDBS was an effective nucleating agent for PP.The haziness of the sample decreased from 56% to 12% with the addition of CDBS and CDBS was a good transparent agent for PP.The nucleating agent and the nanoparticles could increase the tensile strength and impact strength of PP.The impact strength of PP increased from 33 J/m to about 44 J/m.But CDBS reduced the ultimate strain of the sample by about 26%.
2008, 25(1): 73-76
Abstract:
Pseudo ternary phase diagrams of Cyhalothrin microemulsion with four different solvents were plotted based on electric conductivity measurements.The solubilization positions in the micelle of the Cyhalothrin microemulsions with four different solvents were tested by fluorescent using pyrene as a probe.The results showed that O/W Cyhalothrin microemulsions were easier to form in solvents of low polarity than in solvents of high polarity resulting in bigger O/W area in the pseudo ternary phase diagram.In the solvents of lower polarity I1/I3 was smaller,indicating that the Cyhalothrin molecules were closer to the micelle core and less accessible to water,and the raw pesticide was less likely to decompose,and vice versa.The results were proved by measuring the high temperature decomposition rates.
Pseudo ternary phase diagrams of Cyhalothrin microemulsion with four different solvents were plotted based on electric conductivity measurements.The solubilization positions in the micelle of the Cyhalothrin microemulsions with four different solvents were tested by fluorescent using pyrene as a probe.The results showed that O/W Cyhalothrin microemulsions were easier to form in solvents of low polarity than in solvents of high polarity resulting in bigger O/W area in the pseudo ternary phase diagram.In the solvents of lower polarity I1/I3 was smaller,indicating that the Cyhalothrin molecules were closer to the micelle core and less accessible to water,and the raw pesticide was less likely to decompose,and vice versa.The results were proved by measuring the high temperature decomposition rates.
2008, 25(1): 77-80
Abstract:
A N-alkyl chitosan derivative was synthesized by reducing Schiff' base formed from the reaction of n-Heptaldehyde and chitosan via phase transfer catalysis.The modified chitosan was characterized by FTIR and XRD.The chitosan derivative was applied to adsorbing 2,4-dichlorophenol.The effects of adsorption conditions,such as time,pH,the concentration of 2,4-dichlorophenol,and the amount of the modified chitosan on the adsorption quantity of 2,4-dichlorophenol were studied.The N-alkyl chitosan exhibited good acid resistance.The solution pH was the main factor affectomg the adsorption.At pH 6.0,the adsorption of 2,4-dichlorophenol reached the maximum in 2 h.The relationship between the concentration of 2,4-dichlorophenol and the adsorption quantity was fitted well to Freundlich equation.N-alkyl chitosan showed better adsorption capability than chitosan.Adsorption capacity of the modified chitosan and chitosan for 2,4-dichlorophenol of 0.6 g/L concentration was 70.0 mg/g and 7.7 mg/g,respectively.
A N-alkyl chitosan derivative was synthesized by reducing Schiff' base formed from the reaction of n-Heptaldehyde and chitosan via phase transfer catalysis.The modified chitosan was characterized by FTIR and XRD.The chitosan derivative was applied to adsorbing 2,4-dichlorophenol.The effects of adsorption conditions,such as time,pH,the concentration of 2,4-dichlorophenol,and the amount of the modified chitosan on the adsorption quantity of 2,4-dichlorophenol were studied.The N-alkyl chitosan exhibited good acid resistance.The solution pH was the main factor affectomg the adsorption.At pH 6.0,the adsorption of 2,4-dichlorophenol reached the maximum in 2 h.The relationship between the concentration of 2,4-dichlorophenol and the adsorption quantity was fitted well to Freundlich equation.N-alkyl chitosan showed better adsorption capability than chitosan.Adsorption capacity of the modified chitosan and chitosan for 2,4-dichlorophenol of 0.6 g/L concentration was 70.0 mg/g and 7.7 mg/g,respectively.
2008, 25(1): 81-84
Abstract:
The electrochemical behavior of maltol at a multi-walled carbon nanotube(MWNTs) modified glassy carbon electrodes was investigated by cyclic voltammetry(CV) and differential pulse voltammetry(DPV).A direct electroanalytical method for the determination of maltol in beverages was developed.In the medium NH3·H2O-NH4Cl(pH=8.5),maltol produces an irreversible oxidation peak at 0.55 V(vs.SCE) on the MWNTs modified electrode.The modified electrode exhibits good performance for the electrochemical reaction of maltol.The anodic peak current of maltol is linearly dependent on its concentration in a range from 5.0×10-6 to 9.0×10-4 mol/L,with a detection limit of 2.0×10-6 mol/L.The relative standard deviation is 1.1% for a solution containing 5.0×10-5 mol/L maltol(n=10).This modified electrode has a good stability.It can be applied to the direct determination of maltol in beverages without complicated and time-consuming pretreatment.The modified electrode has been satisfactorily used for the determination of maltol in beer,cola and grape wine.The recoveries are in a range of 98%~103%.
The electrochemical behavior of maltol at a multi-walled carbon nanotube(MWNTs) modified glassy carbon electrodes was investigated by cyclic voltammetry(CV) and differential pulse voltammetry(DPV).A direct electroanalytical method for the determination of maltol in beverages was developed.In the medium NH3·H2O-NH4Cl(pH=8.5),maltol produces an irreversible oxidation peak at 0.55 V(vs.SCE) on the MWNTs modified electrode.The modified electrode exhibits good performance for the electrochemical reaction of maltol.The anodic peak current of maltol is linearly dependent on its concentration in a range from 5.0×10-6 to 9.0×10-4 mol/L,with a detection limit of 2.0×10-6 mol/L.The relative standard deviation is 1.1% for a solution containing 5.0×10-5 mol/L maltol(n=10).This modified electrode has a good stability.It can be applied to the direct determination of maltol in beverages without complicated and time-consuming pretreatment.The modified electrode has been satisfactorily used for the determination of maltol in beer,cola and grape wine.The recoveries are in a range of 98%~103%.
2008, 25(1): 85-89
Abstract:
The effects of sodium dodecyl sulfonate(SDS),cetyltrimethyl ammonium bromide(CTAB),oleic acid(OA) and coconut amine(CA) on the dispersion characteristics of asphaltene in the Lungu atmospheric residue(LGAR)-toluene solution were investigated by rheological parameter method.It showed that with surfactants,asphaltene in the LGAR-toluene solution was hydrodynamically spherical and exhibited an obvious solvation phenomenon.Surfactants can accelerate the solvation of the asphaltene,and increase the scrambling of asphaltene particles.The ability of the surfactants promoting the solvation of the asphaltene was in the order of CA> OA> SDS> CTAB.SDS,OA and CA can deaggregate asphaltene,and the ability of the surfactants deaggregating the asphaltene was in the order of CA> OA> SDS,while CTAB can accelerate the aggregation of the asphaltene.
The effects of sodium dodecyl sulfonate(SDS),cetyltrimethyl ammonium bromide(CTAB),oleic acid(OA) and coconut amine(CA) on the dispersion characteristics of asphaltene in the Lungu atmospheric residue(LGAR)-toluene solution were investigated by rheological parameter method.It showed that with surfactants,asphaltene in the LGAR-toluene solution was hydrodynamically spherical and exhibited an obvious solvation phenomenon.Surfactants can accelerate the solvation of the asphaltene,and increase the scrambling of asphaltene particles.The ability of the surfactants promoting the solvation of the asphaltene was in the order of CA> OA> SDS> CTAB.SDS,OA and CA can deaggregate asphaltene,and the ability of the surfactants deaggregating the asphaltene was in the order of CA> OA> SDS,while CTAB can accelerate the aggregation of the asphaltene.
2008, 25(1): 90-94
Abstract:
The article studies electrochemical behavior of gliclazide in buffer solution and demonstrates a fast and sensitive method by measuring gliclazide-parallel catalytic hydrogen wave.The gliclazide yielded a catalytic hydrogen wave whose peak potential was-1.49 V(vs.SCE) in 0.10 mol/L NH3H2O-NH4Cl(pH=8.89±0.1) supporting electrolyte.In the presence of 1.0×10-2 mol/L K2S2O8,a more sensitive parallel catalytic hydrogen wave was produced.The peak current increased by 30 times and the peak potential remained almost the same.The second derivative peak current of the parallel catalytic hydrogen wave was linear to the gliclazide concentration in the range of 1.0×10-8 to 6.0×10-5 mol/L(r=0.997 0,n=10).The limit detection was 5.0×10-9 mol/L.The method was used to measure the content of gliclazide of troche and also used in the reclaimation experiments with emiction standard,whose result was correct and credible.The method can be used to measure the content of gliclazide in pharmaceutical preparations.
The article studies electrochemical behavior of gliclazide in buffer solution and demonstrates a fast and sensitive method by measuring gliclazide-parallel catalytic hydrogen wave.The gliclazide yielded a catalytic hydrogen wave whose peak potential was-1.49 V(vs.SCE) in 0.10 mol/L NH3H2O-NH4Cl(pH=8.89±0.1) supporting electrolyte.In the presence of 1.0×10-2 mol/L K2S2O8,a more sensitive parallel catalytic hydrogen wave was produced.The peak current increased by 30 times and the peak potential remained almost the same.The second derivative peak current of the parallel catalytic hydrogen wave was linear to the gliclazide concentration in the range of 1.0×10-8 to 6.0×10-5 mol/L(r=0.997 0,n=10).The limit detection was 5.0×10-9 mol/L.The method was used to measure the content of gliclazide of troche and also used in the reclaimation experiments with emiction standard,whose result was correct and credible.The method can be used to measure the content of gliclazide in pharmaceutical preparations.
2008, 25(1): 95-100
Abstract:
High-performance liquid chromatographic behavior of eleven basic compounds on a new curcumin bonded silica gel stationary phase(CCSP) was studied.The effects of mobile phase variables,such as methanol content and pH,on their chromatographic behavior,as well as the silanophilic activity of the CCSP were investigated.The retention behavior of the basic compounds was compared with that on ODS.The retention mechanisms of these solutes on the CCSP were also discussed.The results indicate that baseline separation of three series of basic compounds on the CCSP(no end-capped) can be achieved with methanol(55%,40%,30%,respectively)-water as a binary mobile phase without addition of a buffer solution.Compared with ODS,the CCSP exhibited better separation selectivity.Moreover,the elution orders of N,N-dimethylaniline and β-naphthylamine,N-methylaniline and m-nitrobenzaldehyde were very different under the same chromatographic conditions,which indicated that the two stationary phases under went different retention mechanisms in the chromatographic processes.According to the chromatographic data,the separation of the above compounds on the CCSP was based on hydrophobic interaction,n-π and π-π interactions,dipole-dipole interaction,hydrogen-bonding interaction,and charge transfer interaction.The CCSP has the advantages of fast and effective separation for basic compounds with more symmetrical peak shape using simple methanol-water mobile phase,and the capacity factor(k') of these solutes decreases with the increase of methanol content on CCSP without occurrence of the "U" shape.
High-performance liquid chromatographic behavior of eleven basic compounds on a new curcumin bonded silica gel stationary phase(CCSP) was studied.The effects of mobile phase variables,such as methanol content and pH,on their chromatographic behavior,as well as the silanophilic activity of the CCSP were investigated.The retention behavior of the basic compounds was compared with that on ODS.The retention mechanisms of these solutes on the CCSP were also discussed.The results indicate that baseline separation of three series of basic compounds on the CCSP(no end-capped) can be achieved with methanol(55%,40%,30%,respectively)-water as a binary mobile phase without addition of a buffer solution.Compared with ODS,the CCSP exhibited better separation selectivity.Moreover,the elution orders of N,N-dimethylaniline and β-naphthylamine,N-methylaniline and m-nitrobenzaldehyde were very different under the same chromatographic conditions,which indicated that the two stationary phases under went different retention mechanisms in the chromatographic processes.According to the chromatographic data,the separation of the above compounds on the CCSP was based on hydrophobic interaction,n-π and π-π interactions,dipole-dipole interaction,hydrogen-bonding interaction,and charge transfer interaction.The CCSP has the advantages of fast and effective separation for basic compounds with more symmetrical peak shape using simple methanol-water mobile phase,and the capacity factor(k') of these solutes decreases with the increase of methanol content on CCSP without occurrence of the "U" shape.
2008, 25(1): 101-105
Abstract:
Cationic polyacrylamide was prepared,and effects of various factors such as oxidant-reductant concentration,azo-compound concentration,and cationic degree on the intrinsic viscosity of the product were studied.The influence of pH,the intrinsic viscosity,cationic degree,and the dosage of the cationic polyacry-lamide on the flocculating performance were also studied.When the(NH4)2S2O8 and CH3NaO3S·2H2O concentrations were 0.015 0%,the azo-compound concentration was 0.012 5%,the monomer concentration was 40%,and the cationic degree was 40%,the intrinsic viscosity of the product was 13.1 dL/g.The obtained optimum flocculating conditions were that the pH of the wastewater was 6.0,the intrinsic viscosity of the cationic polyacrylamide was 11.9 dL/g,the cationic degree was 40%,and the dosage was 0.027%.Under the above conditions,the transmittance of visible light for the wastewater after treatment was 98.0%,and the flocculating rate was 66.0%,and the dewatering rate was 70.0%.
Cationic polyacrylamide was prepared,and effects of various factors such as oxidant-reductant concentration,azo-compound concentration,and cationic degree on the intrinsic viscosity of the product were studied.The influence of pH,the intrinsic viscosity,cationic degree,and the dosage of the cationic polyacry-lamide on the flocculating performance were also studied.When the(NH4)2S2O8 and CH3NaO3S·2H2O concentrations were 0.015 0%,the azo-compound concentration was 0.012 5%,the monomer concentration was 40%,and the cationic degree was 40%,the intrinsic viscosity of the product was 13.1 dL/g.The obtained optimum flocculating conditions were that the pH of the wastewater was 6.0,the intrinsic viscosity of the cationic polyacrylamide was 11.9 dL/g,the cationic degree was 40%,and the dosage was 0.027%.Under the above conditions,the transmittance of visible light for the wastewater after treatment was 98.0%,and the flocculating rate was 66.0%,and the dewatering rate was 70.0%.
2008, 25(1): 106-110
Abstract:
The interference,caused by 6 kinds of coexisting substances,in esculetin-bovine serum albumin(BSA) binding process was investigated for the first time by means of CD,UV-Vis and fluorescence spectroscopy.The parameters such as KP,KA,n and r were obtained.The detailed interferential quomodo of the coexisting substances were concluded.With I-,r decreased in the range of 0.3%~2.7%,and KP and KA increased in the range of 5.9%~8.1%,and 11.5%~20.6%,respectively;moreover,n increased from 1.58±0.04 to 1.74±0.25,and ion-bridge was the possible interferential quomodo of I-.Sodium Benzoate decreasd r in the range of 2.4%~4.5%,increased KP in the range of 3.9%~6.9%,and decreased KA in the range of 1.9%~3.4%,while n decreased from 1.58±0.04 to 0.92±0.16,which suggested that appositional replacement was sodium benzoate's interferential quomodo.SDS increased r in the range of 1.2%~2.8%,decreased KP and KA in the range of 11.4%~12.2% and 27.5%~27.8%,respectively,and decreased n from 1.58±0.04 to 1.06±0.12.TW80 decreased r and KA in the range of 1.2%~2.4% and 10.0%~20.1%,respectively,and decreased KP in the range of 4.7%~4.9%,and decreased n from 1.58±0.04 to 1.00±0.27.SDS and TW80 probably interfered by destroying the binding site(s).As for TW80,appositional replacement was another probable interferential quomodo.In addition CD results showed that BSA molecular conformational transition caused by the coexisting substances-BSA binding was a common interferential quomodo of the coexisting substances.Furthermore,it was the main interferential quomodo of glucose and VC,too.
The interference,caused by 6 kinds of coexisting substances,in esculetin-bovine serum albumin(BSA) binding process was investigated for the first time by means of CD,UV-Vis and fluorescence spectroscopy.The parameters such as KP,KA,n and r were obtained.The detailed interferential quomodo of the coexisting substances were concluded.With I-,r decreased in the range of 0.3%~2.7%,and KP and KA increased in the range of 5.9%~8.1%,and 11.5%~20.6%,respectively;moreover,n increased from 1.58±0.04 to 1.74±0.25,and ion-bridge was the possible interferential quomodo of I-.Sodium Benzoate decreasd r in the range of 2.4%~4.5%,increased KP in the range of 3.9%~6.9%,and decreased KA in the range of 1.9%~3.4%,while n decreased from 1.58±0.04 to 0.92±0.16,which suggested that appositional replacement was sodium benzoate's interferential quomodo.SDS increased r in the range of 1.2%~2.8%,decreased KP and KA in the range of 11.4%~12.2% and 27.5%~27.8%,respectively,and decreased n from 1.58±0.04 to 1.06±0.12.TW80 decreased r and KA in the range of 1.2%~2.4% and 10.0%~20.1%,respectively,and decreased KP in the range of 4.7%~4.9%,and decreased n from 1.58±0.04 to 1.00±0.27.SDS and TW80 probably interfered by destroying the binding site(s).As for TW80,appositional replacement was another probable interferential quomodo.In addition CD results showed that BSA molecular conformational transition caused by the coexisting substances-BSA binding was a common interferential quomodo of the coexisting substances.Furthermore,it was the main interferential quomodo of glucose and VC,too.
2008, 25(1): 111-115
Abstract:
A simple and effective method to prepare 2,2,2-trifluoroethyl ethers via direct nucleophilic substitution was introduced.Some trifluoroethyl aryl derivatives were obtained from the aryl derivatives with sodium 2,2,2-trifluoroethylate in the presence of CuI.Some trifluoethoxylpyridine ether derivatives were successfully synthesized by reacting 4-nitro-pyridine-N-oxide derivatives with trifluoroethanol in the presence of alkali.Especially the yield of 4-(2,2,2-trifluoroethoxy) phenol,which has not been reported in literature up to now,can reach 83.6%.The products were determined by 1H NMR,IR,MS and elemental analysis.The effects of catalyst amount,solvent and temperature on the trifluoroethylation reaction of 4-bromophenol were discussed,the yield was 85.93% when the molar ratio of 4-bromophenol and CuI was 1:4,in DMAC at 130℃;the effects of alkali amount and temperature on the trifluoroethylation reaction of 2,3-dimethyl-4-nitropyridine-N-oxide were also discussed.The yield was 89.5% when mass ratio of trifluoroethanol and potassium hydroxide was 10:1,and the temperature was 90℃.
A simple and effective method to prepare 2,2,2-trifluoroethyl ethers via direct nucleophilic substitution was introduced.Some trifluoroethyl aryl derivatives were obtained from the aryl derivatives with sodium 2,2,2-trifluoroethylate in the presence of CuI.Some trifluoethoxylpyridine ether derivatives were successfully synthesized by reacting 4-nitro-pyridine-N-oxide derivatives with trifluoroethanol in the presence of alkali.Especially the yield of 4-(2,2,2-trifluoroethoxy) phenol,which has not been reported in literature up to now,can reach 83.6%.The products were determined by 1H NMR,IR,MS and elemental analysis.The effects of catalyst amount,solvent and temperature on the trifluoroethylation reaction of 4-bromophenol were discussed,the yield was 85.93% when the molar ratio of 4-bromophenol and CuI was 1:4,in DMAC at 130℃;the effects of alkali amount and temperature on the trifluoroethylation reaction of 2,3-dimethyl-4-nitropyridine-N-oxide were also discussed.The yield was 89.5% when mass ratio of trifluoroethanol and potassium hydroxide was 10:1,and the temperature was 90℃.
2008, 25(1): 116-118
Abstract:
Thymopentin resin was cleaved under microwave irradiation with an American Mas 5 microwave reactor.The effects of cleavage reagents,reaction time and reaction temperature on TP5's yield,were studied with HPLC.The mechanism of TPS cleaved from thymopentin resin under microwave irradiation was discussed.The product was characterized by MS and 1H NMR.The results indicate that TP5's yield reached up to 93.2% at 50℃ with V(TFA):V(H2O):V(TIS)=95:2.5:2.5 as cleavage reagent under microwave irradiation for five minutes.Compared with the results of conventional method,the cleavage reaction rate and yield of TP5 were increased by 24 times and 21.8%,respectively,while the side reaction and the cost of peptide preparation were reduced.
Thymopentin resin was cleaved under microwave irradiation with an American Mas 5 microwave reactor.The effects of cleavage reagents,reaction time and reaction temperature on TP5's yield,were studied with HPLC.The mechanism of TPS cleaved from thymopentin resin under microwave irradiation was discussed.The product was characterized by MS and 1H NMR.The results indicate that TP5's yield reached up to 93.2% at 50℃ with V(TFA):V(H2O):V(TIS)=95:2.5:2.5 as cleavage reagent under microwave irradiation for five minutes.Compared with the results of conventional method,the cleavage reaction rate and yield of TP5 were increased by 24 times and 21.8%,respectively,while the side reaction and the cost of peptide preparation were reduced.
2008, 25(1): 119-121
Abstract:
Up-conversion fluorescence material Tm3+/Yb3+-codoped NaYF4 was prepared in combustion.Under 980 nm LD excitation,strong blue light was observed.The tests indicated the strongest blue light was observed when the molar concentrations for Yb3+,Tm3+ and urea were 2.68%,0.024%,and 30% respectively,while the temperature was set at 450~550℃,and the reaction time was 110 min.
Up-conversion fluorescence material Tm3+/Yb3+-codoped NaYF4 was prepared in combustion.Under 980 nm LD excitation,strong blue light was observed.The tests indicated the strongest blue light was observed when the molar concentrations for Yb3+,Tm3+ and urea were 2.68%,0.024%,and 30% respectively,while the temperature was set at 450~550℃,and the reaction time was 110 min.
2008, 25(1): 122-124
Abstract:
A series of 5-arylidene thiazolidineone derivatives was synthesized by condensation reaction of aromatic aldehydes with thiazolidineone derivatives in the presence of NaAc and Bu4NBr in water.The reaction was carried out at 95℃ for 2~8 h,the yields of the products were ranged in 65.3%~91.3%,which were higher or similar to those in organic solvent.The results indicate that the cycles of thiazolidineone derivatives may be opened under the action of a strong base,such as NaOH.NaAc is an efficient catalyst for the condensation reaction and could be recycled.The mothod is manipulatively simple and environmental friendly.The products were identified by 1H NMR and IR spectra.
A series of 5-arylidene thiazolidineone derivatives was synthesized by condensation reaction of aromatic aldehydes with thiazolidineone derivatives in the presence of NaAc and Bu4NBr in water.The reaction was carried out at 95℃ for 2~8 h,the yields of the products were ranged in 65.3%~91.3%,which were higher or similar to those in organic solvent.The results indicate that the cycles of thiazolidineone derivatives may be opened under the action of a strong base,such as NaOH.NaAc is an efficient catalyst for the condensation reaction and could be recycled.The mothod is manipulatively simple and environmental friendly.The products were identified by 1H NMR and IR spectra.
