Login In
2013 Volume 30 Issue 1
2013, 30(1): 1-10
doi: DOI:10.3724/SP.J.1095.2013.20180
Abstract:
Supramolecular gels are the self-assembly of low molecular-mass organic gelators through non-bonding interactions to form a 3D entangled fiberous network which immobilizes liquids.This paper reviewed the application of supramolecular gels for catalyzing organic reactions which is a new extended application of supramolecular gels.Recent development of using supromolecular gels as catalysts was summarized and classified according to the gelator structures and reaction types,and particular attentions were given to the unique features of catalysis by the supramolecular system.The challenges and perspectives in this field were discussed.
Supramolecular gels are the self-assembly of low molecular-mass organic gelators through non-bonding interactions to form a 3D entangled fiberous network which immobilizes liquids.This paper reviewed the application of supramolecular gels for catalyzing organic reactions which is a new extended application of supramolecular gels.Recent development of using supromolecular gels as catalysts was summarized and classified according to the gelator structures and reaction types,and particular attentions were given to the unique features of catalysis by the supramolecular system.The challenges and perspectives in this field were discussed.
2013, 30(1): 11-15
doi: DOI:10.3724/SP.J.1095.2013.20062
Abstract:
Butadiene polymerization behaviors of Fe(CF3SO3)2-Al(i-Bu)3 catalyst system using diisooctyl phosphite as electron donor have been investigated.The catalyst system(n(Fe):n(P8):n(Al)=1:4:20) shows fair good activity,syndioselectivity,and especially,both catalytic activity and syndioselectivity increases as elevating polymerization temperature,yielding polybutadiene with over 85% of 1,2-structure content and 99% of syndiotacticity at 50℃.Differentiating from the Fe catalyst systems reported earlier,the current catalyst system possesses much better syndioselectivity and thermal tolerance allowing polymerizing butadiene at relatively high temperature.Particularly,the catalyst system does not involve using any noxious components,implying premising practical application in the area of butadiene polymerization.
Butadiene polymerization behaviors of Fe(CF3SO3)2-Al(i-Bu)3 catalyst system using diisooctyl phosphite as electron donor have been investigated.The catalyst system(n(Fe):n(P8):n(Al)=1:4:20) shows fair good activity,syndioselectivity,and especially,both catalytic activity and syndioselectivity increases as elevating polymerization temperature,yielding polybutadiene with over 85% of 1,2-structure content and 99% of syndiotacticity at 50℃.Differentiating from the Fe catalyst systems reported earlier,the current catalyst system possesses much better syndioselectivity and thermal tolerance allowing polymerizing butadiene at relatively high temperature.Particularly,the catalyst system does not involve using any noxious components,implying premising practical application in the area of butadiene polymerization.
2013, 30(1): 16-21
doi: DOI:10.3724/SP.J.1095.2013.20063
Abstract:
A neodymium chloride ethylene glycol dimethyl ether complex(NdCl3·2DME) was synthesized and used as catalyst for butadiene polymerization.The effects of concentrations of alkylaluminium(AlR3) and methylaluminoxane(MAO) cocatalysts,aging time and polymerization time on polymerization behaviors were investigated.Results show that the as-prepared catalyst displays high activity when both AlR3 and MAO were used as cocatalysts, while the activity became much lower when AlR3 or MAO as cocatalyst was used respectively.The highest catalytic activity was observed with the molar ratio of n(Nd):n(AlR3):n(MAO) was 1:30:45.The catalytic activity,cis-1,4 content and molecular weight of the resulting polymer were much affected with variation of aging temperature of the catalyst system.The optimal aging temperature of the catalyst system was 50℃,while negative effect was observe when aging temperature was higher or lower.The contents of cis-1,4 and the total 1,4-unit of polybutadiene catalyzed by using current catalyst system were up to 98.7%(IR) and 99.6%(1H NMR),respectively.
A neodymium chloride ethylene glycol dimethyl ether complex(NdCl3·2DME) was synthesized and used as catalyst for butadiene polymerization.The effects of concentrations of alkylaluminium(AlR3) and methylaluminoxane(MAO) cocatalysts,aging time and polymerization time on polymerization behaviors were investigated.Results show that the as-prepared catalyst displays high activity when both AlR3 and MAO were used as cocatalysts, while the activity became much lower when AlR3 or MAO as cocatalyst was used respectively.The highest catalytic activity was observed with the molar ratio of n(Nd):n(AlR3):n(MAO) was 1:30:45.The catalytic activity,cis-1,4 content and molecular weight of the resulting polymer were much affected with variation of aging temperature of the catalyst system.The optimal aging temperature of the catalyst system was 50℃,while negative effect was observe when aging temperature was higher or lower.The contents of cis-1,4 and the total 1,4-unit of polybutadiene catalyzed by using current catalyst system were up to 98.7%(IR) and 99.6%(1H NMR),respectively.
2013, 30(1): 22-27
doi: DOI:10.3724/SP.J.1095.2013.20064
Abstract:
In the presence of tert-butyl hydroperoxide(TBHP),metallo-deuteroporphyrin dimethyl esters[M(DPDME)] were used as catalysts in the oxidation of styrene.We have investigated the effects of the amount of the catalyst,the amount of the oxidant,reaction temperature,time,solvents and metallo-deuteroporphyrin dimethyl esters with different central metals on the conversion of styrene and the selectivity of benzaldehyde.The mechanism of the reaction was also discussed.The results indicated that the M(DPDME) could efficiently catalyze selective oxidation of styrene to benzaldehyde in good yields.Under the conditions of 0.002 mmol ClMn(DPDME) as the catalyst,0.4 mmol TBHP as the oxidatant,1 mmol styrene as the substrate,CH3CN(4 mL)/H2O(1 mL) as the solvent,reaction temperature of 75℃,atmospheric pressure,and a reaction time of 20 h,the conversion of styrene reached 98.3% with the benzaldehyde selectivity of 92.7%.
In the presence of tert-butyl hydroperoxide(TBHP),metallo-deuteroporphyrin dimethyl esters[M(DPDME)] were used as catalysts in the oxidation of styrene.We have investigated the effects of the amount of the catalyst,the amount of the oxidant,reaction temperature,time,solvents and metallo-deuteroporphyrin dimethyl esters with different central metals on the conversion of styrene and the selectivity of benzaldehyde.The mechanism of the reaction was also discussed.The results indicated that the M(DPDME) could efficiently catalyze selective oxidation of styrene to benzaldehyde in good yields.Under the conditions of 0.002 mmol ClMn(DPDME) as the catalyst,0.4 mmol TBHP as the oxidatant,1 mmol styrene as the substrate,CH3CN(4 mL)/H2O(1 mL) as the solvent,reaction temperature of 75℃,atmospheric pressure,and a reaction time of 20 h,the conversion of styrene reached 98.3% with the benzaldehyde selectivity of 92.7%.
2013, 30(1): 28-31
doi: DOI:10.3724/SP.J.1095.2013.20072
Abstract:
The oxidation of cyclohexylamine catalyzed by Al2O3-SiO2 catalyst was carried out under mild conditions.The effects of solvent amount,catalyst amount,reaction time and reaction temperature on the reaction were investigated.Under the conditions of V(acetonitrile):V(cyclohexylamine)=3:1,31.0% mass fraction of catalyst,reaction temperature of 75℃,and reaction time of 5 h,the conversion of cyclohexylamine reaches up to 100% and the selectivity for cyclohexanone oxime is 83.6%.A reaction mechanism is proposed.
The oxidation of cyclohexylamine catalyzed by Al2O3-SiO2 catalyst was carried out under mild conditions.The effects of solvent amount,catalyst amount,reaction time and reaction temperature on the reaction were investigated.Under the conditions of V(acetonitrile):V(cyclohexylamine)=3:1,31.0% mass fraction of catalyst,reaction temperature of 75℃,and reaction time of 5 h,the conversion of cyclohexylamine reaches up to 100% and the selectivity for cyclohexanone oxime is 83.6%.A reaction mechanism is proposed.
2013, 30(1): 32-37
doi: DOI:10.3724/SP.J.1095.2013.20037
Abstract:
Nano-SiO2 was modified with titanate coupling agent(TMC-201) under ultrasonic dispersion.n-Butyl titanate[Ti(OC4H9)4]/nano-SiO2 catalysts were successfully prepared by loading Ti(OC4H9)4 on the surface of modified nano-SiO2 particles via impregnation method.The impacts of titanate coupling agent,temperature and time on the surface modification of hydrophilic nano-SiO2 were studied.The impacts of Ti(OC4H9)4 content,supported temperature and supported time loading on modified nano-SiO2 particles were investigated.The results indicated that the titanate coupling agent was fully grafted on nano-SiO2 when TMC-201 content was 35% of nano-SiO2,modification temperature was 90℃,modification time was 3.5 h.The Ti(OC4H9)4/nano-SiO2 catalysts were the best when the using of Ti(OC4H9)4 was 50% of modified nano-SiO2,supported time was 48 h at room temperature.The modified nano-SiO2 and Ti(OC4H9)4/nano-SiO2 catalysts were characterized by ICP-AES and FESEM.Compared with the Ti(OC4H9)4 catalysts,the Ti(OC4H9)4/nano-SiO2 catalysts exhibited excellent catalytic activity.The esterification time in the synthesis of the poly(trimethylene terephthalate)(PTT) with Ti(OC4H9)4/nano-SiO2 catalysts was 177 min.The viscosity was improved to 1.05 after 2 h polycondensation.
Nano-SiO2 was modified with titanate coupling agent(TMC-201) under ultrasonic dispersion.n-Butyl titanate[Ti(OC4H9)4]/nano-SiO2 catalysts were successfully prepared by loading Ti(OC4H9)4 on the surface of modified nano-SiO2 particles via impregnation method.The impacts of titanate coupling agent,temperature and time on the surface modification of hydrophilic nano-SiO2 were studied.The impacts of Ti(OC4H9)4 content,supported temperature and supported time loading on modified nano-SiO2 particles were investigated.The results indicated that the titanate coupling agent was fully grafted on nano-SiO2 when TMC-201 content was 35% of nano-SiO2,modification temperature was 90℃,modification time was 3.5 h.The Ti(OC4H9)4/nano-SiO2 catalysts were the best when the using of Ti(OC4H9)4 was 50% of modified nano-SiO2,supported time was 48 h at room temperature.The modified nano-SiO2 and Ti(OC4H9)4/nano-SiO2 catalysts were characterized by ICP-AES and FESEM.Compared with the Ti(OC4H9)4 catalysts,the Ti(OC4H9)4/nano-SiO2 catalysts exhibited excellent catalytic activity.The esterification time in the synthesis of the poly(trimethylene terephthalate)(PTT) with Ti(OC4H9)4/nano-SiO2 catalysts was 177 min.The viscosity was improved to 1.05 after 2 h polycondensation.
2013, 30(1): 38-42
doi: DOI:10.3724/SP.J.1095.2013.20012
Abstract:
To search for more potential antitumor agents,five new porphyrin-5-fluorouracil compounds were designed and synthesized.The reaction conditions were optimized and the separation method of the target products was explored.The compositions and structures of these compounds were confirmed by IR,UV-Vis,1H NMR and MS.Their cytotoxicity against five human cancer cell lines in vitro was evaluated by MTT assay.Biological screening results demonstrate that some tested compounds exhibit potential antitumor activity,particularly,compound D3 shows more potential cytotoxic activities than the control 5-fluorouracil against Sk-ov-3 cells.
To search for more potential antitumor agents,five new porphyrin-5-fluorouracil compounds were designed and synthesized.The reaction conditions were optimized and the separation method of the target products was explored.The compositions and structures of these compounds were confirmed by IR,UV-Vis,1H NMR and MS.Their cytotoxicity against five human cancer cell lines in vitro was evaluated by MTT assay.Biological screening results demonstrate that some tested compounds exhibit potential antitumor activity,particularly,compound D3 shows more potential cytotoxic activities than the control 5-fluorouracil against Sk-ov-3 cells.
2013, 30(1): 43-47
doi: DOI:10.3724/SP.J.1095.2013.20021
Abstract:
The Schiff base consisted of 3,5-diiodo-salicylalidehyde and o-diaminobenzene(L) and its Ni(Ⅱ) metal complex has been synthesized and characterized by 1H NMR,elemental analysis,UV spectra,IR spectra and molar conductance analysis.The main bond parameters of the complex were calculated by full-optimized molecular geometry using Gaussian03 program.The composition of the complex was determined to be Ni(Ⅱ)L.The binding mode between complex and DNA was investigated by UV spectra,viscosities,and DNA competitive binding with ethidium bromide(EB).The results showed that the intensity of absorption peaks increased when the complex interacted with ct-DNA,and its constant was Kb=1.129×105 L/mol.The complex will lead to dramatic decrease of fluorescent intensity of EB-DNA.The relative viscosity of ct-DNA increased with the concentration increase of the complex.All indicated that the complex was intercalated into ct-DNA.In addition,the complex is assayed against M.luteus by the punch method.
The Schiff base consisted of 3,5-diiodo-salicylalidehyde and o-diaminobenzene(L) and its Ni(Ⅱ) metal complex has been synthesized and characterized by 1H NMR,elemental analysis,UV spectra,IR spectra and molar conductance analysis.The main bond parameters of the complex were calculated by full-optimized molecular geometry using Gaussian03 program.The composition of the complex was determined to be Ni(Ⅱ)L.The binding mode between complex and DNA was investigated by UV spectra,viscosities,and DNA competitive binding with ethidium bromide(EB).The results showed that the intensity of absorption peaks increased when the complex interacted with ct-DNA,and its constant was Kb=1.129×105 L/mol.The complex will lead to dramatic decrease of fluorescent intensity of EB-DNA.The relative viscosity of ct-DNA increased with the concentration increase of the complex.All indicated that the complex was intercalated into ct-DNA.In addition,the complex is assayed against M.luteus by the punch method.
2013, 30(1): 48-53
doi: DOI:10.3724/SP.J.1095.2013.20052
Abstract:
A series of derivatives of symmetrircal bi-oxadiazoles containing azobenzene was synthesized.Their molecular structures were determined by IR and 1H NMR spectroscopies.The effect of azobenzene on the photoluminescence of oxadiazole derivatives was carefully studied by fluorescence spectra.The emission peaks of F3,F6 and F10 are bimodal,at 348,356 nm and 345,357 nm and 345,357 nm,respectively,attributed to the oxadiazole groups of bi-oxadiazoles.The introduction of azobenzene has less impact on the emission maximum peak of oxadiazole derivatives Fn in solution,but the luminous intensity of oxadiazole derivatives Fn decreases.This is mainly because of the intramolecular electronic energy transfer between the azobenzene groups and the oxadiazole groups in the process of photoexcitation.
A series of derivatives of symmetrircal bi-oxadiazoles containing azobenzene was synthesized.Their molecular structures were determined by IR and 1H NMR spectroscopies.The effect of azobenzene on the photoluminescence of oxadiazole derivatives was carefully studied by fluorescence spectra.The emission peaks of F3,F6 and F10 are bimodal,at 348,356 nm and 345,357 nm and 345,357 nm,respectively,attributed to the oxadiazole groups of bi-oxadiazoles.The introduction of azobenzene has less impact on the emission maximum peak of oxadiazole derivatives Fn in solution,but the luminous intensity of oxadiazole derivatives Fn decreases.This is mainly because of the intramolecular electronic energy transfer between the azobenzene groups and the oxadiazole groups in the process of photoexcitation.
2013, 30(1): 54-60
doi: DOI:10.3724/SP.J.1095.2013.20018
Abstract:
A new compound of 4-((2-thiophenecarboxylic acid hydrazide) methylene) benzoic acid was synthesized by the reaction of ethyl 2-thiophenecarboxylate,hydrazine hydrate and 4-formylbenzoic acid,and characterized by elemental analysis,IR,UV and X-ray diffraction methods.The compound forms a 3-D network through intermolecular N-H…O and O-H…O hydrogen bondings.The dihedral angle between the benzene and thiophene ring is 14.9°.The title compound has intense purple emission at 396 nm when excited at 286 nm.The result of TG/DTG analysis showed that the title compound was stable below 298℃ in N2.The quantum chemical calculation was performed by means of Gaussian 03W program.The Mulliken charge population and Wiberg bond order of the compound and its frontier molecular orbital energy have been discussed.Furthermore,we analyzed its active atoms and evaluated its reliability.The results showed that the values of the bond lengths and bond angles of the quantum chemical calculation were almost the same with the values of X-ray diffraction.The difference between the two methods confirmed the presence of intermolecular hydrogen bonds in their crystal structures.The carbonyl groups are the active centers.
A new compound of 4-((2-thiophenecarboxylic acid hydrazide) methylene) benzoic acid was synthesized by the reaction of ethyl 2-thiophenecarboxylate,hydrazine hydrate and 4-formylbenzoic acid,and characterized by elemental analysis,IR,UV and X-ray diffraction methods.The compound forms a 3-D network through intermolecular N-H…O and O-H…O hydrogen bondings.The dihedral angle between the benzene and thiophene ring is 14.9°.The title compound has intense purple emission at 396 nm when excited at 286 nm.The result of TG/DTG analysis showed that the title compound was stable below 298℃ in N2.The quantum chemical calculation was performed by means of Gaussian 03W program.The Mulliken charge population and Wiberg bond order of the compound and its frontier molecular orbital energy have been discussed.Furthermore,we analyzed its active atoms and evaluated its reliability.The results showed that the values of the bond lengths and bond angles of the quantum chemical calculation were almost the same with the values of X-ray diffraction.The difference between the two methods confirmed the presence of intermolecular hydrogen bonds in their crystal structures.The carbonyl groups are the active centers.
2013, 30(1): 61-66
doi: DOI:10.3724/SP.J.1095.2013.20022
Abstract:
Methane conversion in gliding arc discharge plasma has been studied.The focus of this research is to develop a process of converting methane to C2 hydrocarbons.The influences of CH4 flow rate,input voltage and electrode gap on methane conversion were investigated.The results show that the apparent energy requirement(AER) is obviously increased by enhancing CH4 flow rate.The conversion of methane is improved by adjusting input voltage or electrode gap.And when the input voltage or electrode gap is large,the yield for C2 hydrocarbons decreases significantly.The unsaturated hydrocarbons are the main products of C2 hydrocarbons.Optimum conditions for producing C2 hydrocarbons from methane are suggested.A maximum methane conversion of 43.1% is obtained under the optimum conditions.Also,the selectivity and yield for C2 hydrocarbons and AER are 40.1%,93.2% and 2.41 MJ/mol,respectively.
Methane conversion in gliding arc discharge plasma has been studied.The focus of this research is to develop a process of converting methane to C2 hydrocarbons.The influences of CH4 flow rate,input voltage and electrode gap on methane conversion were investigated.The results show that the apparent energy requirement(AER) is obviously increased by enhancing CH4 flow rate.The conversion of methane is improved by adjusting input voltage or electrode gap.And when the input voltage or electrode gap is large,the yield for C2 hydrocarbons decreases significantly.The unsaturated hydrocarbons are the main products of C2 hydrocarbons.Optimum conditions for producing C2 hydrocarbons from methane are suggested.A maximum methane conversion of 43.1% is obtained under the optimum conditions.Also,the selectivity and yield for C2 hydrocarbons and AER are 40.1%,93.2% and 2.41 MJ/mol,respectively.
2013, 30(1): 67-72
doi: DOI:10.3724/SP.J.1095.2013.20044
Abstract:
To reveal the chemical species of copper,typically the low-valence speices,in Cu-Zn-Al catalyst prepared by complete liquid-phase method before reduction,the effects of heat-treatment atmosphere,interactions among all components and copper precursor on heat-treatment have been systematically studied during the heat treatment of several different kind of copper precursor in liquid paraffin.The results showed that Cu2+ could be reduced by liquid paraffin under heating condition.The Cu+ is formed before the formation of Cu.The reductive degree of Cu2+ was related with the category of copper salts and heat-treatment temperature.CuO can be reduced to Cu2O by liquid paraffin at 240℃,and then to Cu at 300℃.The copper nitrate could be easily reduced by liquid paraffin than copper acetate at the same temperature.The reason of the low-valent copper appearing in Cu-base catalyst prepared by complete liquid-phase method before reduction could be attributed to the presence of liquid paraffin.
To reveal the chemical species of copper,typically the low-valence speices,in Cu-Zn-Al catalyst prepared by complete liquid-phase method before reduction,the effects of heat-treatment atmosphere,interactions among all components and copper precursor on heat-treatment have been systematically studied during the heat treatment of several different kind of copper precursor in liquid paraffin.The results showed that Cu2+ could be reduced by liquid paraffin under heating condition.The Cu+ is formed before the formation of Cu.The reductive degree of Cu2+ was related with the category of copper salts and heat-treatment temperature.CuO can be reduced to Cu2O by liquid paraffin at 240℃,and then to Cu at 300℃.The copper nitrate could be easily reduced by liquid paraffin than copper acetate at the same temperature.The reason of the low-valent copper appearing in Cu-base catalyst prepared by complete liquid-phase method before reduction could be attributed to the presence of liquid paraffin.
2013, 30(1): 73-78
doi: DOI:10.3724/SP.J.1095.2013.20042
Abstract:
Soluble carboxymethyl silk fibroin was prepared from the waste silk by etherification of the water-fast silk fibroin and the monochloracetic acid in ethanol.Various factors on etherified degree of products(such as alkalized time,alkalized temperature,etherified time and etherified temperature,etc.) were discussed.The optimized etherification conditions for preparing the carboxymethyl silk fibroin are:alkalization time:90 min;etherification time:90 min;alkalization temperature:25℃,etherification temperature:70℃.The degree of etherification of the carboxymethyl silk fibroin is 0.7425.The critical micellar density of carboxymethyl silk fibroin is 1.25 g/L and the hydrophilic-lipophilic balance(HLB) value is 10.The fibroin solution is unsuitable for using as a foamer,even though it has some foaming ability,and the formed foam is stable in the mass ration range of 1.0%~1.2%.The silk fibroin solution has exhibited excellent emulsifying capacity and emulsion stability,which renders the silk fibroin can be used as good emulsifiers.
Soluble carboxymethyl silk fibroin was prepared from the waste silk by etherification of the water-fast silk fibroin and the monochloracetic acid in ethanol.Various factors on etherified degree of products(such as alkalized time,alkalized temperature,etherified time and etherified temperature,etc.) were discussed.The optimized etherification conditions for preparing the carboxymethyl silk fibroin are:alkalization time:90 min;etherification time:90 min;alkalization temperature:25℃,etherification temperature:70℃.The degree of etherification of the carboxymethyl silk fibroin is 0.7425.The critical micellar density of carboxymethyl silk fibroin is 1.25 g/L and the hydrophilic-lipophilic balance(HLB) value is 10.The fibroin solution is unsuitable for using as a foamer,even though it has some foaming ability,and the formed foam is stable in the mass ration range of 1.0%~1.2%.The silk fibroin solution has exhibited excellent emulsifying capacity and emulsion stability,which renders the silk fibroin can be used as good emulsifiers.
2013, 30(1): 79-87
doi: DOI:10.3724/SP.J.1095.2013.00489
Abstract:
Quercetin is one of the abundant and cheap flavonoids in herbs.In this paper,quercetin was first chemically bonded to silica gel.A natural ligand quercetin-bonded silica gel stationary phase(QUSP) was obtained by using γ-[(2,3)-glycidyloxypropyl trimethoxysilane(KH-560) as a coupling agent.Its chemical structure was characterized by infrared spectrometry,thermogravimetric analysis,elemental analysis and 13C solid-state nuclear magnetic resonance(NMR).The amount of bonded quercetin was determined to be about 1.39 mmol/g.The reversed-phase property of QUSP based on hydrophobic interaction was first evaluated on high-performance liquid chromatography.The separation abilities of new stationary phase for different polar aromatic compounds were systematically studied by using basic and acidic solutes with different structures as probes.Some retention mechanism in the above separations was also discussed.The results showed that the novel quercetin-boned stationary phase exhibited high separation selectivity for polar compounds,including pyridines,aromatic amines,phenols,benzoic acids,and flavonoids.The baseline separations of the above species were easily achieved by using only simple methanol or acetonitrile water as the mobile phases without fine adjustment of pH in isocratic mode.This is because besides the hydrophobic C6-C3-C6 skeleton,the quercetin ligand QUSP can also provide various active sites for polar solutes,such as hydrogen bonding,dipole-dipole,π-π and charge transfer interactions,in which the synergic interactions could improve separation selectivity,especially for the ionized acidic and basic compounds.
Quercetin is one of the abundant and cheap flavonoids in herbs.In this paper,quercetin was first chemically bonded to silica gel.A natural ligand quercetin-bonded silica gel stationary phase(QUSP) was obtained by using γ-[(2,3)-glycidyloxypropyl trimethoxysilane(KH-560) as a coupling agent.Its chemical structure was characterized by infrared spectrometry,thermogravimetric analysis,elemental analysis and 13C solid-state nuclear magnetic resonance(NMR).The amount of bonded quercetin was determined to be about 1.39 mmol/g.The reversed-phase property of QUSP based on hydrophobic interaction was first evaluated on high-performance liquid chromatography.The separation abilities of new stationary phase for different polar aromatic compounds were systematically studied by using basic and acidic solutes with different structures as probes.Some retention mechanism in the above separations was also discussed.The results showed that the novel quercetin-boned stationary phase exhibited high separation selectivity for polar compounds,including pyridines,aromatic amines,phenols,benzoic acids,and flavonoids.The baseline separations of the above species were easily achieved by using only simple methanol or acetonitrile water as the mobile phases without fine adjustment of pH in isocratic mode.This is because besides the hydrophobic C6-C3-C6 skeleton,the quercetin ligand QUSP can also provide various active sites for polar solutes,such as hydrogen bonding,dipole-dipole,π-π and charge transfer interactions,in which the synergic interactions could improve separation selectivity,especially for the ionized acidic and basic compounds.
2013, 30(1): 88-92
doi: DOI:10.3724/SP.J.1095.2013.20024
Abstract:
A copper(Ⅱ) Schiff base complex with ethylene-diamine-bis-(salicylaldehyde)[Cu(Ⅱ)-EDBSAD] was synthesized and a poly vinyl chloride(PVC) membrane electrode with the complex as neutral carrier was prepared.The electrode displays a preferential potentiometric response to SCN-and exhibits near Nernst response for SCN- within a wide concentration range(1.0×10-1~1.0×10-7 mol/L) with calibration curve equation of E(mV)=-51.75lg cSCN--255.29,and a detection limit of 5.6×10-8 mol/L in pH=5.5 phosphate buffer solution at 25℃.This electrode was applied to the determination of SCN- in waste water and the obtained result was in good agreement with those of high-performance liquid chromatography method.
A copper(Ⅱ) Schiff base complex with ethylene-diamine-bis-(salicylaldehyde)[Cu(Ⅱ)-EDBSAD] was synthesized and a poly vinyl chloride(PVC) membrane electrode with the complex as neutral carrier was prepared.The electrode displays a preferential potentiometric response to SCN-and exhibits near Nernst response for SCN- within a wide concentration range(1.0×10-1~1.0×10-7 mol/L) with calibration curve equation of E(mV)=-51.75lg cSCN--255.29,and a detection limit of 5.6×10-8 mol/L in pH=5.5 phosphate buffer solution at 25℃.This electrode was applied to the determination of SCN- in waste water and the obtained result was in good agreement with those of high-performance liquid chromatography method.
2013, 30(1): 93-98
doi: DOI:10.3724/SP.J.1095.2013.20027
Abstract:
Ethylenediamine-grafted silica gel(EDA/SiO2) with the amino content of 1.35 mmol/g was synthesized.Its adsorption capacities toward copper and zinc cations in both single-component and binary-component aqueous solutions were studied.The influences of the flow rate and initial concentration of metal cations in the solution on the adsorption time were quantitatively determined.The results showed that the adsorption time decreased dramatically with the increase of the initial concentration of copper cations as well as the flow rate of the solution.The removal of copper cations by EDA/SiO2 column could be evaluated by the Thomas model.The initial copper concentration exerted significant effect on the Thomas saturation adsorption capacities(q0),which were increased from 0.272 mmol/g to 0.476 mmol/g in the initial concentration range of 1.99 mmol/L to 10.00 mmol/L.But no significant influence of the solution flow rate could be observed.The model rate constant kTh increased when the initial concentration was decreased or the flow rate of solution increased.In single component solutions,the adsorption capacities of EDA/SiO2 toward Cu(Ⅱ) and Zn(Ⅱ) were 0.340 mmol/g and 0.127 mmol/g,respectively.However,such adsorption capacities decreased in binary-component solution.The adsorption of zinc cation was decreased in the presence of copper cations,suggesting that the removal of copper was superior to that of zinc cations from aqueous solution.Furthermore,EDA/SiO2 could be regenerated by hydrochloric acid solution and ammonia water,and its adsorption capacity could be maintained even after regeneration for 6 times.
Ethylenediamine-grafted silica gel(EDA/SiO2) with the amino content of 1.35 mmol/g was synthesized.Its adsorption capacities toward copper and zinc cations in both single-component and binary-component aqueous solutions were studied.The influences of the flow rate and initial concentration of metal cations in the solution on the adsorption time were quantitatively determined.The results showed that the adsorption time decreased dramatically with the increase of the initial concentration of copper cations as well as the flow rate of the solution.The removal of copper cations by EDA/SiO2 column could be evaluated by the Thomas model.The initial copper concentration exerted significant effect on the Thomas saturation adsorption capacities(q0),which were increased from 0.272 mmol/g to 0.476 mmol/g in the initial concentration range of 1.99 mmol/L to 10.00 mmol/L.But no significant influence of the solution flow rate could be observed.The model rate constant kTh increased when the initial concentration was decreased or the flow rate of solution increased.In single component solutions,the adsorption capacities of EDA/SiO2 toward Cu(Ⅱ) and Zn(Ⅱ) were 0.340 mmol/g and 0.127 mmol/g,respectively.However,such adsorption capacities decreased in binary-component solution.The adsorption of zinc cation was decreased in the presence of copper cations,suggesting that the removal of copper was superior to that of zinc cations from aqueous solution.Furthermore,EDA/SiO2 could be regenerated by hydrochloric acid solution and ammonia water,and its adsorption capacity could be maintained even after regeneration for 6 times.
2013, 30(1): 99-106
doi: DOI:10.3724/SP.J.1095.2013.20005
Abstract:
With coke powder as raw materials,coke powder activated carbons(CPAC) were prepared by pretreatment via HNO3 and activated through dipping-calcined activation method by the modifier of KOH.The physical properties of the product were characterized by field emission scanning electron microscopy(SEM),X-ray diffraction(XRD).Nitrogen adsorption was used to characterize the BET surface area,pore structure and pore size distribution,and the influence on electrochemical properties under the different activated temperatures and time was investigated.The composite electrode materials of CPAC/Al-substituted Ni(OH)2 were synthesized through the method of co-precipitation,and the electrochemical performances of CPAC/Al-substituted Ni(OH)2 composite electrode materials were characterized by the constant current charge/discharge testing and cyclic voltammetry testing.The experimental results show that coke powder activated carbon electrode materials has the best electrochemical performance when the activation temperature is 800℃ and the activation time is 3 h.Under such conditions,the specific capacitance of the product achieves 211 F/g.CPAC-800℃-3 h/Al-substituted Ni(OH)2 composite electrode materials have the trend to increase initially,but start to decrease with the increase of doping amount present of aluminium.The specific capacitance of composite material can reach 1173.6 F/g when the mass ratio of CPAC to nickel is 1:1 by maintaining the doping quantity of aluminium at 4%(mass fraction).The composite electrode material with the doping quantity of aluminium as 4% and the mass ratio of CPAC to nickel as 1:1 has the best electrochemical performance after the constant current charge/discharge and cyclic voltammetry tests.
With coke powder as raw materials,coke powder activated carbons(CPAC) were prepared by pretreatment via HNO3 and activated through dipping-calcined activation method by the modifier of KOH.The physical properties of the product were characterized by field emission scanning electron microscopy(SEM),X-ray diffraction(XRD).Nitrogen adsorption was used to characterize the BET surface area,pore structure and pore size distribution,and the influence on electrochemical properties under the different activated temperatures and time was investigated.The composite electrode materials of CPAC/Al-substituted Ni(OH)2 were synthesized through the method of co-precipitation,and the electrochemical performances of CPAC/Al-substituted Ni(OH)2 composite electrode materials were characterized by the constant current charge/discharge testing and cyclic voltammetry testing.The experimental results show that coke powder activated carbon electrode materials has the best electrochemical performance when the activation temperature is 800℃ and the activation time is 3 h.Under such conditions,the specific capacitance of the product achieves 211 F/g.CPAC-800℃-3 h/Al-substituted Ni(OH)2 composite electrode materials have the trend to increase initially,but start to decrease with the increase of doping amount present of aluminium.The specific capacitance of composite material can reach 1173.6 F/g when the mass ratio of CPAC to nickel is 1:1 by maintaining the doping quantity of aluminium at 4%(mass fraction).The composite electrode material with the doping quantity of aluminium as 4% and the mass ratio of CPAC to nickel as 1:1 has the best electrochemical performance after the constant current charge/discharge and cyclic voltammetry tests.
2013, 30(1): 107-113
doi: DOI:10.3724/SP.J.1095.2013.20053
Abstract:
A series of alloyed PtmAg/C catalysts(m:Pt/Ag atomic ratio,0.05~1.0) were prepared by the co-reduction of K2PtCl6 and AgNO3 precursors with NaBH4 as the reducing agent.The electrocatalytic performance of the PtmAg/C catalysts for the methanol electro-oxidation was investigated.These PtmAg/C catalysts after electrochemical dealloying treatment in H2SO4 show enhanced catalytic activities for the methanol electro-oxidation and the CO tolerance as compared with the pure Pt/C catalyst,and the catalytic performance is strongly dependent on the catalyst composition(m).The mass-specific activity(MSA),intrinsic activity(IA) and stability of PtmAg/C catalysts increase with increasing m up to 0.5.The MSA and IA of Pt0.5Ag/C catalyst is ca.5.1 and 4.8 times of that of Pt in Pt/C catalyst,respectively.
A series of alloyed PtmAg/C catalysts(m:Pt/Ag atomic ratio,0.05~1.0) were prepared by the co-reduction of K2PtCl6 and AgNO3 precursors with NaBH4 as the reducing agent.The electrocatalytic performance of the PtmAg/C catalysts for the methanol electro-oxidation was investigated.These PtmAg/C catalysts after electrochemical dealloying treatment in H2SO4 show enhanced catalytic activities for the methanol electro-oxidation and the CO tolerance as compared with the pure Pt/C catalyst,and the catalytic performance is strongly dependent on the catalyst composition(m).The mass-specific activity(MSA),intrinsic activity(IA) and stability of PtmAg/C catalysts increase with increasing m up to 0.5.The MSA and IA of Pt0.5Ag/C catalyst is ca.5.1 and 4.8 times of that of Pt in Pt/C catalyst,respectively.
2013, 30(1): 114-119
doi: DOI:10.3724/SP.J.1095.2013.20026
Abstract:
In this paper,SO4-· was activated by peroxydisulfate(PDS) with zero-valent iron(Fe0) in aqueous,and its activity was tested by removing atrazine.Influencing factors including the initial pH,initial concentration of PDS and dosage of Fe0 were tested.The results indicated that removal efficiencies of atrazine(100 mL 0.10 mmol/L) by Fe0/PDS reached 99.0% within 60 min at pH=6.5,1 mL PDS initial concertration 2.0 mmol/L,28 mg Fe0,which was much higher than that when Fe0 or PDS was used alone,and superior to the Fe2+/PDS or Fe3+/PDS with the same amount of iron.Results also showed that the oxidation process of atrazine by SO4-· was facilitated by lowering pH,and the removal efficiency increased with raising the initial concentration of PDS or iron dosage.In addition,the reactive intermediates were identified as SO4-· and hydroxyl radicals(·OH) by employing methanol(MeOH) and tert-butyl alcohol(TBA) as the radical quenching agents.
In this paper,SO4-· was activated by peroxydisulfate(PDS) with zero-valent iron(Fe0) in aqueous,and its activity was tested by removing atrazine.Influencing factors including the initial pH,initial concentration of PDS and dosage of Fe0 were tested.The results indicated that removal efficiencies of atrazine(100 mL 0.10 mmol/L) by Fe0/PDS reached 99.0% within 60 min at pH=6.5,1 mL PDS initial concertration 2.0 mmol/L,28 mg Fe0,which was much higher than that when Fe0 or PDS was used alone,and superior to the Fe2+/PDS or Fe3+/PDS with the same amount of iron.Results also showed that the oxidation process of atrazine by SO4-· was facilitated by lowering pH,and the removal efficiency increased with raising the initial concentration of PDS or iron dosage.In addition,the reactive intermediates were identified as SO4-· and hydroxyl radicals(·OH) by employing methanol(MeOH) and tert-butyl alcohol(TBA) as the radical quenching agents.
2013, 30(1): 120-122
doi: DOI:10.3724/SP.J.1095.2013.20050
Abstract:
Using o-dihydroxybenzene and 1,11-dichloro-3,6,9-trioxaundecane as raw materials,sodium hydroxide as template,DMF as solvent and appropriate amount of 2,6-di-tert-butyl-4-methylphenol as antioxidant,benzo-15-crown-5 was successfully synthesized under ultrasonication at temperature 60~70℃.Compared with traditional synthetic routes,reaction time could be reduced to within 2 h,and the yield reached up to 30.7%.
Using o-dihydroxybenzene and 1,11-dichloro-3,6,9-trioxaundecane as raw materials,sodium hydroxide as template,DMF as solvent and appropriate amount of 2,6-di-tert-butyl-4-methylphenol as antioxidant,benzo-15-crown-5 was successfully synthesized under ultrasonication at temperature 60~70℃.Compared with traditional synthetic routes,reaction time could be reduced to within 2 h,and the yield reached up to 30.7%.
