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2012 Volume 29 Issue 10
2012, 29(10): 1099-1106
doi: 10.3724/SP.J.1095.2012.20108
Abstract:
Recent development in the preparation and application of porphyrin micro- and nanomaterials was summarized.Currently,a variety of methods for preparing organic nanomaterials have been used for the preparation of porphyrin micro- and nanomaterials,such as surfactants templating,re-precipitation and ultrasound methods.In addition,porphyrin molecules have been chosen as excellent building blocks for the assemblying in supermolecular chemistry due to their unique planar molecular skeleton and conjugated π-π bondings.Up to date,the research on organic nanomaterials has been mainly focused on the preparation of functional porphyrin micro- and nanomaterials in recent years.With excellent optical property and thermal stability,porphyrin micro-nanomaterials will show broadly potentials in application fields of analytical chemistry,biomimetics,catalysis and materials science fields.
Recent development in the preparation and application of porphyrin micro- and nanomaterials was summarized.Currently,a variety of methods for preparing organic nanomaterials have been used for the preparation of porphyrin micro- and nanomaterials,such as surfactants templating,re-precipitation and ultrasound methods.In addition,porphyrin molecules have been chosen as excellent building blocks for the assemblying in supermolecular chemistry due to their unique planar molecular skeleton and conjugated π-π bondings.Up to date,the research on organic nanomaterials has been mainly focused on the preparation of functional porphyrin micro- and nanomaterials in recent years.With excellent optical property and thermal stability,porphyrin micro-nanomaterials will show broadly potentials in application fields of analytical chemistry,biomimetics,catalysis and materials science fields.
2012, 29(10): 1107-1110
doi: 10.3724/SP.J.1095.2012.00487
Abstract:
Linear poly(ester amide)(PEA) with ester segment mass content of 81% was synthesized from ε-caprolactone and 6-aminocaproic acid by ring-opening polymerization and melt polycondensation,which was a kind of biodegradable copolymer with excellent thermal stability and great mechanical properties.Biodegradable polyblends of PEA with poly(propylene carbonate)(PPC) were prepared by melt blending.The effect of PEA content on miscibility,thermal properties and mechanical properties of the blends was investigated.PEA was found to be miscible with PPC and the thermal stability of the blend was significantly improved compared with pure PPC.When the mass ratio of PEA was 3% mass fraction,the temperatures of 5% mass loss(T-5%) and maximum mass loss rate(Tmax) were improved by 52.7% and 46.4%,respectively.Moreover,the mechanical properties of the corresponding blends were improved most remarkably,reinforcing and toughening of PPC were achieved simultaneously.
Linear poly(ester amide)(PEA) with ester segment mass content of 81% was synthesized from ε-caprolactone and 6-aminocaproic acid by ring-opening polymerization and melt polycondensation,which was a kind of biodegradable copolymer with excellent thermal stability and great mechanical properties.Biodegradable polyblends of PEA with poly(propylene carbonate)(PPC) were prepared by melt blending.The effect of PEA content on miscibility,thermal properties and mechanical properties of the blends was investigated.PEA was found to be miscible with PPC and the thermal stability of the blend was significantly improved compared with pure PPC.When the mass ratio of PEA was 3% mass fraction,the temperatures of 5% mass loss(T-5%) and maximum mass loss rate(Tmax) were improved by 52.7% and 46.4%,respectively.Moreover,the mechanical properties of the corresponding blends were improved most remarkably,reinforcing and toughening of PPC were achieved simultaneously.
2012, 29(10): 1111-1116
doi: 10.3724/SP.J.1095.2012.00522
Abstract:
Polychloroprene-polymethylmethacrylate(PCR-PMMA) composite latex particles have been prepared through the seed emulsion polymerization with polychloroprene latex(Pa) and methyl methacrylate(Pb) as the seed and monomer,respectively.Thermodynamic analysis results showed that when Φb(volume fraction of polymer b)0.69,the Pa-Pb core-shell latex particles and(Pa+Pb) separated latex particles were formed;while when Φb0.69,the inverted Pb-Pa core-shell latex particles and Pa-Pb core-shell latex particles were formed.Kinetic analysis results showed that the initiator type,the monomer feed type,crosslinking of the seed latex particles,and the monomer-to-rubber ratios were major factors influencing the particle morphology.When potassium persulfate was used as the initiator,the monomer-starved conditions led to the formation of normal core-shell particles,whereas flooded-feed MMA could not favor in formation of typical core-shell particle.While when azobisisobutyronitrile(AIBN) was used as the initiator,it led to the formation of inverted core-shell particles no matter if monomer-starved or flooded condition was used.Crosslinking of the polychloroprene seed particles was found to favor to form obvious core-shell PCR-PMMA particles.With the monomer-to-rubber ratio increasing,the shell layer turned thicker,the composite latex particle still showed core-shell structure,which was in agreement with the predicted results of thermodynamic analysis.The inverted core-shell PCR-PMMA composite latex particles were gradually changed to interpenetrating structure as the amount of monomer was increased when AIBN was used.
Polychloroprene-polymethylmethacrylate(PCR-PMMA) composite latex particles have been prepared through the seed emulsion polymerization with polychloroprene latex(Pa) and methyl methacrylate(Pb) as the seed and monomer,respectively.Thermodynamic analysis results showed that when Φb(volume fraction of polymer b)0.69,the Pa-Pb core-shell latex particles and(Pa+Pb) separated latex particles were formed;while when Φb0.69,the inverted Pb-Pa core-shell latex particles and Pa-Pb core-shell latex particles were formed.Kinetic analysis results showed that the initiator type,the monomer feed type,crosslinking of the seed latex particles,and the monomer-to-rubber ratios were major factors influencing the particle morphology.When potassium persulfate was used as the initiator,the monomer-starved conditions led to the formation of normal core-shell particles,whereas flooded-feed MMA could not favor in formation of typical core-shell particle.While when azobisisobutyronitrile(AIBN) was used as the initiator,it led to the formation of inverted core-shell particles no matter if monomer-starved or flooded condition was used.Crosslinking of the polychloroprene seed particles was found to favor to form obvious core-shell PCR-PMMA particles.With the monomer-to-rubber ratio increasing,the shell layer turned thicker,the composite latex particle still showed core-shell structure,which was in agreement with the predicted results of thermodynamic analysis.The inverted core-shell PCR-PMMA composite latex particles were gradually changed to interpenetrating structure as the amount of monomer was increased when AIBN was used.
2012, 29(10): 1117-1122
doi: 10.3724/SP.J.1095.2012.00513
Abstract:
Copolymers of aniline and o-methoxyaniline were synthesized by solid-state polymerization method using methanesulphonic acid as the doping acid.The resultant copolymers were characterized by FTIR,UV-Vis,TEM,X-ray diffraction,cyclic voltammetry and conductivity measurements.The results showed that the copolymers prepared under different aniline and o-methoxyaniline molar ratios displayed an emeraldine salt phase,and the doping degree of copolymers decreased with increasing content of o-methoxyaniline in monomers.The as-prepared copolymers had a high crystallinity and displayed a fibrillar morphology.The copolymer prepared under the molar ratio of 1:1,exhibited a higher electrochemical activity than the others,and its conductivity was 1.65 S/cm.
Copolymers of aniline and o-methoxyaniline were synthesized by solid-state polymerization method using methanesulphonic acid as the doping acid.The resultant copolymers were characterized by FTIR,UV-Vis,TEM,X-ray diffraction,cyclic voltammetry and conductivity measurements.The results showed that the copolymers prepared under different aniline and o-methoxyaniline molar ratios displayed an emeraldine salt phase,and the doping degree of copolymers decreased with increasing content of o-methoxyaniline in monomers.The as-prepared copolymers had a high crystallinity and displayed a fibrillar morphology.The copolymer prepared under the molar ratio of 1:1,exhibited a higher electrochemical activity than the others,and its conductivity was 1.65 S/cm.
2012, 29(10): 1123-1129
doi: 10.3724/SP.J.1095.2012.00529
Abstract:
Using methyltriethoxysilane(MTES) as precursor,the polysiloxane gels were obtained by a sol-gel approach based on the acid-base catalysis mechanisms.Subsequently,the superhydrophobic polysiloxane coatings were fabricated on a glass at room temperature by a simple dip coating technique.The chemical composition,hydrophobicity and morphology of the resultant coatings were investigated by Fourier transform infrared spectrum(FT-IR),water contact angle and field emission scanning electron microscopy(FE-SEM).It was confirmed that the polysiloxane network had partially end-capped methyl and residual silanol groups formed inside the coatings.The water contact angles reached as high as 160° and 162°,the water sliding angle as low as 7° for two coatings with the molar ratios of MTES,EtOH and H2O at 1:35:8 and 1:45:8,respectively.Their superhydrophobicities could be retained even heat-treated up to 250℃.FE-SEM showed that the coating surface displayed a micro-nano-sized structure composed of micropore with diameter of 0.5~1.0 μm.The aggregates of nano particles were composed of primary smaller particles with diameter in the range of 50~100 nm.Meanwhile,the coatings possessed higher transparency,superhydrophobic properties for the corrosive liquid.It was expected that these superhydrophobic coatings may be attached on surfaces of glass,textile,metal substrates and so on for protecting and corrosion resistant layers.
Using methyltriethoxysilane(MTES) as precursor,the polysiloxane gels were obtained by a sol-gel approach based on the acid-base catalysis mechanisms.Subsequently,the superhydrophobic polysiloxane coatings were fabricated on a glass at room temperature by a simple dip coating technique.The chemical composition,hydrophobicity and morphology of the resultant coatings were investigated by Fourier transform infrared spectrum(FT-IR),water contact angle and field emission scanning electron microscopy(FE-SEM).It was confirmed that the polysiloxane network had partially end-capped methyl and residual silanol groups formed inside the coatings.The water contact angles reached as high as 160° and 162°,the water sliding angle as low as 7° for two coatings with the molar ratios of MTES,EtOH and H2O at 1:35:8 and 1:45:8,respectively.Their superhydrophobicities could be retained even heat-treated up to 250℃.FE-SEM showed that the coating surface displayed a micro-nano-sized structure composed of micropore with diameter of 0.5~1.0 μm.The aggregates of nano particles were composed of primary smaller particles with diameter in the range of 50~100 nm.Meanwhile,the coatings possessed higher transparency,superhydrophobic properties for the corrosive liquid.It was expected that these superhydrophobic coatings may be attached on surfaces of glass,textile,metal substrates and so on for protecting and corrosion resistant layers.
2012, 29(10): 1130-1137
doi: 10.3724/SP.J.1095.2012.00516
Abstract:
A novel organic silicon surfactant,polyether modified disilane,was prepared via a two-step reaction.The hydrogen-containing disilane was first prepared by(CH3)3SiCl and(CH3)2HSiCl based on Wurtz coupling method using sodium as the reductive coupling agent and xylene as the dissolvant,and the obtained product was characterized by IR,UV and GC.The optimum experiment conditions of the synthesis were as follows:n((CH3)3SiCl):n((CH3)2HSiCl)=1.2:1,the concentration of reactants with 1.8 mol/L,15-crown-5 dosage with 2% of the reaction materials,the reaction temperature and time were 80℃ and 11 h,respectively.The polyether modified disilane surfactant was then synthesized via hydrosilation of the obtained hydrogen-containing disilane and methoxy-terminated polyether polyols using Karstedt Pt as catalysts,the experiment conditions of the synthesis were as follows:the reaction temperature was 95℃ and the reaction time was 4 h.Experimental results showed that the critical micelle concentration(CMC) was 0.9 g/L and the surface tension was 22.49 mN/m.The hydrolytic stability of product was good under pH=6.94 and pH=4.12 conditions.
A novel organic silicon surfactant,polyether modified disilane,was prepared via a two-step reaction.The hydrogen-containing disilane was first prepared by(CH3)3SiCl and(CH3)2HSiCl based on Wurtz coupling method using sodium as the reductive coupling agent and xylene as the dissolvant,and the obtained product was characterized by IR,UV and GC.The optimum experiment conditions of the synthesis were as follows:n((CH3)3SiCl):n((CH3)2HSiCl)=1.2:1,the concentration of reactants with 1.8 mol/L,15-crown-5 dosage with 2% of the reaction materials,the reaction temperature and time were 80℃ and 11 h,respectively.The polyether modified disilane surfactant was then synthesized via hydrosilation of the obtained hydrogen-containing disilane and methoxy-terminated polyether polyols using Karstedt Pt as catalysts,the experiment conditions of the synthesis were as follows:the reaction temperature was 95℃ and the reaction time was 4 h.Experimental results showed that the critical micelle concentration(CMC) was 0.9 g/L and the surface tension was 22.49 mN/m.The hydrolytic stability of product was good under pH=6.94 and pH=4.12 conditions.
2012, 29(10): 1138-1142
doi: 10.3724/SP.J.1095.2012.20011
Abstract:
Fluorinated polyurethane prepolymer(FPU) was synthesized using 2,4-toluene diisocyanate(TDI),poly(ethylene glycol) adipate(PEA),dimethylol propionic acid(DMPA),fluoride monohydric alcohol(F-OH).FPUSi was then synthesized by the in situ acylation reaction of isocyanatopropyltriethoxysilane(Si-NCO) with FPU forming a polymer bearing triethoxysilyl groups.The structures of polymers and self-assembled fluorocarbon films were characterized by FT-IR.The surface properties of self-assembled films were tested by atomic force microscopy et al.FPU and FPUSi showed thermal stability with 5% mass loss at 178℃ by thermal gravimetric analysis in nitrogen.The contact angle of the obtained FPUSi self-assembled film was improved to 81°.The tribological experiment showed that the self-assembled films had a very low friction coefficient(about 0.09) and good anti-wear properties under a load of 400 mN.The improved tribological properties of the modified substrate were attributed to the good adherence of FPUSi self-assembled films on the substrate and synergy of FPUSi matrix.
Fluorinated polyurethane prepolymer(FPU) was synthesized using 2,4-toluene diisocyanate(TDI),poly(ethylene glycol) adipate(PEA),dimethylol propionic acid(DMPA),fluoride monohydric alcohol(F-OH).FPUSi was then synthesized by the in situ acylation reaction of isocyanatopropyltriethoxysilane(Si-NCO) with FPU forming a polymer bearing triethoxysilyl groups.The structures of polymers and self-assembled fluorocarbon films were characterized by FT-IR.The surface properties of self-assembled films were tested by atomic force microscopy et al.FPU and FPUSi showed thermal stability with 5% mass loss at 178℃ by thermal gravimetric analysis in nitrogen.The contact angle of the obtained FPUSi self-assembled film was improved to 81°.The tribological experiment showed that the self-assembled films had a very low friction coefficient(about 0.09) and good anti-wear properties under a load of 400 mN.The improved tribological properties of the modified substrate were attributed to the good adherence of FPUSi self-assembled films on the substrate and synergy of FPUSi matrix.
2012, 29(10): 1143-1147
doi: 10.3724/SP.J.1095.2012.20002
Abstract:
The pH stimuli-sensitive polymer,poly(methylacrylic acid)(PMAA),was firstly obtained by reversible addition-fragmentation transfer(RAFT) polymerization of tert-butylmethacrylate(PtBMA) and then hydrolysis.The PMAA monolayer-protected gold nanoparticles(PMAA-GNPs) was prepared via the strong binding between the thiol groups on the polymer chain-ends and gold.The dispersion and aggregation of PMAA-GNPs could be tuned by controlling the pH values of the solution,which was investigated by UV-Vis spectra and TEM.It was found that the catalytic activity was responsive to pH when it is applied in the catalytic reduction of the 4-nitrophenol by NaBH4.The responsive mechanism could be interpreted as:the hydrophobic PMAA collapsed onto the surface of the GNPs in the acid solution,which hindered the contaction between reactant and GNPs,and reduced the catalytic activity.On the contrary,in the alkaline system,polymer chains repulsion due to electrostatic effect can improve the catalytic activity.
The pH stimuli-sensitive polymer,poly(methylacrylic acid)(PMAA),was firstly obtained by reversible addition-fragmentation transfer(RAFT) polymerization of tert-butylmethacrylate(PtBMA) and then hydrolysis.The PMAA monolayer-protected gold nanoparticles(PMAA-GNPs) was prepared via the strong binding between the thiol groups on the polymer chain-ends and gold.The dispersion and aggregation of PMAA-GNPs could be tuned by controlling the pH values of the solution,which was investigated by UV-Vis spectra and TEM.It was found that the catalytic activity was responsive to pH when it is applied in the catalytic reduction of the 4-nitrophenol by NaBH4.The responsive mechanism could be interpreted as:the hydrophobic PMAA collapsed onto the surface of the GNPs in the acid solution,which hindered the contaction between reactant and GNPs,and reduced the catalytic activity.On the contrary,in the alkaline system,polymer chains repulsion due to electrostatic effect can improve the catalytic activity.
2012, 29(10): 1148-1157
doi: 10.3724/SP.J.1095.2012.00483
Abstract:
Seven platinum(Ⅱ) complexes containing 2-phenylisoquinoline or its derivatives were prepared and the structures and properties of complexes were characterized by 1H/13C NMR,TGA,X-ray single crystal diffraction,CV,UV-Vis and PL etc.The results show that these platinum(Ⅱ) complexes keep planar coordination geometry around Pt atom,and exhibit red phosphorescence from the metal-to-ligand charge-transfer(MLCT)(407,444,463 nm) and ligand center(LC)(353,363,376 nm) of mixed-state with quantum efficiency of 0.02~0.06 and lifetimes of 1.78~3.33 μs at room temperature in the DCM solution.Steric hindrance of the peripheral substituent effectively inhibits the intermolecular interaction.
Seven platinum(Ⅱ) complexes containing 2-phenylisoquinoline or its derivatives were prepared and the structures and properties of complexes were characterized by 1H/13C NMR,TGA,X-ray single crystal diffraction,CV,UV-Vis and PL etc.The results show that these platinum(Ⅱ) complexes keep planar coordination geometry around Pt atom,and exhibit red phosphorescence from the metal-to-ligand charge-transfer(MLCT)(407,444,463 nm) and ligand center(LC)(353,363,376 nm) of mixed-state with quantum efficiency of 0.02~0.06 and lifetimes of 1.78~3.33 μs at room temperature in the DCM solution.Steric hindrance of the peripheral substituent effectively inhibits the intermolecular interaction.
2012, 29(10): 1158-1162
doi: 10.3724/SP.J.1095.2012.00524
Abstract:
We synthesized a complex formed between D-mannose oxime and copper cations with mixed-valence.The title compound was characterized by means of elemental analysis,IR,thermal analysis and XPS,etc.The results indicate that the compound is a tetranuclear copper complex having two Cu(Ⅱ) and two Cu(Ⅰ) metal centers.One Cu(Ⅱ) atom is coordinated by two nitrogen atoms and two oxygen atoms from two ligands while the other Cu(Ⅱ) coordinates with one nitrogen atom and three oxygen atoms.Each Cu(Ⅰ) atom bonds to three oxygen atoms and one hydroxyl ion.The four copper atoms are linked by three deprotonated D-mannose oxime molecules to form a chain.The pH plays a decisive role in the formation of the complex.
We synthesized a complex formed between D-mannose oxime and copper cations with mixed-valence.The title compound was characterized by means of elemental analysis,IR,thermal analysis and XPS,etc.The results indicate that the compound is a tetranuclear copper complex having two Cu(Ⅱ) and two Cu(Ⅰ) metal centers.One Cu(Ⅱ) atom is coordinated by two nitrogen atoms and two oxygen atoms from two ligands while the other Cu(Ⅱ) coordinates with one nitrogen atom and three oxygen atoms.Each Cu(Ⅰ) atom bonds to three oxygen atoms and one hydroxyl ion.The four copper atoms are linked by three deprotonated D-mannose oxime molecules to form a chain.The pH plays a decisive role in the formation of the complex.
2012, 29(10): 1163-1170
doi: 10.3724/SP.J.1095.2012.00399
Abstract:
An analytical method based on high-performance liquid chromatography tandem mass spectrometry has been developed for the determination of 10 perfluorinated compounds.Various lubricant samples were extracted with the solvent.Then the extract was cleaned up by Oasis WAX and Envi-carb solid phase cartridge.Qualitative and quantitative analyses were carried out for the analyte under the multiple reaction monitoring(MRM) mode after the chromatographic separation over Waters Xbridge C18(150 mm×2.1 mm,3.5 μm)column.The limits of detection for 10 perfluorinated compounds were 0.001~0.005 mg/kg.The mean recoveries at the three spiked levels were 79.05%~106.26%,with the intra-day precision less than 10% and the inter-day precision less than 20%.
An analytical method based on high-performance liquid chromatography tandem mass spectrometry has been developed for the determination of 10 perfluorinated compounds.Various lubricant samples were extracted with the solvent.Then the extract was cleaned up by Oasis WAX and Envi-carb solid phase cartridge.Qualitative and quantitative analyses were carried out for the analyte under the multiple reaction monitoring(MRM) mode after the chromatographic separation over Waters Xbridge C18(150 mm×2.1 mm,3.5 μm)column.The limits of detection for 10 perfluorinated compounds were 0.001~0.005 mg/kg.The mean recoveries at the three spiked levels were 79.05%~106.26%,with the intra-day precision less than 10% and the inter-day precision less than 20%.
2012, 29(10): 1171-1176
doi: 10.3724/SP.J.1095.2012.00495
Abstract:
The adsorption separation and thermodynamic behavior of 2,4-diaminotoluene and 2,6-diaminotoluene on macropore acrylic acid weak acid cation exchange resin(D151 resin),which was selected from ten resins,were investigated.The adsorption isotherms of 2,4-diaminotoluene and 2,6-diaminotoluene were measured.The result showed that the adsorption isotherm curves of 2,4-diaminotoluene and 2,6-diaminotoluene on D151 resin fitted Freundlich adsorption isotherm better than Langmuir with the correlation coefficient larger than 0.99.The study of thermodynamics showed that when the initial concentration of 2,4-diaminotoluene were 60~80 g/L within 293~313 K,the adsorption ΔH was-4.3490~-5.7558 kJ/mol,ΔG was-0.2911~-1.0346 kJ/mol,ΔS was-12.965~-16.150 J/(mol·K);and when the initial concentration of 2,6-diaminotoluene were 60~80 g/L within 293~313 K,adsorption ΔH was-2.9645~-3.6054 kJ/mol,ΔG was-0.1610~-0.6384 kJ/mol,and ΔS was-7.939~-11.005 J/(mol·K).The results show that the concentration of 2,6-diaminotoluene can be enriched from 20% to 99.93%,and 2,4-diaminotoluene can be increased from 80% to 99.42% with the dynamic adsorption separation.
The adsorption separation and thermodynamic behavior of 2,4-diaminotoluene and 2,6-diaminotoluene on macropore acrylic acid weak acid cation exchange resin(D151 resin),which was selected from ten resins,were investigated.The adsorption isotherms of 2,4-diaminotoluene and 2,6-diaminotoluene were measured.The result showed that the adsorption isotherm curves of 2,4-diaminotoluene and 2,6-diaminotoluene on D151 resin fitted Freundlich adsorption isotherm better than Langmuir with the correlation coefficient larger than 0.99.The study of thermodynamics showed that when the initial concentration of 2,4-diaminotoluene were 60~80 g/L within 293~313 K,the adsorption ΔH was-4.3490~-5.7558 kJ/mol,ΔG was-0.2911~-1.0346 kJ/mol,ΔS was-12.965~-16.150 J/(mol·K);and when the initial concentration of 2,6-diaminotoluene were 60~80 g/L within 293~313 K,adsorption ΔH was-2.9645~-3.6054 kJ/mol,ΔG was-0.1610~-0.6384 kJ/mol,and ΔS was-7.939~-11.005 J/(mol·K).The results show that the concentration of 2,6-diaminotoluene can be enriched from 20% to 99.93%,and 2,4-diaminotoluene can be increased from 80% to 99.42% with the dynamic adsorption separation.
2012, 29(10): 1177-1181
doi: 10.3724/SP.J.1095.2012.00514
Abstract:
Thermodynamics of the adsorption of Zwittermicin A by D151 cation exchange resin was studied using a static adsorption method.Adsorption equilibrium data for the adsorption of Zwittermicin A at 288 K,298 K,318 K and investigating concentration range were obtained and found to follow the Freundlich-type isotherm equation.The results indicated that the adsorption process of Zwittermicin A by D151 cation exchange resin was a spontaneous,exothermic and favorable adsorption.
Thermodynamics of the adsorption of Zwittermicin A by D151 cation exchange resin was studied using a static adsorption method.Adsorption equilibrium data for the adsorption of Zwittermicin A at 288 K,298 K,318 K and investigating concentration range were obtained and found to follow the Freundlich-type isotherm equation.The results indicated that the adsorption process of Zwittermicin A by D151 cation exchange resin was a spontaneous,exothermic and favorable adsorption.
2012, 29(10): 1182-1188
doi: 10.3724/SP.J.1095.2012.00449
Abstract:
The foaming and emulsifying properties of three new twin-tailed zwitterionic Gemini surfactants(C8C8L3Sz,C8C8L4Sz,C10C8L3Sz) were studied by modified Ross-Miles method and watershed-time method,respectively.The effects of the concentration of surfactants,molecular structure,and temperature were investigated.Experimental results show that the three surfactants all have good foaming properties,and their maximum foam heights and half-lives exist stable values under experimental concentration.The results show that the longer the hydrophobic chains,the worse the performance of their foaming and the better foam stability.In addition,temperature increasing can make foaming properties better and foam stability worse.The foam stability can be improved by adding either short-chain alcohols or inorganic salts.The most appropriate dosage of the emulsifiers of C8C8L3Sz,C8C8L4Sz and C10C8L3Sz is 6×10-4,6×10-4 and 4×10-4 mol/L,respectively.It shows the longer the hydrophobic chains,the better the emulsifying properties,and the effects of spacers on emulsifying properties are little.The emulsifying properties become worse by increasing temperature.When the oil phase has the same carbon number,cycloalkanes achieve the best emulsifying effect more easily than straight chain alkanes,but the stable time of emulsion of the two is almost the same.For alkanes with different carbon number,the longer the carbon chains of alkanes,the worse the stability of the emulsion and the better the emulsifying properties.
The foaming and emulsifying properties of three new twin-tailed zwitterionic Gemini surfactants(C8C8L3Sz,C8C8L4Sz,C10C8L3Sz) were studied by modified Ross-Miles method and watershed-time method,respectively.The effects of the concentration of surfactants,molecular structure,and temperature were investigated.Experimental results show that the three surfactants all have good foaming properties,and their maximum foam heights and half-lives exist stable values under experimental concentration.The results show that the longer the hydrophobic chains,the worse the performance of their foaming and the better foam stability.In addition,temperature increasing can make foaming properties better and foam stability worse.The foam stability can be improved by adding either short-chain alcohols or inorganic salts.The most appropriate dosage of the emulsifiers of C8C8L3Sz,C8C8L4Sz and C10C8L3Sz is 6×10-4,6×10-4 and 4×10-4 mol/L,respectively.It shows the longer the hydrophobic chains,the better the emulsifying properties,and the effects of spacers on emulsifying properties are little.The emulsifying properties become worse by increasing temperature.When the oil phase has the same carbon number,cycloalkanes achieve the best emulsifying effect more easily than straight chain alkanes,but the stable time of emulsion of the two is almost the same.For alkanes with different carbon number,the longer the carbon chains of alkanes,the worse the stability of the emulsion and the better the emulsifying properties.
2012, 29(10): 1189-1193
doi: 10.3724/SP.J.1095.2012.00520
Abstract:
The carbon-supported PdAu(PdAu/C) catalysts are prepared using surfactants of sodium dodecylbenzene sulfonate and P123 via a microwave-assisted reduction method.The results showed that Pd and Au could form alloys and altered the electronic structure of the catalysts' surfaces.The activity and stability of the catalysts were greatly enhanced by using surfactants in the their preparation as the surfactants can improve the dispersions of metallic particles on the catalysts' surface as well as increase the proportion of highly active crystal planes.The peak current density on PdAu/C prepared in nonionic surfactant P123 was as high as 196.8×10-3 A/cm2 and the pseudo-steady current density after 4030 s was 21.6×10-3 A/cm2.The strong CO adsorption by the noble metals on the catalyst remained remained as the major reason for the decrease of the oxidation current.
The carbon-supported PdAu(PdAu/C) catalysts are prepared using surfactants of sodium dodecylbenzene sulfonate and P123 via a microwave-assisted reduction method.The results showed that Pd and Au could form alloys and altered the electronic structure of the catalysts' surfaces.The activity and stability of the catalysts were greatly enhanced by using surfactants in the their preparation as the surfactants can improve the dispersions of metallic particles on the catalysts' surface as well as increase the proportion of highly active crystal planes.The peak current density on PdAu/C prepared in nonionic surfactant P123 was as high as 196.8×10-3 A/cm2 and the pseudo-steady current density after 4030 s was 21.6×10-3 A/cm2.The strong CO adsorption by the noble metals on the catalyst remained remained as the major reason for the decrease of the oxidation current.
2012, 29(10): 1194-1198
doi: 10.3724/SP.J.1095.2012.00512
Abstract:
Lead alkoxide complexes were prepared by electrochemical dissolution of pure lead in the glycol solution.The PbO sols were achieved by the direct sol-gel process of electrolyte solution.The PbO sols coated on pure titanium substrate were calcined at 450℃ for 2 h in a muffle furnace,the nano-PbO/Ti electrode was obtained.The electrocatalytic reduction activity of the nano-PbO/Ti electrode was investigated by cyclic voltammetry(CV) in solution containing 0.2~1.0 mol/L LiOH and 0.1~0.5 mol/L LiBO2.The main factors of electrocatalytic reduction of LiBO2 to LiBH4,such as LiBO2 and LiOH concentrations,were studied.The mono-disperse structure and the diameter of nano-PbO/Ti electrode were observed by XRD and SEM,respectively.The results show that the nano PbO is uniformly dispersed on the electrode surface.The electrocatalytic reduction performance of nano-PbO/Ti electrode is stable.A yield of 15.6% and current efficiency of 25.3% were obtained respectively.
Lead alkoxide complexes were prepared by electrochemical dissolution of pure lead in the glycol solution.The PbO sols were achieved by the direct sol-gel process of electrolyte solution.The PbO sols coated on pure titanium substrate were calcined at 450℃ for 2 h in a muffle furnace,the nano-PbO/Ti electrode was obtained.The electrocatalytic reduction activity of the nano-PbO/Ti electrode was investigated by cyclic voltammetry(CV) in solution containing 0.2~1.0 mol/L LiOH and 0.1~0.5 mol/L LiBO2.The main factors of electrocatalytic reduction of LiBO2 to LiBH4,such as LiBO2 and LiOH concentrations,were studied.The mono-disperse structure and the diameter of nano-PbO/Ti electrode were observed by XRD and SEM,respectively.The results show that the nano PbO is uniformly dispersed on the electrode surface.The electrocatalytic reduction performance of nano-PbO/Ti electrode is stable.A yield of 15.6% and current efficiency of 25.3% were obtained respectively.
2012, 29(10): 1199-1205
doi: 10.3724/SP.J.1095.2012.00491
Abstract:
Nickelous hexacyanoferrate(NiHCF) was prepared by functionalization of the nano-nickel surface.Then the magnetic controllable nano-NiHCF electrode was prepared by modifying a glassy carbon electrode with nano-NiHCF via magnetic force.In the phosphate buffer solution(pH=7.4),the electrode exhibits an excellent catalytic effect on the oxidation of hydrazine hydrate.The oxidation peak currents of hydrazine hydrate showed a good linear relationship(r=0.9987) within the range of 0~1.29×10-4 mol/L,with a detection limit of 2.1×10-8 mol/L.The electrochemical performance of hydrazine hydrate on the magnetic nano-NiHCF modified electrode was studied.The method was used for the determination of hydrazine hydrate in samples.The modified electrode has the advantages of high sensitivity,selectivity,stability,and it is also easily prepared and renewable.
Nickelous hexacyanoferrate(NiHCF) was prepared by functionalization of the nano-nickel surface.Then the magnetic controllable nano-NiHCF electrode was prepared by modifying a glassy carbon electrode with nano-NiHCF via magnetic force.In the phosphate buffer solution(pH=7.4),the electrode exhibits an excellent catalytic effect on the oxidation of hydrazine hydrate.The oxidation peak currents of hydrazine hydrate showed a good linear relationship(r=0.9987) within the range of 0~1.29×10-4 mol/L,with a detection limit of 2.1×10-8 mol/L.The electrochemical performance of hydrazine hydrate on the magnetic nano-NiHCF modified electrode was studied.The method was used for the determination of hydrazine hydrate in samples.The modified electrode has the advantages of high sensitivity,selectivity,stability,and it is also easily prepared and renewable.
2012, 29(10): 1206-1211
doi: 10.3724/SP.J.1095.2012.00523
Abstract:
The graphene-chitosan modified glassy carbon(CRG-CS/GC) electrode was prepared.Based on this,the electrochemical behavior of pentachlorophenol(PCP) was investigated by cyclic voltammetry and differential pulse voltammetry.It was found that the oxidation current at CRG-CS/GC electrode is obviously larger than at GC electrode,indicating that the CRG-CS/GC electrode has strong adsorption ability and can promote the electron transport.Then,the CRG-CS/GC electrode with the simple,sensitive,stable and reliable property was developed for the detection of PCP.Using this electrode,analytical performance with the linear range from 1.0×10-7 to 1.0×10-5 mol/L and a limit of detection to 2.3×10-8 mol/L were obtained.The electrochemical sensor with the CRG-CS/GC electrode was successfully employed to detect PCP in several water samples.The recovery can reach 97%~103%.
The graphene-chitosan modified glassy carbon(CRG-CS/GC) electrode was prepared.Based on this,the electrochemical behavior of pentachlorophenol(PCP) was investigated by cyclic voltammetry and differential pulse voltammetry.It was found that the oxidation current at CRG-CS/GC electrode is obviously larger than at GC electrode,indicating that the CRG-CS/GC electrode has strong adsorption ability and can promote the electron transport.Then,the CRG-CS/GC electrode with the simple,sensitive,stable and reliable property was developed for the detection of PCP.Using this electrode,analytical performance with the linear range from 1.0×10-7 to 1.0×10-5 mol/L and a limit of detection to 2.3×10-8 mol/L were obtained.The electrochemical sensor with the CRG-CS/GC electrode was successfully employed to detect PCP in several water samples.The recovery can reach 97%~103%.
2012, 29(10): 1212-1217
doi: 10.3724/SP.J.1095.2012.00486
Abstract:
A novel imprinted composite film electrochemical sensor was fabricated based on molecularly imprinted composite film for the determination of chloramphenicol(CAP).The imprinted composite film was prepared by electrochemical polymerization of pyrrole(PPY) and polyaniline(PAN) on the surface of stainless steel needle(SSN) electrode in the presence of CAP as a template.The morphology and electrochemical property of the film were characterized by SEM and differential pulse voltammetry with ferricyanide as an electrochemical probe,respectively.The film exhibited the good sensitivity,selectivity and the ability of regeneration.A linear relationship between the current of electrochemical probe and the concentration of CAP was found in the range of 5.00×10-8~1.05×10-6 mol/L with a detection limit of 2.09×10-9 mol/L.
A novel imprinted composite film electrochemical sensor was fabricated based on molecularly imprinted composite film for the determination of chloramphenicol(CAP).The imprinted composite film was prepared by electrochemical polymerization of pyrrole(PPY) and polyaniline(PAN) on the surface of stainless steel needle(SSN) electrode in the presence of CAP as a template.The morphology and electrochemical property of the film were characterized by SEM and differential pulse voltammetry with ferricyanide as an electrochemical probe,respectively.The film exhibited the good sensitivity,selectivity and the ability of regeneration.A linear relationship between the current of electrochemical probe and the concentration of CAP was found in the range of 5.00×10-8~1.05×10-6 mol/L with a detection limit of 2.09×10-9 mol/L.
2012, 29(10): 1218-1220
doi: 10.3724/SP.J.1095.2012.00572
Abstract:
A combination system of simultaneous thermal analysis(STA),Fourier-transform infrared(FT-IR) spectroscopy and GC-MS was established for simultaneously determination of pyrolysised products of the pectin samples under nitrogen or nitrogen-oxygen atmosphere.According to the pyrolysis behavior of pectin,26 substances were detected at three temperatures(243℃,270℃ and 335℃) on line with the system.
A combination system of simultaneous thermal analysis(STA),Fourier-transform infrared(FT-IR) spectroscopy and GC-MS was established for simultaneously determination of pyrolysised products of the pectin samples under nitrogen or nitrogen-oxygen atmosphere.According to the pyrolysis behavior of pectin,26 substances were detected at three temperatures(243℃,270℃ and 335℃) on line with the system.
