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2008 Volume 25 Issue 2
2008, 25(2): 125-131
Abstract:
Thieno[2,3-b]pyridine derivatives are of great importance because of their remarkable biological properties.They are of chemical and pharmacological interests due to their isosterism with quinolines and isoquinolines,two important heterocycles involved in many alkaloids.Some of them have been used as herbicides,fungicides,pesticides,medicines and dyes.Three general routes have been described so far for the preparation of thieno[2,3-b]pyridine derivatives of this ring system:a)formation of the thiophene ring by cyclization of suitable substitutents of a pyridine;b)formation of the pyridine ring by cyclization of a suitable thiophene;c)condensation of unsaturated thionone derivatives.This paper reviews the advances in synthesis and applications of thieno[2,3-b]pyridine derivatives.
Thieno[2,3-b]pyridine derivatives are of great importance because of their remarkable biological properties.They are of chemical and pharmacological interests due to their isosterism with quinolines and isoquinolines,two important heterocycles involved in many alkaloids.Some of them have been used as herbicides,fungicides,pesticides,medicines and dyes.Three general routes have been described so far for the preparation of thieno[2,3-b]pyridine derivatives of this ring system:a)formation of the thiophene ring by cyclization of suitable substitutents of a pyridine;b)formation of the pyridine ring by cyclization of a suitable thiophene;c)condensation of unsaturated thionone derivatives.This paper reviews the advances in synthesis and applications of thieno[2,3-b]pyridine derivatives.
2008, 25(2): 132-136
Abstract:
Thermoplastic vulcanizate(TPV)/montmorillonite nanocomposite based on polypropylene(PP),ethylene-propylene rubber(EPDM),and organically modified montmorillonite(OMMT) was prepared via dynamic vulcanization.XRD and TEM measurements showed that the TPV/montmorillonite nanocomposite(TPVOMMT) was a nanocomposite with intercalated structure.The increase in the tensile strength of the TPVOMMT nanocomposite was 55% vs TPV,and 33% vs the dynamic vulcanizate that based on PP/EPDM/Na-MMT(TPVNMMT).Dynamic mechanical analysis showed that the storage modulus of the TPVOMMT nanocomposite increased by 35% compared with that of TPV,while Tg of TPVOMMT increased by 8℃.Complex viscosity decreased with the addtion of OMMT.Moreover,the tensile strength of the vulcanizate with different rubber/resin ratios was discussed.
Thermoplastic vulcanizate(TPV)/montmorillonite nanocomposite based on polypropylene(PP),ethylene-propylene rubber(EPDM),and organically modified montmorillonite(OMMT) was prepared via dynamic vulcanization.XRD and TEM measurements showed that the TPV/montmorillonite nanocomposite(TPVOMMT) was a nanocomposite with intercalated structure.The increase in the tensile strength of the TPVOMMT nanocomposite was 55% vs TPV,and 33% vs the dynamic vulcanizate that based on PP/EPDM/Na-MMT(TPVNMMT).Dynamic mechanical analysis showed that the storage modulus of the TPVOMMT nanocomposite increased by 35% compared with that of TPV,while Tg of TPVOMMT increased by 8℃.Complex viscosity decreased with the addtion of OMMT.Moreover,the tensile strength of the vulcanizate with different rubber/resin ratios was discussed.
2008, 25(2): 137-141
Abstract:
A molecular imprinting polymer(MIP) using ursolic acid(UA) as template molecule,4-VP as functional monomer,EGDMA as the cross-linking agent was synthesized on the surface of silica.The interactions between the template molecule and functional monomer via hydrogen-bond and ionic-bond were studied by UV-Vis spectra.The MIP was characterized by IR spectroscopy and SEM.The static adsorption equilibrium experiments and the Scatchard analysis show that there were two kinds of binding sites in the MIP and the dissociation constants were 1.02×10-4 mol/L and 8.97×10-4 mol/L respectively.The MIP exhibited better adsorption properties and selectivity compared with the corresponding non-imprinted polymers.UA can be enriched effectively by using the MIP as a solid-phase extraction reagent and the enrichment index was 30 times that of oleanolic acid(OA).
A molecular imprinting polymer(MIP) using ursolic acid(UA) as template molecule,4-VP as functional monomer,EGDMA as the cross-linking agent was synthesized on the surface of silica.The interactions between the template molecule and functional monomer via hydrogen-bond and ionic-bond were studied by UV-Vis spectra.The MIP was characterized by IR spectroscopy and SEM.The static adsorption equilibrium experiments and the Scatchard analysis show that there were two kinds of binding sites in the MIP and the dissociation constants were 1.02×10-4 mol/L and 8.97×10-4 mol/L respectively.The MIP exhibited better adsorption properties and selectivity compared with the corresponding non-imprinted polymers.UA can be enriched effectively by using the MIP as a solid-phase extraction reagent and the enrichment index was 30 times that of oleanolic acid(OA).
2008, 25(2): 142-146
Abstract:
A conducting polyaniline doped with multiple sulfonic acid was prepared by microemuslion polymerization.Effects of reaction temperature and doping agent loading on the properties of the PAn were discussed.The properties of the PAn were studied and characterized by four-probe,Tafer curve,laser granularity analysis,thermogravimetric analysis(TGA) and FT-IR.The results show that when polymerization temperature was 15℃ and the mass ratio of sulfosalicylic acid(SSA) to sodium dodecylbenzenesulfonate(SDBS) was 2.5:1,both the conductivity and the solubility reached maximum,which was 11 S/cm,and 85%(in NMP),respectively.The corrosion potential was -0.391 V.The thermal decomposition temperature was about 440℃,and about 90% of the PAn particles were between 50~100 nm.
A conducting polyaniline doped with multiple sulfonic acid was prepared by microemuslion polymerization.Effects of reaction temperature and doping agent loading on the properties of the PAn were discussed.The properties of the PAn were studied and characterized by four-probe,Tafer curve,laser granularity analysis,thermogravimetric analysis(TGA) and FT-IR.The results show that when polymerization temperature was 15℃ and the mass ratio of sulfosalicylic acid(SSA) to sodium dodecylbenzenesulfonate(SDBS) was 2.5:1,both the conductivity and the solubility reached maximum,which was 11 S/cm,and 85%(in NMP),respectively.The corrosion potential was -0.391 V.The thermal decomposition temperature was about 440℃,and about 90% of the PAn particles were between 50~100 nm.
2008, 25(2): 147-151
Abstract:
Several new caprolactam-based Brφnsted acidic ionic liquids[Caprolactam]X(X-=pTSOX-,BSOX-,BFX4-,NOX3-) with relatively low cost and low toxicity were synthesized and used for the first time in catalyzing organic reaction.They showed good catalytic activity in the nitration of toluene with HNO3/Ac2O.Among them,[Caprolactam]pTSO was the best one probably because of its better affinity for aromatics than the others.[Caprolactam]pTSO catalyzed the reaction at room temperature for 2 h,achieving a high yield(99.7% from GC) of mono-nitrotoluenes and good para-selectivity(ortho/para=1.03) when the molar ratio of nitric acid to toluene was 1:1 and the molar fraction of[Caprolactam]pTSO was 10%.When[Capro-lactam]pTSO was reused for the fourth time,the yield of mono-nitrotoluenes was 93.4%(from GC) and the ortho/para ratio was 1.12.
Several new caprolactam-based Brφnsted acidic ionic liquids[Caprolactam]X(X-=pTSOX-,BSOX-,BFX4-,NOX3-) with relatively low cost and low toxicity were synthesized and used for the first time in catalyzing organic reaction.They showed good catalytic activity in the nitration of toluene with HNO3/Ac2O.Among them,[Caprolactam]pTSO was the best one probably because of its better affinity for aromatics than the others.[Caprolactam]pTSO catalyzed the reaction at room temperature for 2 h,achieving a high yield(99.7% from GC) of mono-nitrotoluenes and good para-selectivity(ortho/para=1.03) when the molar ratio of nitric acid to toluene was 1:1 and the molar fraction of[Caprolactam]pTSO was 10%.When[Capro-lactam]pTSO was reused for the fourth time,the yield of mono-nitrotoluenes was 93.4%(from GC) and the ortho/para ratio was 1.12.
2008, 25(2): 152-156
Abstract:
In order to search for new antineoplastic drugs,nine novel N-2-thiophenesulfonyl-α-L-amino-acid esters were synthesized.The structures of the target compounds were determined by means of IR,1H NMR,MS and elemental analysis.The crystal structure of the target compound 3a was determined by X-ray diffraction analysis.Crystal data:Monoclinic,space group:Cc,a=1.453 8(2) nm,b=0.569 02(9) nm,c=1.433 7(2) nm,Z=4,V=1.097 8(3) nm3,Dc=1.508 mg/m3,α=90.00°,β=112.245(2)°,γ=90.00°,F(000)=520,R=0.085 8,wR=0.226 5.Via MTT assay,the inhibitory rate of the title compounds against the K562 Cell Proliferation was measured.The inhibition rate of the compounds(3f,3g,3i) against leukemia K562 cell proliferation were 40.22%,33.47%,and 31.86%,respectively,when the concentration of was 1.0×10-8 g/mL.The IC50 concentration(1×10-6 g/mL) of the compounds(3a~3i) was 35.65,13.87,9.23,4.9,9.24,8.16,7.84,7.73,7.73,and 6.57,respectively.The result of preliminary bioassay shows that some of the target compounds possess antiproliferation effects on K562 cells.Some of the compounds induced cell apoptosis in the experiment.
In order to search for new antineoplastic drugs,nine novel N-2-thiophenesulfonyl-α-L-amino-acid esters were synthesized.The structures of the target compounds were determined by means of IR,1H NMR,MS and elemental analysis.The crystal structure of the target compound 3a was determined by X-ray diffraction analysis.Crystal data:Monoclinic,space group:Cc,a=1.453 8(2) nm,b=0.569 02(9) nm,c=1.433 7(2) nm,Z=4,V=1.097 8(3) nm3,Dc=1.508 mg/m3,α=90.00°,β=112.245(2)°,γ=90.00°,F(000)=520,R=0.085 8,wR=0.226 5.Via MTT assay,the inhibitory rate of the title compounds against the K562 Cell Proliferation was measured.The inhibition rate of the compounds(3f,3g,3i) against leukemia K562 cell proliferation were 40.22%,33.47%,and 31.86%,respectively,when the concentration of was 1.0×10-8 g/mL.The IC50 concentration(1×10-6 g/mL) of the compounds(3a~3i) was 35.65,13.87,9.23,4.9,9.24,8.16,7.84,7.73,7.73,and 6.57,respectively.The result of preliminary bioassay shows that some of the target compounds possess antiproliferation effects on K562 cells.Some of the compounds induced cell apoptosis in the experiment.
2008, 25(2): 157-161
Abstract:
The extraction of Cr3+ by a series of calixarenes and their derivatives was studied,and it was found that the extraction selectivity for Cr3+ of p-tert-butylcalix[4]arene acetate(HnL(O)) was outstanding.Based on the molecular structure of the cup aromatic hydrocarbon and its derivative,the mechanism of extraction of Cr3+ from the tannery wastewater for p-tert-butylcalix[4]-arene acetate(hydrolysis of cup[4]) was studied.The dependence of the participation ratio D on pH was studied,and it was confirmed that the extraction of Cr3+ performed via the hydrolysis of cup[4] obeyed the positive ion exchange mechanism,i.e.,Cr3++HnL(O)→(CrHn-1L(O))2++H+,and the apparent equilibrium constant of the extraction was 1.815×103.The influence of temperature on D was also studied,and the enthalpy for the extraction was 69.89 kJ/mol,and the free energy-18.601 kJ/mol and the entropy 294.97 J/(mol·K).In addition K was calculated.The extraction was exothermic.The influences of major factors such as the initial concentration of Cr3+,the initial concentration of extractant,and the agitation rate on the participation ratio of Cr3+ were also investigated.The experimental results show that 85% of Cr3+ can be removed from tannery waste water with HnL(O) as extractant.
The extraction of Cr3+ by a series of calixarenes and their derivatives was studied,and it was found that the extraction selectivity for Cr3+ of p-tert-butylcalix[4]arene acetate(HnL(O)) was outstanding.Based on the molecular structure of the cup aromatic hydrocarbon and its derivative,the mechanism of extraction of Cr3+ from the tannery wastewater for p-tert-butylcalix[4]-arene acetate(hydrolysis of cup[4]) was studied.The dependence of the participation ratio D on pH was studied,and it was confirmed that the extraction of Cr3+ performed via the hydrolysis of cup[4] obeyed the positive ion exchange mechanism,i.e.,Cr3++HnL(O)→(CrHn-1L(O))2++H+,and the apparent equilibrium constant of the extraction was 1.815×103.The influence of temperature on D was also studied,and the enthalpy for the extraction was 69.89 kJ/mol,and the free energy-18.601 kJ/mol and the entropy 294.97 J/(mol·K).In addition K was calculated.The extraction was exothermic.The influences of major factors such as the initial concentration of Cr3+,the initial concentration of extractant,and the agitation rate on the participation ratio of Cr3+ were also investigated.The experimental results show that 85% of Cr3+ can be removed from tannery waste water with HnL(O) as extractant.
2008, 25(2): 162-168
Abstract:
The structure and electrochemical properties of Ti0.8Zr0.2V1.1Mn0.9-xNi0.4Crx(x=0.0~0.4) solid solution electrode alloys were investigated systematically.It was found that these alloys mainly consisted of a solid solution phase with a body centered cubic(bcc) structure and a C14 Laves secondary phase.The solid solution alloys showed easy activation behavior(to reach the maximum capacity within 3 cycles) and favorable rate dischargeability as a negative electrode material in Ni-MH batteries.The cycle stability of the alloy electrodes was improved markedly with the increase of Cr content in the alloys because the substitution of Cr for Mn suppresses vanadium dissolution in the alkali solution.The cycle stability parameter S20 of the alloy electrodes increased from 6.4% to 73.8% with x increasing from 0 to 0.4.The maximum discharge capacity of the alloy electrodes decreased from 420 mA·h/g to 279 mA·h/g with x changing from 0 to 0.4.The high temperature discharge capacity of the alloy electrodes decreased from 744 mA·h/g to 246 mA·h/g with x changing from 0 to 0.4 at 333 K.Furthermore,both the exchange current density and the hydrogen diffusion coefficient of the alloy electrode increased first and then decreased with the amount of Mn substituted by Cr increasing,and the maximum values of them were 275 mA/g and 5.956×10-10 cm2/s with x=0.3,respectively.
The structure and electrochemical properties of Ti0.8Zr0.2V1.1Mn0.9-xNi0.4Crx(x=0.0~0.4) solid solution electrode alloys were investigated systematically.It was found that these alloys mainly consisted of a solid solution phase with a body centered cubic(bcc) structure and a C14 Laves secondary phase.The solid solution alloys showed easy activation behavior(to reach the maximum capacity within 3 cycles) and favorable rate dischargeability as a negative electrode material in Ni-MH batteries.The cycle stability of the alloy electrodes was improved markedly with the increase of Cr content in the alloys because the substitution of Cr for Mn suppresses vanadium dissolution in the alkali solution.The cycle stability parameter S20 of the alloy electrodes increased from 6.4% to 73.8% with x increasing from 0 to 0.4.The maximum discharge capacity of the alloy electrodes decreased from 420 mA·h/g to 279 mA·h/g with x changing from 0 to 0.4.The high temperature discharge capacity of the alloy electrodes decreased from 744 mA·h/g to 246 mA·h/g with x changing from 0 to 0.4 at 333 K.Furthermore,both the exchange current density and the hydrogen diffusion coefficient of the alloy electrode increased first and then decreased with the amount of Mn substituted by Cr increasing,and the maximum values of them were 275 mA/g and 5.956×10-10 cm2/s with x=0.3,respectively.
2008, 25(2): 169-172
Abstract:
The racemic mixture of menthone was synthesized by catalytic hydrogenation of thymol based on hydroxyl protection using TMS(trimethylchorosilane) with excellent selectivity and good yield(both of 100%) under mild and neutral reaction conditions.The racemic menthone was hydrogenated to racemic menthol over 8% Cu/SiO2 in a medium with pH=4 by tartaric acid modifying.A selectivity of 72% for the desired product,(±)-menthol,was achieved under a pressure of 2 MPa,at a temperature of 150℃.For this novel process,the mechanism of reaction was proposed.Menthenol is firstly accomplished by hydrogenation of thymol with hydroxyl protection,secondly the menthenol which is unstable in air was transformed completely to the corresponding racemic menthones,and finally,racemic menthones were hydrogenated to racemic menthols.This proposed approach is promising for independent manufacture of flavors with the optical purity of(-)-menthol in the future.
The racemic mixture of menthone was synthesized by catalytic hydrogenation of thymol based on hydroxyl protection using TMS(trimethylchorosilane) with excellent selectivity and good yield(both of 100%) under mild and neutral reaction conditions.The racemic menthone was hydrogenated to racemic menthol over 8% Cu/SiO2 in a medium with pH=4 by tartaric acid modifying.A selectivity of 72% for the desired product,(±)-menthol,was achieved under a pressure of 2 MPa,at a temperature of 150℃.For this novel process,the mechanism of reaction was proposed.Menthenol is firstly accomplished by hydrogenation of thymol with hydroxyl protection,secondly the menthenol which is unstable in air was transformed completely to the corresponding racemic menthones,and finally,racemic menthones were hydrogenated to racemic menthols.This proposed approach is promising for independent manufacture of flavors with the optical purity of(-)-menthol in the future.
2008, 25(2): 173-176
Abstract:
To understand the isomerization mechanism from L-ephedrine hydrochloride to Dipseudoephedrine hydrochlroride,the intermediate products were obtained by controlling reaction condition of the isomerization and characterized by 1H NMR,13C NMR,2D-NMR and single crystal X-ray diffraction.The absolute construction was determined from above results,and the mechanism was determined.
To understand the isomerization mechanism from L-ephedrine hydrochloride to Dipseudoephedrine hydrochlroride,the intermediate products were obtained by controlling reaction condition of the isomerization and characterized by 1H NMR,13C NMR,2D-NMR and single crystal X-ray diffraction.The absolute construction was determined from above results,and the mechanism was determined.
2008, 25(2): 177-180
Abstract:
Inclusion complex of 2,2-bis(4-hydroxy-3-methylphenyl)propane(BPC) with β-cyclodextrin(β-CD) was studied by using steady-state fluorescence spectroscopy.A 1:1 inclusion complex can be concluded with the formation constant of 4.94×103 L/mol.The photodegradation behavior of BPC in aqueous solutions with β-CD was investigated under UV irradiation(λmax=254 nm).The results show that β-CD can enhance the photodegradation of bisphenol C in aqueous solution.The photodegradation of BPC in aqueous solution was found to follow pseudo-first order kinetics law.After 60 min of UV irradiation,β-CD could increase the photodegradation efficiency from 36% to 86% for 10 mg/L BPC.There was no obvious variation for the photodegradation rate of BPC in a pH range from 2 to 8.However,there was obvious increase above pH 8.The photodegradation rate of BPC increased with increasing concentration of β-CD,and there was no further increase in the photodegradation rate when concentration of β-CD exceeded 8.0×10-5 mol/L.The enhancement of photodegradation of BPC is mainly resulted from the lower bonding energy between some atoms in the BPC molecule after inclusion interaction with β-CD.
Inclusion complex of 2,2-bis(4-hydroxy-3-methylphenyl)propane(BPC) with β-cyclodextrin(β-CD) was studied by using steady-state fluorescence spectroscopy.A 1:1 inclusion complex can be concluded with the formation constant of 4.94×103 L/mol.The photodegradation behavior of BPC in aqueous solutions with β-CD was investigated under UV irradiation(λmax=254 nm).The results show that β-CD can enhance the photodegradation of bisphenol C in aqueous solution.The photodegradation of BPC in aqueous solution was found to follow pseudo-first order kinetics law.After 60 min of UV irradiation,β-CD could increase the photodegradation efficiency from 36% to 86% for 10 mg/L BPC.There was no obvious variation for the photodegradation rate of BPC in a pH range from 2 to 8.However,there was obvious increase above pH 8.The photodegradation rate of BPC increased with increasing concentration of β-CD,and there was no further increase in the photodegradation rate when concentration of β-CD exceeded 8.0×10-5 mol/L.The enhancement of photodegradation of BPC is mainly resulted from the lower bonding energy between some atoms in the BPC molecule after inclusion interaction with β-CD.
2008, 25(2): 181-184
Abstract:
Li-intercalated MoS2 compounds(LixMoS2) were prepared by intercalating MoS2 with lithium in a solution of n-butyl lithium in hexane.The effects of reaction temperature,mass ratio of the reactants and reaction time were studied.It was found that LixMoS2 could be obtained when the molar ratio of n-C4H9Li and MoS2 was 5~9,temperature 30℃,and time 36~48 h under mechanical stirring.The MoS2 suspensions with different intercalation degrees were produced after LixMoS2 was exfoliated in water.MoS2 with different intercalation contents were characterized with XRD,and it was concluded that the bigger the x value in LixMoS2,the broader the diffraction peaks of MoS2,the smaller the grain,and the worse the crystal lattice.The effect of variation of x in LixMoS2 on the lubricity of the aqueous suspension of exfoliated LixMoS2 was studied via four-ball tribometer.It was found that both friction coefficient and wear scar diameter decreased initially,and then increased with x value within a range of 0.618~1.39,and the best wear resistance and friction reduction were presented when the x in LixMoS2 was 0.75.
Li-intercalated MoS2 compounds(LixMoS2) were prepared by intercalating MoS2 with lithium in a solution of n-butyl lithium in hexane.The effects of reaction temperature,mass ratio of the reactants and reaction time were studied.It was found that LixMoS2 could be obtained when the molar ratio of n-C4H9Li and MoS2 was 5~9,temperature 30℃,and time 36~48 h under mechanical stirring.The MoS2 suspensions with different intercalation degrees were produced after LixMoS2 was exfoliated in water.MoS2 with different intercalation contents were characterized with XRD,and it was concluded that the bigger the x value in LixMoS2,the broader the diffraction peaks of MoS2,the smaller the grain,and the worse the crystal lattice.The effect of variation of x in LixMoS2 on the lubricity of the aqueous suspension of exfoliated LixMoS2 was studied via four-ball tribometer.It was found that both friction coefficient and wear scar diameter decreased initially,and then increased with x value within a range of 0.618~1.39,and the best wear resistance and friction reduction were presented when the x in LixMoS2 was 0.75.
2008, 25(2): 185-188
Abstract:
Toluene nitration was carried out with supported heteropolyacids as catalysts and N2O5 as nitrating agent.Many factors were investigated,including the type of heteropolyacid and carrier,loading of heteropolyacid,and recycle times of the catalyst.Results shows that the nitration with N2O5 is an acid catalyzed reaction,and the supported heteropolyacids can highly enhance the nitration ability of N2O5;the catalysts can be directly reused after recycle,and their activity is not obviously decreased.Under the optimum conditions,the yield of nitration was 34%,and the para-selectivity was up to 58.9%,which indicated that N2O5 is a prospective nitration agent,and the process meets the environmental protection requirements.
Toluene nitration was carried out with supported heteropolyacids as catalysts and N2O5 as nitrating agent.Many factors were investigated,including the type of heteropolyacid and carrier,loading of heteropolyacid,and recycle times of the catalyst.Results shows that the nitration with N2O5 is an acid catalyzed reaction,and the supported heteropolyacids can highly enhance the nitration ability of N2O5;the catalysts can be directly reused after recycle,and their activity is not obviously decreased.Under the optimum conditions,the yield of nitration was 34%,and the para-selectivity was up to 58.9%,which indicated that N2O5 is a prospective nitration agent,and the process meets the environmental protection requirements.
2008, 25(2): 189-193
Abstract:
One monolayer containing thiol-tailed groups was formed via the covalent binding of Ru(Ⅱ) phthlocyanine(RuPc) on a dimercaptosuccinic amine-modified gold electrode by self-assembly,which was characterized by IR and XPS.The modified gold electrode showed an excellent electrocatalytic activity for the oxidation of homocysteine(Hcy) in a phosphate buffer solution(pH=5.5).The electrocatalytic mechanism and effect of pH of the buffer solution were also investigated.The steady-state current of chronoamperometry increased linearly with Hcy concentration in the range of 5.0×10-7~5.4×10-5 mol/L with a detection limit of 0.18 μmol/L(S/N=3).The sensor also showed excellent reproducibility that makes it an ideal amperometric detector for Hcy in human serum.
One monolayer containing thiol-tailed groups was formed via the covalent binding of Ru(Ⅱ) phthlocyanine(RuPc) on a dimercaptosuccinic amine-modified gold electrode by self-assembly,which was characterized by IR and XPS.The modified gold electrode showed an excellent electrocatalytic activity for the oxidation of homocysteine(Hcy) in a phosphate buffer solution(pH=5.5).The electrocatalytic mechanism and effect of pH of the buffer solution were also investigated.The steady-state current of chronoamperometry increased linearly with Hcy concentration in the range of 5.0×10-7~5.4×10-5 mol/L with a detection limit of 0.18 μmol/L(S/N=3).The sensor also showed excellent reproducibility that makes it an ideal amperometric detector for Hcy in human serum.
2008, 25(2): 194-198
Abstract:
2,5-Bis(5-thione-1,2,4-dithiazole-3-ylcarbamoyl)-terephthalic acid(BtdyTA),which was synthesized from 3-amido-1,2,4-dithiazole-5-thione(ADTT),was used to modify the surface of silver nanoparticles with NaBH4 as the reducing agent in AgNO3 solution.The morphology,structure and stability of the BtdyTA-coated Ag(Ag-BtdyTA) nanoparticles were characterized with transmission electron microscopy(TEM),Fourier transform infrared spectrometry(FT-IR) and thermogravimetric analysis(TG).Anti-wear properties of the Ag-BtdyTA nanoparticles were tested with a four-ball tribological testing machine.The results show that the Ag-BtdyTA nanoparticles exhibited a homogeneous grain size distribution,and the average diameter was about 8 nm without aggregation,which enable the Ag-BtdyTA nanoparticles to be used as an oil additive.The Ag-BtdyTA nanoparticles had good anti-wear properties in liquid paraffin,and they can improve the anti-wear properties of the base oil.
2,5-Bis(5-thione-1,2,4-dithiazole-3-ylcarbamoyl)-terephthalic acid(BtdyTA),which was synthesized from 3-amido-1,2,4-dithiazole-5-thione(ADTT),was used to modify the surface of silver nanoparticles with NaBH4 as the reducing agent in AgNO3 solution.The morphology,structure and stability of the BtdyTA-coated Ag(Ag-BtdyTA) nanoparticles were characterized with transmission electron microscopy(TEM),Fourier transform infrared spectrometry(FT-IR) and thermogravimetric analysis(TG).Anti-wear properties of the Ag-BtdyTA nanoparticles were tested with a four-ball tribological testing machine.The results show that the Ag-BtdyTA nanoparticles exhibited a homogeneous grain size distribution,and the average diameter was about 8 nm without aggregation,which enable the Ag-BtdyTA nanoparticles to be used as an oil additive.The Ag-BtdyTA nanoparticles had good anti-wear properties in liquid paraffin,and they can improve the anti-wear properties of the base oil.
2008, 25(2): 199-203
Abstract:
The proton-conducting solid oxide fuel cell composed of H2S,(CoS-Mo2S)/BaCe0.475Zr0.475Y0.05O3-δ/Ag,air was studied at atmospheric pressure and 600~800℃ with the aim of preparation and perfor-mance of the cell,the effects of different temperatures and different fuel flow rates on the removal of H2S.The results indicate that the removal of H2S was linearly proportional to current density.The performance of the cell and H2S removal were improved by increasing temperature,the optimal working temperature was in a range of 700~800℃.Increasing fuel flow rate promoted the removal of H2S between 30~80 mL/min.71% of H2S removal was obtained at 800℃ and 80 mL/min,with an open circuit voltage of 0.72 V and a maximum current density of 2.9×10-2 A/cm2.
The proton-conducting solid oxide fuel cell composed of H2S,(CoS-Mo2S)/BaCe0.475Zr0.475Y0.05O3-δ/Ag,air was studied at atmospheric pressure and 600~800℃ with the aim of preparation and perfor-mance of the cell,the effects of different temperatures and different fuel flow rates on the removal of H2S.The results indicate that the removal of H2S was linearly proportional to current density.The performance of the cell and H2S removal were improved by increasing temperature,the optimal working temperature was in a range of 700~800℃.Increasing fuel flow rate promoted the removal of H2S between 30~80 mL/min.71% of H2S removal was obtained at 800℃ and 80 mL/min,with an open circuit voltage of 0.72 V and a maximum current density of 2.9×10-2 A/cm2.
2008, 25(2): 204-207
Abstract:
Nanometer composite S2O82-/SnO2-TiO2,a novel solid superacid,was prepared by sol-gel method and its structure was characterized by XRD,TEM,FT-IR and BET surface area measurement.The composite S2O82-/SnO2-TiO2 had a narrow particle size distribution with an average diameter of about 15~20 nm.S2O82- was attached on the surface of SnO2-TiO2 so that its strong acid sites were formed.The surface area of the catalyst was obviously increased after the incorporation of SnO2.Nanometer composite S2O82-/SnO2-TiO2 was used as a catalyst in α-pinene isomerization.The experimental results showed that the catalyst had better catalytic activity and selectivity.The main product of the isomerization reaction was camphene,and the by-products were limonene,terpinolene and tricyclene etc.Compared with ordinary S2O82-/TiO2,the composite catalyst can lower the reaction temperature by 20~30℃ for the isomerization.Under suitable conditions,the conversion of α-pinene reached 98% and the selectivity of camphene reached 63%.
Nanometer composite S2O82-/SnO2-TiO2,a novel solid superacid,was prepared by sol-gel method and its structure was characterized by XRD,TEM,FT-IR and BET surface area measurement.The composite S2O82-/SnO2-TiO2 had a narrow particle size distribution with an average diameter of about 15~20 nm.S2O82- was attached on the surface of SnO2-TiO2 so that its strong acid sites were formed.The surface area of the catalyst was obviously increased after the incorporation of SnO2.Nanometer composite S2O82-/SnO2-TiO2 was used as a catalyst in α-pinene isomerization.The experimental results showed that the catalyst had better catalytic activity and selectivity.The main product of the isomerization reaction was camphene,and the by-products were limonene,terpinolene and tricyclene etc.Compared with ordinary S2O82-/TiO2,the composite catalyst can lower the reaction temperature by 20~30℃ for the isomerization.Under suitable conditions,the conversion of α-pinene reached 98% and the selectivity of camphene reached 63%.
2008, 25(2): 208-211
Abstract:
The Cr,Ni,Cu,As,Se,Cd,Pb in cigarette paper samples were determined by ICP-MS after these samples were digested with microwave digestion.The contents of these elements were from 0.012 μg/g to 2.160 μg/g.The relative standard deviations(RSD) for Se and Cd were higher than 10%,and that for the other elements were less than 4%.The recoveries of the 7 elements were from 92.1% to 111.9%,and the limits of detection were from 25.2 to 245.1 ng/L.Five kinds of foreign cigarette paper and 9 kinds of domestic cigarette paper were analyzed.Except for Cr,Pb,the difference of the contents of other elements in the 14 samples were significant;the difference of the Ni,Cu,and Se contents in the domestic cigarette papers were significant;the difference of the contents of all 7 elements in foreign cigarette paper were not significant.
The Cr,Ni,Cu,As,Se,Cd,Pb in cigarette paper samples were determined by ICP-MS after these samples were digested with microwave digestion.The contents of these elements were from 0.012 μg/g to 2.160 μg/g.The relative standard deviations(RSD) for Se and Cd were higher than 10%,and that for the other elements were less than 4%.The recoveries of the 7 elements were from 92.1% to 111.9%,and the limits of detection were from 25.2 to 245.1 ng/L.Five kinds of foreign cigarette paper and 9 kinds of domestic cigarette paper were analyzed.Except for Cr,Pb,the difference of the contents of other elements in the 14 samples were significant;the difference of the Ni,Cu,and Se contents in the domestic cigarette papers were significant;the difference of the contents of all 7 elements in foreign cigarette paper were not significant.
2008, 25(2): 212-217
Abstract:
Quaternary Polyethyleneimine(QPEI) was prepared via two steps of polymer reaction,tertiary amination and quaterisation,and the corrosion inhibition property and mechanism of QPEI for low carbon steel dipped in aqueous solution of H2SO4 of 0.5 mol/L were investigated by mass-loss method,electrochemical polarization measurement,and scanning electron microscopy.The experiment results showed that QPEI possessed excellent corrosion inhibition property,and at a concentration of 5 mg/L,the corrosion inhibition rate was up to 91% for A3 steel sample which had been dipped in sulfuric acid medium of 0.5 mol/L for 72 h.QPEI can simultaneously hinder cathode process and anode process,so its corrosion inhibition belongs to the mixed type.With the synergistic action of physics and chemistry adsorptions,QPEI can produce compact and dense film on the steel surface.The adsorption of QPEI on the surface of low carbon steel obeyed Langmuir equation.
Quaternary Polyethyleneimine(QPEI) was prepared via two steps of polymer reaction,tertiary amination and quaterisation,and the corrosion inhibition property and mechanism of QPEI for low carbon steel dipped in aqueous solution of H2SO4 of 0.5 mol/L were investigated by mass-loss method,electrochemical polarization measurement,and scanning electron microscopy.The experiment results showed that QPEI possessed excellent corrosion inhibition property,and at a concentration of 5 mg/L,the corrosion inhibition rate was up to 91% for A3 steel sample which had been dipped in sulfuric acid medium of 0.5 mol/L for 72 h.QPEI can simultaneously hinder cathode process and anode process,so its corrosion inhibition belongs to the mixed type.With the synergistic action of physics and chemistry adsorptions,QPEI can produce compact and dense film on the steel surface.The adsorption of QPEI on the surface of low carbon steel obeyed Langmuir equation.
2008, 25(2): 218-223
Abstract:
The all-acrylate micro-latex with ω(polymer)=40% and ω(emulsifier)=2.5% was synthesized by microemulsion polymerization.Influences of various factors such as monomers feeding rate,emulsifier level,amount of electrolyte,polymerization temperature and agitation speed on the properties of the latex were discussed,and a polymerization mechanism was proposed.The results suggested that the polymerization took place in the locus as in Winsor-polymerization system that included dropping monomer phase as reservoir and the O/W microemulsion phase as the polymerization locus.The dropped monomer diffused into the O/W microemulsion phase and propagated under such a slow agitation that the balance of polymerization was maintained and successive big polymer particles could not emerge,and then high solid content all-acrylate microlatex was prepared.The all-acrylate microlatex with m(monomer):m(emulsifer)=15:1 was prepared with 2.5% mass content of DowFax2A-1/OP-10,0.16% mass content of NaHCO3 and 150 r/min of stirring rate at 75~80℃ for 4 h.
The all-acrylate micro-latex with ω(polymer)=40% and ω(emulsifier)=2.5% was synthesized by microemulsion polymerization.Influences of various factors such as monomers feeding rate,emulsifier level,amount of electrolyte,polymerization temperature and agitation speed on the properties of the latex were discussed,and a polymerization mechanism was proposed.The results suggested that the polymerization took place in the locus as in Winsor-polymerization system that included dropping monomer phase as reservoir and the O/W microemulsion phase as the polymerization locus.The dropped monomer diffused into the O/W microemulsion phase and propagated under such a slow agitation that the balance of polymerization was maintained and successive big polymer particles could not emerge,and then high solid content all-acrylate microlatex was prepared.The all-acrylate microlatex with m(monomer):m(emulsifer)=15:1 was prepared with 2.5% mass content of DowFax2A-1/OP-10,0.16% mass content of NaHCO3 and 150 r/min of stirring rate at 75~80℃ for 4 h.
2008, 25(2): 224-228
Abstract:
The nearly monodispersed Ni-La-B amorphous alloy nanocluster was prepared from the reduced reaction of Ni(Ac)2 and La(NO3)3 by KBH4 in W/O microemulsion.Samples were characterized by SEM,TEM,XRD,DSC and XPS.The results show that the sample exhibits a spherical morphology with a size of around 10~15 nm and an even size distribution.The DSC curves show that there are exothermic peaks corresponding to phase transition at 657.6 K and 724.3 K at a heating rate of 20 K/min.The crystallization temperature of the sample is significantly higher than that of the nano Ni-B amorphous alloy powder obtained by chemical reduction with KBH4 in aqueous solution.Thus,the Ni-La-B amorphous alloy nanocluster prepared by microemulsion method has excellent thermal stability.The XRD results identify the two phase transition steps as determined by DSC analysis:one is the transformation of Ni-La-B amorphous alloy into Ni-La-B crystalline alloy,the other is the decomposition of Ni-La-B crystalline alloy into Ni-La crystalline alloy and release of B.The rate of the latter is higher than that of the former,which has been found via determining phase transition activation energy.
The nearly monodispersed Ni-La-B amorphous alloy nanocluster was prepared from the reduced reaction of Ni(Ac)2 and La(NO3)3 by KBH4 in W/O microemulsion.Samples were characterized by SEM,TEM,XRD,DSC and XPS.The results show that the sample exhibits a spherical morphology with a size of around 10~15 nm and an even size distribution.The DSC curves show that there are exothermic peaks corresponding to phase transition at 657.6 K and 724.3 K at a heating rate of 20 K/min.The crystallization temperature of the sample is significantly higher than that of the nano Ni-B amorphous alloy powder obtained by chemical reduction with KBH4 in aqueous solution.Thus,the Ni-La-B amorphous alloy nanocluster prepared by microemulsion method has excellent thermal stability.The XRD results identify the two phase transition steps as determined by DSC analysis:one is the transformation of Ni-La-B amorphous alloy into Ni-La-B crystalline alloy,the other is the decomposition of Ni-La-B crystalline alloy into Ni-La crystalline alloy and release of B.The rate of the latter is higher than that of the former,which has been found via determining phase transition activation energy.
2008, 25(2): 229-232
Abstract:
Amino functional silica gel was synthesized by reacting silane coupling agent with silica gel.Then dendrimer-like polyamidoamine on the silica gel surface(PAMAM-SG) was prepared using Micheal addition of the amino and methyl acrylate,and ester-exchange of ethylene diamine and the ester group.FTIR was used to characterize the structure of PAMAM-SG.The effects of solution pH,concentration and temperature on the adsorption capacity of PAMAM-SG for Fe(Ⅲ) were studied.It was found that the optimum pH range for the adsorption was 3.0~6.0.The adsorption rate decreased with the increase of time,but increased remarkably with temperature.The adsorption was saturated in 3 h at 40℃,and the adsorption capacity reached 55.85 mg/g.The adsorption capacity increased with the increase of concentration until it reached balance.The adsorption capacities for each generation of PAMAM-SG were in the order of 2.0 G > 1.0 G > 1.5 G > 0.5 G > 0 G.
Amino functional silica gel was synthesized by reacting silane coupling agent with silica gel.Then dendrimer-like polyamidoamine on the silica gel surface(PAMAM-SG) was prepared using Micheal addition of the amino and methyl acrylate,and ester-exchange of ethylene diamine and the ester group.FTIR was used to characterize the structure of PAMAM-SG.The effects of solution pH,concentration and temperature on the adsorption capacity of PAMAM-SG for Fe(Ⅲ) were studied.It was found that the optimum pH range for the adsorption was 3.0~6.0.The adsorption rate decreased with the increase of time,but increased remarkably with temperature.The adsorption was saturated in 3 h at 40℃,and the adsorption capacity reached 55.85 mg/g.The adsorption capacity increased with the increase of concentration until it reached balance.The adsorption capacities for each generation of PAMAM-SG were in the order of 2.0 G > 1.0 G > 1.5 G > 0.5 G > 0 G.
2008, 25(2): 233-236
Abstract:
2-Formyl-3-acetyl-4-methyl-5-carbobenzoxypyrrole(6) was synthesized via the selective oxidation of 2,4-dimethyl-3-acetyl-5-carbobenzoxypyrrole(5),which was produced from acetylacetic benzylester(1) via nitrosation,reduction and addition-cyclization with acetylacetone.The total yield of the product was about 34%.The effects of reaction conditions and oxidants on the yield of compound 5 and the selective oxidation were studied,respectively.The results show that the yield of compound 5 reached a maximum of 65% under the optimum reaction conditions,where the pH of the reaction medium was 3.8~4.0,the reaction temperature was 85~90℃,and the molar ratio of zinc powder to compound 1 was 2.6:1.The optimum oxidant for the selective oxidation of α-methyl on compound 5 was sulfuryl chloride,and the yield of the product was 52.5%.The structures of the compounds were characterized by elemental analysis,1H NMR,IR,and MS spectra.
2-Formyl-3-acetyl-4-methyl-5-carbobenzoxypyrrole(6) was synthesized via the selective oxidation of 2,4-dimethyl-3-acetyl-5-carbobenzoxypyrrole(5),which was produced from acetylacetic benzylester(1) via nitrosation,reduction and addition-cyclization with acetylacetone.The total yield of the product was about 34%.The effects of reaction conditions and oxidants on the yield of compound 5 and the selective oxidation were studied,respectively.The results show that the yield of compound 5 reached a maximum of 65% under the optimum reaction conditions,where the pH of the reaction medium was 3.8~4.0,the reaction temperature was 85~90℃,and the molar ratio of zinc powder to compound 1 was 2.6:1.The optimum oxidant for the selective oxidation of α-methyl on compound 5 was sulfuryl chloride,and the yield of the product was 52.5%.The structures of the compounds were characterized by elemental analysis,1H NMR,IR,and MS spectra.
2008, 25(2): 237-240
Abstract:
Aqueous gels(NIPA-co-MAA) containing naproxen were encapsulated with cellulose acetate membrane,and then drug release was performed under a simulated body environment.A newly intelligent drug delivery system was established to research the releasing of naproxen in the systems.It was identified that the drug in the hydrogel material could be delivered at fairly high release ratio at 37℃.Furthermore,the drug was released at a slower ratio(2%~5%) in the simulated gastric juice,but at a higher releasing ratio in intestines juice.The more PEG,the higher the releasing ratio.When the membrane contained 50% PEG,the releasing ratio was 40%.It is a good way to avoid the side effect caused by the drug absorption in stomach.
Aqueous gels(NIPA-co-MAA) containing naproxen were encapsulated with cellulose acetate membrane,and then drug release was performed under a simulated body environment.A newly intelligent drug delivery system was established to research the releasing of naproxen in the systems.It was identified that the drug in the hydrogel material could be delivered at fairly high release ratio at 37℃.Furthermore,the drug was released at a slower ratio(2%~5%) in the simulated gastric juice,but at a higher releasing ratio in intestines juice.The more PEG,the higher the releasing ratio.When the membrane contained 50% PEG,the releasing ratio was 40%.It is a good way to avoid the side effect caused by the drug absorption in stomach.
2008, 25(2): 241-244
Abstract:
On the self-constructed electrochemical detection system,antipyrinum and amidopyrine in injection antondint were separated and determined by capillary electrophoresis with amperometric detection(CE-AD).Under the optimized conditions:a running buffer composed of 30 mmol/L Na2B4O7 buffer pH 9.0,separation voltage 20 kV,injection time 8 seconds and detection voltage 0.8 V,a linear relationaships between peak areas(Y) and mass concentrations(c) of the two analytes were established,with a determination limit of 0.1 mg/L for antipyrinum and that of 0.05 mg/L for amidopyrine,respectively.
On the self-constructed electrochemical detection system,antipyrinum and amidopyrine in injection antondint were separated and determined by capillary electrophoresis with amperometric detection(CE-AD).Under the optimized conditions:a running buffer composed of 30 mmol/L Na2B4O7 buffer pH 9.0,separation voltage 20 kV,injection time 8 seconds and detection voltage 0.8 V,a linear relationaships between peak areas(Y) and mass concentrations(c) of the two analytes were established,with a determination limit of 0.1 mg/L for antipyrinum and that of 0.05 mg/L for amidopyrine,respectively.
2008, 25(2): 245-250
Abstract:
Ni/MgO and Ni/O-D(oxidized diamond) catalysts were prepared by wetness impregnation method.The effects of reaction temperature and space velocity of methane on the methane conversion were investigated in a fixed-bed.The surface area,structure and morphology were characterized with BET,XPS,SEM,EDS techniques.The results show that the conversion of methane was above 8% within 150 min(t=500℃) in the presence of 33Ni/O-D catalyst and higher than 25% within 120 min(t=650℃) in the presence of 41Ni/MgO catalyst.The initial conversion increases with the increasing temperature of the decomposition reaction,but their catalytic activities decrease rapidly if the temperature is too high.Decreasing the space velocity of methane is propitious to improving the methane conversion,but not favorable for the hydrogen yield.The appearance of carbon resulted from the methane decomposition lies on the support type and the condition of catalytic reaction.It showed fiber shape on the surface of Ni/O-D at the relatively lower temperature such as 500℃ and 550℃,but grain shape stacked on and overlaid on the surface of the metal nickel at 650℃.The carbon fiber can form on the Ni/MgO surface at 650℃ and the diameter of the carbon fiber increases with the decreasing space velocity.
Ni/MgO and Ni/O-D(oxidized diamond) catalysts were prepared by wetness impregnation method.The effects of reaction temperature and space velocity of methane on the methane conversion were investigated in a fixed-bed.The surface area,structure and morphology were characterized with BET,XPS,SEM,EDS techniques.The results show that the conversion of methane was above 8% within 150 min(t=500℃) in the presence of 33Ni/O-D catalyst and higher than 25% within 120 min(t=650℃) in the presence of 41Ni/MgO catalyst.The initial conversion increases with the increasing temperature of the decomposition reaction,but their catalytic activities decrease rapidly if the temperature is too high.Decreasing the space velocity of methane is propitious to improving the methane conversion,but not favorable for the hydrogen yield.The appearance of carbon resulted from the methane decomposition lies on the support type and the condition of catalytic reaction.It showed fiber shape on the surface of Ni/O-D at the relatively lower temperature such as 500℃ and 550℃,but grain shape stacked on and overlaid on the surface of the metal nickel at 650℃.The carbon fiber can form on the Ni/MgO surface at 650℃ and the diameter of the carbon fiber increases with the decreasing space velocity.
2008, 25(2): 251-253
Abstract:
4-[p-Benzoyl(thiophenyl) phenyl] phenyl iodonium hexafluorophosphate(Ⅲ) was synthesized from iodobenzene and diphenyl sulfide as main starting materials through Friedel-Crafts acylation,substitution reaction and metathesis.Its structure was identified by UV,1H NMR,IR and MS.The optimal reaction conditions were dertermined through orthogonal experiment to be:2.033 g of 4-thiophenyl benzophenone,3.294 g of hydroxyl(tosyloxy)iodobenzene,the mol ratio of catalysts(acetic anhydride/concentrated sulfuric acid) 1.5,reaction temperature of 60℃ and time of 24 h.The yield was 47.9%.The photoinitiability of the product was tested.
4-[p-Benzoyl(thiophenyl) phenyl] phenyl iodonium hexafluorophosphate(Ⅲ) was synthesized from iodobenzene and diphenyl sulfide as main starting materials through Friedel-Crafts acylation,substitution reaction and metathesis.Its structure was identified by UV,1H NMR,IR and MS.The optimal reaction conditions were dertermined through orthogonal experiment to be:2.033 g of 4-thiophenyl benzophenone,3.294 g of hydroxyl(tosyloxy)iodobenzene,the mol ratio of catalysts(acetic anhydride/concentrated sulfuric acid) 1.5,reaction temperature of 60℃ and time of 24 h.The yield was 47.9%.The photoinitiability of the product was tested.
2008, 25(2): 254-256
Abstract:
BaYF5:Ce3+ nanoparticles were synthesized from the quaternary water/CTAB/bulanol/octane microemulsion system.The complex fluorides were characterzed by means of X-ray powder diffraction(XRD),environmental scanning electron microscopy(ESEM) and fluorescence spectrometry.XRD analysis shows that the products are in accord with the standard JCPDS card NO.18-715,the products are single phase and the crystal structure of BaYF5:Ce3+ particles is not changed obviously.The average grain size of the products is about 20 nm obtained from the ESEM.The fluorescence of BaYF5:Ce3+ particles was observed.The emission peak located at 330 nm is attributed to the d→f transition of Ce3+.Compared with those of the powder crystal prepared by high temperature solid reaction,the emission peaks of the fluorescent spectra showed a blue shift of 5 nm.
BaYF5:Ce3+ nanoparticles were synthesized from the quaternary water/CTAB/bulanol/octane microemulsion system.The complex fluorides were characterzed by means of X-ray powder diffraction(XRD),environmental scanning electron microscopy(ESEM) and fluorescence spectrometry.XRD analysis shows that the products are in accord with the standard JCPDS card NO.18-715,the products are single phase and the crystal structure of BaYF5:Ce3+ particles is not changed obviously.The average grain size of the products is about 20 nm obtained from the ESEM.The fluorescence of BaYF5:Ce3+ particles was observed.The emission peak located at 330 nm is attributed to the d→f transition of Ce3+.Compared with those of the powder crystal prepared by high temperature solid reaction,the emission peaks of the fluorescent spectra showed a blue shift of 5 nm.
