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2016 Volume 33 Issue 3
2016, 33(3): 245-266
doi: 10.11944/j.issn.1000-0518.2016.03.150202
Abstract:
Transition metal-catalyzed cross-coupling reaction which has advantages of simple operation, mild reaction conditions, and broad scope of substrates is one of the most efficient methods for the construction of carbon-carbon bonds. Iron is one of the potential green catalysts as it is one of the most abundant, inexpensive metals on earth, and environmentally friendly. Iron salts and iron-containing compounds are widely commercially available. Recently, more and more studies report the use of iron as catalyst in cross-coupling reactions. This paper reviews the recent advances in iron-catalyzed cross-coupling reactions based on different raw materials and we hope to provide some inspiration for relative research.
Transition metal-catalyzed cross-coupling reaction which has advantages of simple operation, mild reaction conditions, and broad scope of substrates is one of the most efficient methods for the construction of carbon-carbon bonds. Iron is one of the potential green catalysts as it is one of the most abundant, inexpensive metals on earth, and environmentally friendly. Iron salts and iron-containing compounds are widely commercially available. Recently, more and more studies report the use of iron as catalyst in cross-coupling reactions. This paper reviews the recent advances in iron-catalyzed cross-coupling reactions based on different raw materials and we hope to provide some inspiration for relative research.
2016, 33(3): 267-276
doi: 10.11944/j.issn.1000-0518.2016.03.150273
Abstract:
Due to the excellent physical and chemical properties, transition metal ternary compounds have attracted more and more attention and were applied in electronics, optics and optoelectronic devices, etc. In this paper we summarized the research progress on the preparation and application of electrochemical supercapacitors of transition metal ternary compounds during recent years. Meanwhile, the electrochemical properties, the advantages and disadvantages, and prospects of supercapacitors were discussed.
Due to the excellent physical and chemical properties, transition metal ternary compounds have attracted more and more attention and were applied in electronics, optics and optoelectronic devices, etc. In this paper we summarized the research progress on the preparation and application of electrochemical supercapacitors of transition metal ternary compounds during recent years. Meanwhile, the electrochemical properties, the advantages and disadvantages, and prospects of supercapacitors were discussed.
2016, 33(3): 277-283
doi: 10.11944/j.issn.1000-0518.2016.03.150213
Abstract:
Activity coefficient calculation is of great significance to the phase equilibrium of hydrate and the development of hydrate technology. Margules, Wilson, NRTL, UNIQUAC and UNIFAC models were studied by large amounts of survey with detailed analysis. The results show that Margules activity coefficient model is widely used in binary systems. Wilson activity coefficient model is not suitable for the system that solute and ion can not mix completely. The error of UNIQUAC in the calculation of aqueous or imidazole ion is bigger. We often choose NRTL for multiple ion systems. UNIFAC is widely used and can achieve precise calculation in high concentration solutions. Activity correlation equation parameters can be fit very well with high accuracy, but it is still difficult for systems of high temperature and pressure and needs to be developed in the future.
Activity coefficient calculation is of great significance to the phase equilibrium of hydrate and the development of hydrate technology. Margules, Wilson, NRTL, UNIQUAC and UNIFAC models were studied by large amounts of survey with detailed analysis. The results show that Margules activity coefficient model is widely used in binary systems. Wilson activity coefficient model is not suitable for the system that solute and ion can not mix completely. The error of UNIQUAC in the calculation of aqueous or imidazole ion is bigger. We often choose NRTL for multiple ion systems. UNIFAC is widely used and can achieve precise calculation in high concentration solutions. Activity correlation equation parameters can be fit very well with high accuracy, but it is still difficult for systems of high temperature and pressure and needs to be developed in the future.
2016, 33(3): 284-292
doi: 10.11944/j.issn.1000-0518.2016.03.150226
Abstract:
The optimal conditions for the synthesis of chitosan oligosaccharide-hydrolyzed gliadin copolymer by roughly-purified microbial transglutaminase(MTGase) catalysis were investigated, and the structures of obtained copolymer were characterized. These optimal conditions are estimated as the substrates mass ratio of chitosan chitosan oligosaccharide and hydrolyzed gliadin is 1:40 under pH 6.00~6.50, and 50 min stirring at 50℃. The grafting rate at these conditions can reach up to 60%~70%. Infrared spectrum analysis of the copolymer shows that, compared with chitosan oligosaccharide, the introduction of electron withdrawing group to chitosan oligosaccharide-hydrolyzed gliadin copolymer has inductive effects on the amide C=O, and causes the vibration peak shift to higher wave number with enhanced absorption intensity. DTA curve indicates that the chitosan oligosaccharide-hydrolyzed gliadin copolymer begins to lose the associated water at 60.91℃, melt at 387.55℃, and completely degrade at 665.25℃. This is significantly different to that of chitosan oligosaccharide and gliadin. XRD analysis shows that the crystallinity of grafted copolymers is greatly reduced, the cell data is different from those of chitosan oligosaccharide. HPLC analysis shows that the copolymer has two main components, accounting together for 80.6% of the total mass. The relative molecular masses of the two main components are 66069 and 27285, respectively. The copolymer does not dissolve in water and many organic solvents, but is slightly soluble in 1% NaOH, with a solubility at 0.184 mg/100 g. The melting range of the copolymer is 162~163℃.
The optimal conditions for the synthesis of chitosan oligosaccharide-hydrolyzed gliadin copolymer by roughly-purified microbial transglutaminase(MTGase) catalysis were investigated, and the structures of obtained copolymer were characterized. These optimal conditions are estimated as the substrates mass ratio of chitosan chitosan oligosaccharide and hydrolyzed gliadin is 1:40 under pH 6.00~6.50, and 50 min stirring at 50℃. The grafting rate at these conditions can reach up to 60%~70%. Infrared spectrum analysis of the copolymer shows that, compared with chitosan oligosaccharide, the introduction of electron withdrawing group to chitosan oligosaccharide-hydrolyzed gliadin copolymer has inductive effects on the amide C=O, and causes the vibration peak shift to higher wave number with enhanced absorption intensity. DTA curve indicates that the chitosan oligosaccharide-hydrolyzed gliadin copolymer begins to lose the associated water at 60.91℃, melt at 387.55℃, and completely degrade at 665.25℃. This is significantly different to that of chitosan oligosaccharide and gliadin. XRD analysis shows that the crystallinity of grafted copolymers is greatly reduced, the cell data is different from those of chitosan oligosaccharide. HPLC analysis shows that the copolymer has two main components, accounting together for 80.6% of the total mass. The relative molecular masses of the two main components are 66069 and 27285, respectively. The copolymer does not dissolve in water and many organic solvents, but is slightly soluble in 1% NaOH, with a solubility at 0.184 mg/100 g. The melting range of the copolymer is 162~163℃.
2016, 33(3): 293-298
doi: 10.11944/j.issn.1000-0518.2016.03.150251
Abstract:
A kind of thermally stable epoxy resin containing aromatic thiazole groups(TDABZ) was prepared. The structure of TDABZ was characterized by Fourier transform infrared spectra(FTIR), and the thermal degradation kinetics parameters were determined by thermogravimetric analysis-derivative thermogravimetry(TGA-DTG). The thermal stability of the cured resin was studied by thermogravimetric analysis(TGA) and dynamic thermomechanical analysis(DMTA). TDABZ was completely cured under controled condition by the reaction between epoxy group and the active nitrogen in DDS/2-ABZ. The activation energy value calculated by the Kissinger's and Ozawa's methods is 205.5 kJ/mol and 221.9 kJ/mol, respectively. The cured TDABZ exhibits excellent thermal stability with the glass transition temperature(Tg) of 242.3℃, the temperature of 5% mass loss(Td5) and the temperature at maximum mass loss rate(Tdmax) are 242.3℃ and 395.5℃, respectively, and the residue at 600℃ is up to 24.1%, which can improve the thermal stability of epoxy resin, and broaden its applications.
A kind of thermally stable epoxy resin containing aromatic thiazole groups(TDABZ) was prepared. The structure of TDABZ was characterized by Fourier transform infrared spectra(FTIR), and the thermal degradation kinetics parameters were determined by thermogravimetric analysis-derivative thermogravimetry(TGA-DTG). The thermal stability of the cured resin was studied by thermogravimetric analysis(TGA) and dynamic thermomechanical analysis(DMTA). TDABZ was completely cured under controled condition by the reaction between epoxy group and the active nitrogen in DDS/2-ABZ. The activation energy value calculated by the Kissinger's and Ozawa's methods is 205.5 kJ/mol and 221.9 kJ/mol, respectively. The cured TDABZ exhibits excellent thermal stability with the glass transition temperature(Tg) of 242.3℃, the temperature of 5% mass loss(Td5) and the temperature at maximum mass loss rate(Tdmax) are 242.3℃ and 395.5℃, respectively, and the residue at 600℃ is up to 24.1%, which can improve the thermal stability of epoxy resin, and broaden its applications.
2016, 33(3): 299-306
doi: 10.11944/j.issn.1000-0518.2016.03.150230
Abstract:
The curing process of epoxy resin tooling board for slush mold with different temperature was studied by the rheological method. To find the suitable test condition, the influence of strain and oscillatory frequency on the curing process of epoxy resin tooling board for slush mold was investigated firstly. During the process of curing, the degree of curing becomes larger with time. However, for different stages, the curing rate is different, from slow to fast and finally becomes slow again until plateau. This variation trend is also similar with the storage modulus and loss modulus. On the basis of the relation between the maximum increasing speed of modulus and the reaction temperature, the activation energy of epoxy resin tooling board for slush mold is calculated to be 27.2 kJ/mol. As the reaction temperature increases, the curing rate of the two-component epoxy resin for slush mold speeds up and less time is needed to finish the curing reaction of the epoxy resin. At the same time, the time which can be used to handle the epoxy resin for making mold becomes less with the increase of temperature.
The curing process of epoxy resin tooling board for slush mold with different temperature was studied by the rheological method. To find the suitable test condition, the influence of strain and oscillatory frequency on the curing process of epoxy resin tooling board for slush mold was investigated firstly. During the process of curing, the degree of curing becomes larger with time. However, for different stages, the curing rate is different, from slow to fast and finally becomes slow again until plateau. This variation trend is also similar with the storage modulus and loss modulus. On the basis of the relation between the maximum increasing speed of modulus and the reaction temperature, the activation energy of epoxy resin tooling board for slush mold is calculated to be 27.2 kJ/mol. As the reaction temperature increases, the curing rate of the two-component epoxy resin for slush mold speeds up and less time is needed to finish the curing reaction of the epoxy resin. At the same time, the time which can be used to handle the epoxy resin for making mold becomes less with the increase of temperature.
2016, 33(3): 307-312
doi: 10.11944/j.issn.1000-0518.2016.03.150217
Abstract:
Various porphyrin-containing nanostructures were facilely synthesized by self-assembly technology via modulations of the pH of mixture solution. At low pH, one-dimensional bar is formed, and at high pH, two-dimensional lamellar structure appears. These nanostructures were analyzed by UV-Vis, IR and XRD. One dimensional J-aggregates is formed at low pH through the packing of porphyrin molecules by π-π, and electrostatic interactions. As the pH increases, hydrogen bond plays a key role to switch the porphyrin aggregates into two-dimensional sheets. Photoelectric property test shows a good response of the porphyrin nano-rods to the visible light. This kind of porphyrin nano materials with photoelectric response is expected to be a photoelectric element in electronic devices.
Various porphyrin-containing nanostructures were facilely synthesized by self-assembly technology via modulations of the pH of mixture solution. At low pH, one-dimensional bar is formed, and at high pH, two-dimensional lamellar structure appears. These nanostructures were analyzed by UV-Vis, IR and XRD. One dimensional J-aggregates is formed at low pH through the packing of porphyrin molecules by π-π, and electrostatic interactions. As the pH increases, hydrogen bond plays a key role to switch the porphyrin aggregates into two-dimensional sheets. Photoelectric property test shows a good response of the porphyrin nano-rods to the visible light. This kind of porphyrin nano materials with photoelectric response is expected to be a photoelectric element in electronic devices.
2016, 33(3): 313-319
doi: 10.11944/j.issn.1000-0518.2016.03.150254
Abstract:
To increase the survival ability of military supplies, expedite the usage of infrared stealth material, Al, La doped ZnO was used as filler to prepare infrared stealth coating and coated on tent fabrics. The influences of filler content and film thickness on infrared emissivity were studied in detail. The relationship between heat conduction and infrared emissivity was also studied. The infrared emissivity decreased with the increase of the thickness and content of coating filler. The infrared emissivity of coating tent fabric can decrease to 0.622 when filler mass content is 70%. The tent fabrics with infrared emissivity between 0.622 and 0.932 can be obtained by changing the filler content and coating thickness. Moreover, we also found that thermal conductivity has the influence on the infrared stealth ability to some extent. The infrared stealth ability improved with the increase of thermal conductivity. Different infrared emissivity coatings were made by adjusting the filler content and coating thickness and took thermographs under different surroundings. It showed that the coatings have good camouflage ability under different surroundings.
To increase the survival ability of military supplies, expedite the usage of infrared stealth material, Al, La doped ZnO was used as filler to prepare infrared stealth coating and coated on tent fabrics. The influences of filler content and film thickness on infrared emissivity were studied in detail. The relationship between heat conduction and infrared emissivity was also studied. The infrared emissivity decreased with the increase of the thickness and content of coating filler. The infrared emissivity of coating tent fabric can decrease to 0.622 when filler mass content is 70%. The tent fabrics with infrared emissivity between 0.622 and 0.932 can be obtained by changing the filler content and coating thickness. Moreover, we also found that thermal conductivity has the influence on the infrared stealth ability to some extent. The infrared stealth ability improved with the increase of thermal conductivity. Different infrared emissivity coatings were made by adjusting the filler content and coating thickness and took thermographs under different surroundings. It showed that the coatings have good camouflage ability under different surroundings.
2016, 33(3): 320-329
doi: 10.11944/j.issn.1000-0518.2016.03.150258
Abstract:
A PW11Cr/TiO2 nano film photocatalyst was prepared on the surface of a glass slide via the sol-gel dipping pulling method using tetrabutyl titanate Ti(OC4H9)4 as the precursor of TiO2 and the Keggin type chromium substituted heteropolyanion(PW11Cr) as the visible light active component. Then the light absorption properties, chemical composition, crystal phase and surface morphology of the as-prepared catalyst were characterized using solid ultraviolet-visible diffuse reflection spectroscopy, infrared spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The interaction between PW11Cr and TiO2 in the film was discussed. Visible photocatalytic activity of the catalyst was assessed using photocatalytic degradation of RhB as a probe. Meanwhile, a photocatalysis mechanism was suggested and compared with that of TiO2. Influences of the calcination temperature, the PW11Cr dosage and the solution pH on the catalyst activity were also examined. In the end, a recycle test of the catalyst for RhB degradation was employed to evaluate the stability of the catalyst. The PW11Cr/TiO2 photocatalyst has a good absorption of visible light. The film obtained at low calcination temperature(100℃) is amorphous but crystal at high calcination temperature(500℃). The former has higher photocatalytic activity, and is employed to degrade RhB with a concentration of 10 μmol/L under the irradiation of 200 W metal halide lamp. The degradation ratio is 95% at 120 min and the COD removal is 72% at 4 h. The hydroxyl radicals are the main reactive oxygen species leading to RhB degradation. Low processing temperature, high PW11Cr dosage and high solution acidity are favorable to enhance the photocatalytic activity of the PW11Cr/TiO2 film. After recycles of 10 times for RhB degradaion, the photocatalytic activity of the PW11Cr/TiO2 film lose insignificantly.
A PW11Cr/TiO2 nano film photocatalyst was prepared on the surface of a glass slide via the sol-gel dipping pulling method using tetrabutyl titanate Ti(OC4H9)4 as the precursor of TiO2 and the Keggin type chromium substituted heteropolyanion(PW11Cr) as the visible light active component. Then the light absorption properties, chemical composition, crystal phase and surface morphology of the as-prepared catalyst were characterized using solid ultraviolet-visible diffuse reflection spectroscopy, infrared spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The interaction between PW11Cr and TiO2 in the film was discussed. Visible photocatalytic activity of the catalyst was assessed using photocatalytic degradation of RhB as a probe. Meanwhile, a photocatalysis mechanism was suggested and compared with that of TiO2. Influences of the calcination temperature, the PW11Cr dosage and the solution pH on the catalyst activity were also examined. In the end, a recycle test of the catalyst for RhB degradation was employed to evaluate the stability of the catalyst. The PW11Cr/TiO2 photocatalyst has a good absorption of visible light. The film obtained at low calcination temperature(100℃) is amorphous but crystal at high calcination temperature(500℃). The former has higher photocatalytic activity, and is employed to degrade RhB with a concentration of 10 μmol/L under the irradiation of 200 W metal halide lamp. The degradation ratio is 95% at 120 min and the COD removal is 72% at 4 h. The hydroxyl radicals are the main reactive oxygen species leading to RhB degradation. Low processing temperature, high PW11Cr dosage and high solution acidity are favorable to enhance the photocatalytic activity of the PW11Cr/TiO2 film. After recycles of 10 times for RhB degradaion, the photocatalytic activity of the PW11Cr/TiO2 film lose insignificantly.
2016, 33(3): 330-335
doi: 10.11944/j.issn.1000-0518.2016.03.150305
Abstract:
Extraction of Sc(Ⅲ) from HNO3 medium and HCl medium using a bifunctional ionic liquid extractant [A336][P507] was investigated. The results show that the extractability of Sc(Ⅲ) by [A336][P507] is high at low acidity. The extraction efficiency of Sc(Ⅲ) decreases when the aqueous phase acidity increases from 0.5 mol/L to 4 mol/L. The extraction mechanism was investigated. The extracted complex of Sc(Ⅲ) is different from light REs due to the smaller radius of Sc(Ⅲ) and the competitive effect of P-O and P=O. The extraction efficiency of Sc(Ⅲ) is enhanced with the increase concentration of NaCl or NaNO3 in the aqueous phase. Thermodynamic functions of the extraction reaction demonstrate that the extraction of Sc(Ⅲ) is an exothermic process. Extraction of other rare earth ions at low acidity by the extractant is negligible suggesting that [A336][P507] has potential in industrial applications of Sc(Ⅲ) extraction and separation over other rare earth ions.
Extraction of Sc(Ⅲ) from HNO3 medium and HCl medium using a bifunctional ionic liquid extractant [A336][P507] was investigated. The results show that the extractability of Sc(Ⅲ) by [A336][P507] is high at low acidity. The extraction efficiency of Sc(Ⅲ) decreases when the aqueous phase acidity increases from 0.5 mol/L to 4 mol/L. The extraction mechanism was investigated. The extracted complex of Sc(Ⅲ) is different from light REs due to the smaller radius of Sc(Ⅲ) and the competitive effect of P-O and P=O. The extraction efficiency of Sc(Ⅲ) is enhanced with the increase concentration of NaCl or NaNO3 in the aqueous phase. Thermodynamic functions of the extraction reaction demonstrate that the extraction of Sc(Ⅲ) is an exothermic process. Extraction of other rare earth ions at low acidity by the extractant is negligible suggesting that [A336][P507] has potential in industrial applications of Sc(Ⅲ) extraction and separation over other rare earth ions.
2016, 33(3): 336-342
doi: 10.11944/j.issn.1000-0518.2016.03.150257
Abstract:
Humic acid(HA)-coated manganese ferrite(MnFe2O4/HA) magnetic composite materials were prepared with chemical coprecipitation method and its nanoparticles were characterzied by X-ray diffraction(XRD), scanning electron microscopy(SEM) and Fourier transform infrared(FT-IR) analysis. The results show that the size of the product is about 200 nm. MnFe2O4/HA has a typical spinel structure and is successfully coated with humic acid on its surface. The saturation magnetization of MnFe2O4/HA is 34.01 A·m2/kg. MnFe2O4/HA can be separated from water with low magnetic field within 30 seconds. The adsorption of methylene blue is a pseudo second-rate kinetic process and reaches equilibrium in about 2 h, in good agreement with the Langmuir adsorption model. MnFe2O4/HA has higher adsorption ability than that of pure MnFe2O4. The max adsorbing capacity can reach 29.94 mg/g at room temperature and pH=9. MnFe2O4/HA can be used as adsorption material for effective removal of methylene blue from waste water.
Humic acid(HA)-coated manganese ferrite(MnFe2O4/HA) magnetic composite materials were prepared with chemical coprecipitation method and its nanoparticles were characterzied by X-ray diffraction(XRD), scanning electron microscopy(SEM) and Fourier transform infrared(FT-IR) analysis. The results show that the size of the product is about 200 nm. MnFe2O4/HA has a typical spinel structure and is successfully coated with humic acid on its surface. The saturation magnetization of MnFe2O4/HA is 34.01 A·m2/kg. MnFe2O4/HA can be separated from water with low magnetic field within 30 seconds. The adsorption of methylene blue is a pseudo second-rate kinetic process and reaches equilibrium in about 2 h, in good agreement with the Langmuir adsorption model. MnFe2O4/HA has higher adsorption ability than that of pure MnFe2O4. The max adsorbing capacity can reach 29.94 mg/g at room temperature and pH=9. MnFe2O4/HA can be used as adsorption material for effective removal of methylene blue from waste water.
2016, 33(3): 343-349
doi: 10.11944/j.issn.1000-0518.2016.03.150243
Abstract:
In order to study the fate and transport behavior of polyphosphate in water body, the adsorption process of pyrophosphate on synthetic goethite which stablely exists in the supergene environment has been studied systematically. The adsorption behaviors under different conditions(pH, electrolyte, time, temperature) were investigated and the adsorption mechanism was discussed. The results indicate that the adsorption capacity decreases from 3.00 mg/g to 0.75 mg/g with the increase of pH from 6.27 to 10.99. The lower the electrolyte concentration, the more favorable to the adsorption. The adsorption characteristic within 48 h was investigated. The adsorption capacity increases rapidly within 1 h, and then reaches the adsorption equilibrium. Moreover, the adsorption capacity increases with the increase of the adsorption temperature. Kinetic models and thermodynamic models were used to analyze the adsorption process, and the results show that the adsorption is in accord with the pseudo second-order equation and Langmuir model. Furthermore, combined with the characterization of materials, the adsorption may be mainly based on surface complexation and physical adsorption.
In order to study the fate and transport behavior of polyphosphate in water body, the adsorption process of pyrophosphate on synthetic goethite which stablely exists in the supergene environment has been studied systematically. The adsorption behaviors under different conditions(pH, electrolyte, time, temperature) were investigated and the adsorption mechanism was discussed. The results indicate that the adsorption capacity decreases from 3.00 mg/g to 0.75 mg/g with the increase of pH from 6.27 to 10.99. The lower the electrolyte concentration, the more favorable to the adsorption. The adsorption characteristic within 48 h was investigated. The adsorption capacity increases rapidly within 1 h, and then reaches the adsorption equilibrium. Moreover, the adsorption capacity increases with the increase of the adsorption temperature. Kinetic models and thermodynamic models were used to analyze the adsorption process, and the results show that the adsorption is in accord with the pseudo second-order equation and Langmuir model. Furthermore, combined with the characterization of materials, the adsorption may be mainly based on surface complexation and physical adsorption.
2016, 33(3): 350-356
doi: 10.11944/j.issn.1000-0518.2016.03.150242
Abstract:
The metastable zone is one of the most important properties of the crystallization process. In the present study the solubility and supersolubility of sodium perborate tetrahydrate(SPT) in water were measured by the laser detection technique. The dependence of the solubility and supersolubility on the temperature, cooling rate, stirring rate and concentrations of additives was discussed carefully. The curves of solubility and supersolubility were obtained and the empirical equation of the solubility for sodium perborate was employed to fit the data of sodium perborate solubility. The experimental results show that the solubility of SPT increases with the increase of temperature, the stable area of SPT becomes narrower at higher temperature, and the metastable zone increases with the increase of cooling rate and decrease of stirring rate. Further results show that the metastable zone width(MZW) of SPT is remarkably affected by the concentrations of additive agents and a maximum metastable zone is obtained when the concentrations of sodium hexametaphosphate and sodium polyacrylate are 0.065% and 0.045%, respectively.
The metastable zone is one of the most important properties of the crystallization process. In the present study the solubility and supersolubility of sodium perborate tetrahydrate(SPT) in water were measured by the laser detection technique. The dependence of the solubility and supersolubility on the temperature, cooling rate, stirring rate and concentrations of additives was discussed carefully. The curves of solubility and supersolubility were obtained and the empirical equation of the solubility for sodium perborate was employed to fit the data of sodium perborate solubility. The experimental results show that the solubility of SPT increases with the increase of temperature, the stable area of SPT becomes narrower at higher temperature, and the metastable zone increases with the increase of cooling rate and decrease of stirring rate. Further results show that the metastable zone width(MZW) of SPT is remarkably affected by the concentrations of additive agents and a maximum metastable zone is obtained when the concentrations of sodium hexametaphosphate and sodium polyacrylate are 0.065% and 0.045%, respectively.
2016, 33(3): 357-363
doi: 10.11944/j.issn.1000-0518.2016.03.150238
Abstract:
A novel fluorescein derivative, 5-bromosalicylicaldehyde fluorescein hydrazone(BSFH), has been synthesized by reacting fluorescein hydrazine with 5-bromosalicylicaldehyde and characterized by IR, NMR, MS, elemental analysis. The selectivity of BSFH to common metal ions in aqueous solution was investigated by absorption spectroscopy. BSFH has almost no absorption in visible region and very low absorption at 496 nm with addition of other metal ions except Cu2+. However, in the presence of Cu2+, a rapid color change of BSFH from colorless to yellow along with a very obvious absorption appears at 496 nm in the absorption spectrum. The absorbance of BSFH at 496 nm increases gradually with the increase of Cu2+. The selective binding of BSFH to Cu2+ over other metal ions is remarkably high in the aqueous solution. Experimental results indicate that the chemical stoichiometric ratio between BSFH and Cu2+ is 1:1, the linear range of detecting Cu2+ concentration is 0.30~10 μmol/L, common metal ions do not show any interference on the determination of Cu2+, the detection limit is 0.30 μmol/L, and BSFH is highly sensitive to Cu2+ in the aqueous solution. Therefore, BSFH can be utilized to detect Cu2+ at low concentration with simple, rapid and sensitive method.
A novel fluorescein derivative, 5-bromosalicylicaldehyde fluorescein hydrazone(BSFH), has been synthesized by reacting fluorescein hydrazine with 5-bromosalicylicaldehyde and characterized by IR, NMR, MS, elemental analysis. The selectivity of BSFH to common metal ions in aqueous solution was investigated by absorption spectroscopy. BSFH has almost no absorption in visible region and very low absorption at 496 nm with addition of other metal ions except Cu2+. However, in the presence of Cu2+, a rapid color change of BSFH from colorless to yellow along with a very obvious absorption appears at 496 nm in the absorption spectrum. The absorbance of BSFH at 496 nm increases gradually with the increase of Cu2+. The selective binding of BSFH to Cu2+ over other metal ions is remarkably high in the aqueous solution. Experimental results indicate that the chemical stoichiometric ratio between BSFH and Cu2+ is 1:1, the linear range of detecting Cu2+ concentration is 0.30~10 μmol/L, common metal ions do not show any interference on the determination of Cu2+, the detection limit is 0.30 μmol/L, and BSFH is highly sensitive to Cu2+ in the aqueous solution. Therefore, BSFH can be utilized to detect Cu2+ at low concentration with simple, rapid and sensitive method.
2016, 33(3): 364-366
doi: 10.11944/j.issn.1000-0518.2016.03.150339
Abstract:
The phosphotungstic acid(HPW)/nano-ZSM-5 catalyst was prepared by the impregnation method. When the nano-ZSM-5 is supported by HPW alone, the Keggin structure HPW changes to a Dawson structure heteropoly compounds, and the Keggin structure remains unchanged after binding with nickel salt. With oxidative desulfurization of organic sulfides as a probe, the oil desulfurization rate in simulation oils with dibenzothiophene components of n-octane reaches 94.5% at 40℃.
The phosphotungstic acid(HPW)/nano-ZSM-5 catalyst was prepared by the impregnation method. When the nano-ZSM-5 is supported by HPW alone, the Keggin structure HPW changes to a Dawson structure heteropoly compounds, and the Keggin structure remains unchanged after binding with nickel salt. With oxidative desulfurization of organic sulfides as a probe, the oil desulfurization rate in simulation oils with dibenzothiophene components of n-octane reaches 94.5% at 40℃.
