In the present study, the modified （non-Keggin-type） aqueous solutions of Mo-V-phosphoric heteropoly acids HaPzMoyVx,Oh （HPA-x＇） were applied as homogeneous catalysts for the two-stage oxidation of TMP （2,3,6-tr...In the present study, the modified （non-Keggin-type） aqueous solutions of Mo-V-phosphoric heteropoly acids HaPzMoyVx,Oh （HPA-x＇） were applied as homogeneous catalysts for the two-stage oxidation of TMP （2,3,6-trimethylphenol） by oxygen into TMQ （2,3,5-trimethyl-l,4-benzoquinone）, the latter being the key intermediate in the synthesis of vitamin E. The TMQ yield was analyzed regarding solvent type, reaction temperature, molar HPA-x ＇：TMP ratio, and the concentration of vanadium （V） in the HPA-x＇ solution. The TMQ yield was found to depend strongly on the catalyst redox potential and the rate of electron transfer. The results obtained enabled to establish the optimal reaction conditions as well as to suggest the reaction mechanism. In the target reaction, which proceeds in the two-phase system, the TMQ yield is higher than 99%. After phase separation, the catalyst is rapidly regenerated by oxygen and reused.展开更多
Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization,...Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.展开更多
The catalytic performance of Cs-substituted phosphomolybdic salts was studied for selective oxidation of isobutane. The results of activity tests revealed that 360 °C was the optimal reaction temperature. It was ...The catalytic performance of Cs-substituted phosphomolybdic salts was studied for selective oxidation of isobutane. The results of activity tests revealed that 360 °C was the optimal reaction temperature. It was demonstrated that oxidizing sites not only took dominating part in the activation of isobutane, but also influenced the product distribution. Besides, appropriate Cs addition led to moderate acidity of catalysts, favoring the selectivity to desired products. Furthermore, to obtain partially reduced catalysts, different calcination atmospheres were investigated and certain proportion of Mo^（5＋） produced during calcination was crucial for the redox reaction. The catalyst calcined in N2 showed the highest yield of MAA（7.0%）. Fe-substitution enhanced the activity of catalysts by rapid reoxidation of Mo^（5＋）.展开更多
The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantl...The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantly improved the oxidation selectivity of cyclopentene. The effects of the reaction conditions on the conversion of cyclopentene were investigated in detail. The optimal reaction conditions are as follows: the H3PW12O40 to TBAB molar ratio, 1:1–1:3;H3PW12O40 to cyclopentene molar ratio,0.54:100–0.64:100;and molar ratio of H2O2 to cyclopentene, 1.6:1. The conversion reached to 59.8% in 4h at 35.0 ℃, while the selectivity of glutaraldehyde was 38.0% and the selectivity of 1,2-cyclopentanediol was 55.6%. In addition, a route for oxidation of cyclopentene by aqueous H2O2 using a heteropoly acid and quaternary ammonium salt as a phase transfer catalyst was proposed.展开更多
A kind of heteropoly compound film supported on Ce0.5Zr0.5O2 oxide was prepared on a porous titanium tube. The catalytic activity of the film for the selective oxidation of iso-butylene was tested and compared with th...A kind of heteropoly compound film supported on Ce0.5Zr0.5O2 oxide was prepared on a porous titanium tube. The catalytic activity of the film for the selective oxidation of iso-butylene was tested and compared with the fixed-bed reactor. Results show that the catalytic film increases the yield of the target product-methacrylic acid, and avoids the temperature fluctuation caused by the reaction heat.展开更多
Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method. Selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox. The results showed that the ca...Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method. Selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox. The results showed that the catalyst had high catalytic activity. Under the optimum reaction conditions (n(i-C4=):n(O2)=1:2-1:4, space velocity=180 h-1, T=360℃), the yields of methacrolein and methacrylic acid can reach 80% and 8%, respectively. The total yield of liquid products (methacrolein, methacrylic acid and acetic acid) can reach about 90%.展开更多
A facile approach to the preparation of a novel magnetically separable H_5PMo_（10）V_2O_（40）/Fe_3O_4/g-C_3N_4（PMoV/Fe_3O_4/g-C_3N_4） nanocomposite by chemical impregnation is demonstrated.The prepared nanocomposi...A facile approach to the preparation of a novel magnetically separable H_5PMo_（10）V_2O_（40）/Fe_3O_4/g-C_3N_4（PMoV/Fe_3O_4/g-C_3N_4） nanocomposite by chemical impregnation is demonstrated.The prepared nanocomposite was characterized and its acidity was measured by potentiometric titration.PMoV/Fe_3O_4/g-C_3N_4 showed high catalytic activity in the selective oxidative desulfurization of sulfides to their corresponding sulfoxides or sulfones.The catalytic oxidation of a dibenzothiophene（DBT）-containing model oil and that of real oil were also studied under optimized conditions.In addition,the effects of various nitrogen compounds,as well as the use of one- and two-ring aromatic hydrocarbons as co-solvents,on the catalytic removal of sulfur from DBT were investigated.The catalyst was easily separated and could be recovered from the reaction mixture by using an external magnetic field.Additionally,the remaining reactants could be separated from the products by simple decantation if an appropriate solvent was chosen for the extraction.The advantages of this nanocatalyst are its high catalytic activity and reusability;it can be used at least four times without considerable loss of activity.展开更多
In this paper Al2O3 and MgO were studied as targets for the radiation grafting of MAA by electron beams. The reaction conditions and materials were characterized by IR spectroscopy, Scanning electron microscopy, X-ray...In this paper Al2O3 and MgO were studied as targets for the radiation grafting of MAA by electron beams. The reaction conditions and materials were characterized by IR spectroscopy, Scanning electron microscopy, X-ray diffraction methods. It is concluded that grafting copolymerization of inorganic oxides and organic monomers has been confirmed. We focus our attention on using ESR spectrum to study the effects of ionizing radiation on inorganic oxides and the properties of initiating active centers. In addition, the radiation grafting mechanism of inorganic oxides and organic monomers has been primarily investigated.展开更多
In order to reduce the emission of SO_x in the environment,sulfur compounds must be removed efficiently from fuels.Three-dimensional highly ordered meso-macroporous HPW/TiO_(2)(3DO m/M HPW/TiO_(2))materials were synth...In order to reduce the emission of SO_x in the environment,sulfur compounds must be removed efficiently from fuels.Three-dimensional highly ordered meso-macroporous HPW/TiO_(2)(3DO m/M HPW/TiO_(2))materials were synthesized successfully by sol-gel method and applied as oxidative desulfurization catalyst for the model fuel.The characterization results displayed the existence of highly ordered meso-macroporous structures and the Keggin type of HPW was highly dispersed in TiO_(2)framework.The effect of catalyst on desulfurization under different reaction conditions was studied systematically.The results showed that the catalyst exhibited excellent desulfurization performance in the hydrogen peroxide oxidation system,which could be explained by the unique meso-macroporous structure of catalyst.In addition,the catalyst showed good cycling performance and the removal rate of DBT still reached 96.1%even after 6 cycles,providing a feasible method for the development and application of fuel deep desulfurization catalysts.展开更多
Both the partially reduced and non-reduced multi-component heteropoly compound catalysts with Keggin structure were prepared and used for the selective oxidation of propane. The catalysts were characterized by IR, H...Both the partially reduced and non-reduced multi-component heteropoly compound catalysts with Keggin structure were prepared and used for the selective oxidation of propane. The catalysts were characterized by IR, H2-TPR, NH3-TPD, SEM and XRD. The addition of Cs increased the selectivity of acrylic acid and acetic acid. The selective oxidation performance was greatly improved with the addition of As. Among all of the tested catalysts, the catalytic performance of the Cs1.8Fe0.16HxPVAs0.4Mo11O40 (non-reduced) was the best and the maximum yield of acrylic acid reached 16.42%.展开更多
文摘In the present study, the modified （non-Keggin-type） aqueous solutions of Mo-V-phosphoric heteropoly acids HaPzMoyVx,Oh （HPA-x＇） were applied as homogeneous catalysts for the two-stage oxidation of TMP （2,3,6-trimethylphenol） by oxygen into TMQ （2,3,5-trimethyl-l,4-benzoquinone）, the latter being the key intermediate in the synthesis of vitamin E. The TMQ yield was analyzed regarding solvent type, reaction temperature, molar HPA-x ＇：TMP ratio, and the concentration of vanadium （V） in the HPA-x＇ solution. The TMQ yield was found to depend strongly on the catalyst redox potential and the rate of electron transfer. The results obtained enabled to establish the optimal reaction conditions as well as to suggest the reaction mechanism. In the target reaction, which proceeds in the two-phase system, the TMQ yield is higher than 99%. After phase separation, the catalyst is rapidly regenerated by oxygen and reused.
文摘Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.
基金supported by the National Natural Science Foundation of China(No.U1362201)the National 973 Program of China(No.2012CB215006)
文摘The catalytic performance of Cs-substituted phosphomolybdic salts was studied for selective oxidation of isobutane. The results of activity tests revealed that 360 °C was the optimal reaction temperature. It was demonstrated that oxidizing sites not only took dominating part in the activation of isobutane, but also influenced the product distribution. Besides, appropriate Cs addition led to moderate acidity of catalysts, favoring the selectivity to desired products. Furthermore, to obtain partially reduced catalysts, different calcination atmospheres were investigated and certain proportion of Mo^（5＋） produced during calcination was crucial for the redox reaction. The catalyst calcined in N2 showed the highest yield of MAA（7.0%）. Fe-substitution enhanced the activity of catalysts by rapid reoxidation of Mo^（5＋）.
基金Supported by the National Natural Science Foundation of China(21406146)
文摘The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantly improved the oxidation selectivity of cyclopentene. The effects of the reaction conditions on the conversion of cyclopentene were investigated in detail. The optimal reaction conditions are as follows: the H3PW12O40 to TBAB molar ratio, 1:1–1:3;H3PW12O40 to cyclopentene molar ratio,0.54:100–0.64:100;and molar ratio of H2O2 to cyclopentene, 1.6:1. The conversion reached to 59.8% in 4h at 35.0 ℃, while the selectivity of glutaraldehyde was 38.0% and the selectivity of 1,2-cyclopentanediol was 55.6%. In addition, a route for oxidation of cyclopentene by aqueous H2O2 using a heteropoly acid and quaternary ammonium salt as a phase transfer catalyst was proposed.
文摘A kind of heteropoly compound film supported on Ce0.5Zr0.5O2 oxide was prepared on a porous titanium tube. The catalytic activity of the film for the selective oxidation of iso-butylene was tested and compared with the fixed-bed reactor. Results show that the catalytic film increases the yield of the target product-methacrylic acid, and avoids the temperature fluctuation caused by the reaction heat.
基金Foundation item: Supported by Scientific Research Fund of Hunan Provincial Education Department (02C463 and 03C515)Hunan Provincial Natural Science Foundation of China (04JJ6003).
文摘Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method. Selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox. The results showed that the catalyst had high catalytic activity. Under the optimum reaction conditions (n(i-C4=):n(O2)=1:2-1:4, space velocity=180 h-1, T=360℃), the yields of methacrolein and methacrylic acid can reach 80% and 8%, respectively. The total yield of liquid products (methacrolein, methacrylic acid and acetic acid) can reach about 90%.
基金the Razi University Research Council for support of this work
文摘A facile approach to the preparation of a novel magnetically separable H_5PMo_（10）V_2O_（40）/Fe_3O_4/g-C_3N_4（PMoV/Fe_3O_4/g-C_3N_4） nanocomposite by chemical impregnation is demonstrated.The prepared nanocomposite was characterized and its acidity was measured by potentiometric titration.PMoV/Fe_3O_4/g-C_3N_4 showed high catalytic activity in the selective oxidative desulfurization of sulfides to their corresponding sulfoxides or sulfones.The catalytic oxidation of a dibenzothiophene（DBT）-containing model oil and that of real oil were also studied under optimized conditions.In addition,the effects of various nitrogen compounds,as well as the use of one- and two-ring aromatic hydrocarbons as co-solvents,on the catalytic removal of sulfur from DBT were investigated.The catalyst was easily separated and could be recovered from the reaction mixture by using an external magnetic field.Additionally,the remaining reactants could be separated from the products by simple decantation if an appropriate solvent was chosen for the extraction.The advantages of this nanocatalyst are its high catalytic activity and reusability;it can be used at least four times without considerable loss of activity.
文摘In this paper Al2O3 and MgO were studied as targets for the radiation grafting of MAA by electron beams. The reaction conditions and materials were characterized by IR spectroscopy, Scanning electron microscopy, X-ray diffraction methods. It is concluded that grafting copolymerization of inorganic oxides and organic monomers has been confirmed. We focus our attention on using ESR spectrum to study the effects of ionizing radiation on inorganic oxides and the properties of initiating active centers. In addition, the radiation grafting mechanism of inorganic oxides and organic monomers has been primarily investigated.
基金Funded by the National Nature Science Foundation of China(No.21476177)。
文摘In order to reduce the emission of SO_x in the environment,sulfur compounds must be removed efficiently from fuels.Three-dimensional highly ordered meso-macroporous HPW/TiO_(2)(3DO m/M HPW/TiO_(2))materials were synthesized successfully by sol-gel method and applied as oxidative desulfurization catalyst for the model fuel.The characterization results displayed the existence of highly ordered meso-macroporous structures and the Keggin type of HPW was highly dispersed in TiO_(2)framework.The effect of catalyst on desulfurization under different reaction conditions was studied systematically.The results showed that the catalyst exhibited excellent desulfurization performance in the hydrogen peroxide oxidation system,which could be explained by the unique meso-macroporous structure of catalyst.In addition,the catalyst showed good cycling performance and the removal rate of DBT still reached 96.1%even after 6 cycles,providing a feasible method for the development and application of fuel deep desulfurization catalysts.
基金Project supported by the Scientific Research Foundation of Hunan Provincial Education Department and Hunan Provincial Natural Science Founda-tion of China.
文摘Both the partially reduced and non-reduced multi-component heteropoly compound catalysts with Keggin structure were prepared and used for the selective oxidation of propane. The catalysts were characterized by IR, H2-TPR, NH3-TPD, SEM and XRD. The addition of Cs increased the selectivity of acrylic acid and acetic acid. The selective oxidation performance was greatly improved with the addition of As. Among all of the tested catalysts, the catalytic performance of the Cs1.8Fe0.16HxPVAs0.4Mo11O40 (non-reduced) was the best and the maximum yield of acrylic acid reached 16.42%.
