A carbon solid acid catalyst was prepared by the sulfonation of partially carbonized peanut shell with concentrated H2SO4. The structure and acidity of the catalyst were characterized by Fourier transform infrared spe...A carbon solid acid catalyst was prepared by the sulfonation of partially carbonized peanut shell with concentrated H2SO4. The structure and acidity of the catalyst were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and elemental analysis, which showed that it was an amorphous carbon material composed of aromatic carbon sheets in random orientations. Sulfonic acid groups were present on the surface at a density of 0.81 mmol/g. The carbon solid acid catalyst showed better performance than HZSM‐5 for the esterification of cyclohexene with formic acid. At a3：1 molar ratio of formic acid to cyclohexene, catalyst loading of 0.07 g/mL of cyclohexene, and reaction time of 1 h at 413 K, the cyclohexene conversion was 88.4% with 97.3% selectivity to cyclohexyl formate. The carbon solid acid catalyst showed better reusability than HZSM‐5 because its large pores were minimally affected by the accumulation of oligomerized cyclohexene, which deactivated HZSM‐5. The activity of the carbon solid acid catalyst decreased somewhat in the first two recycles due to the leaching of polycyclic aromatic hydrocarbon containing –SO3H groups and then it remained constant in the following reuse.展开更多
The influence of adipic acid on the formation and corrosion resistance of anodic oxide film fabricated on 2024 aluminum alloy was investigated. The morphology was investigated by scanning electron microscopy （SEM） a...The influence of adipic acid on the formation and corrosion resistance of anodic oxide film fabricated on 2024 aluminum alloy was investigated. The morphology was investigated by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, respectively. The corrosion resistance was evaluated by electrochemical impedance spectroscopy （EIS）. The results showed that the adipic acid was absorbed at the electrolyte/anodic layer interface during anodizing. The corrosion rate of anodic film decreased and the film thickness increased. The film was uniform and compact especially at the film/substrate interface. After sealing procedure, anodic film formed with the addition of adipic acid exhibited improved dielectric property and corrosion resistance in aggressive environment.展开更多
Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-...Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers.展开更多
New solid complex of the antimony trichloride and dioxane was obtained th rough a reaction of the dioxane and the absolute methanol solution of the antimony trichloride.The formula of the complex is[SbCl_(3)·{(CH...New solid complex of the antimony trichloride and dioxane was obtained th rough a reaction of the dioxane and the absolute methanol solution of the antimony trichloride.The formula of the complex is[SbCl_(3)·{(CH_(2))_(4)O_(2)}_(1.5)].The crystal structure of the comple x belongs to cubic system,space group I-43d,a=17.1417(5)?,Z=16.The trivalent antimony ion not only bonds directly to three chlorine anions,but also is co ordinated by three oxygen atoms of th e dioxane molecules.Two oxygen atoms in a dioxane molecule wi ll coordinate to different antimony ions,respectively.展开更多
The effects of calcination temperature on the physicochemical properties of manganese oxide catalysts prepared by a precipitation method were assessed by X-ray diffraction,N2 adsorption-desorption,X-ray photoelectron ...The effects of calcination temperature on the physicochemical properties of manganese oxide catalysts prepared by a precipitation method were assessed by X-ray diffraction,N2 adsorption-desorption,X-ray photoelectron spectroscopy,H2 temperature-programmed reduction,O2 temperature-programmed desorption,and thermogravimetry-differential analysis.The catalytic performance of each of these materials during the selective oxidation of cyclohexane with oxygen in a solvent-free system was subsequently examined.It was found that the MnOx-500 catalyst,calcined at 500 °C,consisted of a Mn2O3 phase in addition to Mn5O8 and Mn3O4 phases and possessed a low surface area.Unlike MnOx-500,the MnOx-400 catalyst prepared at 400 °C was composed solely of Mn3O4 and Mn5O8 and had a higher surface area.The pronounced catalytic activity of this latter material for the oxidation of cyclohexene was determined to result from numerous factors,including a higher concentration of surface adsorbed oxygen,greater quantities of the surface Mn4＋ ions that promote oxygen mobility and the extent of O2 adsorption and reducibility on the catalyst.The effects of various reaction conditions on the activity of the MnOx-400 during the oxidation of cyclohexane were also evaluated,such as the reaction temperature,reaction time,and initial oxygen pressure.Following a 4 h reaction at an initial O2 pressure of 0.5 MPa and 140 °C,an 8.0% cyclohexane conversion and 5.0% yield of cyclohexanol and cyclohexanone were achieved over the MnOx-400 catalyst.In contrast,employing MnOx-500 resulted in a 6.1% conversion of cyclohexane and 75% selectivity for cyclohexanol and cyclohexanone.After being recycled through 10 replicate uses,the catalytic activity of the MnOx-400 catalyst was unchanged,demonstrating its good stability.展开更多
Silicoaluminophosphate（SAPO） molecular sieves doped with cobalt（Co-SAPO-5） were synthesized hydrothermally with different concentrations of Co.Each sample was characterized by X-ray diffraction,N2 adsorption-desor...Silicoaluminophosphate（SAPO） molecular sieves doped with cobalt（Co-SAPO-5） were synthesized hydrothermally with different concentrations of Co.Each sample was characterized by X-ray diffraction,N2 adsorption-desorption,scanning electron microscopy,ultraviolet-visible spectroscopy,temperature-programmed desorption of NH3（NH3-TPD）,and infrared spectrascopy of adsorbed pyridine（Py-IR）.The results showed that Co was highly dispersed in the Co-SAPO-5 samples.In addition,a part of the Co content had been incorporated into the SAPO-5 framework,while the remainder existed on the surface as extra-framework Co.The surface areas of the Co-SAOP-5 samples were similar to the SAPO-5 sample.However,the pore volumes of the Co-SAOP-5 samples were lower than that of the SAOP-5 sample.As the concentration of Co increased,the pore volume gradually decreased because extra-framework cobalt oxide was present on the catalyst surface.NH3-TPD and Py-IR results revealed that the amount of Br（？）nsted acid and the total amount of acid for the Co-SAPO-5 samples were higher than that for the SAPO-5 sample.These values were also higher for samples with higher Co content.The catalytic activity of the Co-SAPO-5 samples was evaluated for the oxidation of cyclohexane with molecular oxygen.When Co was added to the SAPO-5 catalyst,the catalytic activity of the Co-SAPO-5 catalysts improved.In addition,the conversion of cyclohexane increased as the Co content in the Co-SAPO-5 catalysts increased.However,with a high conversion of cyclohexane（6.30%）,the total selectivity of cyclohexanone（K） and cyclohexanol（A） decreased sharply.The K/A ratio ranged from 1.15 to 2.47.The effects of reaction conditions（i.e.,reaction temperature,reaction time,initial oxygen pressure,and the catalyst amount） on the performance of the Co-SAPO-5 catalysts have also been measured.Furthermore,the stability of the Co-SAPO-5 catalyst was explored and found to be good for the selective oxidation of cyclohexane by molecular oxygen.展开更多
基金supported by the National Natural Science Foundation of China(2123600121176056)+1 种基金the Programme for 100 Excellent Talents in Universities of Hebei Province(II)(BR2-208)the Natural Science Foundation of Hebei Province(B2015202228)~~
文摘A carbon solid acid catalyst was prepared by the sulfonation of partially carbonized peanut shell with concentrated H2SO4. The structure and acidity of the catalyst were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and elemental analysis, which showed that it was an amorphous carbon material composed of aromatic carbon sheets in random orientations. Sulfonic acid groups were present on the surface at a density of 0.81 mmol/g. The carbon solid acid catalyst showed better performance than HZSM‐5 for the esterification of cyclohexene with formic acid. At a3：1 molar ratio of formic acid to cyclohexene, catalyst loading of 0.07 g/mL of cyclohexene, and reaction time of 1 h at 413 K, the cyclohexene conversion was 88.4% with 97.3% selectivity to cyclohexyl formate. The carbon solid acid catalyst showed better reusability than HZSM‐5 because its large pores were minimally affected by the accumulation of oligomerized cyclohexene, which deactivated HZSM‐5. The activity of the carbon solid acid catalyst decreased somewhat in the first two recycles due to the leaching of polycyclic aromatic hydrocarbon containing –SO3H groups and then it remained constant in the following reuse.
基金Project(51271012)supported by the National Natural Science Foundation of China
文摘The influence of adipic acid on the formation and corrosion resistance of anodic oxide film fabricated on 2024 aluminum alloy was investigated. The morphology was investigated by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, respectively. The corrosion resistance was evaluated by electrochemical impedance spectroscopy （EIS）. The results showed that the adipic acid was absorbed at the electrolyte/anodic layer interface during anodizing. The corrosion rate of anodic film decreased and the film thickness increased. The film was uniform and compact especially at the film/substrate interface. After sealing procedure, anodic film formed with the addition of adipic acid exhibited improved dielectric property and corrosion resistance in aggressive environment.
基金supported by the National Natural Science Foundation of China(21403070 and 21373088)Innovation Program of Shanghai Municipal Education Commission(13zz038)+2 种基金Key Project of the Shanghai Committee of Science and Technology(12JC1403600)National Key Technology R&D Program(2012BAE05B02)Shanghai Leading Academic Discipline Project(B409)~~
文摘Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers.
文摘New solid complex of the antimony trichloride and dioxane was obtained th rough a reaction of the dioxane and the absolute methanol solution of the antimony trichloride.The formula of the complex is[SbCl_(3)·{(CH_(2))_(4)O_(2)}_(1.5)].The crystal structure of the comple x belongs to cubic system,space group I-43d,a=17.1417(5)?,Z=16.The trivalent antimony ion not only bonds directly to three chlorine anions,but also is co ordinated by three oxygen atoms of th e dioxane molecules.Two oxygen atoms in a dioxane molecule wi ll coordinate to different antimony ions,respectively.
基金supported by the National Basic Research Program of China(973 Program,2010CB732300)the National Natural Science Foundation of China(21103048)~~
文摘The effects of calcination temperature on the physicochemical properties of manganese oxide catalysts prepared by a precipitation method were assessed by X-ray diffraction,N2 adsorption-desorption,X-ray photoelectron spectroscopy,H2 temperature-programmed reduction,O2 temperature-programmed desorption,and thermogravimetry-differential analysis.The catalytic performance of each of these materials during the selective oxidation of cyclohexane with oxygen in a solvent-free system was subsequently examined.It was found that the MnOx-500 catalyst,calcined at 500 °C,consisted of a Mn2O3 phase in addition to Mn5O8 and Mn3O4 phases and possessed a low surface area.Unlike MnOx-500,the MnOx-400 catalyst prepared at 400 °C was composed solely of Mn3O4 and Mn5O8 and had a higher surface area.The pronounced catalytic activity of this latter material for the oxidation of cyclohexene was determined to result from numerous factors,including a higher concentration of surface adsorbed oxygen,greater quantities of the surface Mn4＋ ions that promote oxygen mobility and the extent of O2 adsorption and reducibility on the catalyst.The effects of various reaction conditions on the activity of the MnOx-400 during the oxidation of cyclohexane were also evaluated,such as the reaction temperature,reaction time,and initial oxygen pressure.Following a 4 h reaction at an initial O2 pressure of 0.5 MPa and 140 °C,an 8.0% cyclohexane conversion and 5.0% yield of cyclohexanol and cyclohexanone were achieved over the MnOx-400 catalyst.In contrast,employing MnOx-500 resulted in a 6.1% conversion of cyclohexane and 75% selectivity for cyclohexanol and cyclohexanone.After being recycled through 10 replicate uses,the catalytic activity of the MnOx-400 catalyst was unchanged,demonstrating its good stability.
基金supported by the National Basic Research Program of China(2010CB732300)the National Natural Science Foundation of China(21103048)~~
文摘Silicoaluminophosphate（SAPO） molecular sieves doped with cobalt（Co-SAPO-5） were synthesized hydrothermally with different concentrations of Co.Each sample was characterized by X-ray diffraction,N2 adsorption-desorption,scanning electron microscopy,ultraviolet-visible spectroscopy,temperature-programmed desorption of NH3（NH3-TPD）,and infrared spectrascopy of adsorbed pyridine（Py-IR）.The results showed that Co was highly dispersed in the Co-SAPO-5 samples.In addition,a part of the Co content had been incorporated into the SAPO-5 framework,while the remainder existed on the surface as extra-framework Co.The surface areas of the Co-SAOP-5 samples were similar to the SAPO-5 sample.However,the pore volumes of the Co-SAOP-5 samples were lower than that of the SAOP-5 sample.As the concentration of Co increased,the pore volume gradually decreased because extra-framework cobalt oxide was present on the catalyst surface.NH3-TPD and Py-IR results revealed that the amount of Br（？）nsted acid and the total amount of acid for the Co-SAPO-5 samples were higher than that for the SAPO-5 sample.These values were also higher for samples with higher Co content.The catalytic activity of the Co-SAPO-5 samples was evaluated for the oxidation of cyclohexane with molecular oxygen.When Co was added to the SAPO-5 catalyst,the catalytic activity of the Co-SAPO-5 catalysts improved.In addition,the conversion of cyclohexane increased as the Co content in the Co-SAPO-5 catalysts increased.However,with a high conversion of cyclohexane（6.30%）,the total selectivity of cyclohexanone（K） and cyclohexanol（A） decreased sharply.The K/A ratio ranged from 1.15 to 2.47.The effects of reaction conditions（i.e.,reaction temperature,reaction time,initial oxygen pressure,and the catalyst amount） on the performance of the Co-SAPO-5 catalysts have also been measured.Furthermore,the stability of the Co-SAPO-5 catalyst was explored and found to be good for the selective oxidation of cyclohexane by molecular oxygen.
