An Hβ-supported heteropoly acid （H3PW12O40 （HPW）/Hβ） catalyst was successfully prepared by wetness impregnation, and investigated in the alkylation of toluene with tert-butyl alcohol for the synthesis of 4-tert-...An Hβ-supported heteropoly acid （H3PW12O40 （HPW）/Hβ） catalyst was successfully prepared by wetness impregnation, and investigated in the alkylation of toluene with tert-butyl alcohol for the synthesis of 4-tert-butyltoluene （PTBT）. X-ray diffraction, scanning electron microscopy, transmis- sion electron microscopy, fourier-transform infrared spectroscopy, inductively coupled plas- ma-optical emission spectrometry, the brunauer emmett teller （BET） method, tempera- ture-programmed NH3 desorption, and pyridine adsorption infrared spectroscopy were used to characterize the catalyst. The results showed that loading HPW on Hβ effectively increased the B acidity and decreased the pore size of Hβ. The B acidity of HPW/Hβ was 142.97 μmol/g, which is 69.74% higher than that of Hβ （84.23 μmol/g）. The catalytic activity of the HPW/Hβ catalyst was much better than that of the parent Hβ zeolite because of its high B acidity. The toluene conversion over HPW/Hβ reached 73.1%, which is much higher than that achieved with Hβ （54.0%）. When HPW was loaded on Hβ, the BET surface area of Hβ decreased from 492.5 to 379.6 m2/g, accompa- nied by a significant decrease in the pore size from 3.90 to 3.17 nm. Shape selectivity can therefore play an important role and increase the product selectivity of the HPW/Hβ catalyst compared with that of the parent Hβ. PTBT （kinetic diameter 0.58 nm） can easily diffuse through the narrowed pores of HPW/Hβ, but 3-tert-butyltoluene （kinetic diameter 0.65 nm） diffusion is restricted because of steric hindrance in these narrow pores. This results in high PTBT selectivity over HPW/Hβ （around 81%）. The HPW/Hβ catalyst gave a stable catalytic performance in reusability tests.展开更多
A kinetic model fitted by the empirical equation has been proposed to describe the liquid drainage behavior. Rate constants （kd） of liquid drainage equation could be obtained from the above empirical equation. In th...A kinetic model fitted by the empirical equation has been proposed to describe the liquid drainage behavior. Rate constants （kd） of liquid drainage equation could be obtained from the above empirical equation. In this paper, the stability of the colloidal gas aphrons （CGAs）, the effect of concentrations of sodium dodecyl benzene sulphate （SDBS）, dodecyl trimethylammonium bromide （HTAB） and polyoxyethylene sorbitol anhydride monolaurate（Tween-20）, temperature, stirring speed, stirring time, and various kinds of salts on the kd of liquid drainage are further investigated. The results show that the Arrhenius equation can be successfully used to describe the relation between kd arid absolute temperature （T）, and concentrations of surfactants, stirring speed, stirring time and salinities also have great effect on the kd. At last, the CGAs drainage mechanism is explained from analysis of the rate of liquid drainage as a function of time.展开更多
A series of hexadecylphosphate acid(HDPA) terminated mixed-oxide nanoparticles have been investigated to catalyze the oxidation of toluene exclusive to benzaldehyde under mild conditions in an emulsion of toluene/wate...A series of hexadecylphosphate acid(HDPA) terminated mixed-oxide nanoparticles have been investigated to catalyze the oxidation of toluene exclusive to benzaldehyde under mild conditions in an emulsion of toluene/water with the catalysts as stabilizers. With the HDPA-Fe2 O3/Al2 O3 as the basic catalyst, a series of transition metals, such as Mn, Co, Ni, Cu, Cr, Mo, V, and Ti, was respectively doped to the basic catalyst to modify the performance of the catalytic system, in expectation of influencing the mobility of the lattice oxygen species in the oxide catalysts. Under normally working conditions of the catalytic system, the nanoparticles of catalysts located themselves at the interface between the oil and water phases, constituting the Pickering emulsion. Both the doped iron oxide and its surface adsorbed hexadecylphosphate molecules were essential to the catalytic system for excellent performances with high toluene conversions as well as the exclusive selectivity to benzaldehyde. Under optimal conditions, ~83% of toluene conversion and >99% selectivity to benzaldehyde were obtained, using molecular oxygen as oxidant and HDPA-(Fe2 O3-Ni O)/Al2 O3 as the catalyst. This process is green and low cost to produce high quality benzaldehyde from O2 oxidation of toluene.展开更多
The completely selective oxidation of toluene to benzaldehyde with dioxygen,without the need touse H_(2)O_(2),halogens,or any radical initiators,is a reaction long desired but never previously successful.Here,we demon...The completely selective oxidation of toluene to benzaldehyde with dioxygen,without the need touse H_(2)O_(2),halogens,or any radical initiators,is a reaction long desired but never previously successful.Here,we demonstrate the enzyme‐like mechanism of the reaction over hexadecylphosphateacid(HDPA)‐bonded nano‐oxides,which appear to interact with toluene through specific recognition.The active sites of the catalyst are related to the ability of HDPA to change its bonding to theoxides between monodentate and bidentate during the reaction cycle.This greatly enhances themobility of the crystal oxygen or the reactivity of the catalyst,specifically in toluene transformations.The catalytic cycle of the catalyst is similar to that of methane monooxygenase.In thepresence of catalyst and through O_(2)oxidation,the conversion of toluene to benzaldehyde is initiatedat 70°C.We envision that this novel mechanism reveals alternatives for an attractive route to designhigh‐performance catalysts with bioinspired structures.展开更多
Adopting Poly（ethylene glycol） adipate Dilpoly- （ethylene glycol）] adipate polydiglycol adipate glycol （PDAG）, 1,4-butanediol （BDO）, hydroxy silicone oil, methylene diphenyl diisocyanate （MDI） as the raw mat...Adopting Poly（ethylene glycol） adipate Dilpoly- （ethylene glycol）] adipate polydiglycol adipate glycol （PDAG）, 1,4-butanediol （BDO）, hydroxy silicone oil, methylene diphenyl diisocyanate （MDI） as the raw material, a new polyurethane elastic body can be made through prepolymerization. After measurement of the moisture permeability, adsorption quantity and mechanical properties of the membrane made with the elastic body, we also proofed its formula by infrared spectroscopy. The result showed that the moisture permeability of the membrane, with a certain intelligent thermotropic quality, will increase by 3 to 4 times when the temperature is between 25℃-45℃.展开更多
文摘An Hβ-supported heteropoly acid （H3PW12O40 （HPW）/Hβ） catalyst was successfully prepared by wetness impregnation, and investigated in the alkylation of toluene with tert-butyl alcohol for the synthesis of 4-tert-butyltoluene （PTBT）. X-ray diffraction, scanning electron microscopy, transmis- sion electron microscopy, fourier-transform infrared spectroscopy, inductively coupled plas- ma-optical emission spectrometry, the brunauer emmett teller （BET） method, tempera- ture-programmed NH3 desorption, and pyridine adsorption infrared spectroscopy were used to characterize the catalyst. The results showed that loading HPW on Hβ effectively increased the B acidity and decreased the pore size of Hβ. The B acidity of HPW/Hβ was 142.97 μmol/g, which is 69.74% higher than that of Hβ （84.23 μmol/g）. The catalytic activity of the HPW/Hβ catalyst was much better than that of the parent Hβ zeolite because of its high B acidity. The toluene conversion over HPW/Hβ reached 73.1%, which is much higher than that achieved with Hβ （54.0%）. When HPW was loaded on Hβ, the BET surface area of Hβ decreased from 492.5 to 379.6 m2/g, accompa- nied by a significant decrease in the pore size from 3.90 to 3.17 nm. Shape selectivity can therefore play an important role and increase the product selectivity of the HPW/Hβ catalyst compared with that of the parent Hβ. PTBT （kinetic diameter 0.58 nm） can easily diffuse through the narrowed pores of HPW/Hβ, but 3-tert-butyltoluene （kinetic diameter 0.65 nm） diffusion is restricted because of steric hindrance in these narrow pores. This results in high PTBT selectivity over HPW/Hβ （around 81%）. The HPW/Hβ catalyst gave a stable catalytic performance in reusability tests.
基金Supported by the Eleventh Five Year National Key Technology R&D Program (2008BAE58B01)New Century Excellent Talents of Ministry of Education (NCET-07-0577),the People’s Republic of China
文摘A kinetic model fitted by the empirical equation has been proposed to describe the liquid drainage behavior. Rate constants （kd） of liquid drainage equation could be obtained from the above empirical equation. In this paper, the stability of the colloidal gas aphrons （CGAs）, the effect of concentrations of sodium dodecyl benzene sulphate （SDBS）, dodecyl trimethylammonium bromide （HTAB） and polyoxyethylene sorbitol anhydride monolaurate（Tween-20）, temperature, stirring speed, stirring time, and various kinds of salts on the kd of liquid drainage are further investigated. The results show that the Arrhenius equation can be successfully used to describe the relation between kd arid absolute temperature （T）, and concentrations of surfactants, stirring speed, stirring time and salinities also have great effect on the kd. At last, the CGAs drainage mechanism is explained from analysis of the rate of liquid drainage as a function of time.
基金supported by the National Natural Science Foundation of China(91434101,91745108)the Ministry of Science and Technology of the People’s Republic of China(2017YFB0702900)~~
文摘A series of hexadecylphosphate acid(HDPA) terminated mixed-oxide nanoparticles have been investigated to catalyze the oxidation of toluene exclusive to benzaldehyde under mild conditions in an emulsion of toluene/water with the catalysts as stabilizers. With the HDPA-Fe2 O3/Al2 O3 as the basic catalyst, a series of transition metals, such as Mn, Co, Ni, Cu, Cr, Mo, V, and Ti, was respectively doped to the basic catalyst to modify the performance of the catalytic system, in expectation of influencing the mobility of the lattice oxygen species in the oxide catalysts. Under normally working conditions of the catalytic system, the nanoparticles of catalysts located themselves at the interface between the oil and water phases, constituting the Pickering emulsion. Both the doped iron oxide and its surface adsorbed hexadecylphosphate molecules were essential to the catalytic system for excellent performances with high toluene conversions as well as the exclusive selectivity to benzaldehyde. Under optimal conditions, ~83% of toluene conversion and >99% selectivity to benzaldehyde were obtained, using molecular oxygen as oxidant and HDPA-(Fe2 O3-Ni O)/Al2 O3 as the catalyst. This process is green and low cost to produce high quality benzaldehyde from O2 oxidation of toluene.
文摘The completely selective oxidation of toluene to benzaldehyde with dioxygen,without the need touse H_(2)O_(2),halogens,or any radical initiators,is a reaction long desired but never previously successful.Here,we demonstrate the enzyme‐like mechanism of the reaction over hexadecylphosphateacid(HDPA)‐bonded nano‐oxides,which appear to interact with toluene through specific recognition.The active sites of the catalyst are related to the ability of HDPA to change its bonding to theoxides between monodentate and bidentate during the reaction cycle.This greatly enhances themobility of the crystal oxygen or the reactivity of the catalyst,specifically in toluene transformations.The catalytic cycle of the catalyst is similar to that of methane monooxygenase.In thepresence of catalyst and through O_(2)oxidation,the conversion of toluene to benzaldehyde is initiatedat 70°C.We envision that this novel mechanism reveals alternatives for an attractive route to designhigh‐performance catalysts with bioinspired structures.
基金Acknowledgments： This work was supported in part by the National Natural Science Foundation of China （No. 20504023）.
文摘Adopting Poly（ethylene glycol） adipate Dilpoly- （ethylene glycol）] adipate polydiglycol adipate glycol （PDAG）, 1,4-butanediol （BDO）, hydroxy silicone oil, methylene diphenyl diisocyanate （MDI） as the raw material, a new polyurethane elastic body can be made through prepolymerization. After measurement of the moisture permeability, adsorption quantity and mechanical properties of the membrane made with the elastic body, we also proofed its formula by infrared spectroscopy. The result showed that the moisture permeability of the membrane, with a certain intelligent thermotropic quality, will increase by 3 to 4 times when the temperature is between 25℃-45℃.
