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
Hierarchical zeolite materials were prepared via one‐pot synthesis of ZSM‐11zeolites with different molar ratios(R)of a mesoporogen,i.e.,cetyltrimethylammonium bromide template(CTAB),to a microporogen,i.e.,tetra‐n...Hierarchical zeolite materials were prepared via one‐pot synthesis of ZSM‐11zeolites with different molar ratios(R)of a mesoporogen,i.e.,cetyltrimethylammonium bromide template(CTAB),to a microporogen,i.e.,tetra‐n‐butylammonium bromide(TBABr).The structures,morphologies,and textural properties of the resultant materials were investigated.Initially,with increasing R,the crystal size of the synthesized product decreased,the number of intercrystalline mesopores increased,and a pure ZSM‐11zeolite phase was present.Then an MCM‐41‐like phase was produced and embedded in the ZSM‐11zeolite phase.Finally,an MCM‐41‐like phase was obtained.The alkalinity had important effects on the physicochemical and textural properties of the prepared samples.A possible mechanism of formation of the hierarchical ZSM‐11zeolite was proposed on the basis of a combination of various characterization results.The role of CTAB varied depending on the R value,and it showed a capping effect,micellar effect,and template effect.These effects of CTAB were synergetic in ZSM‐11synthesis,but they were competitive with the structure‐directing effect of TBABr.In addition,the impact of the acidic properties and porosities of the hierarchical ZSM‐11catalysts on their performances in the alkylation of benzene with dimethyl ether was investigated.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
[Objective] The paper was to study the dynamic adsorption of microwave modified attapulgite on micro-polluted phenol wastewater. [Method] Cetyl trimethyl ammonium bromide （CATB） modified attapulgite was used to modi...[Objective] The paper was to study the dynamic adsorption of microwave modified attapulgite on micro-polluted phenol wastewater. [Method] Cetyl trimethyl ammonium bromide （CATB） modified attapulgite was used to modify attapulgite, and conducted dynamic test on micro-polluted phenol wastewater. The dynamic charac- teristics of phenol removal were also studied. [Result] Attapulgite modified by CATB has strong adsorption ability on phenol in micro-polluted water, the phenol removal rate increased with the decrease of flow rate of wastewater. When pH value was 6- 8, phenol concentration in wastewater was 17.74 mg/L, flow rate was 2 m/s and ad- sorption time was 25 rain, the removal rate reached 93.07%. The modified atta- pulgite could be regenerated with alkali, and its adsorption ability after regeneration had no obvious decline. The dynamic adsorption process of phenol accorded with the first-order kinetic equation. [Conclusion] The study provided basis for further study on ＂organic matter removal in wastewater.展开更多
Photocatalytic reduction of 6-chloro-3-nitrotoluene-4-sulfonic acid (CNSA) was studied in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. A mixture of CNSA, TiO2, water, additives and surfa...Photocatalytic reduction of 6-chloro-3-nitrotoluene-4-sulfonic acid (CNSA) was studied in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. A mixture of CNSA, TiO2, water, additives and surfactants was put into a quartz glass reactor with a jacket, which was irradiated with a high pressure Hg lamp in the purging of nitrogen gas. With methanol, the conversion of CNSA increased from 7.7% to 34.6%. Three surfactants significantly promoted the photocatalytic reduction conversion in reduced order of sodium dodecylbenzenesulfonate (DBS), cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS). In suspensions involving DBS and CTAB respectively, CNSA conversion increased in consistence with the adsorption ratio with methanol, but varied inversely with the adsorption ratio without methanol. But no obvious influence on the adsorption ratio was observed with or without methanol added when the SDS concentration was critical micelle concentration (cmc). The photocatalytic reduction of CNSA was enhanced in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. Methanol inhibited the recombination of photogenerated holes and electrons efficiently. Surfactants around 1 cmc led to the highest reduction conversion.展开更多
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.
文摘Hierarchical zeolite materials were prepared via one‐pot synthesis of ZSM‐11zeolites with different molar ratios(R)of a mesoporogen,i.e.,cetyltrimethylammonium bromide template(CTAB),to a microporogen,i.e.,tetra‐n‐butylammonium bromide(TBABr).The structures,morphologies,and textural properties of the resultant materials were investigated.Initially,with increasing R,the crystal size of the synthesized product decreased,the number of intercrystalline mesopores increased,and a pure ZSM‐11zeolite phase was present.Then an MCM‐41‐like phase was produced and embedded in the ZSM‐11zeolite phase.Finally,an MCM‐41‐like phase was obtained.The alkalinity had important effects on the physicochemical and textural properties of the prepared samples.A possible mechanism of formation of the hierarchical ZSM‐11zeolite was proposed on the basis of a combination of various characterization results.The role of CTAB varied depending on the R value,and it showed a capping effect,micellar effect,and template effect.These effects of CTAB were synergetic in ZSM‐11synthesis,but they were competitive with the structure‐directing effect of TBABr.In addition,the impact of the acidic properties and porosities of the hierarchical ZSM‐11catalysts on their performances in the alkylation of benzene with dimethyl ether was investigated.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
基金Supported by Innovation Fund Project of Ministry of Science and Technology(10C26213201183)~~
文摘[Objective] The paper was to study the dynamic adsorption of microwave modified attapulgite on micro-polluted phenol wastewater. [Method] Cetyl trimethyl ammonium bromide （CATB） modified attapulgite was used to modify attapulgite, and conducted dynamic test on micro-polluted phenol wastewater. The dynamic charac- teristics of phenol removal were also studied. [Result] Attapulgite modified by CATB has strong adsorption ability on phenol in micro-polluted water, the phenol removal rate increased with the decrease of flow rate of wastewater. When pH value was 6- 8, phenol concentration in wastewater was 17.74 mg/L, flow rate was 2 m/s and ad- sorption time was 25 rain, the removal rate reached 93.07%. The modified atta- pulgite could be regenerated with alkali, and its adsorption ability after regeneration had no obvious decline. The dynamic adsorption process of phenol accorded with the first-order kinetic equation. [Conclusion] The study provided basis for further study on ＂organic matter removal in wastewater.
基金Supported by Tianjin Science and Technology Committee (No. 033604711)Science and Technology Foundation of Ministry of Housing and Urban-Rural Development of the People’s Republic of China (MOHURD) (No. 03-2-064)
文摘Photocatalytic reduction of 6-chloro-3-nitrotoluene-4-sulfonic acid (CNSA) was studied in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. A mixture of CNSA, TiO2, water, additives and surfactants was put into a quartz glass reactor with a jacket, which was irradiated with a high pressure Hg lamp in the purging of nitrogen gas. With methanol, the conversion of CNSA increased from 7.7% to 34.6%. Three surfactants significantly promoted the photocatalytic reduction conversion in reduced order of sodium dodecylbenzenesulfonate (DBS), cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS). In suspensions involving DBS and CTAB respectively, CNSA conversion increased in consistence with the adsorption ratio with methanol, but varied inversely with the adsorption ratio without methanol. But no obvious influence on the adsorption ratio was observed with or without methanol added when the SDS concentration was critical micelle concentration (cmc). The photocatalytic reduction of CNSA was enhanced in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. Methanol inhibited the recombination of photogenerated holes and electrons efficiently. Surfactants around 1 cmc led to the highest reduction conversion.
