Ball milling modification was performed on Cs/X catalysts before or after cesium ion exchange.Multiple characterization results(such as pyridine-FTIR,XPS,and solid-state NMR)demonstrated that ball milling played a dis...Ball milling modification was performed on Cs/X catalysts before or after cesium ion exchange.Multiple characterization results(such as pyridine-FTIR,XPS,and solid-state NMR)demonstrated that ball milling played a distinct role in these two different preparation procedures of the catalyst.Ball milling performed after the cesium modification has a strong influence on the Cs/X structure and acid-base properties,which results in the enhancement of the catalytic performance for side-chain methylation of toluene with methanol.Detailed studies revealed that ball milling intensified the interactions between oxides and molecular sieves,which not only increased the dispersion of the Cs species but also generated some weaker basic centers.It is proposed that the new basic centers could be Si-O-Cs and Al-O-Cs,which are produced by breaking of the Si-O-Al bonds of the zeolite framework under the synergetic effect of ball milling and alkali treatment.These new active sites may help to promote the side-chain methylation reaction.However,excessive ball milling will lead to the vanishing of zeolite micropores,thus deactivating side-chain methylation activity,which indicates that microporosity plays a key role in side-chain methylation and individual basic centers cannot catalyze this reaction.展开更多
TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,t...TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,the presence of alcohol and the temperature were carefully investigated on the crystallization process.The high alkalinity was proved to be highly important for the preservation of the microsphere morphology initially formed,due to the unique intergrown stacking style.An alkali treatment with the aqueous solution of structure-directing agent,organic amine and ammonium salt and subsequent Na+ion-exchange were performed to enhance the catalytic activity of TS-2 microsphere in the cyclohexanone ammoximation reactions,with both the conversion and selectivity higher than 99%.In the continuous reaction,the TS-2 microspheres exhibited to be durable catalyst with potential application in industrial ammoximation processes.展开更多
Ammoides verticillata （Desf.） Briq. is an Algerian endemic species; the phytochemical screening （methods of Harborne, 1973） of the aerials parts wealth in polyphenol compounds： flavonoids, saponins, leucoanthocya...Ammoides verticillata （Desf.） Briq. is an Algerian endemic species; the phytochemical screening （methods of Harborne, 1973） of the aerials parts wealth in polyphenol compounds： flavonoids, saponins, leucoanthocyanes, terpens and steroids and tannins; there is no alkaloids. There is an important quantity of essential oils in the flowers; the interest of this study is that this species remains until then it is not very known. The results of Aromatogram method by incorporation of Mtiller-Hinton on solid medium, showed a significant antimicrobial activity （method of Duraffourd, 1987） of the infusion and the ethanolic extract; the infusion of stems and flowers is indeed much more active on Echerichia coli, Citrobacter, Enterobacter, Staph aureus and Staph epidermidis, such as flowers extracts demonstrate an important antimicrobial activity on Staph aureus, Staph epidermidis, Streptococcus, Pseudomonas and Acinetobacter recognized as antibiotic resistant. This could give opportunities for using this species in the treatment of diverse infections and as a disinfecting additive on nosocomial area. The valorization, preservation and sustainable use ofAmmoides verticillata require the protection of its habitats.展开更多
文摘Ball milling modification was performed on Cs/X catalysts before or after cesium ion exchange.Multiple characterization results(such as pyridine-FTIR,XPS,and solid-state NMR)demonstrated that ball milling played a distinct role in these two different preparation procedures of the catalyst.Ball milling performed after the cesium modification has a strong influence on the Cs/X structure and acid-base properties,which results in the enhancement of the catalytic performance for side-chain methylation of toluene with methanol.Detailed studies revealed that ball milling intensified the interactions between oxides and molecular sieves,which not only increased the dispersion of the Cs species but also generated some weaker basic centers.It is proposed that the new basic centers could be Si-O-Cs and Al-O-Cs,which are produced by breaking of the Si-O-Al bonds of the zeolite framework under the synergetic effect of ball milling and alkali treatment.These new active sites may help to promote the side-chain methylation reaction.However,excessive ball milling will lead to the vanishing of zeolite micropores,thus deactivating side-chain methylation activity,which indicates that microporosity plays a key role in side-chain methylation and individual basic centers cannot catalyze this reaction.
文摘TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,the presence of alcohol and the temperature were carefully investigated on the crystallization process.The high alkalinity was proved to be highly important for the preservation of the microsphere morphology initially formed,due to the unique intergrown stacking style.An alkali treatment with the aqueous solution of structure-directing agent,organic amine and ammonium salt and subsequent Na+ion-exchange were performed to enhance the catalytic activity of TS-2 microsphere in the cyclohexanone ammoximation reactions,with both the conversion and selectivity higher than 99%.In the continuous reaction,the TS-2 microspheres exhibited to be durable catalyst with potential application in industrial ammoximation processes.
文摘Ammoides verticillata （Desf.） Briq. is an Algerian endemic species; the phytochemical screening （methods of Harborne, 1973） of the aerials parts wealth in polyphenol compounds： flavonoids, saponins, leucoanthocyanes, terpens and steroids and tannins; there is no alkaloids. There is an important quantity of essential oils in the flowers; the interest of this study is that this species remains until then it is not very known. The results of Aromatogram method by incorporation of Mtiller-Hinton on solid medium, showed a significant antimicrobial activity （method of Duraffourd, 1987） of the infusion and the ethanolic extract; the infusion of stems and flowers is indeed much more active on Echerichia coli, Citrobacter, Enterobacter, Staph aureus and Staph epidermidis, such as flowers extracts demonstrate an important antimicrobial activity on Staph aureus, Staph epidermidis, Streptococcus, Pseudomonas and Acinetobacter recognized as antibiotic resistant. This could give opportunities for using this species in the treatment of diverse infections and as a disinfecting additive on nosocomial area. The valorization, preservation and sustainable use ofAmmoides verticillata require the protection of its habitats.
