Inter-connected and open pore hierarchical TS-1 with controlled framework titanium for catalytic cyclohexene epoxidation

Yilai Jiao, Abdul Lateef Adedigba, Qian He, Peter Miedziak, Gemma Brett, Nicholas F. Dummer, Micheal Perdjon, Jinmin Liu, Graham J. Hutchings*

*Awdur cyfatebol y gwaith hwn

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

Crynodeb

A post-synthesis method was developed to reduce the extra-framework titanium (Ti) in TS-1 zeolites (Si/Ti ratio = 50), in which tetrapropylamonium hydroxide (TPAOH) aqueous solution was used to promote the dissolution, redistribution and recrystallization processes, and hence to convert amorphous Ti species into zeolitic phases. It was found that TPAOH could effectively convert the extra-framework Ti into framework Ti, and the TPAOH concentration influenced the pore structure significantly. Under lower TPAOH concentration (i.e. 0.05-0.4 M), only closed meso-/macropores (grooves and hollow cavities) can be created in the TS-1 crystals. At an optimum concentration of 0.5 M TPAOH, open and connected hierarchical mesopores and macropores were created in the resulting TS-1 zeolites. Compared with the parent TS-1, the amount of extra-framework titanium was reduced significantly from 14.4% to 0.3% and the meso-/macropore volume was increased from 0.014 to 0.168 cm3 g-1 accordingly upon TPAOH post treatment. Along with the parent TS-1 zeolite, the developed hierarchical TS-1 zeolites were assessed in the catalytic epoxidation of cyclohexene. It was confirmed that the amount of framework titanium and hierarchical pore structure influenced the catalytic activity considerably. Closed porosity slightly improved the cyclohexene conversion, whereas the open-pore sample shows the optimum catalytic activity in cyclohexene conversion.

Iaith wreiddiolSaesneg
Tudalennau (o-i)2211-2217
Nifer y tudalennau7
CyfnodolynCatalysis Science and Technology
Cyfrol8
Rhif cyhoeddi8
Dyddiad ar-lein cynnar29 Maw 2018
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsE-gyhoeddi cyn argraffu - 29 Maw 2018
Cyhoeddwyd yn allanolIe

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