Titanosilicalites (MFI-type): Composition, statistical and local structure, catalytic properties

This article presents the results of a study of three commercial titanosilicalites (TS-1, TS-1N, TS-1G) with general formula [(TixSi12-x)O24] × wH2O (MFI-type) using the X-ray study (XRPD), IR spectroscopy (FT-IR), X-ray absorption spectroscopy (EXAFS/XANES), differential scanning calorimetry (DSC), Brunauer–Emmett–Teller method (BET), UV-VIS spectroscopy. It was established that the samples contain amorphous oxygenous titanium-containing formations, which does not allow the use of quantitative elemental methods of analysis to determine the content of titanium ions in the framework. The full-profile Rietveld method was used to determine the silicate modules (Si/Ti = 53 for TS-1, Si/Ti~47 for TS-1N and TS-1G) and the coordination numbers of titanium: CNTi~5.0, CNTi = 4.5, CNTi>5.0, respectively in the structures of TS-1, TS-1N, TS-1G. The distribution of Ti4+ ions over the sites of the MFI-type structure with the orthorhombic symmetry (space group Pnma, z = 8) were found: T2, T6, T10 for TS-1, T8, T10, T5 (unlikely) for TS-1N (Т10 double positions in sinusoidal channels) and Т2, Т10, Т12, Т9 (unlikely) for TS-1G (Т10 and Т12 double positions in sinusoidal channels). The best indicators of the allyl chloride epoxidation in the epichlorohydrin process at 30 °C were achieved for TS-1N and TS-1G. A higher yield of acetaldehyde was found on the TS-1(75) sample (TS-1 sample annealed at 75 °C for 2 h) at 290 °C (non-oxidative ethanol conversion), and ethylene - on the TS-1G(500) sample (TS-1G annealed at 500 °C for 2 h) at 700 °C (propane conversion). The revealed correlations between the catalytic parameters and the characteristics of the samples studied were discussed. © 2021

Авторы
Kuz'micheva G.M. 1 , Svetogorov R.D. 2 , Khramov E.V. 2 , Kravchenko G.V.1 , Bruk L.G.1 , Pastukhova Z.Y.1 , Мarkova E.B. 3 , Zhukova A.I. 3 , Chuklina S.G. 1 , Dorokhov A.V.1
Издательство
Elsevier B.V.
Язык
Английский
Статус
Опубликовано
Номер
111377
Том
326
Год
2021
Организации
  • 1 MIREA-Russian Technological UniversityMoscow 119454, Russian Federation
  • 2 National Research Center “Kurchatov Institute”Moscow 123182, Russian Federation
  • 3 Peoples Friendship University of Russia RUDN University (RUDN)Moscow 117198, Russian Federation
Ключевые слова
Composition; Crystal structure; Full-profile Rietveld method; Titanium-containing zeolites; XAS
Дата создания
16.12.2021
Дата изменения
16.12.2021
Постоянная ссылка
https://repository.rudn.ru/ru/records/article/record/76605/
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