Characterization of sulfated zirconias by DTA-TG and drift spectroscopy

K. Biró, F. Figueras, C. Márquez Alvarez, S. Békássy, J. Valyon

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Abstract

Sulfated zirconias were prepared either by impregnation of zirconia with sulfuric acid or by a one step sol gel process by using different solvents. Solids prepared under closely similar conditions in different solvents show different amounts of sulfur and surface areas, thus demonstrating that the crystallization is different. Clear differences occur in the DTA-DTG curves with the appearance of a composite peak for the sol-gel catalysts, whereas the solid obtained by the classical two-step technique shows only one peak. The number of acid sites of these samples is changed by a factor of 3 depending on the preparation. Two types of hydroxyls are observed by infrared spectroscopy: one with bands at 3640 and 3585 cm-1, associated with protons of moderate acidity, and a second at about 3300 cm-1 able to exchange D with C6D6. Moreover, the infrared band of sulfates also contains two components: one at 1405 cm-1 more intense for the most acidic solids and a second one at 1380 cm-1. After activation, these solids are as active as zeolite beta for the acylation of anisole with acetic anhydride.

Original languageEnglish
Pages (from-to)345-353
Number of pages9
JournalJournal of Thermal Analysis and Calorimetry
Volume56
Issue number1
Publication statusPublished - 1999

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Differential thermal analysis
thermal analysis
Spectroscopy
spectroscopy
anisole
Zeolites
acylation
Acylation
anhydrides
sol-gel processes
sulfuric acid
Crystallization
Sulfuric acid
Sulfur
zirconium oxides
Acidity
Impregnation
acidity
Zirconia
Hydroxyl Radical

ASJC Scopus subject areas

  • Chemical Engineering(all)

Cite this

Biró, K., Figueras, F., Márquez Alvarez, C., Békássy, S., & Valyon, J. (1999). Characterization of sulfated zirconias by DTA-TG and drift spectroscopy. Journal of Thermal Analysis and Calorimetry, 56(1), 345-353.

Characterization of sulfated zirconias by DTA-TG and drift spectroscopy. / Biró, K.; Figueras, F.; Márquez Alvarez, C.; Békássy, S.; Valyon, J.

In: Journal of Thermal Analysis and Calorimetry, Vol. 56, No. 1, 1999, p. 345-353.

Research output: Contribution to journalArticle

Biró, K, Figueras, F, Márquez Alvarez, C, Békássy, S & Valyon, J 1999, 'Characterization of sulfated zirconias by DTA-TG and drift spectroscopy', Journal of Thermal Analysis and Calorimetry, vol. 56, no. 1, pp. 345-353.
Biró, K. ; Figueras, F. ; Márquez Alvarez, C. ; Békássy, S. ; Valyon, J. / Characterization of sulfated zirconias by DTA-TG and drift spectroscopy. In: Journal of Thermal Analysis and Calorimetry. 1999 ; Vol. 56, No. 1. pp. 345-353.
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