Effect of Acid Treatment on Silica-Titania Aerogel as Oxidative-Acidic Bifunctional Catalyst

Abstract:

Acid treatment using H₂SO₄, HCl and H₃PO₄ has been carried out in an attempt to improve catalytic performance of silica-titania aerogel. X-ray diffraction results showed the amorphous structure of the aerogels remained after the acid impregnation and calcinations steps. Hammert analysis revealed these acid modified silica-titania aerogels were superacids with pKa < -14.52. Different Ti species was observed in the samples upon the acid treatment. As compared to silica-titania aerogel, Lewis acidity increased remarkably in HCl treated sample without formation of any Brønsted acid site. Meanwhile, H₂SO₄ and H₃PO₄ treated samples possessed both Lewis and Brønsted acid sites. The catalytic performance of these samples was evaluated through a consecutive transformation of 1-octene to 1,2-octanediol through the formation of 1,2-epoxyoctane using aqueous hydrogen peroxide as oxidant.

• Periodical: Applied Mechanics and Materials (Volumes 110-116)
• Pages: 457-464
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.110-116.457
• Online since: October 2011
• Authors: Siew Ling Lee, Hadi Nur, Soo Chien Wei
• Keywords: Acid, Bifunctional, Brönsted Acidity, Catalyst, Oxidative, Silica-Titania Aerogel

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