Infrared Spectroscopy Studies on sol-gel prepared alumina Powders

Abstract

Gamma-alumina fine particles were synthesized by sol-gel process. Aluminum tri-sec-butoxide (ATB), anhydrous ethyl alcohol (EtOH), water (H 2 O) and hydrochloric acid (HCl) were used as starting materials. Different samples were synthesized with EtOH/ATB = 60/1, HCl/ATB = 0.08/1 and H 2 O/ATB = 1/1 ratios and calcined at different temperatures. Molar ratios of H 2 O/ATB (from 1 to 25) and HCl/ATB (from 0.08 to 0.4) were changed for some other samples, during the synthesizing process. The products were characterized by both XRD and FTIR measurements. Studies were carried out on the effect of calcination temperature and change of H 2 O/ATB and HCl/ATB ratios on structure and processes involved in phase transformations.

A magnetically separable SO4/Fe-Al-TiO2 solid acid catalyst for biodiesel production from waste cooking oil

“…These features are consistent with polynuclear sulphates S2O7 2or S3O10 2- [56], presumably arising from the chlorosulfonic acid dimerization ( Figure S10) prior to surface sulfation. The bands in the region of ~550 to 780 cm -1 in Fe-Al-TiO2 and SO4/Fe-Al-TiO2 likely arise from M-O-M bridging stretches [30,57], and the broad band between 3050-3800 cm -1 to surface surface hydroxyls [20,39,55,58] whose presence has been reported to enhance catalytic activity [59]. FTIR thus confirms successful sulfation of Fe-Al-TiO2 particles.…”