Page - 117 - in Advanced Chemical Kinetics

recorded the absence of Brønsted acid sites in similar alumina systems, results whichwere further confirmed by their infrared studies, for example, by Lianecki et al. [24] and byXRD studies byHeracleous et al. [25]. It has beenproposedbyGong et al. [26] that as long as the loadingofMoO3onγ-Al2O3 is less than16% (w/w), thenature of surface acid-base sites that existon thesurfacewouldbepredominantlyof theLewis type. 3.2.Reactioncontrol:kinetic studies 3.2.1.The effect of base as a reaction initiator Catalyst testingcommencedwithinvestigatingtheeffectofNaOHasareactioninitiatoronthe kinetics of glycerol oxidation usingMintek’s 0.9-wt%Au/γ-Al2O3 (AUROlite TM) commercial catalyst.Figure2displaysaplotdepictingglycerol conversionasa functionof time indicating thathigherbaseconcentrations led togreaterglycerol conversions therebyshorteningreaction time. Ithas indeedbeenpreviously reported that thebaseactsan initiator for this reaction [5]. 3.2.2.Mass transfer limitations In order to optimise the reaction conditions for mass transfer, a number of influencing parameters, e.g. stirring speed, oxygen partial pressure, amount of catalyst and the initial Figure1. Qualitativeanalysisof thecatalyst’sacidityby theNH3-TPDmethod. Oxidation of Glycerol to Lactic Acid by Gold on Acidified Alumina: A Kinetic and DFT Case Study http://dx.doi.org/10.5772/intechopen.70485 117