Sulfonic acid functionalised periodic mesoporous organosilicas (PrSO3 H-PMOs) with tunable hydrophobicity were synthesised via a surfactant-templating route, and characterised by porosimetry, TEM, XRD, XPS, inverse gas chromatography (IGC) and ammonia pulse chemisorption. IGC reveals that incorporation of ethyl or benzyl moieties into a mesoporous SBA-15 silica framework significantly increases the non-specific dispersive surface energy of adsorption for alkane adsorption, while decreasing the free energy of adsorption of methanol, reflecting increased surface hydrophobicity. The non-specific dispersive surface energy of adsorption of PMO-SO3H materials is strongly correlated with their activity towards palmitic acid esterification with methanol, demonstrating the power of IGC as an analytical tool for identifying promising solid acid catalysts for the esterification of free fatty acids. A new parameter [-ΔGCNP-P], defined as the per carbon difference in Gibbs free energy of adsorption between alkane and polar probe molecules, provides a simple predictor of surface hydrophobicity and corresponding catalyst activity in fatty acid esterification.
|Number of pages||7|
|Early online date||23 Feb 2014|
|Publication status||Published - 1 Oct 2014|
|Event||2nd international congress on Catalysis for Biorefineries - Dalian, China|
Duration: 22 Sept 2013 → 25 Sept 2013
Bibliographical noteFunding: EPSRC (EP/K000616/1, EP/F063423/1 and EP/G007594/3) and a Leadership Fellowship; and the Royal Society for the award of an Industry Fellowship.
- solid acid
- free fatty acid esterification
- periodic mesoporous organic materials
- inverse gas chromatography