Commercial routes for the manufacture of methyl methacrylate monomer have recently been developed that involve the reaction of esters over modified silicas, which are amphoteric in nature. Despite the successful industrialisation of this technology, surprisingly little is known as to how exactly the ester molecules (e.g. methyl proprionate) actually interacts with the substrate. IR studies are currently underway at the academic centre but these are frustrated due to a spectral cut-off below 1300 cm-1. This proposal seeks to use MAPS to obtain the momentum transfer dependence of specific low wavenumber modes on a number of modified silicas. In particular it will permit access to methyl rock and torsional modes inaccessible in the IR studies. A linked application for TOSCA seeks to exploit the high spectral resolution available with that instrument in the 50-800 cm-1 range.