A High Pressure Study of Para-Xylene

This proposal will explore the effect of elevated pressure on para-xylene. It is a raw material in the large scale synthesis of various polymers, including polyethylene terephthalate (PET).Recently p-xylene was crystallised and polymerised under high pressure. No structural details were obtained. We are proposing a careful high-pressure neutron diffraction study on p-xylene under quasi-hydrostatic conditions, with the aims of (i) identifying the evolution of structure as a function of pressure, including the changes in intermolecular interactions, (ii) to solve the structure of the monoclinic phase that was obtained by pressure-induced crystallisation at room temperature; iii) to study pressure induced polymerisation. These experimental results will be compared with the outputs from DFT-D calculations. These results will provide an enhanced understanding of the behaviour of p-xylene.