The structure of glycerol in the liquid state: a neutron diffraction study

Neutron diffraction coupled with hydrogen/deuterium isotopic substitution has been used to investigate the structure of the pure cryoprotectant glycerol in the liquid state at 298 K and 1 atm. The neutron diffraction data were used to constrain a 3 dimensional computational model that is experimentally relevant using the empirical potential structure refinement (EPSR) technique. These simulations lead to a model structure of the glycerol molecule that is consistent with the experimental data. Interestingly, from interrogation of this structure, it is found that the number of hydrogen bonds per molecule is larger than had previously been suggested. Furthermore, converse to previous work, no evidence for intra-molecular hydrogen bonds is found. These results highlight the importance and relevance of using experimental data to inform computational modelling of even simple liquid systems.