Changes in the percentage conversion (C) and ee (%) values for PREPs with time. Citronellol and vinyl acetate were taken in the 1:6 (mol/mol) ratio in the screw-capped vials. The PREPs, both anhydrous and hydrated by 0.75% water (v/v), (10%, w/w reactants) were used. The vials were incubated at 30°C at 200 rpm. Each point represents the outcome of a pair of readings, which differed by less than 3%, with many points showing errors which are smaller than the symbols.