Regioselectivity was visualised using diffusion-edited 1 H NMR and the crystallinity of the 6 d samples were visualised using WAXS. DS values and crystallinity details are in the SI (Table -3). As acid-catalysed methods of liquid-state acetylation are already well studied and known to lead to CTA, we focused on non-catalysed (pure Ac2O), pyridine catalysed and DABCO-catalysed liquid-state reactions, for comparison with the gas-phase reaction.