Synthesis of vinyl polymers substituted with 2-propanol and acetone and investigation of their reversible hydrogen storage capabilities

Developing a safe hydrogen carrier without the risks of high pressures and toxicities is an issue of significant urgency. In this study, we prepared a polymeric hydrogen carrier with high thermal stability by incorporating 2-propanol and acetone units into polymers. Poly(methyl vinyl ketone) with a high molecular weight (~10⁵) was synthesized via bulk polymerization of methyl vinyl ketone and then dehydrogenated in one step to give poly(3-buten-2-ol) in high yield. Reversible hydrogen fixation and release by these polymers were achieved with full conversion under mild conditions (80–180 °C, ≦3 atm hydrogen pressure). A simple temperature-dependent hydrogenation/dehydrogenation cycle that operated at temperatures higher than the boiling points of 2-propanol and acetone in the presence of an iridium complex catalyst was established by virtue of having these groups as pendants of the vinyl chain, with a compact repeating unit to maximize the mass hydrogen storage density of 2.8 wt%.