Towards molecular sieve inorganic catalysts that are akin to enzymes: studies of a selective cyclo-dimerization over ferrierite at ambient temperature

The solid-acid (Bronsted)-catalyzed cyclo-dimerization of 3-hydroxy-3-methy lbutan-2-one (HMB) over a synthetic ferrierite molecular sieve is reported. HMB is a stable liquid at ambient temperatures but in acidic solutions it readily undergoes reaction to generate a variety of products. However. in t he acidic molecular sieve catalyst studied here, only one product - the cyc lic dimer (proven by in situ solid state C-13 NMR and other evidence) - is observed, together with some unreacted HMB. A plausible, proton-catalyzed m echanism is proposed, and prompts comparison between the cyclo-dimerization of HMB within ferrierite and the mode of action of certain enzymes.