Reactions of cis- and trans-2-butene adsorbed on deuterated ZSM-5 and mordenite were studied by IR spectroscopy below 300 K. 2-butene molecules hydrogen-bonding to Bronsted acid sites (OD) reacted when the temperature was increased above 250 and 230 K on D-ZSM-5 and D-mordenite, respectively. H/D isotope exchange reaction of Bronsted acidic hydroxy groups accompanied the isomerization of cis- to trans-2-butene, and then dimerization of trans-2-butene followed on ZSM-5, while rapid formation of paraffinic alkoxy groups was dominantly observed on mordenite.