Kinetic studies of zeolite-catalyzed methylation reactions1. Coreaction of [12C]ethene and [13C]methanol

Methylation of benzene by methanol: Single-site kinetics over H-ZSM-5 and H-beta zeolite catalysts

“…Product and isotopic selectivities apparently do not extrapolate to unity, implying that reactions other than methylation will occur even at infinitesimal conversions. Possible causes of this observation have been discussed previously [17].…”

“…Notably, this is the same H-ZSM-5 catalyst as employed in our previous studies of the methylation of alkenes [17,18]. These catalysts were selected due to similarities with respect to crystal size and acid site density.…”

“…A description of the experimental setup has been given in a previous paper [17,18]. Briefly, all kinetic measurements were carried out at atmospheric total pressure using a 3 mm inner diameter fixed bed reactor.…”

“…In every catalytic cycle proposed to date to explain olefin formation, methylations were found to be key reaction steps [14][15][16]. For these reasons methylations have received a lot of attention in several recent studies, in which they were examined from both an experimental and a theoretical angle [17][18][19][20][21].…”

“…Obtaining detailed information about any individual reaction is therefore non-trivial from an experimental point of view, as the rate of a single reaction is not easily monitored. Svelle et al first accomplished this for specific methylation reactions of alkenes by methanol on zeolite H-ZSM-5 [17,18], and more recently Hill et al performed an experimental study on the kinetics of alkene methylation by dimethyl ether on zeolites H-ZSM-5, H-beta, H-ferrierite, and H-mordenite [22], but in general experimental kinetic measurements of isolated zeolite-catalyzed reactions are rarely reported.…”