Control of zeolite pore interior for chemoselective alkyne/olefin separations
A strategy to control the pore interior of faujasite zeolites by the confinement of isolated open nickel(II) sites in their six-membered rings is reported, which unlocked their potential in challenging industrial separations.
Abstract
<jats:title>Zeolites that prefer alkynes</jats:title> <jats:p> Alkenes such as ethylene and propene must be separated from alkynes before they can be converted in polymers. Drawbacks in current methods, such as hydrogenation of alkynes producing unwanted alkanes, has spurred interest in sorption separation methods. Zeolites have generally been inefficient, given the similar sizes and volatilities of the molecules. Chai <jats:italic>et al.</jats:italic> incorporated atomically dispersed divalent transition metal cations into faujasite zeolite and found that the nickel-containing analog efficiently removed alkynes from olefins through chemoselective binding at open nickel(II) sites. At ambient conditions in the presence of water and carbon dioxide, the zeolites retained separation selectivities of 100 and 92, respectively, for acetylene over ethylene and propyne over propylene for 10 adsorption-desorption cycles. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6494" page="1002" related-article-type="in-this-issue" vol="368" xlink:href="10.1126/science.aay8447">1002</jats:related-article> </jats:p>