The efficient separation of styrene(ST)and ethylbenzene(EB)remains a significant challenge in the petrochemical industry due to their similar physical properties and kinetic molecular sizes.In this study,we cleverly u...The efficient separation of styrene(ST)and ethylbenzene(EB)remains a significant challenge in the petrochemical industry due to their similar physical properties and kinetic molecular sizes.In this study,we cleverly utilized the voids of a fluorescent flexible hydrogen-bonded organic framework(X-HOF-10)constructed from a pure organic phenothiazine derivative with three cyano groups(PTTCN)to selectively adsorb and separate ST and EB based on their slight size difference.Single crystal structure analysis and fluorescence spectra reveal that the adsorption process of ST involves a gate-opening mechanism accompanied by a fluorescent color switch behavior.Upon simple heating,ST can be released from the voids through a gate-closing process.Conversely,exposure to EB vapor does not promote X-HOF-10a to adsorb EB due to its slightly larger size in comparison with ST,facilitating a single crystal to single crystal transition,leading to the formation of a new non-porous crystal without EB.Under equimolar vapor condition,X-HOF-10a transforms into X-HOF-10 rather than X-HOF-11 owing to the superior stability of X-HOF-10over X-HOF-11,accompanied by selective adsorption of ST.The purity of ST can reach 92%after release from the framework,which further increases to over 98%when exposed to the mixed vapor containing 90%ST.Additionally,this HOF material exhibits recyclability without any discernible loss in performance.展开更多
基金supported by the Scientific Research Foundation of Tianjin Normal University(No.5RL151)the Tianjin Research Innovation Project for Postgraduate Students(No.2022SKY252)+1 种基金the National Natural Science Foundation of China(NSFC,Nos.22265026,22002108)the Project of Qinghai Science&Technology Department(No.2024-ZJ-935)。
文摘The efficient separation of styrene(ST)and ethylbenzene(EB)remains a significant challenge in the petrochemical industry due to their similar physical properties and kinetic molecular sizes.In this study,we cleverly utilized the voids of a fluorescent flexible hydrogen-bonded organic framework(X-HOF-10)constructed from a pure organic phenothiazine derivative with three cyano groups(PTTCN)to selectively adsorb and separate ST and EB based on their slight size difference.Single crystal structure analysis and fluorescence spectra reveal that the adsorption process of ST involves a gate-opening mechanism accompanied by a fluorescent color switch behavior.Upon simple heating,ST can be released from the voids through a gate-closing process.Conversely,exposure to EB vapor does not promote X-HOF-10a to adsorb EB due to its slightly larger size in comparison with ST,facilitating a single crystal to single crystal transition,leading to the formation of a new non-porous crystal without EB.Under equimolar vapor condition,X-HOF-10a transforms into X-HOF-10 rather than X-HOF-11 owing to the superior stability of X-HOF-10over X-HOF-11,accompanied by selective adsorption of ST.The purity of ST can reach 92%after release from the framework,which further increases to over 98%when exposed to the mixed vapor containing 90%ST.Additionally,this HOF material exhibits recyclability without any discernible loss in performance.
