Abstract
Various types of mesoporous silica were used as carriers to synthesize a series of immobilized imidazolium-based ionic liquids. Their activity was tested in the synthesis of styrene carbonate from CO2 and styrene. This is one-pot process, whereby two stages are carried out in one reactor and there is no need to isolate the intermediate product, epoxide. A systematic study on the influence of parameters such as temperature, the reaction time, CO2 pressure, as well as the amount and type of catalyst used was carried out. A strong synergistic catalytic effect of ionic liquid and Lewis acid was observed in promoting this reaction. The addition sequence of regents and amount of immobilized catalyst were considered crucial for the synthesis of styrene carbonate from CO2 and styrene. The tested silica-supported ionic liquids gave an easily-recyclable system which under the most favorable conditions ([mtespim]Cl/@SiO2; ZnBr2, 0.1 mol%; 110 °C, 4 h, 1 MPa) can be reused without a significant loss of catalytic activity nor selectivity.
Highlights
Five-membered ring cyclic carbonates are widely used as, among other purposes, polar aprotic high boiling solvents for natural and synthetic polymers, in the production of polyacrylic fibers, selective solvents in separation processes, electrolytes in the production of batteries, or starting materials for the production of polycarbonates and intermediates for many useful chemicals [1,2].On an industrial scale, these compounds are mainly obtained by the 100% atom-economic reaction of carbon dioxide with an epoxide
The synthesis of ionic liquids covalently bound to a silica support was performed according to
The obtained ionic liquids were anchored onto solid support (Scheme 1)
Summary
Five-membered ring cyclic carbonates are widely used as, among other purposes, polar aprotic high boiling solvents for natural and synthetic polymers, in the production of polyacrylic fibers, selective solvents in separation processes, electrolytes in the production of batteries, or starting materials for the production of polycarbonates and intermediates for many useful chemicals [1,2].On an industrial scale, these compounds are mainly obtained by the 100% atom-economic reaction of carbon dioxide with an epoxide. Epoxidation of terminal olefins takes place, and in the second, the in situ formed epoxide reacts with CO2 The advantage of this method is that both process steps can take place in one reaction vessel (one-pot synthesis), so there is no need to isolate and purify the resulting intermediate product, which is the epoxide. Great emphasis is placed on the search for active and selective catalysts, and on those that can be separated from the reaction mixture. In this regard, the immobilization of homogeneous catalysts on the surface of organic or inorganic supports are of particular interest. Examples of the use of immobilized catalysts in the direct synthesis of cyclic carbonates can be found in the literature [18,19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
