Direct preparation of styrene carbonates from styrene using an ionic-liquid-based one-pot multistep synthetic process

One-pot synthesis of styrene carbonate from styrene is investigated using a multistep protocol in the presence of an ionic-liquid-based catalytic system that is consisted of MTO/UHP/Zn[EMIm]2Br4/[BMIm]BF4. Owing to the multistep operations and the compatibility of MTO and Zn[EMIm]2Br4 in ionic liquid, remarkable improvements of the reaction performance regarding the reaction of one-pot synthesis of styrene carbonate from styrene have been achieved. Compared to other methods reported previously concerning this reaction, the current approach can increase the yield of styrene carbonate to 83%. Other improvements such as better utilization percentage of oxidant, easy separation of product and reusability of ionic liquid can also be obtained.

An ionic-liquid-based one-pot multistep process was investigated for direct synthesis of styrene carbonate from styrene. The whole method was consisted of Methyltrioxorhenium catalyzed epoxidation of styrene with urea hydrogen peroxide to styrene oxide using ionic liquid as solvent in the beginning, and then followed by coupling reaction of styrene oxide with CO2 by addition of ZnBr2/ionic liquid as catalyst, and ended with separation of styrene carbonate by m-xylene extraction and recycling of ionic liquid after retrieved by CH2Cl2 extraction. A 65% yield of styrene carbonate, the highest one reported so far for this reaction, was obtained, and some other advantages such as higher efficiency of oxidant utilization, easy separation of product and recyclability of ionic liquid were also achieved.Figure optionsDownload as PowerPoint slide