Tuning the cross-linked structure of basic poly(ionic liquid) to develop an efficient catalyst for the conversion of vinyl carbonate to dimethyl carbonate

ABSTRACT Dimethyl carbonate (DMC) is a crucial chemical raw material widely used in organic synthesis, lithium-ion battery electrolytes, and various other fields. The current primary industrial process employs a conventional sodium methoxide basic catalyst to produce DMC through the transesterification reaction between vinyl carbonate and methanol. However, the utilization of this catalyst presents several challenges during the process, including equipment corrosion, the generation of solid waste, susceptibility to deactivation, and complexities in separation and recovery. To address these limitations, a series of alkaline poly(ionic liquid)s, i.e.  [DVBPIL][PHO], [DVCPIL][PHO], and [TBVPIL][PHO], with different cross-linking degrees and structures, were synthesized through the construction of cross-linked polymeric monomers and functionalization. These poly(ionic liquid)s exhibit cross-linked structures and controllable cationic and anionic characteristics. Research was conducted to investigate the effect of the cross-linking degree and structure on the catalytic performance of transesterification in synthesizing DMC. It was discovered that the appropriate cross-linking degree and structure of the [DVCPIL][PHO] catalyst resulted in a DMC yield of up to 80.6%. Furthermore, this catalyst material exhibited good stability, maintaining its catalytic activity after repeated use five times without significant changes. The results of this study demonstrate the potential for using alkaline poly(ionic liquid)s as a highly efficient and sustainable alternative to traditional catalysts for the transesterification synthesis of DMC.