Poly(ionic liquid)s as efficient catalyst in transformation of CO2 to cyclic carbonate

• We synthesized a novel kind of urethane-based poly(ionic liquid)s (PILs).
• The new PILs were used as catalyst in CO2 transformation.
• The variation of PILs composition influences their properties and catalytic activity.
• The PILs were effective catalysts at mild conditions of 25 bar, 110 °C and 6 h.
• The PILs can be easy separated when compared to ionic liquids and recycled without loss of catalytic activity.

A new kind of urethane-based poly(ionic liquid)s (PILs) was synthesized by the addition of diisocyanate to a difunctional polyol and diol mixture, which then went through an exchange reaction with the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]). Different PILs were attained by means of the addition of diethanolamine, hydrazine and ethylenediamine as chain extenders, and in the course of the variation of the polyol’ molecular weight. Such materials were used as catalysts in the cycloaddition of CO2 to epoxide and obtain cyclic carbonate. The effects that the variations carried out with the PILs composition is as catalysts in its performance, as the catalytic reaction parameters (temperature, pressure & time) were investigated just as well. The results demonstrate that the variation of PILs compositions influence their physical and thermal properties, along with its catalytic activity. A higher CO2 conversion was obtained by extending PIL with ethylenediamine (PUEA BMIM) at mild conditions of 25 bar, 110 C and 6 h, which can be easily separated and recycled without the loss of catalytic activity.

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