Zinc(II)-pyridine-2-carboxylate / 1-methyl-imidazole: a binary catalytic system for in the synthesis of cyclic carbonates from carbon dioxide and epoxides

Abstract

A new "halogen-free" binary catalytic system for the synthesis of cyclic carbonate from epoxides and carbon dioxide is described. The catalysis relies on a synergy between the main catalyst, zinc(II) pyridine-2-carboxylate, and a Lewis base, 1-methyl imidazole. In this preliminary study four epoxides have been tested and the operating capabilities of this system have been evaluated. Using propylene oxide as test substrate and performing the catalysis in a high-pressure NMR tube, allowed us to gather some spectroscopic information on this catalytic system and to propose a reaction mechanism.

Synthesis of cyclic carbonates from epoxides and carbon dioxide catalyzed by an easy-to-handle ionic iron(iii) complex

“…They are ranging from complexes of the "less toxic" zinc and aluminium to the more problematic tin, cobalt and chromium. [11][12][13] The two latter metals are currently the most promising candidates despite a high toxicity causing an effective separation of the catalyst to be paramount.…”

Simple halogen-free synthesis of aryl cinnamates using Mo-Keggin heteropoly acids as catalyst

“…In this way, chlorine-free conditions in organic synthesis have been developed in various strategies replacing thionyl chloride (avoiding the acyl chloride preparation step); for example, acylation by means of Friedel-Craft reaction [8][9][10][11][12], synthesis of carbamates [13,14], cyclic carbonates [15,16], and urethanes [17].…”