En Route to CO2-Based (a)Cyclic Carbonates and Polycarbonates from Alcohols Substrates by Direct and Indirect Approaches

Abstract

This review is dedicated to the state-of-the art routes used for the synthesis of CO2-based (a)cyclic carbonates and polycarbonates from alcohol substrates, with an emphasis on their respective main advantages and limitations. The first section reviews the synthesis of organic carbonates such as dialkyl carbonates or cyclic carbonates from the carbonation of alcohols. Many different synthetic strategies have been reported (dehydrative condensation, the alkylation route, the “leaving group” strategy, the carbodiimide route, the protected alcohols route, etc.) with various substrates (mono-alcohols, diols, allyl alcohols, halohydrins, propargylic alcohols, etc.). The second section reviews the formation of polycarbonates via the direct copolymerization of CO2 with diols, as well as the ring-opening polymerization route. Finally, polycondensation processes involving CO2-based dimethyl and diphenyl carbonates with aliphatic and aromatic diols are described.

The advent of recyclable CO2-based polycarbonates

“…1,18,72 The well-established [3 + 2] coupling of CO 2 with epoxide provides a large portfolio of five-membered cyclic carbonates (5CCs) under very attractive process conditions. 22,31,73–76 These heterocycles with small ring strain are stable and their ring-opening polymerization is thermodynamically disfavored and typically accompanied by the elimination of CO 2 to deliver poly(ether- co -carbonate)s (Scheme 11a). 72 The in-chain ether linkage defects are suppressed by polymerizing five-membered cyclic carbonates fused in a trans -fashion to a six-membered ring ( trans -cyclohexene carbonate (CHC)) (Scheme 11b).…”

Efficient Propylene Carbonate Synthesis from Urea and Propylene Glycol over Calcium Oxide–Magnesium Oxide Catalysts

“…The carbonate transesterification route leads to the formation of azeotropes, making the separation of products difficult [ 4 ]. PC synthesis by carbonylation of alcohols is an environmentally friendly method, as it involves the utilization of unwanted CO 2 gas [ 16 , 17 , 18 ]. However, the thermodynamic and kinetic limitations of this route lead to low conversion and low yield of PC.…”

Visible-light driven reaction of CO2 with alcohols using a Ag/CeO2 nanocomposite: first photochemical synthesis of linear carbonates under mild conditions

“…The activation of the substrates took place through the adsorption of CO 2 and –OH of benzyl alcohol by oxygen vacant sites of CeO 2 via Lewis acid–base interactions. 15 The generation of the radicals was verified by performing a controlled experiment in the presence of TEMPO (2,2,6,6-tetramethylpiperidin-1-yl)oxyl as a radical scavenger under otherwise described conditions. No reaction occurred in the presence of TEMPO, even after 20 h of irradiation, confirming that the photocatalytic reaction was initiated by radicals.…”

“…The activation of the substrates took place through the adsorption of CO 2 and -OH of benzyl alcohol by oxygen vacant sites of CeO 2 via Lewis acid-base interactions. 15 The generation of the radicals was verified by performing a controlled experiment in the presence of TEMPO…”