Polymers Based on Cyclic Carbonates as Trait d'Union Between Polymer Chemistry and Sustainable CO₂ Utilization

Abstract

Given the large amount of anthropogenic CO2 emissions, it is advantageous to use CO2 as feedstock for the fabrication of everyday products, such as fuels and materials. An attractive way to use CO2 in the synthesis of polymers is by the formation of five‐membered cyclic organic carbonate monomers (5CCs). The sustainability of this synthetic approach is increased by using scaffolds prepared from renewable resources. Indeed, recent years have seen the rise of various types of carbonate syntheses and applications. 5CC monomers are often polymerized with diamines to yield polyhydroxyurethanes (PHU). Foams are developed from this type of polymers; moreover, the additional hydroxyl groups in PHU, absent in classical polyurethanes, lead to coatings with excellent adhesive properties. Furthermore, carbonate groups in polymers offer the possibility of post‐functionalization, such as curing reactions under mild conditions. Finally, the polarity of carbonate groups is remarkably high, so polymers with carbonates side‐chains can be used as polymer electrolytes in batteries or as conductive membranes. The target of this Review is to highlight the multiple opportunities offered by polymers prepared from and/or containing 5CCs. Firstly, the preparation of several classes of 5CCs is discussed with special focus on the sustainability of the synthetic routes. Thereafter, specific classes of polymers are discussed for which the use and/or presence of carbonate moieties is crucial to impart the targeted properties (foams, adhesives, polymers for energy applications, and other functional materials).

The Role of Water Revisited and Enhanced: A Sustainable Catalytic System for the Conversion of CO2 into Cyclic Carbonates under Mild Conditions

“…Water was an effective HBD even upon halvingi ts amount (Table1,e ntry 6), although the increase in styrene carbonatey ield was lessm arked than with 0.05 mL H 2 O. In contrast, increasing the amount of water used together with the Bu 4 NI catalyst to 0.1 mL led to afurther increasei nt he yield of styrene carbonate, reaching 29 % ( Table 1, entry 8) compared to 13 %y ield in the absence of water.F urther increase in the amount of water did not lead to higher styrene carbonate yield and gradually caused ad ecrease in the selectivity towards the cyclic carbonate product, owing to the formation of 1-phenyl-1,2-ethanediol (styrene glycol) as as ide product (Table 1, entries [9][10][11]. No other side products were observed.…”

“…This issue can be overcomeb yr eacting CO 2 with high-free-energy substrates such as H 2 ,a mines, and epoxides. [5][6][7][8][9] The cycloaddition of CO 2 to epoxides requires ac atalyst to proceed at ah igh rate under mild conditions. [5] The obtained cyclic carbonates are useful compounds finding relevant applications as intermediates for the preparation of fine chemicals and polymers, asg reen aproticp olar solvents, and as electrolytes in Li-ion batteries.…”

“…[5] The obtained cyclic carbonates are useful compounds finding relevant applications as intermediates for the preparation of fine chemicals and polymers, asg reen aproticp olar solvents, and as electrolytes in Li-ion batteries. [5][6][7][8][9] The cycloaddition of CO 2 to epoxides requires ac atalyst to proceed at ah igh rate under mild conditions. The most active catalytic systems for this reaction comprise Lewis acid sites for the activation of the epoxide and Lewis bases acting as nucleophiles for the subsequent The role of water as highly effective hydrogen-bond donor (HBD) forp romoting the coupling reaction of CO 2 with av ariety of epoxides was demonstrated under very mild conditions (25-60 8C, 2-10 bar CO 2 ).…”

Synthesis of Bio‐Based Cyclic Carbonates Using a Bio‐Based Hydrogen Bond Donor: Application of Ascorbic Acid to the Cycloaddition of CO2 to Oleochemicals

“…Cyclic organic carbonates have recently grown into one of the most widely researched classes of compounds because of potential applications as solvents, chemical intermediates and monomers . The synthesis of cyclic carbonates via catalytic cycloaddition of CO 2 to epoxides is regarded, therefore, as one among several possible routes for the highly in demand transformation of CO 2 into value‐added products .…”

“…However, the cycloaddition of CO 2 to internal di‐ and tri‐substituted epoxides remains challenging because of intrinsically higher steric demand . The latter process is particularly attractive for the exploitation and valorization of industrially attractive bio‐derived epoxides produced from naturally available olefins such as unsaturated fatty acids and terpenes and, more in general, for the synthesis of internal cyclic carbonates as precursors of NIPUs . Quaternary ammonium and phosphonium halide salts are active species for the cycloaddition of CO 2 to EFAEs and other internal epoxides.…”