Deep Eutectic Solvents as Catalysts for Cyclic Carbonates Synthesis from CO2 and Epoxides

Abstract

In recent years, the chemical industry has put emphasis on designing or modifying chemical processes that would increasingly meet the requirements of the adopted proecological sustainable development strategy and the principles of green chemistry. The development of cyclic carbonate synthesis from CO2 and epoxides undoubtedly follows this trend. First, it represents a significant improvement over the older glycol phosgenation method. Second, it uses renewable and naturally abundant carbon dioxide as a raw material. Third, the process is most often solvent-free. However, due to the low reactivity of carbon dioxide, the process of synthesising cyclic carbonates requires the use of a catalyst. The efforts of researchers are mainly focused on the search for new, effective catalysts that will enable this reaction to be carried out under mild conditions with high efficiency and selectivity. Recently, deep eutectic solvents (DES) have become the subject of interest as potential effective, cheap, and biodegradable catalysts for this process. The work presents an up-to-date overview of the method of cyclic carbonate synthesis from CO2 and epoxides with the use of DES as catalysts.

Assessment of Green Chemistry Metrics for Carbon Dioxide Fixation into Cyclic Carbonates Using Eutectic Mixtures as Catalyst: Comprehensive Evaluation on the Example of a Tannic Acid-Derived System

“…This result is consistent with other reported in literature. 35 The optimization of the reaction conditions was studied for the [ChCl]TA (20:1) system. First, the influence of reaction temperature from 100−140 °C was examined (entries 5−9).…”

“…As observed in this and other works, forming a eutectic mixture before the reaction can improve the carbonates yield from 2 to 22%, relative to using both components separately in the reaction. 35 Tannic acid can be considered an inexpensive, bioderived additive, added at a low loading (1 mol per 20 mol of ChI/ChCl). However, due to its poor recyclability, it has been marked with an amber flag.…”

“…The influence of the CO 2 pressure (from 0.5–2 MPa) on the PC yield was studied (entries 7 and 10–12). The highest PC yield, reaching 95%, was achieved using 1 MPa, a common pressure for this process . Subsequently, the influence of the catalyst loading was studied by altering [ChCl]­TA (20:1) loading between 3.3 and 13 wt % relative to propylene oxide (entries 7, 13, and 14).…”

Ionic Liquids in Metal, Photo-, Electro-, and (Bio) Catalysis

“…However, these processes usually involve the use of over-stoichiometric amounts of ILs and will not be treated in this review. The reader is invited to consult excellent and extensive reviews on this topic from the past few years. − …”

Epoxidation of Methyl Esters as Valuable Biomolecules: Monitoring of Reaction

“…The epoxidation is a reaction of double bonds between two carbon atoms with hydrogen peroxide which leads to the formation of the epoxide group [ 4 ]. The epoxides can be used as: (i) bio-lubricants in means of transport (additives to oils) [ 5 ] or (ii) raw materials for bio-polymers (as monomers), higher alcohols, olefins, glycols, polyesters and polycarbonates (reaction with CO 2 , which is consumed) [ 6 , 7 ]. These chemicals are currently produced from crude oil and it is appropriate to replace them by renewable sources.…”