Rediscovering monoalkyl carbonates: a class of ubiquitous compounds

Abstract

Monoalkyl carbonates (MACs) or, more broadly, hemiesters of carbonic acid (HECAs), constitute a class of compounds that are omnipresent in our lives, once formed by the reaction of carbon dioxide with alcohols. Despite their commonness, MACs are elusive in solution and went largely unnoticed by most researchers until the recent resurgence of interest in studying their properties, relevance (e.g., in CO₂ capture), and analysis (for example, in foods, drinks, and sugars), by using techniques like NMR, MS, and CE. This literature review, spanning almost two centuries, sheds light on the importance of the chemistry of MACs. Their subtle formation can be responsible for significant changes in the charge and electronic characteristics of compounds with an alcohol functional group, altering properties such as solubility, polarity, diffusion coefficient, and conductivity. Such changes in properties lead to the hypothesis that MAC formation may play an important role also in the biological environment, including membrane transport. Many questions remain open in the rich emerging research field of the chemistry of MACs, and better understanding is essential for advancing the knowledge of these ubiquitous compounds and their potential impact on various processes and products.