A scale-up procedure to dialkyl carbonates; evaluation of their properties, biodegradability, and toxicity

In this work, we explored a scale-up procedure to non-commercially available or expensive dialkyl carbonates via transcarbonylation reaction of an alcohol with dimethyl carbonate promoted by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). DACs selected for this study include symmetrical and unsymmetrical compounds incorporating alkyl, alkoxyalkyl, aminoalkyl, and thioalkyl moieties. Compared to previously published works, the proposed procedure was customized for large-scale production of DACs (up to 100 mL); purification of the products was achieved by distillation, and recycling of the exceeding reagents was addressed. Furthermore, the role of the catalyst was investigated, and a possible reaction mechanism proposed. The chemical-physical properties of the new DACs were evaluated employing softwares and models based on quantitative structure-activity relationships (QSAR). Biodegradability and toxicity tests have also been carried out both experimentally and by computational studies so to investigate the effect of the sulfur, nitrogen, or oxygen-containing moieties on the greenness of these – in some cases new –solvents and reagents.