Perspectives for the Upgrading of Bio‐Based Vicinal Diols within the Developing European Bioeconomy

Abstract

The previous decade has witnessed a drastic increase of European incentives aimed at pushing forward the transition from an exclusively petro‐based economy toward a strong and homogeneous bio‐based economy. Since 2012, numerous programs have been developed to stimulate and promote research and innovation relying on sustainable and renewable resources. Terrestrial biomass is a virtually infinite reservoir of biomacromolecules, the biorefining of which provides platform molecules of low complexity yet with tremendous industrial potential. Among such bio‐based platform molecules, polyols and, more specifically, molecules featuring vicinal diols have gained tremendous interest and have stimulated an increasing research effort from the chemistry and chemical engineering communities. This Review revolves around the most promising process conditions and technologies reported since 2012 that specifically target bio‐based vicinal diols and promote their transformation into value‐added molecules of wide industrial interest, such as olefins, epoxides, cyclic carbonates, and ketals.

Selective Biocatalytic Defunctionalization of Raw Materials

“…While impressive advances have been achieved with various chemocatalysts, both transition metalbased and metal-free, further research and development is clearly needed for improving the selectivity, outcome, and sustainability of these reactions, such as high-performing, stable, and sustainable catalysts, additives, and solvents, in order to design industrially viable biobased processes. [142] Biocatalytic versions of these reactions and inspirations from Nature for the design of process conditions are therefore very desirable. Regarding a deoxydehydration-hydrogenation reaction sequence for vicinal diols in sugar acids, the sequence of two dehydratase-catalyzed reactions in aqueous solution has been demonstrated (see Scheme 9) to provide a sustainable biocatalytic version, [76,81,143] which is attractive for O-defunctionalization of bio-based sugars and promising for further development.…”

“…Reactions for upgrading biobased polyhydroxylated compounds by the selective removal of hydroxy groups are of great interest, for example, in deoxydehydration, [133–137] hydrodeoxygenation, [138,139] didehydroxylation, [140] or dehydrative epoxidation [141] of vicinal diols. While impressive advances have been achieved with various chemocatalysts, both transition metal‐based and metal‐free, further research and development is clearly needed for improving the selectivity, outcome, and sustainability of these reactions, such as high‐performing, stable, and sustainable catalysts, additives, and solvents, in order to design industrially viable biobased processes [142] …”

Bifunctional Metal‐free Heterogeneous Catalyst for the Synthesis of Methanol and Diols from CO2 and Epoxide

“…[27][28][29][30][31] It is interesting to note that along with methanol the reduction of cyclic carbonate gives valuables diols, which are used in various industrial applications. [32,33] But till now milder reaction condition and use of heterogeneous catalyst for efficient methanol synthesis from CO 2 and epoxide is unavailable in the literature. Use of heterogeneous catalytic system could make this reaction highly sustainable for the synthesis of methanol.…”

“…intermediate cyclic carbonates or carbamates [27–31] . It is interesting to note that along with methanol the reduction of cyclic carbonate gives valuables diols, which are used in various industrial applications [32,33] . But till now milder reaction condition and use of heterogeneous catalyst for efficient methanol synthesis from CO 2 and epoxide is unavailable in the literature.…”

Sequence-controlled polyhydroxyurethanes with tunable regioregularity obtained from biobased vicinal bis-cyclic carbonates

“…Herein, we propose to use enantiopure bis-5CC obtained from the direct carbonatation of sugarbased butadiene tetraols that are enantiopure themselves, namely (i) meso-erythritol and (ii) its (S,S) diastereoisomer, (L)-threitol (Scheme 1). 27 Recently, Dannecker and Meier introduced a simple and sustainable method for the organocatalytic carbonatation of meso-erythritol in the presence of dimethyl carbonate used both as a reagent and a solvent [8]. The corresponding erythritol di(carbonate) (EDC) retains the stereochemistry of the starting tetraol and is obtained in very high yield (90%).…”