Selective HDO · Selective sustainable hydrodeoxygenation of bioaromatics

The depletion of fossil resources and the requirement to significantly reduce our CO2 footprint made the production of chemicals from non-edible biorenewable feedstocks an intensive contemporary research field. Remarkably, amongst the bioderived chemicals available, bioaromatics are still scarce. A typical feature of biobased platform molecules is their high oxygen content, which is in sharp contrast with current base chemicals obtained via a classical petrochemical approach. While petrochemical industry requires efficient and selective oxidation protocols, biorenewables on the other hand require the reverse, i.e. efficient and selective reduction reactions, necessitating new reaction development. Chemical and (bio)catalytic processes on biorenewable resources (e.g. wood, cloves, gallnuts) deliver a variety of oxygenated arenes (guaiacols, syringols, catechols, pyrogallols). Hydrodeoxygenation (HDO) reactions on these biobased arene building blocks can give access to functional chemicals suitable for the chemical industry. Though extensively researched, selective HDO on these oxygenated arenes is still poorly developed. Therefore, the main objective of this proposal is to develop selective HDO in catechols, guaiacols, pyrogallols, and syringols. Our approach involves sustainable activation of Ar-OH and Ar- (OH)2 with a renewable and cheap reactant, and subsequent reduction with a renewable reductant. As catalysts readily available and cheap base metals will be explored rather than scarce and expensive precious transition metals. Both homogeneous and heterogeneous catalysis will be evaluated.