A green approach to the edge functionalization of graphene layers with a bio-based 2-pyrone

Increasing awareness and concerns about climate change have spotlighted the need for a sustainable development. Green chemistry, defined as “the design of chemical products and processes to reduce or eliminate the use and generation of hazardous substances”, pursues the aim to transform hydrolyzed biomass, mainly composed by carbohydrates, into suitable building blocks. In this context, 2-pyrones build up a class of C-6 unsaturated lactone from lignocellulosic feedstock and intriguing building blocks for the preparation of key intermediates in synthetic organic, medicinal and polymeric chemistry. In this work, a green and efficient pathway for the preparation of a 2-pyrone starting from mucic acid is presented. Furthermore, a 2-pyrone derivative, ethyl 3-hydroxy-2-oxo-2H-pyran-6-carboxylate (Pyr-COOEt ), was used for selectively decorating the edge of a nano-sized graphite with high surface area (HSAG), without altering the graphitic bulk structure. The preparation of adducts between HSAG and Pyr-COOEt was performed through a sustainable method, with the help of either thermal or mechanical energy, reaching high functionalization yield (up to 90%). Few layers of graphene were easily obtained by means of a mild sonication of a water dispersion of the HSAG/Pyr-COOEt adducts.