Search

The increasing depletion of fossil feeds and the environmental concerns linked to the use of traditional energy sources have stimulated both academic and industrial worlds in exploiting new sustainable and renewable suppliers of raw materials [1]. In this framework, lignocellulosic biomass can play an important role, acting as the starting material of a biorefinery leading to biofuels, chemicals, and other value-added products, commonly obtained from petroleum. Recently, numerous protocols for processing lignocellulosic biomass of selected plants have been reported. However, developing an environment-friendly method is still a big goal. This challenge becomes more interesting if lignocellulosic biomass coming from wood wastes could be efficiently treated. Deep eutectic solvents (DESs) are new sustainable and cheap reaction media, combining the features of ionic liquids and organic solvents. They are made by association of hydrogen-bond donors and hydrogen-bond acceptors, and they can promote the hydrolysis of lignocellulosic bonds [2]. Herein, we report on the microwave-assisted treatment of waste wood flours with DESs formed by choline chloride and oxalic acid to get a cellulosic residue separated from lignin degradation products, identified by NMR spectroscopy. The insoluble deposit was characterized by SEM, TGA, DSC, FTIR-ATR and 13C CP/MAS NMR techniques and could be available for further uses such as nanocellulose production. [1] Haldar D., Purkait M.K. Chemosphere 2021, 128523. [2] Liu S., Zhang Q., Gou S., Zhang L., Wang Z. Carbohydr. Polym. 2021, 251, 117018

A nickel containing monomer, Ni(AAEMA)2 (AAEMA− = deprotonated form of 2-(acetoacetoxy) ethyl methacrylate) is co-polymerized with ethyl methacrylate (co-monomer) and ethylene glycol dimethacrylate (cross-linker). The obtained polymer is a green methacrylic resin containing Ni(II) centers homogeneously dispersed in the catalyst, which results insoluble in all common organic solvents and in water. The specific features of this material classify it as an amphiphilic resin, air and moisture stable, with the peculiarity to swell in halogenated solvents, acetone and water and to shrink in diethyl ether and petroleum ether. The polymer is calcined under reductive conditions (dihydrogen with initial pressure of 5bar) following two procedures, differing from each other for the cooling conditions. In the first procedure, the calcined material is cooled under dihydrogen gas, while in the second one the cooling step occurs under air. After calcination, the green Ni(II)-based co-polymer turns into black resins, Ni-res1 (obtained by cooling under hydrogen) and Ni-res2 ((obtained by cooling under air). FESEM analyses show that both Ni-res1 and Ni-res2 support Ni nanoparticles with different morphologies, being the metal nanoparticles onto Ni-res1 smaller than the ones dispersed in Ni-res2, that have an urchin-like shape. Both Ni-based co-polymers are tested as catalysts in the reduction of nitrobenzene with NaBH4. Ni-res1 results more active and selective towards aniline with respect to Ni-res2.