Microwave-Assisted\nHydrothermal Conversion of Potato\nPeel into Levulinic Acid and Formic Acid

The current chemical industry primarily relies on basic\nmolecules\nfrom petroleum. Nevertheless, these molecules, known as building block\nchemicals, can be synthesized from biomass. Therefore, the aim of\nthis work was to evaluate the production of formic acid (FA) and levulinic\nacid (LA) from agro-industrial waste, particularly potato peel (PP),\nusing a microwave-assisted hydrothermal treatment. The sample was\nconditioned and characterized by a physicochemical analysis. The results\nindicated that the PP had a high moisture content (≈ 82%) and\na total carbohydrate content of 39.8%. Subsequently, a 2<sup>3</sup> factorial design was established to study the effect of temperature\n(100 to 180 °C), H<sub>2</sub>SO<sub>4</sub> concentration (0\nto 0.6 M) and reaction time (5 to 30 min.) on FA and LA conversion.\nFrom the experimental trials, it was possible to establish that the\nhighest FA (2.51%) and LA (13.77%) yields were obtained at 180 °C\nand 0.6 M H<sub>2</sub>SO<sub>4</sub>. When ANOVA analysis was performed,\nit was observed that the temperature and H<sub>2</sub>SO<sub>4</sub> concentration were the most influential parameters on FA and LA\nconversion. Finally, to improve the process, some tests were performed\nwith a new set of temperatures (160, 180, and 200 °C) and acid\nconcentrations (0.3, 0.6, and 1.0 M), and a previous hydrolysis stage\nwas established, where the highest FA (3.19%) and LA (27.95%) yields\nwere found at 160 °C and 1.0 M H<sub>2</sub>SO<sub>4</sub>. This\nwork showed that it is possible to obtain value-added products from\nagro-industrial waste such as PP; however, further studies and experiments\nfocused on improving the yield of the process are still required.