Levulinic Acid Production from Artichoke Leaves (Cynara Scolymus L.) by Catalytic Hydrothermal Reaction

In addition to examining the highest yield production of Levulinic acid (LA) from artichoke leaves by the subcritical catalytic hydrothermal decomposition, the studies were carried out on also increasing the production yields of 5-Hydroxymethylfurfural (HMF), Acetic and Formic acid from this biomass. In order to obtain the most suitable reaction conditions, the effect of different reaction conditions, including different temperature, reaction time, pH and catalyst types, on the decomposition of artichoke leaves and product yields were investigated. The subcritical thermal decomposition studies of artichoke leaves were carried out in an autoclave system at temperatures (120°C, 140°C, 160°C, and 180°C) for reaction times of 10, 20, 30, 40, and 50 min in the presence of H2SO4, HNO3, and HCL catalysts with different pH values; these reactions were realized also without adding a catalyst. As a result of the detailed research, it was seen that the most suitable experimental conditions for the production of LA with the highest yield from artichoke leaves could be achieved by adding sulfuric acid with a pH of 0.5 at a reaction temperature of 180°C and a reaction time of 50 min. The investigations were continued till achieving the highest product yields. After carrying out the experiments stated above, the optimal yields of the products produced from the artichoke biomass by the reactions were found as 209.39 g/kg biomass for LA, 117.40 g/kg biomass for formic acid, 72.27 g/kg biomass for acetic acid, and 39.04 g/kg biomass for 5-HMF.