Subcritical hydrothermal decomposition of leek stalk and production of valuable chemicals

With up to 90% of world energy consumption, the chemical industry's basic raw material needs are met by fossil resources in limited reserves, which are rapidly consuming up to 75%. The most important source for relieving this addiction and reducing environmental pollution is lignocellulosic biomass. The reason for the importance of lignocellulosic biomass is that it is edible, has a balanced distribution, is CO2-neutral and abundant. 5-HMF, levulinic acid (LA) and many other substances are obtained by hydrolysis, dehydration and rehydration in acidic medium. In this project, the production of valuable chemicals by hydrothermal degradation of leek stalk under the catalytic subcritical conditions was investigated. Hydrothermal degradation of leek stalk under the catalytic subcritical conditions have been carried out in batch autoclave system and as catalyst H2SO4, HNO3, Al(NO3)3, and Cr(NO3)3 were used. To reach maximum efficiency, effect of reaction temperature (120, 140, 160, 180 oC ), reaction time (10, 20, 30, 40, 60 min), pH (0.5, 1, 1.5) was investigated. Liquid products obtained from experiments were analyzed via HPLC ( High Performance Liquid Chromtography) and TOC (Total Organic Carbon) devices. Conversions and LA yields have been estimated.