A non-catalytic process to produce levulinic acid from the flesh fruits of trembesi (Samanea saman) using a subcritical water

Levulinic acid (LA) has been identified as a promising green, biomass-derived platform chemical. A non-catalytic method to produce LA from the flesh fruits of trembesi (Samanea saman) using subcritical water has been performed. Effect of reaction time and operating pressure under CO2 atmosphere on the conversion of glucose and yield of LA has been investigated. The conversion of glucose was found to be affected by the reaction time rather than operating pressure. The longer reaction time from 30 to 480 min. increased the conversion of glucose from 87.72% ± 1.57% to 98.74 ± 1.76% or increased by 12.56% at 200 °C, 4 MPa and ratio of flesh fruit and water of 1/8 (g/ml). Increasing the operating pressure from 4 MPa to 8 MPa, only increased the conversion of glucose by 4.67%. The yield of LA was found to be affected by the reaction time and operating pressure. The yield of LA was increased by 61.88 % by increasing reaction time from 30 to 240 min, while extended further reaction time to 480 min. the reduced yield of LA by 24.05 %. The highest yield of LA (22.28 ± 0.04 %) can be achieved in 240 min at 200 °C and 8 MPa. The result showed that LA could be obtained by a green method.