Efficiency of blended polyhydric alcohols solution on liquefaction of oil palm trunk (Elaeis guineensis Jacq.)

The oil palm tree is a monocotyledon, and the chemical composition varies relative to the part of its trunk. Therefore, the purpose of this study was to investigate the relationship between the chemical composition in different parts of an oil palm trunk and the rate of liquefaction. PEG#400/glycerol (4:1, w/w) was the liquefying reagent with 2% sulfuric acid as a catalyst. Liquefaction was done at the optimum conditions of liquor ratio, temperature (130 to 180 °C), and reaction time (30 to 120 min). The results revealed that the rate of liquefying was dependent on the part of the trunk. The inner zone in the top parts of the trunk had the least amount of lignin and lowest crystallinity. Thus, these parts could be liquefied faster than the other parts of the trunk. According to FTIR, XRD, and 13C NMR analyses, the amorphous polymer content (comprised of lignin, hemicellulose, and disordered zones of cellulose and starch) mostly degraded at the low temperature of 140 °C for 30 min, while the crystalline regions required higher temperature (180 °C). Increasing the temperature had stronger effects than extending reaction time or the liquor ratio. Furthermore, excess in these reaction parameters caused re-condensation of the degraded liquefied products.