Isolation and Green Methylation of Cardanol from Cashew Nut Shell Liquid

Abstract

In this work, cardanol was isolated from decarboxylated Cashew Nut Shell Liquid (CNSL) and then methylated using a green reagent, dimethyl carbonate (DMC). The decarboxylated CNSL was obtained from the mechanical press method and followed by heating at 140 °C for 1 hour. Afterward, cardanol was isolated using methanol and ammonium hydroxide, and then extracted with n-hexane. Methylation of cardanol was carried out by the use of DMS and green reagent of DMC, and some variation was done to get the optimum condition, such as variation of the type of phase transfer catalyst (PTC), amount of base K2CO3, the temperature, and time of reaction. It was found that CNSL contains anacardic acid (46%), cardanol (30%), and cardol (23%), while decarboxylated CNSL contains anacardic acid (11%), cardanol (60%), and cardol (19%). The optimum condition of cardanol isolation was obtained by reacting CNSL with methanol and ammonium hydroxide with a volume ratio of 8:5 at room temperature for 2 hours to yield cardanol in 79.01% with 96.59% purity. Furthermore, the optimum condition of green methylation cardanol was achieved at a mole ratio of cardanol:DMC:TBAB:K2CO3 = 5:160:3:3.75 for 10 hours at 200 °C to give methyl cardanol in 82.20% with 96.92% purity.