Experimentation on solvent extraction of polyphenols from natural waste

The main commercial product of the cashew tree is the cashew apple and nut. Cashew nut is regarded as lost crop in the content of agricultural produce of India despite its industrial and export potentials. After separation of nut from the cashew fruit, the nut shell is disposed into the environment and this is acting as a waste. The nut shell containing a dark reddish brown viscous liquid is called cashew nut shell liquid (CNSL) and consists of 70% anacardic acid (polyphenol), 18% cardol, and 5% cardanol. This waste material is having twofold advantages: CNSL is a low-cost phenol, which is having many industrial applications and after extraction of CNSL from the shell, the shell is acting as a fuel for many boilers. Cashew nut shell liquid was extracted from cashew nut shell by indirect leaching process using soxhlet extraction equipment. Different solvents were used in the extraction of CNSL from the cashew nut shell (CNS) and a comparison was made between them. Among all the solvents acetone gives more amounts of CNSL and its properties rely with the industrial CNSL. The operating conditions for the extraction were 60 °C and 1 atm; in every 25 g of cashew nut shell used for the extraction, 8.75 g CNSL was obtained. The CNSL was further separated into cardol, cardanol, and anacardic acid (polyphenol) using an extractant, ammonium hydroxide, with the aid of mechanical shaker equipment. Subsequently, the polyphenol was further separated into dihydric phenols (resorcinol) and monohydric phenol (phenol).