Cardanol

Brief Overview
Cardanol, also known as cashew phenol, is a monohydroxyl phenol with a long carbon chain in the metaposition. It is derived from natural occurring phenol viz. cashew nut shell liquid (CNSL) which contains anacardic acid. It has great potential to substitute phenol in resin phenolic-based chemical compounds. Different components of cardanol differs in degree of saturation of side chain where around 41% is tri-unsaturated, 31% is monounsaturated, 22% is bi-unsaturated and 2% is saturated.
Cardanol mainly contains cardanol, cardol and some other polymeric materials. Its chemical structure contributes to its chemical resistance, flexibility and increase the hydrocarbon toleration in the resins prepared from it and its unique molecular structure, unsaturation of long hydrocarbon side chain, makes the cross linking easy on polymerization and these side chains also impact on the hydrophobic nature of polymer.
Manufacturing process
From the processing of cashew nuts, cashew nut shell liquid (CNSL) is obtained. Cardanol extraction from Natural CNSL comprises of the conversion of natural CNSL into CNSL in which anacardic acid is decarboxylated into cardanol under vacuum and heated to 170 to 180 ⁰C. Technical CNSL is obtained, consisting of mainly 60-65% cardanol, 15-20% cardol and 10% polymeric material and traces of methyl cardol. Cardanol is sent to distillation for further purification.