Chemical Valorization of Cashew Nut Shell Waste

Abstract

Cashew nut shells are agro-wastes produced from cashew nut processing factories and contain about 30–35 wt% oil called cashew nut shell liquid (CNSL). This liquid is a mixture of four potential compounds, namely anacardic acid, cardanol, cardol and 2-methyl cardol. Various reactions have been developed to convert the components of cashew nut shell liquid into industrially important chemicals, and these materials are herein described. Such reactions employed in the transformation include transfer hydrogenation reactions, isomerization reactions, metathesis reactions, carbonylation reactions, polymerization reactions, isomerizing metathesis reaction, and isomerizing carbonylation reactions. Through these descriptions, one realizes that cashew nut shells are not a waste, but they are rather a good source of a potential liquid, CNSL, which is a promising renewable resource for synthesizing various industrial chemicals.

Chapter 3 was originally published as Mubofu, E. B. & Mgaya, J. E. Top Curr Chem (Z) (2018) 376: 8.https://doi.org/10.1007/s41061-017-0177-9.