Valentina Bragoni
Ruhr Universität Bochum, Germany
Title: Synthesis of new bio-based surfactants from cashew nutshell liquid in water
Biography
Biography: Valentina Bragoni
Abstract
Cashew nutshell liquid (CNSL) is an inedible waste product (1.000.000t/a) in the cashew nut processing and is an excellent candidate for the synthesis of bio-based synthetically valuable compounds, as its production does not compete with the land use for food production.[1,2] CNSL is a mixture of phenols bearing a 15-carbon side chain with different degrees of unsaturation.[3,4] We have developed an eco-friendly and waste minimised concept for the synthesis of amine-based surfactants from CNSL. The key step of the procedure is a reductive amination of CNSL with molecular hydrogen in water as solvent, and palladium on charcoal as catalyst. The resulting cyclohexyl amines are successfully converted into N-oxide, betaine and quaternary ammonium tensides. Their surfactant properties (surface tension and critical micellar concentration) have been determined and resulted comparable with those of state-of the-art commercial tensides, opening up a wealth of commercial applications. In the case of the particularly valuable N-oxide surfactant, a one pot synthesis with a remarkably low E-factor of 2 was realised in water as the sole solvent, with a hydrogen peroxide oxidation and purification by simple water extraction, thus avoiding the use of waste-intensive purification techniques. Overall, the process provides a new, eco-friendly procedure for the transformation of renewable waste products into industrially valuable compounds.
