UV absorbers out of cashew nut shells

The team of “green chemists” from the University of the Witwatersrand, along with colleagues from Universities in Germany, Malawi and Tanzania, are working on techniques to produce useful compounds from wood and other fast growing non-edible plant waste, through a chemical process named xylochemistry (wood chemistry). By using cashew nut shells, the team has produced new aromatic compounds that show good UVA and UVB absorbance, which may be applied to protect humans, livestock, as well as polymers or coatings from harmful rays from the sun.

New UV absorbers from cashew nut shell liquid

“With the current concerns over the use of fossil resources for chemical synthesis of functional molecules and the effect of current UV absorbers in sunscreens on the ecosystem, we aimed to find a way to produce new UV absorbers from cashew nut shell liquid (CNSL) as a non-edible, bio renewable carbon resource,” says Professor Charles de Koning, of the Wits School of Chemistry and principal author of the paper, together with Till Opatz from Johannes Gutenberg University in Mainz, Germany.

“Cashew nut shells are a waste product in the cashew-farming community, especially in Tanzania, so finding a useful, sustainable way to use these waste products can lead to completely new, environmentally friendly ways of doing things.” The team has already filed a patent application in order to commercialise the process in South Africa.

The study is published in: European Journal of Organic Chemistry, 2019, Issue 30, pp. 4778-4790.

Event tip

In October the European Coatings Technology Forum | Bio-based Coatings will gather international experts from the coatings sector to discuss and present the latest innovations and products that can help to reduce dependency on fossil raw materials.