Synthesis of UV absorbers from cashew nut shell oil

The international research team led by Prof. Dr. Till Opatz from the Institute of Organic Chemistry at Johannes Gutenberg University in Mainz, Germany, and Prof. Dr. Charles de Koning from the University of the Witwatersrand in Johannesburg, South Africa, uses cashew nut shell oil that is produced in considerable quantities during the processing of the nuts as a sustainable starting material for new organic UV filters. This means that there is no competition with food and feed production. The use of shell oil can be considered in the broader sense of xylochemistry, in which woody biomass serves as a carbon source for chemical synthesis.

Sustainable protection against UV-induced damage

The ultraviolet (UV) share of sunlight can lead to health problems for humans and animals. Premature skin aging and even life-threatening cancer can be the result. Natural UV radiation can also have a destructive effect on materials such as plastics, paints and coatings. In such cases, chemical UV filters can be used to protect against UV-induced damage. These are either mineral in nature, such as titanium dioxide, or organic in nature, i.e. they consist of carbon compounds. In both cases, they can be applied in sunscreens as well as in paints or directly in the materials to be protected.

Currently, both classes of UV filters are under criticism for different reasons. For some of the organic filters, for example, their compatibility with aquatic life is too low. In addition, practically all organic UV filters – like most other organic chemicals – are currently manufactured from oil.

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