Sila-Phot - Synthesis of Silicon-Based Type I Photoinitiators

There is an urgent demand for non-toxic, light induced, free radical photoinitiators for various applications. The current state-of-the-art phosphorus-based derivatives have toxicity issues and the European Chemical Agency (ECHA) is currently closely evaluating and also banning various acylphosphine oxides from the market (see situation diphenyl-2,4,6-trimethylbenzoyl-phosphine-oxide (TPO)). A non-toxic alternative are acylgermanes, but due to the low abundance of germanium, these derivatives are very expensive and cannot meet the requirements for photoinitiators in high-throughput polymer synthesis. Consequently, a non-toxic replacement will be disruptive and based on the gained knowledge a replacement with silicon has the greatest chances to be competitive on the market. For this project we propose the evaluation of simple silyl substituted oxime esters as photoinitiators.