Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide

487-68-3

4559-70-0

75980-60-8

The general procedure for the synthesis of the photoinitiator TPO from 2,4,6-trimethylbenzaldehyde and diphenylphosphine oxide is as follows: 37.61 g of 2,4,6-trimethylbenzaldehyde and 56.17 g of diphenylphosphine oxide were added to a three-necked flask containing 450 ml of methylene chloride, and mixed with stirring. After 6 hours of reaction, the reaction system was cooled in a low temperature water bath to 810°C. Subsequently, 0.2925 g of ammonium metavanadate (NH4VO3) and 37 ml of 30% H2O2 were added and reacted at low temperature for 0.5 hours. After that, the reaction mixture was moved to room temperature conditions to continue the reaction for 5 hours. Upon completion of the reaction, 5% aqueous Na2S2O3 was added to the reaction solution to neutralize the unreacted H2O2. Next, an extraction operation was carried out and the organic layer was collected and washed three times with saturated brine. After dehydration by adding anhydrous sodium sulfate, the product was purified by recrystallization. Finally, the product was collected by filtration and dried to give a light yellow powdery solid, the TPO product, in 98% yield.