Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate Photoinitiator TPO-L

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Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate(Photoinitiator TPO-L) is a liquid photoinitiator for low yellowing, low odor formulations, commonly used in screen printing inks, lithographic printing inks, flexo printing inks, photoresists, varnishes, printing Plates and other fields.
P-Phenyl-P-(2,4,6-trimethylbenzoyl)-Phosphinic acid Ethyl Ester is a photoinitiator for UV curable coatings.
0.1 mol phenylphosphinic acid and 100 mL chlorobenzene were added to the reaction vessel. 0.11 mol 2,4,6-trimethylbenzaldehyde was added dropwise under controlled temperature, followed by 2 hours of incubation at 100-120°C. After cooling, pH was adjusted to 4-6 with hydrochloric acid, then 0.13 g vanadium acetylacetonate was added as a catalyst. 0.15 mol of 35% hydrogen peroxide was added dropwise at a rate of 5-10 drops per minute, with the mixture insulated at 5-10°C. The reaction was monitored by TLC until completion.
The reaction mixture was diluted with 100 mL water, neutralized with saturated sodium bicarbonate, and the organic layer was separated and washed twice with water. Excess oxidant was reduced with aqueous sodium sulfite, and the organic layer was separated and washed again. The mixture was dehydrated with anhydrous sodium sulfate, filtered to remove the desiccant.
To the dehydrated organic layer, 0.11 mol sodium hydroxide was added, followed by dropwise addition of 0.55 mol diethyl sulfate at 60-80°C. After the reaction was complete, the mixture was adjusted to pH 8-10 with sodium hydroxide, washed with water, and the organic layer was separated. The organic layer was dried over anhydrous sodium sulfate, filtered, and the solvent was evaporated under reduced pressure to yield Ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate.