Identification of the Structure of Triethanolamine Oxygenation Products in Carbon Nitride Photocatalysis

Triethanolamine (TEOA) is one of the most commonly used sacrificial agents in photocatalysis. Due to its more complex structure compared to, for example, ethanol, and its sacrificial role in photocatalysis, it gives a mixture of products. The structures of these molecules are not usually analyzed. Herein, we obtain and isolate the products of TEOA and N‐tert‐butyl diethanolamine oxygenation under photocatalytic conditions with ≈15 % yield, and followingly characterized them by NMR and mass spectroscopy. The reaction is mediated by potassium poly(heptazine imide) (K‐PHI) in the presence of O2 and affords formyl esters of β‐hydroxyethylene formamides from the corresponding ethanolamines. Whatever happened to TEOA? Triethanolamine (TEOA) is one of the most commonly used electron donors in carbon nitride photocatalysis. Due to its “sacrificial” role and more complex structure compared to simple alcohols, TEOA produces a complex mixture of products. Photocatalytic oxygenation of TEOA with O2 from air, mediated by carbon nitride photocatalysis, gives di formyl ester of N,N‐di(β‐hydroxyethylene) formamide among others products.