Efficient and More Sustainable Catalytic Glycerol Acetylation Using Non‐Toxic and Non‐Corrosive Phosphoric Acid‐Based Organocatalysts

Improving and controlling selectivity to obtain a certain product is crucial in academic and industrial processes. Two phosphoric acid‐based piperazine salts are water‐soluble, and this property facilitates their separation and recycling. The FTIR and 31 P NMR spectroscopic techniques were used to differentiate between the two different anions. The strong network exists in both organic salts owing to the N─H···O and P─O···H hydrogen bonds. Thermal analysis techniques, including TG‐DTG and DSC, further demonstrated the existence of different anions, and the thermal degradation mechanism was proposed based on mass losses in TG‐DTG plots. Finally, their catalytic activity was investigated for the selective production of mono‐, di‐, and tri‐acetin to evaluate the anion effect on catalytic performance. The Pz‐PA (1:1) and Pz‐PA (1:2) exhibited excellent catalytic activity in the preparation of acetylated glycerol under mild conditions, with Pz‐PA (1:2) demonstrating higher activity. The combined effects of organic salts and immiscible two‐phase reactions improve selectivity in the glycerol acetylation. The aqueous phase was employed in the next run of the reaction without separation or purification. Both organic salts showed high recyclability, and the recovered catalyst could be reused in successive runs without any detectable reduction in activity.