One-Step, Catalyst-Free Formation of Phenol from Benzoic Acid Using Water Microdroplets

Benzoic acid dissolved in water is electrosprayed (-4 kV) by using nitrogen gas at a pressure of 120 psi to form similar to 10 mu m diameter microdroplets. Analysis with mass spectrometry (MS) and tandem mass spectrometry (MS2) of the resulting microdroplets shows the direct formation of phenol via decarboxylation without any catalyst or added reagents. This process represents an ecofriendly, environmentally benign method for producing phenol and related aromatic alcohols from their corresponding aromatic acids. The mechanism of this transformation was unambiguously characterized using mass spectrometry, radical trapping, and O-18 labeling.

Automated summary

In this study, a catalyst-free and reagent-free method for converting benzoic acid to phenol in water solution using electrospray technique was reported. The conversion mechanism was characterized using mass spectrometry, tandem mass spectrometry, and oxygen isotope labeling, revealing the direct decarboxylation of benzoic acid to phenol in microdroplets. This environmentally friendly approach provides a new route for the synthesis of phenol and related aromatic alcohols.