Specific Solvent Issues with Fluorination

A key issue is safety. Many F⁺ reagents can react with common solvents—sometimes explosively. Before any reaction, the compatibility of the fluorinating reagent and solvent should be assessed.

There are very few solvents that can safely be used with F₂/N₂ mixtures. MeCN, HCO₂H, H₂SO₄ have been reported as compatible with F₂/N₂ mixtures.

Selectfluor reacts rapidly and exothermically with DMF, pyridine and DMSO.

A number of fluorination reactions have been reported under solvent-free conditions.

Zupan, I.; Stavber, S. Introduction of Halogen Atoms into Organic Compounds Under Solvent-Free Reaction Conditions. Curr. Org. Chem. 2009, 13 (1), 47-70.

The cationic N-F fluorinating agents can be used in water. For a review of fluorination in aqueous media, see:

Yang, L.; Dong, T.; Revankar, H. M.; Zhang, C.-P. Recent Progress on Fluorination in Aqueous Media. Green Chem. 2017, 19, 3951-3992.