Various aromatic and aliphatic aldehydes reacted at 35-40 OC in CH3CN with CsS04F giving acid fluorides in a good yield. In some cases formation of fluorohydrocarbone was also observed. Hammett correlation analysis of the transformation of various substituted benzaldehydes (p-OCH3, p-CH3, pF, p-CF3, m-NOz) gave the reaction constant p+=-0.38. Solvent polarity strongly influenced the conversion of aldehydes into acid fluorides, being ...