Equilibrium Acidity of Carbon–Hydrogen Bonds in Organic Compounds

A survey is made of experimental results on the equilibrium acidity of CH acids in the gas phase and in aqueous solution, as well as in dimethyl sulphoxide, cyclohexylamine, benzene, ether, and other aprotic solvents. Reasons are discussed for the sharp difference between CH and OH acids that appears on passing from the gas phase to aqueous solutions. Various acidity scales for CH acids in aprotic solvents – the McEwen, Streitwieser, Cram, Breslow, and polarographic scales, and the acidity scale in dimethyl sulphoxide – are compared. A list of 114 references is included.