Abstract
Three new organosulphur phosphorus acid compounds have been obtained by sulphonation with liquid SO3: 2-fluorobenzylphosphonic gave 2-fluorobenzylphosphono-3,5-disulphonic, 3-fluorobenzylphosphonic acid gave 3-fluorobenzylphosphono-4,6-disulphonic acid, and 4-fluorobenzylphosphonic acid gave 4-fluorobenzylphosphono-3,5-disulphonic acid in nearly quantitative yields. The products analysis is based on n.m.r. spectroscopy.