DEHYDROFLUORINATION OF AMINE METALLOID FLUORIDES .2. REACTION OF PHOSPHORUS PENTAFLUORIDE WITH PRIMARY AMINES

Phosphorus pentafluoride is shown to react with primary amines to give a variety of products depending upon the amine, solvent, and reaction conditions. An adduct was isolated from aniline, 2,6-dimethylaniline, and n-propylamine but could not be isolated from 2,6-diethylaniline or isopropylamine under the mildest conditions employed (0-10°) in heptane or benzene. Disproportionation of the adduct from aniline and n-propylamine in the presence of phosphorus pentafluoride gave the corresponding amine hexafluorophosphate salt and diazadiphosphetidine. Disproportionation of the adduct from more hindered amines such as 2,4-dimethylaniline, 2,6-dimethylaniline, and 2,6-diethylaniline gave the corresponding amine hexafluorophosphate salt and aminophosphorus tetrafluoride. Addition of triethylamine (or other tertiary amine) to the reaction of primary amines with phosphorus pentafluoride causes formation of diazadiphosphetidines from hindered as well as unhindered amines, with formation of the tertiary amine hexafluorophosphate salt. The infrared and 19F nmr spectra are discussed for certain of the products. Dehydrofluorination of ammonia-phosphorus pentafluoride with triethylamine or diisopropylethylamine-phosphorus pentafluoride gives small yields of phosphonitrilic fluorides but the major product is an incompletely dehydrofluorinated oil. © 1968, American Chemical Society. All rights reserved.