| abstract |
The invention relates to a process for the preparation of secondary phosphines of the formula (I) ##STR1## in which R 1 to R 6 independently of one another are hydrogen, halogen, (C 1 -C 6 )-alkyl or (C 1 -C 6 )-alkoxy, wherein secondary phosphine oxides of the formula (II) ##STR2## are reacted with Lewis acids as catalysts, at elevated temperature, and the secondary phosphines of the formula (I) formed are distilled off under reduced pressure. |