A process for the preparation of benzophenonimine (BPI) of the general formula I ##STR00001## where R.sup.1 and R.sup.2 are C.sub.1- to C.sub.4-alkoxy, C.sub.1- to C.sub.2-alkylamine and C.sub.2- to C.sub.4-dialkylamine and m and n are integers from 0 to 5 and R.sup.1 and R.sup.2, independently of one another, may be identical or different, by reacting benzophenone (BP) of the general formula II ##STR00002## where R1, R2, m and n have the abovementioned meanings, in ammonia and in the presence of titanium dioxide, the titanium dioxide being present substantially in the anatase modification.