Quaternary ammonium compounds, their preparation and use Compounds of the formula I ##STR1## are claimed, as are their preparation and use, in which the radicals R.sub.1, R.sub.2 and R.sub.3 are organic substituents, L is either a lactam or a cyclic amidine and X is an appropriate anion. The novel compounds are employed as bleach activators in cleaners and detergents which have a bleaching action.