A solid composition consisting essentially of 5-98 parts by weight of heterocyclic compounds I where L1 is groups with a cyclic carbamate, a lactonoxy or a lactam structure, X is a carbonyl, a doubled carbonyl or a heterocarbonyl group, and R1 is an organic radical or a second moiety L1, and/or oxime esters II where L2 is an oxime moiety where R2, R3 and Z4 are organic radicals or linkers, L3 is the radical R1, a second oxime moiety L2 or a carboxylic ester residue, carboxamide residue, phenolate residue, vinyloxy radical, sulfonamide residue, imidazole residue, amidolactam residue, cyclic carbamate residue, lactonoxy residue or lactam residue, and m is 0 or 1, and 2-95 parts by weight of inert porous carrier materials with an internal surface area of from 10 to 500 m2/g. The solid composition described is suitable as stable bleach activator component in detergents, bleaches and cleaners.