Abstract: A dental-care composition having improved shelf life in respect of rheology and abrasiveness, which as a novel feature, contains, as a cleansing agent, a bifunctional (thickening and abrasive) precipitated silica characterized by the following physico-chemical properties:______________________________________ Pendulum roller mill Jet mill ______________________________________ BET surface area m.sup.2 /g 15-110 15-110 Tamped density g/l 150-750 90-650 Secondary particle size FIG. 1 FIG. 2 distribution according to Coulter Counter "ALPINE" screen % by <1.5 <0.1 retainings > 63 .mu.m weight Cu abrasion in 10% mg 5-30 5-30 strength glycerol disper- sion Lightness value A % 86-96 90-96 Viscosity in a 30% 30,000-60,000 30,000-60,000 strength dispersion in a 1:1 glycerol/water mixture, Brookfield RTV, Sp5 ______________________________________The dental-care composition may additionally contain 0.

Abstract: Aromatic peroxycarboxylic acids are produced by reacting aromatic carboxylic acids with hydrogen peroxide in the presence of sulfuric acid by having a mixture of aqueous 50-99 weight % H.sub.2 O.sub.2 and sulfuric acid present in the reaction vessel, introducing the solid aromatic carboxylic acid with stirring, the reaction being carried out in heterogeneous phase, the stirring being continued to the end of the reaction and then the reaction mixture obtained worked up in known manner.