Biphenyl diquaternary ammonium compounds

The present invention relates to new diquaternary ammonium compounds, to a process for the preparation thereof, to the use thereof as antimicrobial agents against gram-positive and gram-negative bacteria, yeasts, fungi and algae, to the use thereof as disinfectants and preservatives, and to the use thereof in the preparation of formulations for technical use, cosmetic use and use in hygiene. There are described diquaternary ammonium compounds of the general formula: whereinRand Rare each independently of the other C-Calkyl, phenyl or phenyl-C-Calkyl,R, R, Rand Rare each independently of the others C-Calkyl, andA is a monovalent anion. The compounds exhibit a pronounced action against gram-positive and gram-negative bacteria, and also against yeast, molds and algae. They are accordingly suitable for the antimicrobial treatment of surfaces and for the preservation and disinfection of materials and cosmetic products, and especially also for the preparation of solid or liquid formulations and for the preservation of foodstuffs and drinks. The compounds are furthermore suitable for imparting antimicrobial properties to technical plant and for antimicrobial water treatment.