T 1285 (OTTO) Tetrabutylammonium bromide, 98% Cas 1643-19-2 - used with phosphorus pentoxide for greener deoxybromination. T 1285 (OTTO) Tetrabutylammonium bromide, 98% Cas 1643-19-2 - used to prepared many other tetrabutylammonium salts via salt metathesis reactions.