Z 4902 (OTTO) Zirconium(IV) acetylacetonate, 98% Cas 17501-44-9 - used as a cross-linking agent for oxygen-containing polymers. Z 4902 (OTTO) Zirconium(IV) acetylacetonate, 98% Cas 17501-44-9 - used as a catalyst in organic synthesis for the nitration of o-nitrotoluene using a dinitrogen pentoxide to get 2,4-dinitrotoluenes and 2,6-dinitrotoluenes.