This visual indicator titration method is for determining maleicanhydride reactivity with a wide variety of oils ranging fromdebutanized light hydrocarbon distillates to heavy drying oils.

The method gives a measure of the conjugated diolefincontent of the sample. The determination is somewhat empirical1since some diolefins may not react completely, while certaincompounds other than conjugated diolefins may be reactive, also.For example, anthracene, many of its homologs, and thecorresponding alkylated compounds react quantitatively as dieneswith maleic anhydride. Similarly, certain vinyl aromatics react.The molecular weight of the conjugated diolefins must either beknown or estimated. Therefore, the results obtained by this methodmust be carefully interpreted in the light of these specifiedlimitations.