or branched chain or a cyclic or aromatic group dodecenylsuccinic anhydride ddsa has been found to be an especially useful hydrocarbyl succinic anhydride in the present invention another suitable hydrocarbyl succinic anhydride is an u03b1 olefin succinic anhydride aosa wherein the u03b1 olefin group is a mixture of c 12 c 26 moieties ddsa for example is prepared as the reaction product of 1 dodecene and maleic anhydride at equimolar proportions at an elevated temperature by methods well known in the art aosa is prepared by the reaction product of a c 12 c 26 olefin paraffin mixture and maleic anhydride while maleic anhydride is a preferred starting material for producing the hydrocarbyl succinic anhydride reactant due to its widespread commercial availability other hydrocarbyl anhydrides formed by the reaction product of an alkene and an alternative unsaturated anhydride or dicarboxylic acid compound could be used examples of alternative unsaturated anhydride or acid starting materials include citraconic acid itaconic acid and the like ddsa is reacted with an amine to produce the preferred dodecenylsuccinimide compound of the present invention suitable amines generally have one but preferably two or more primary amine groups an example of a suitable monoamine having a single primary amine group which can react with ddsa to form a monoimide compound is ethyleneamine ea examples of suitable polyamines having two primary amine groups which react with ddsa for example at a suitable molar proportion to form a diimide compound include polyalkylamine ethylenediamine eda diethylenetriamine deta triethylenetetramine teta tetraethylenepemamine tepa pentaethylenehexamine peha 1 3 diaminopropane 1 3 pd 1 2 diaminopropane 1 2 pda iminobispropylamine ibpa methanediamine mda and hexamethylenediamine hmda preferred polyamines include diethylenetriamine.