Polyalkene-substituted carboxylic acid compositions having reduced chlorine content

The invention is directed to polyalkene-substituted carboxylic acid compositions having a reduced chlorine content, derivatives thereof useful as fuel and lubricating oil dispersants and dispersant/viscosity modifiers and methods for forming such compositions. The residual chlorine content of a polyolefin-substituted carboxylic acylating agent formed by a chlorine-assisted reaction of a polyolefin and an , -unsaturated carboxylic reactant can be reduced by heating the polyolefin-substituted carboxylic acylating agent having a residual chlorine content in the presence of an , -unsaturated carboxylic reactant, optionally in the further presence of a sulfonic acid. Residual chlorine content can be further reduced by using, in the reaction of the polyolefin , -unsaturated carboxylic reactant, a high speed mixer provided with a dual pitch blade.