Patent ID: 7091306

Claim:
A process of preparing polyalkenylsuccinimides comprising the steps of: (a) preparing a polyalkenyl derivative of an unsaturated acidic reagent by (i) reacting a polyalkylene having a Mn of at least 300 with an unsaturated acidic reagent at elevated temperatures in the range of from about 180° C. to 240° C. and at a pressure below 2 atmospheres in the absence of a strong acid until at least 25% of the polyalkylene is converted to a polyalkenyl derivative of an unsaturated acidic reagent; (ii) continuing the reaction of the polyalkylene with an excess of the unsaturated acidic reagent at elevated temperatures in the range of from about 180° C. to 240° C. and at a pressure below 2 atmospheres in the presence of a strong acid having a pK a of less than about 4 to convert at least some of the unreacted polyalkylene to additional polyalkenyl derivative of an unsaturated acidic reagent; and (iii) removing the unreacted unsaturated acidic reagent to yield an unfiltered polyalkenyl derivative of an unsaturated acidic reagent containing a sediment level of less than 0.1 wt %, based on the total weight of the polyalkenyl derivative of the unsaturated acidic reagent; (b) reacting the unfiltered product of step (a) with a polyamine having at least one basic nitrogen atom; (c) diluting the product of step (b) with mineral oil-free solvent; and (d) subsequently filtering the diluted product of step (c) to yield a polyalkenylsuccinimide product having a sediment level less than 0.1 vol %, based on the total volume of the diluted product.