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AssigneeExxon Chemical Patents Inc.
InventorsWilliam B. Diana, Joseph V. Cusumano, Keith R. Gorda, Jacob Emert, William B. Eckstrom, David C. Dankworth, Jon E. Stanat, James P. Stokes
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The invention pertains to improved lubricating oil dispersants wherein a fractionating polymer is prepared prior to functionalization (e.g., in the Koch reaction) for making dispersant additives. In one aspect, it was discovered that by fractionating a polymer to remove light hydrocarbon and unreacted monomer from the polymer before the carbonylation step of the Koch reaction, the amount of light ester impurities generated was minimized. Light ester is an undesirable byproduct that adversely affects the recycle of the catalyst from the functionalization step of the Koch reaction. The invention also pertains to improved lubricating oil nitrogen-containing dispersant additives derived from fractionated polymer.
A lubricating oil nitrogen-containing dispersant additive exhibiting improved dispersancy comprising a nitrogen-containing polymeric material derived from a fractionated polymer having a M.sub.n of from about 700 to 10,000, a molecular weight distribution (MWD) of from about 1.2 to 3 and containing less than about 10 mole % of polymer chains having a molecular weight of less than 500.
A process for preparing a lubricating oil nitrogen-containing dispersant exhibiting improved dispersancy properties which comprises:
Dependencies are inferred from the claim text.