| abstract |
An improved sulfurized, overbased alkaline earth metal phenate lubricant additive is prepared by (a) sulfurizing an alkylphenol with a sulfur halide (e.g. SClâ‚‚) in an alkane solvent, n(b) neutralizing with an alkaline earth metal compound in an alkane/alkanol solvent mixture, n(c) overbasing with carbon dioxide, and n(d) filtering and solvent stripping. n The process can avoid the use of glycol solvent or petroleum sulfonate surfactants, and provide a highly-sulfurized product, in a shorter processing time, while producing enhanced performance of a diesel engine. |