Patent ID: 7868209

Claim:
A process for preparing an overbased borated alkaline earth metal alkyltoluene sulfonate comprising: (a) reacting (i) at least one oil soluble alkyltoluene sulfonic acid, or an oil soluble alkaline earth alkyltoluene sulfonate salt, or a mixture thereof; (ii) at least one source of an alkaline earth metal; and (iii) one or more overbasing acids, at least one of which is a boric acid, in the presence of a mixture comprising: (1) at least one hydrocarbon solvent; and (2) at least one low molecular weight alcohol; (b) heating the reaction product from step (a) to a temperature that is greater than the distillation temperatures of the hydrocarbon solvent, the low molecular weight alcohol, and any water generated in step (a), so that the solvent, alcohol and water generated may be distilled from the product from step (a); wherein no external source of water is added during the process; and further comprising (c) an overbasing step wherein the overbased borated alkaline earth metal alkyltoluene sulfonate prepared from steps (a) and (b) is further overbased with one or more overbasing acids.