Method of desalting oil solutions of oil soluble salts

Claim 1

A PROCESS FOR RECOVERING AN OIL-SOLUBLE METAL SALT FORM A PETROLEUM LUBRICATING OIL SOLUTION THEREOF, SAID SALT HAVING A HIGHER RATIO OF METAL CONSTITUENT TO ACID CONSTITUENT THAN A NORMAL SALT, THE METAL CONSTITUENT OF SAID SALT BEING SELECTED FROM THE GROUP CONSISTING OF CALCIUM AND BARIUM AND THE ACID CONSTITUENT OF SAID SALT, BEING SELECTED FROM THE GROUP CONSISTING OF (A) PETROLEUM SULFONIC ACIDS, (B) OXIDIZED PETROLEUM OIL-PHOSPHORUS SULFIDE REACTION PRODUCT ACIDS, AND (C) ALKYL PHENOL SULFIDES, SAID PROCESS COMPRISING THE STEPS OF (1) ADMIXING WITH ONE UNIT VOLUME OF SAID OIL SOLUTION FROM ABOUT 1 TO ABOUT 12 UNIT VOLUMES OF A SOLVENT MATERIAL SELECTED FROM THE GROUP CONSISTING OF HYDROCARBON SOLVENTS, HYDROCARBYL HALIDE SOLVENTS AND MIXTURES OF SAID SOLVENTS, SAID SOLVENT MATERIAL HAVING A BOILING POINT BETWEEN ABOUT 100*F. AND ABOUT 400*F., TO FORM A SOLUTION OF SAID OIL SOLUTION IN SAID SOLVENT MATERIAL, (2) ADDING TO THE SOLVENT SOLUTION FORMED IN STEP 1 FROM ABOUT 1 TO ABOUT 6 UNIT VOLUMES OF A DI-LOWER ALKYL KETONE PER UNIT VOLUME OF SOLVENT USED IN STEP 1, SAID KETONE HAVING A BOILING POINT BETWEEN ABOUT 140*F. TO ABOUT 350*F., TO PRECIPITATE SAID METAL SALT FROM SAID SOLVENT SOLUTION, AND (3) RECOVERING THE PRECIPITATED METAL SALT.