Refining sour hydrocarbon oils

Claim 1

THE PROCESS OF REMOVING MERCAPTANS FROM A SOUR HYDROCARBON DISTILLATE WHICH IS HIGHER BOILING THAN GASOLINE WITH A MINIMUM OF COLOR DEGRADATION WHICH COMPRISES CONTACTING THE SOUR DISTILLATE WITH ABOUT 5 TO 200 PER CENT BY VOLUME OF NON-ALKALINE METHANOL SOLVENT WHICH CONTAINS NOT MORE THAN ABOUT 10 VOLUME PER CENT OF WATER; SEPARATING THE SOLVENT AND DISSOLVED COLORFORMING BODIES FROM THE EXTRACTED OIL, WATER WASHING THE EXTRACTED OIL TO REMOVE DISSOLVED METHANOL SOLVENT, TREATING THE WASHED OIL WITH ABOUT 1 TO 15 PER CENT BY VOLUME OF A CONCENTRATED AQUEOUS CAUSTIC SOLUTION, INTRODUCING A FREE-OXYGEN CONTAINING GAS INTO THE MIXTURE OF OIL AND CAUSTIC SOLUTION, MAINTAINING THE TEMPERATURE OF TREATING AT BETWEEN ABOUT 80* TO 125* F., SAID CAUSTIC SOLUTION ALSO CONTAINING AN EFFECTIVE AMOUNT OF A COPPER COMPOUND WHICH IS ACTIVE AS AN OXIDATION CATALYST, AND SEPARATING SPENT CAUSTIC SOLUTION AND ASSOCIATED REACTION PRODUCTS FROM THE TREATED OIL.