Combination adsorption and dewaxing process

Claim 1

METHOD OF PREPARING A LUBRICATING OIL HAVING A LOW POUR POINT AND IMPROVED V. I. FROM A WAXY LUBRICATING OIL STOCK WHICH COMPRISES DILUTING THE STOCK WITH A SATURATE HYDROCARBON DILUENT OF THE C3-C6 RANGE, TREATING THE DILUTED STOCK WITH SILICA GEL TO SELECTIVELY ADSORB AROMATIC CONSTITUENTS, DISPLACING HYDROCARBONS FROM THE SILICA GEL BY MEANS OF A LIQUID DESORBING AGENT CONTAINING ETHYLENE DICHLORIDE AND OBTAINED AS HEREINAFTER SPECIFIED, OBTAINING FROM THE SILICA GEL TREATMENT (1) A FIRST RAFFINATE FRACTION CONTAINING SATURATE COMPONENTS OF SAID STOCK INCLUDING WAX IN ADMIXTURE WITH DESORBING AGENT AND SATURATE HYDROCARBON DILUENT, AND (2) AN EXTRACT FRACTION CONTAINING AROMATIC COMPONENTS OF SAID STOCK IN ADMIXTURE MAINLY WITH DESORBING AGENT, DISTILLING THE FIRST RAFFINATE FRACTION TO REMOVE OVERHEAD A MAJOR PORTION OF THE DILUENT CONTAINED THEREIN WHILE RECOVERING AS BOTTOMS A SECOND RAFFINATE FRACTION COMPRISING SATURATE COMPONENTS OF THE CHARGE TOGEHTER WITH SUBSTANTIALLY ALL THE DESORBING AGENT PRESENT IN THE FIRST RAFFINATE FRACTION, ADDING ADDITIONAL DESORBING AGENT TO THE SECOND RAFFINATE FRACTION, REGULATING THE DISTILLATION AND THE ADDITION OF DESORBING AGENT SO AS TO PRODUCE AN ADMIXTURE OF A DEWAXING SOLVENT TO CHARGE STOCK COMPONENTS THEREIN OF THE TOTAL SOLVENT TO CHARGE STOCK COMPONENTS THEREIN IS WITHINTHE RANGE BY VOLUME OF 1:1 TO 6:1 AND THE TOTAL SOLVENT COMPOSITION CONFORMS TO THE AREA ABCD OF FIG. 2, COOLING THE ADMIXTURE TO A WAX CRYSTALLIZING TEMPERATURE, SEPARATING WAX FROM THE COOLED MIXTURE, RECOVERING SOLVENT FROM THE DEWAXED OIL AND WAX PRODUCTS, RECOVERING DESORBING AGENT FROM SAID EXTRACT FRACTION, AND UTILIZING SUCH RECOVERED SOLVENT IN ADMIXTURE WITH RECOVERED DESORBING AGENT AS THE SAID LIQUID DESORBING AGENT.