Patent ID: 6974535

Claim:
A process for producing a lubricating oil basestock which comprises: (a) conducting a lubricating oil feedstock to a solvent extraction zone and under-extracting the feedstock to form an under-extracted raffinate wherein the extraction zone solvent contains water added in the amount from about 1 to about 10 vol. %, based on extraction solvent, such that the e traction solvent contains from 3 to 10 vol. % water; (b) stripping the under-extracted raffinate of solvent to produce an under-extracted raffinate feed having a dewaxed oil viscosity index from about 75 to about 105; (c) passing at least a portion of the raffinate feed to a first hydroconversion zone d processing the raffinate feed in the presence of a non-acidic catalyst at a temperature of from 320 to 420° C., a hydrogen pat pressure of from 1000 to 2500 psig (7.0 to 17.3 mPa), space velocity of 0.2 to 5.0 LHSV and a hydrogen to feed ratio of from 500 t 5000 Scf/B (89 to 890 m 3 /m 3 ) to produce a first hydroconverted raffinate; (d) passing the first hydroconverted raffinate from the first hydroconversion zone to a second hydroconversion zone and processing the hydroconverted raffinate in the presence of a non-acidic catalyst at a temperature of from 320 to 420° C. provided that the temperature in the second hydroconversion is not greater than the temperature in the first hydroconversion zone, a hydrogen partial pressure of from 1000 to 2500 psig (7.0 to 17.3 mPa), a space velocity of from 0.2 to 5.0 LHSV and a hydrogen to feed ratio of from 500 to 5000 Scf/B (89 to 890 m 3 /m 3 ) to produce a second hydroconverted raffinate; (e) passing at least a portion of the second hydroconverted raffinate to a hydrofinishing reaction zone and conducting cold hydrofinishing of the second hydroconverted raffinate in the presence of a hydrofinishing catalyst which is at least one Group VIB or Group VIII metal on a refractory metal oxide support at a temperature of from 200 to 360° C., a hydrogen partial pressure of from 1000 to 2500 psig (7.0 to 17.3 mPa), a space velocity of from 0.2 to 10 LHSV and hydrogen to feed ratio of from 500 to 5000 Scf/B (89 to 890 m 3 /m 3 ) to produce a hydrofinished raffinate.