Process for producing lubricating oils

Claim 1

A process for producing lubricating oils of enhanced photostability comprising the following steps in combination: i. hydrocracking a hydrocarbon oil having a kinematic viscosity of more than about 3 cst. at 98.9°C. over a hydrocracking catalyst under hydrocracking reaction conditions thereby producing a hydrocrackate product containing more than about 50 volume % of hydrocarbon oil fractions having lubricating oil viscosity; ii. fractionating said hydrocrackate to obtain at least one hydrocarbon oil fraction having lubricating oil viscosity; and iii. contacting said fraction having lubricating oil viscosity with hydrogen under hydrogenation reaction conditions comprising a reaction temperature of from about 180° to 300°C., a reaction pressure of more than about 10 kg/cm 2 , a liquid hourly space velocity of less than about 10 V/hr/V, and a hydrogen gas flow rate of from about 30 to 3000 Nm 3 /kl in the presence of a hydrogenation catalyst comprising palladium supported on a silicacontaining refractory inorganic oxide carrier in which the silica content is from about 5 to less than 40 weight %, said carrier having a specific surface area of from about 100 to 500 m 2 /g, a pore volume of from about 0.5 to 1.2 ml/g, an average pore radius of from about 30 to 120A and a bulk density of from about 0.5 to 0.7 g/ml.