Lubricant production process

Abstract From the Canadian patent

A process for producing lubricant oils of low pour point and high viscosity index by partial dewaxing of a lubricant base stock by isomerization dewaxing followed by a selective dewaxing step. The isomerization dewaxing step is carried out using a large pore, high silica zeolite dewaxing catalyst such as high silica .gamma. or zeolite beta which isomerizes the waxy components of the base stock to less waxy branch chain isoparaffins. The severity is controlled to effect only a partial removal of the waxy components. Further removal of the waxy components is effected during a subsequent dewaxing step which selectively removes of the more waxy n-paraffin components, leaving the branched chain …