Refrig. compressors rely on returning refrigerant for cooling, if used for any other use, they will likely overheat, and yes, the lubricant also circulates, they have no piston rings, so keeping oil in it could be a problem. Small hermetic type compressors designed for low pressure refrigerants do make acceptable vacuum pumps, I have used them that way for refrig. work. Sulfur dioxide compressors can be problematic, the traces of S02 left in the compressor, combined with moisture from the air can create sulfurous acid, tending to cause rusting, and subsequent seizing up of the compressor, this can be countered by passing a little anhydrous ammonia through it to neutralize the sulfur. Likely one will not run into too much sulfur equipment any more, but it is all interesting. Years ago, I worked on a lot of ammonia refrigeration here locally.