Electrical insulating oil

Claim 2

An electrical insulating oil in accordance with claim 1 wherein the blend of solvent-extracted residue and the hydrogenated distillate is contacted with clay.

Claim 3

An electrical insulating oil in accordance with claim 1 wherein the solvent used in obtaining the solvent-extracted residue is furfural and the hydrogenating component of the catalyst used in obtaining the hydrogenated naphthenic petroleum distillate is a sulfided combination of nickel, cobalt and molybdenum.

Claim 4

An electrical insulating oil in accordance with claim 1 wherein the solvent used in obtaining the solvent-extracted residue is furfural and the hydrogenating component of the catalyst used in obtaining the hydrogenated naphthenic petroleum distillate is a sulfided combination of nickel and tungsten.

Claim 5

An electrical insulating oil consisting essentially of a clay treated blend of: A. about 5 to about 15 percent by volume of a residue having a viscosity of about 35 to about 50 SUS at 210* F., said residue being the product which remains after removing furfural from the extract obtained by extracting a naphthenic petroleum distillate oil having an API gravity of about 24* , a boiling range within the range of about 560* to about 875* F., a viscosity at 100* F. in the range of about 100 to about 110 SUS, a pour point below about - 40* F. and a naphthene content of about 85 percent by volume with furfural and B. about 85 to about 95 percent by volume of a hydrogenated naphthenic petroleum distillate oil, said naphthenic petroleum distillate oil having an API gravity of about 26* , a boiling range of about 545* to about 710* F., a viscosity at 100* F. in the range of about 58 to about 63 SUS, a pour point below about - 60* F. and a naphthene content of about 80 percent by volume; said hydrogenated naphthenic petroleum distillate oil being produced by contacting a naphthenic petroleum distillate oil with hydrogen in the presence of a catalyst comprising a sulfided combination of about 4 to 16 percent by weight of nickel, cobalt and molybdenum, said contacting being carried out at an average catalyst temperature of about 575* to about 645* F., at a space velocity of about 1.5 to about 3 liquid volumes of oil per volume of catalyst per hour, and at a pressure of about 1,000 p.s.i.g.

Claim 6

An electrical insulating oil in accordance with claim 6 wherein the solvent-extracted residue and the hydrogenated distillate are derived from the same naphthenic crude oil base stock.

Claim 7

An electrical insulating oil in accordance with claim 6 wherein the clay treated blend is obtained by filtering the combined solvent-extracted residue and hydrogenated distillate at ambient temperature through a body of 16 to 60 mesh clay in a proportion of aBout 100 to about 400 barrels of oil per ton of clay.

Claim 8

An electrical insulating oil comprising a major proportion of the clay treated blend of claim 8 and from 0.01 to 1.0 percent by weight of an oxidation inhibitor.

Claim 9

An electrical insulating oil comprising a major proportion of the clay treated blend of claim 8 and a minor oxidation inhibiting amount of 2,6-ditertiary butyl-4-methylphenol.