Manufacture of transformer oils

Claim 1

A PROCESS FOR MANUFACTURING A TRANSFORMER OIL WHICH CONSISTS ESSENTIALLY OF SELECTING A NAPHTHENIC DISTILLAT BOILING IN THE RANGE OF ABOUT 450*F. TO ABOUT 775*F., CHARACTERIZED BY AN AROMATIC CONTENT LESS THAN 30 PERCENT, AN ALKANE CONTENT LESS THAN 5 PERCENT, THE BALANCE BEING SUBSTANTIALLY ALLNAPHTHENES AND HAVING A FLASH POINT NOT LESS THAN ABOUT 275*F., A VISCOSITY AT 100*F. OF FROM ABOUT 55 TO ABOUT 75 SUS AND A SPECIFFIC GRAVITY OF ABOUT 0.865 TO ABOUT 0.905; CONTACTING SAID DISTILLATE WITH HYDROGEN IN THE PRESENCE OF A HYDROGENATION CATALYST AT A TEMPERATURE OF ABOUT 550*F. AT A PRESSURE IN THE RANGE FROM ABOUT 200 TO ABOUT 5,000 PSIG. AT A SPACE VELOCITY BETWEEN ABOUT 0.2 AND ABOUT 5 VOLUMES PER HOUR PER VOLUME OF CATALYST AND A HYDROGEN CIRCULATION RATE FROM ABOUT 250 TO ABOUT 15,000 S.C.F PER BARREL PERCLOATING THE RESULTING HYDROTREATED OIL THROUGH CLAY, UTILIZING A VOLUME RATIO OF OIL TO CLAY BETWEEN ABOUT 5 AND ABOUT 10 AND RECOVERING FROM SUCH OPERATION A PRODUCT CONSTITUTING A TRANSFORMER OIL.