Insulating oil compositions containing a fraction derived from the alkylation product of benzene with ethylene

#1. Field of the Invention

#This invention relates to novel insulating oil compositions comprising a major amount of an insulating oil and a minor amount of a product obtained as a result of a process which comprises reacting benzene with ethylene in the presence of an alkylation catalyst to obtain a reaction mixture containing largely unreacted benzene, ethylbenzene, polyethylbenzenes, 1,1-diphenylethane and heavier material, separating at least benzene, ethylbenzene and polyethylbenzenes from said reaction mixture and thereafter recovering from said heavier material a fraction whose boiling points fall within a temperature range of about 255.degree. to about 420.degree. C. as said product.

#2. Description of the Prior Art

#The following Table II compares the properties of the naphthenic base oil employed herein with the ASTM D-3487 insulating oil specifications for Type I Oil. The naturally-derived base oil (naphthenic) was obtained from Interprovincial Pipeline No. 1 and was a mixture of low sulfur, low pour point crudes. After conventional distillation, the fraction consisting of a 50:50 mixture of light vacuum and heavy vacuum oils (Gravity .degree.API 25) was subjected to hydrotreating following the conditions in U.S. Pat. No. 3,764,518. The purpose of this treatment was to upgrade the product through hydrocracking, isomerization and saturation. After the first stage hydrotreatment, the product was then subjected to a second stage hydrotreatment following the conditions in Canadian Pat. No. 978,881, wherein the primary purpose of such treatment is to saturate aromatic structures with hydrogen. The product from the two stage hydrotreatment has the properties shown in Table II. The synthetic base oil was prepared in accordance with the procedure of Example 1 of U.S. Pat. No. 4,045,507 of Cupples et al, employing 1-decene as feedstock. The product from this oligomerization, after stripping off unreacted 1-decene, indicated 53 percent conversion, and was found to contain 24 weight percent dimer, the remainder being the trimer, tetramer and pentamer of 1-decene. The total product was then passed over a commercial nickel catalyst (Ni0104T, 1/8-inch pellets having a surface area of 125 square meters per gram) at 165.degree. C. and 600 pounds per square inch gauge (41 kilograms per square centimeter) of hydrogen pressure at a rate sufficient to effect stabilization of the product through hydrogenation. Distillation under vacuum afforded the synthetic base oil used herein, a dimer fraction boiling in the temperature range of 160.degree.-168.degree. C. at five millimeters of mercury.

#TABLE II __________________________________________________________________________ ASTM D-3487, Naturally-derived Synthetic Insulating Oil Description Base Oil (Naph- Base Oil Specifications or Test thenic) (Paraffinic) Type I Oil __________________________________________________________________________ Gravity: .degree.API (ASTM D-1298 34 46.5 -- Specific Gravity, (ASTM-D941) 60.degree./60.degree. F. (15.5.degree./15.5.degree. C.) 0.8550 0.7949 max 0.91 Viscosity, SUV: s (ASTM D-2161) 37.8.degree. C. (100.degree. F.) 59.5 42.6 max 70 98.9.degree. C. (210.degree. F.) 34.7 31.6 max 36.5 Viscosity, Kin: cSt 37.8.degree. C. (100.degree. F.) 10.17 5.06 max 13.0 98.9.degree. C. (210.degree. F.) 2.55 1.65 max 3.1 Interfacial Tension: mN/M (ASTM D-971) 55 50 min 40 Flash, COC: .degree.F. (.degree.C.) (ASTM D-92) 350 (177) 315 (157) min 293 (145) Fire, COC: .degree.F. (.degree.C.) (ASTM D-92) 370 (188) 345 (174) -- Pour Point: .degree.F. (.degree.C.) (ASTM D-97) -55(-48) below -100 (-73) max -40 (-40) Appearance (Visual) bright water white clear & bright Color, (ASTM D-1500) L 0.5 L 0.5 max 0.5 Corrosive Sulfur, (ASTM D-1275 Non-corrosive Non-corrosive Non-corrosive Water: PPM (ASTM D-1315 24 15 max 35 Neutralization No., (ASTM D-974) Total Acid No. <0.03 <0.03 max 0.03 Analine Point, (ASTM D-611): .degree.F. (.degree.C.) 204 (95) 215 (102) 145-172 (63-78) Power Factor, (ASTM D-924): Percent 25.degree. C. (77.degree. F.) 0.002 0.002 max 0.05 100.degree. C. (212.degree. F.) 0.065 0.05 max 0.30 Dielectric Strength: Kv (ASTM D-877) 47 46 min 30 Oxidation Test, (ASTM D-2440) (0.075 Percent DBPC*) 72 Hour Sludge: Percent 0.008 0.001 max 0.15 Total Acid No. 0.10 0.06 max 0.5 164 Hour Sludge: Percent 0.009 0.003 max 0.3 Total Acid No. 0.10 0.10 max 0.6 Rotary Bomb Oxida- tion: Min (0.075 Percent DBPC) (ASTM D-2112), 140.degree. C. 125 480+ -- Analysis, Weight Per- cent Aromatics 0.4 0.0 Saturates 99.6 100 Percent Branched Isoparaffins Mass Spec Analysis, Weight Percent Alkanes 24.0 Average Mol. Weight = 280 1-Ring Cycloalkanes 27.3 2-Ring Cycloalkanes 18.7 3-Ring Cycloalkanes 13.7 4-Ring Cycloalkanes 12.0 5-Ring Cycloalkanes 4.2 Aromatics 0.1 Gassing Tendency; (ASTM D-2300), mm.sup.3 /min Procedure B, 80.degree. C. 50 Minutes Using Hydrogen as Saturant Gas + 38.5 +32.0 -- __________________________________________________________________________ *2,6-ditertiarybutyl-p-cresol

#A product for adding to the naphthenic oil was prepared as follows: Benzene and ethylene in a molar ratio of 9:1 were contacted in the liquid phase, while stirring, in a reactor at a temperature of 130.degree. C. and a pressure of 70 pounds per square inch gauge (4.9 kilograms per square centimeter) in the presence of AlCl.sub.3 catalyst over a period of one hour, which was sufficient to convert all of the ethylene. The AlCl.sub.3 complex catalyst was prepared by dissolving AlCl.sub.3 in a polyethylbenzene cut from a previous run so that after the addition the composition of the catalyst complex was as follows: 31:5 weight percent AlCl.sub.3, 7.0 weight percent benzene, 19.3 weight percent ethylbenzene, 29.8 weight percent polyalkylated benzenes, 3.4 weight percent 1,1-diphenylethane and 9.0 weight percent higher-boiling components. The amount of AlCl.sub.3 present in the catalyst mixture amounted to 0.0034 parts by weight per one part by weight of ethylbenzene produced. Also present in the catalyst was ethyl chloride as promoter in an amount corresponding 0.0034 parts by weight per one part by weight of ethylbenzene produced to maintain a high catalyst efficiency. Analysis of the alkylation product showed the presence of 49.0 weight percent benzene, 32.9 weight percent ethylbenzene, 17.5 weight percent of polyalkylated benzenes (6.0 weight percent diethylbenzene, 2.7 weight percent triethylbenzenes, 2.1 weight percent tetraethylbenzenes and 6.7 weight percent other alkylbenzenes)., 0.1 weight percent 1,1-diphenylethane and 0.4 weight percent residue. The alkylation product was subjected to distillation to recover unreacted benzene, ethylbenzene, polyalkylated benzenes and 1,1-diphenylethane, and the benzene and polyalkylated benzenes were recycled to the reaction zone. The residue remaining was a dark, viscous, high-boiling material, and was produced in an amount corresponding to 0.012 parts for each part of ethylbenzene produced. The residue so obtained was subjected to distillation to obtain a cut having a boiling point at atmospheric pressure within the temperature range of 275.degree. to 400.degree. C. This cut was the product added to the naphthenic oil and to the paraffinic oil in a later example. The incorporation of the product in the naphthenic oil was easily effected by physical blending, since each is miscible in the other in all proportions. Two blends were prepared, one containing 12 weight percent of the product from the residue (Blend No. 1) and the other 15 weight percent (Blend No. 2). The results obtained are tabulated below in Table III.