Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/20—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils
  • H01B3/22—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils hydrocarbons

Definitions

• This invention relates to a liquid dielectric composition obtained from the alkylation product of benzene with ethylene.
• Belgian Patent A-504293 discloses that an oil for use as electrical insulation for cables can be obtained from the product of alkylation of aromatic hydrocarbons by heating the alkylation product which has a molecular weight above 500, for example with an absorbent such as a decolourising earth, silica gel or alumina.
• a liquid dielectric composition obtained as a result of a process which comprises reacting benzene with ethylene in the presence of an alkylation catalyst to obtain an alkylation product containing unreacted benzene, ethylbenzene, polyethylbenzenes and higher molecular weight products, separating benzene, ethylbenzene and polyethylbenzenes from said alkylation product and thereafter recovering from said higher molecular weight products by distillation a fraction having a boiling point in the range of 255°C to 420°C, said fraction having dielectric properties, characterised in that said distillation is conducted in the presence of a basic material selected from the group consisting of Group I alkali metals and Group II alkaline earth metals, their oxides and hydroxides.
• the process employed in obtaining the new liquid dielectric compositions defined and claimed herein comprises reacting benzene with ethylene in the presence of an alkylation catalyst to obtain an alkylation product containing largely unreacted benzene, ethylbenzene, polyethylbenzenes and heavier products, separating benzene, ethylbenzene and polyethylbenzenes from said alkylation product and thereafter recovering from said heavier products by distillation in the presence of a basic material a fraction having a boiling point at atmospheric pressure (ambient pressure) in the temperature range of about 255° to about 420°C, preferably about 265° to about 400°C, most preferably about 275° to about 400°C, as said liquid dielectric composition.
• ambient pressure atmospheric pressure
• the alkylation of benzene with ethylene that can be employed to obain the new liquid dielectric compositions claimed herein can be any of the processes known in the art for producing a product containing ethylenzene, for example either liquid phase alkylation or vapor phase alkylation.
• the molar ratios of benzene to ethylene employed can be, for example, in the range of about 25:1 to about 2:1, prefeably about 10:1 to about 3:1.
• the benzene and ethylene together with an alkylation catalyst, for example, a Friedel Crafts catalyst, such as aluminum chloride, or aluminum bromide or some other organoaluminum halide; Lewis acid, such as promoted ZnCl 2 , FecI 3 and BF 3 , and Bronsted acids, including sulfuric acid, sulfonic acid and p-toluene sulfonic acid, hydrofluoric acid, etc., in an amount corresponding to about 0.002 to about 0.050 parts, preferably about 0.005 to about 0.030 parts, relative to ethylbenzene produced, are reacted in a temperature range of about 20° to about 175°C, preferably about 90° to about 150°C, and a pressure in the range of about atmospheric to about 250 pounds per square inch gauge (about atmospheric to about 17.6 kilograms per square centimeter that is, about 170x104 Pa), preferably about seven to about 200 pounds per square inch gauge (about
• the reactants can be passed over a suitable alkylation catalyst bed containing alkylation catalysts such as phosphoric acid on kieselguhr, silica or alumina, aluminum silicates, etc. at a convenient space velocity in a temperature range of about 250° to about 450°C, preferably about 300° to about 400 °C, and a pressure of about 400 to about 1200 pounds per square inch gauge (about 28 to about 85 kilograms per square centimeter that is, about 265x10 4 Pa to about 830x104 Pa), preferably about 600 to about 1000 pounds per square inch gauge (about 42 to about 70 kilograms per square centimeter that is, about 410x10 4 Pa to about 690x104 pa).
• alkylation catalysts such as phosphoric acid on kieselguhr, silica or alumina, aluminum silicates, etc.
• an alkylation product is obtained containing unreacted benzene, the desired ethylbenzene, polyethylbenzenes, such as diethylbenzene and triethylbenzene, and higher-boiling products.
• the alkylation product can be treated in any conventional manner to remove any alkylation catalyst present therein.
• the alkylation product can be sent to a settler wherein the aluminum chloride complex is removed and recycled to the reaction zone and the remaining product can then be water washed and neutralized.
• the resulting alkylation product is then distilled atmospheric pressure or under vacuum to recover unreacted benzene (B.P. 80°C), ethylbenzene (B.P.136°C) and polyethylbenzenes (B.P. 176-250°C).
• the heavier product remaining after removal of benzene, ethylbenzene and polyethylbenzenes, as described above, is a dark, viscous, high-boiling material from which the novel liquid dielectric compositions defined and claimed herein are obtained.
• the said heavier product is simply subjected to distillation in the presence of a basic material and those portions recovered having a boiling point at atmospheric pressure (14.7 pounds per square inch or 760 millimeters of mercury that is 10.13x10 4 Pa) in the temperature range of about 255° to about 420°C, preferably about 265° to about 400°C, most preferably about 275° to about 400°C, constitute the desired and novel liquid dielectric composition.
• the remaining heavier material or residue is a black asphalt-like material solid at ambient temperature believed, in part, to be polynuclear structure having fuel value only.
• the basic material present during the distillation defined above is selected from the group consisting of Group I and Group II alkali metals and alkaline earth metals, their oxides and hydroxides. Of these lithium, sodium, potassium, magnesium, calcium, strontium and barium, their oxides and hydroxides are preferred.
• the amount of basic material in the distillation zone can be, for example, in the range of about 0.5 to about 20 weight per cent, preferably about one to about 10 weight per cent, based on the weight of the charge being subjected to distillation.
• the distillation is carried out while stirring the mixture or in the presence of boiling chips to avoid bumping.
• reduced or increased pressure can be used during the distillation, with the temperature being correlated therewith so that the material distilled off and recovered herein will be those portions of the heavier product, defined above, corresponding to those portions having a boiling point at atmospheric pressure of about 255 0 to about 420°C, preferably to about 265" to about 400°C, most preferably about 275° to about 400 °C.
• the residue remaining after such distillation is a black asphalt-like material solid at ambient temperature having fuel value only.
• a number of liquid dielectric compositions were prepared from the residue, or heavier products, obtained as a result of the production of ethylbenzene.
• This residue was obtained as follows. Benzene and ethylene in a molar ratio of9:1 were contacted in the liquid phase, while stirring, in a reactor at a temperature of 130°C and a pressure of 70 pounds per square inch gauge (4.9 kilograms per square centimeter that is, 48x104 Pa) in the presence of AICI 3 catalyst over a period of one hour, which was sufficient to convert all of the ethylene.
• the AICI 3 complex catalyst was prepared by dissolving AICI 3 in a polyethylben- zene cut from a previous run so that after the addition the composition of the catalyst complex was as follows: 31.5 weight per cent AICI 3 , 7.0 weight per cent benzene, 19.3 weight per cent ethylbenzene, 29.8 weight per cent polyalkylated benzenes, 3.4 weight per cent 1,1-diphenylethane and 9.0 weight per cent higher-boiling components.
• the amount of AICI 3 present in the catalyst mixture amounted to 0.0034 parts by weight per one part by weight of ethylbenzene produced.
• ethyl chloride promoter in an amount corresponding to 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 per cent benzene, 32.9 weight per cent ethylbenzene, 17.5 weight per cent of polyalkylated benzenes (6.0 weight per cent diethylbenzene, 2.7 weight per cent triethylbenzenes, 2.1 weight per cent tetra- ethylbenzenes and 6.7 weight per cent other alkylbenzenes), 0.1 weight per cent 1,1-diphenylethane and 0.4 weight per cent residue.
• the alkylation product was subjected to distillation to recover unreacted benzene, ethylbenzene and polyalkylated benzenes, 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 0.014 parts for each part of ethylbenzene produced.
• aged aluminum chloride complex the amount of high-boiling residue formed can be increased substantially.
• the residue obtained was subjected to distillations at atmospheric pressure arbitrarily to obtain selected cuts thereof.
• One cut (Run No. 1 in the Table below) was untreated.
• Another cut (Run No. 2) was washed three times with a 10 per cent aqueous sodium hydroxide solution prior to distillation.
• a third cut (Run No. 3) was washed three times with a 10 per cent aqueous sodium hydroxide solution, then with water and dried.
• the remaining cuts (Runs Nos. 4, 5, 6, and 8) were distilled in the presence of selected basic materials at atmospheric pressure.
• Each of the above was subjected to tests (ASTM-D924) at 25° and 100°C to determine its power factors and dielectric strenght. The results obtained are set forth below in the following Table.
• Run No. 2 the procedure was difficult to carry out because of emulsion problems. Some emulsion problems were also noted in Run No. 3. It can be seen from the data in the Table that greatly improved results are obtained when the dictates of the process employed herein are adhered to.
• Run No. 1 wherein the defined cut was not treated, the product possessed an excellent dielectric strength and a good power factor at 25°C. Its power factor at 100°C was somewhat high. Although there was a slight improvement in the power factor at 100°C in Run No. 2, as noted emulsion problems were encountered.
• the defined cut was treated with sodium hydroxide in Run No. 3 after distillation, its dielectric strength and power factors were adversely affected. However, in each of Runs Nos.
• compositions can be further treated, if desired, for example, to further improve their properties for a particular purpose, for example, to improve their flash point, interfacial tension, pour point, viscosity, oxidation stability, corrosion resistance, etc.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Organic Insulating Materials (AREA)

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• 1977
  • 1977-07-21 US US05/817,694 patent/US4108788A/en not_active Expired - Lifetime
• 1978
  • 1978-06-14 CA CA305,409A patent/CA1104161A/en not_active Expired
  • 1978-06-27 EP EP78300088A patent/EP0000621B1/en not_active Expired
  • 1978-06-27 DE DE7878300088T patent/DE2860516D1/de not_active Expired
  • 1978-07-20 IT IT25917/78A patent/IT1099580B/it active
  • 1978-07-20 JP JP8779278A patent/JPS5423087A/ja active Granted

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