Electricity: electrical systems and devices – Electrostatic capacitors – Fixed capacitor
Patent
1991-01-07
1992-04-21
Griffin, Donald A.
Electricity: electrical systems and devices
Electrostatic capacitors
Fixed capacitor
174 25C, H01G 422, H01B 324
Patent
active
051073951
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a method of producing an electrical insulating oil comprising dibenzylbenzenes. The insulating oil prepared according to the present invention is suitably used for oil-filled electrical appliances in which at least a part of insulating material of dielectric material is made of a plastic film. It is used more preferably for oil-filled capacitors, especially suitable for oil-filled metallized plastic film capacitors.
2. Background Art
The reduction of sizes and weights of oil-filled capacitors and oil-filled cables are recently eagerly required. In order to comply with the requirement, the insulating materials or dielectric materials are, at least partially, made of plastics, for example, polyolefin such as polypropylene.
In spite of the attempt to improve the structure itself of oil-filled electrical appliances, there is no satisfactory improvement in the electrical insulating oil to be used for impregnation. In other words, for example, the conventional insulating oils such as refined mineral oils, polybutenes, alkylbenzenes, diarylalkanes, alkylbiphenyls and alkylnaphthalenes are not always satisfactory in view of their properties and characteristics. Under the existing circumstances, there are few electrical insulating oils which are suitable for the oil-filled electrical appliances such as oil-filled capacitors, especially metallized-film capacitors (hereinafter referred to as "MF capacitor") in which a metallized film made by depositing a metal such as aluminum is wound as an electrode and an electrical insulating oil is impregnated.
That is, presently used MF capacitors are mainly the so-called dry-type MF capacitors which are not impregnated with an electrically insulating material such as insulating oil. In capacitors as well as in other electrical appliances, the potential gradient is generally high when an electrically insulating material exists around electrodes or conductors. Accordingly, the voltage-withstanding property of an impregnated MF capacitor is higher than that of a dry-type capacitor and the former capacitor can comply with the requirements for reducing the sizes and weights of capacitors. Nevertheless, the metallized film using a plastic base film such as polypropylene film receives a large influence of oil impregnation. For example, the size of base film is changed by oil impregnation and even when impregnation oil slightly permeates between a deposited metal layer and a base film, deposited metal layer is creacked, and what is worse, the deposited metal film is often peeled off, which results into dielectric breakdown. Accordingly, the electrical insulating oil suitable for MF capacitors is few.
For example, in an MF capacitor which is impregnated with benzyltoluene or phenylxylylethane, the capacity is lowered severely in use and the corona (partial) discharge characteristic is not always good.
DISCLOSURE OF THE INVENTION
The present invention relates to a method for producing electrical insulating oil which is characterized in that benzene or toluene is reacted with diphenylmethane or its derivative at a reaction temperature of 170.degree. to 400.degree. in the presence of a synthetic crystalline zeolite catalyst having a molar ratio of SiO.sub.2 to Al.sub.2 O.sub.3 of 20 or above, wherein the inlets of main pores are constituted of ten-membered oxygen rings.
The present invention will be described in more detail in the following.
A method to produce xylene by the disproportionation between toluene molecules in the presence of ZSM-5 type zeolite catalyst (British Patent No. 1,463,359). This is naturally accomplished by transfer of methyl groups.
When dibenzylbenzene is produced from toluene and diphenylmethane using ZSM-5 type zeolite, assuming that the transfer of methyl group is caused to occur, the formation of xylene is naturally presumed because toluene exists. If xylene is produced, it is not desirable because the yield of dibenzylbenzene is lowered owing to the consumption of toluene. Therefore, it was presumed
REFERENCES:
patent: 3481997 (1969-12-01), Vanderwerff
patent: 4568793 (1986-02-01), Sato et al.
Dohi Hideyuki
Endo Keiji
Kawakami Shigenobu
Sato Atsushi
Griffin Donald A.
Nippon Petrochemicals Company Limited
LandOfFree
Method of producing insulating oil comprising dibenzylbenzene does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of producing insulating oil comprising dibenzylbenzene, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing insulating oil comprising dibenzylbenzene will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1592020