JPS60230305A - Electrically insulating composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to electrical insulating compositions, particularly compositions useful as high viscosity insulating oils for oil-filled electrical equipment such as capacitors, transformers, reactors, cables and the like.

Conventional technology old cloud top side 1 tube position 41i practice 1 〆訃1shotichi 1o1
1-'-.)- and polybutene mixed with various additives have been used, but high viscosity electrical insulating oils containing cyclic acetal compounds have not been proposed.

In recent years, as the demand for electric power has increased, there has been a growing demand for higher voltage and larger capacity of electrical equipment such as transformers, capacitors, and power cables. As a result, electrical insulating oils used in electrical equipment are now required to have even higher performance in terms of electrical properties, thermal stability, etc.

OBJECTS OF THE INVENTION The present invention provides an electrical insulating composition that has a high dielectric constant and excellent voltage resistance and thermal stability.

Structure of the Invention The present invention has the general formula:
The present invention relates to an electrically insulating composition containing a compound represented by 1, in which +7 tyl group and R represent an alkyl group having 1 to 3 carbon atoms.

The compound used in the present invention is a new compound, and is a cyclic acetal compound having a characteristic six-membered ring hindered structure. Based on this hindered structure, it has extremely high thermal stability and can be used over a wide range of temperatures. It is liquid.

In order to provide preferable electrical properties to the compound represented by the general formula [I], it is preferable that X is a naphthyl group or a tetrahydronaphthyl group, and R is a lower alkyl group, particularly an alkyl group having 1 to 3 carbon atoms. is preferable. In order to be liquid over a wide range of temperatures, cyclic acetals should have a large number of side chains and a hindered structure to provide heat resistance.

The compound represented by formula [I] may be used alone as a high viscosity insulating oil, or may be used in combination with polybutene, etc., which have been conventionally generally used as a high viscosity insulating oil.

The compound represented by Formula II] is produced using 2,2.4-)'J methyl-j,3-bentanediol as a raw material, to which naphthylalkyl ketone or tetrahydronaphthyl ketone is added and dehydrated in the presence of a commonly used esterification catalyst. It can be easily obtained by reaction.

The raw material 2,2.4-)dimethyl-1,3-pentanol has 72 hydroxyl groups in positions suitable for forming a cyclic acetal in terms of its steric structure, and can produce the compound of the present invention in high yield. The cyclic acetal produced from this structural feature provides a characteristic hindered structure to the six-membered ring, resulting in a stable compound.

2.2.4-) In the dehydration reaction between trimethyl-1,3-bentanediol and 7-tyl alkyl ketone or tetrahydronaphthyl ketone, both are used in equivalent amounts and an appropriate azeotropic dehydration solvent such as aromatic benzene is used. Preferably, the reaction is carried out using a group solvent under heating conditions in the presence of a conventional esterification catalyst, such as p-)luenesulfonic acid, and the produced water is taken out of the system. The rinsing using an aromatic solvent is preferably carried out under reflux conditions, for example, in the case of benzene, it is preferably carried out at 80° C. or higher.

Although this dehydration reaction can be carried out without a solvent, the azeotropic dehydration reaction using an aromatic solvent has mild reaction conditions and is easy to control, and the yield is extremely high, making it extremely productive industrially. ing.

Effects of the Invention The compound represented by formula [I] has a higher dielectric constant and a higher visible gas generation voltage than polybutene, which has been generally used as a high viscosity insulating oil, so it is possible to increase the voltage of oil-filled electrical equipment. , especially when used as an impregnating agent for capacitors, the capacitors can be made smaller.

The present invention will be explained below with reference to Examples.

Reference example 1 2-su7thi-2-methyl-4-isopropyl-5,5
-Production of dimethyl-1,3-nooxane: 2.2.4-
Trimethyl-1,3-pentafunol 0. 0, 7 mol (12 og), p-)luenesulfonic acid 0
, 5B, and 300 J of benzene were charged into a stirrer-equipped B flask equipped with a Dean Stark distiller, and stirred while removing the produced water from the system by azeotropy. Approximately 3 (1 g) of anhydrous potassium carbonate was added to the product to neutralize it, and after drying, the salt was filtered, and the benzene layer was distilled.
A portion of 2 mm H1B was collected.

The physical properties of the product are shown in Table-1.

Reference example 2 2-su7thi-2-ethyl-4-isopropyl-5,5
-Production of methyl-1.3-7 oxane: 2,2.4-
Trimethyl-1,3-pentanol (), 7 mol (
102.4 g') to 0.7 mole of 7thyl ethyl ketone (
130g) was reacted in the same manner as in Reference Example 1 in the presence of 0.5g of 1)-toluenesulfonic acid and 200J of benzene, resulting in a reaction of 132-135'C/0, 1. 5
The m+nHB portion was collected. Table 1 shows the physical properties of the obtained compound.

Reference Example 3 Production of 2-7thi-2-(n-propyl)-4-inpropyl-5,5-dimethyl-1,3-one dioxane: 2.2.4-)dimethyl-1,3- Pentan all 0
．． 608 moles (89 g) of 7 thi-11-propyl ketone o,so4 moles (100 g) were reacted in the same manner as in Reference Example 1 in the presence of 0.5 g of 1)-toluenesulfonic acid and 1 ml of benzene, and 132137 °C/l
'l, 12 mmHg portion was collected.

Table 1 shows the physical properties of the obtained compound.

Reference Example 4 Production of 2-tetrahydronaphthyl-2-methyl-4-isopropyl-5,5-dimethyl-1,3-nooxane: 2.2.4-)Tmethyl-1,3-bentanediol 0
．． 0.4 mol (6!'J, 4 g) of tetrahydronaphthyl to 4 mol (58.5 g) 1)-Toluenesulfonic acid 0.5 g and benzene 21', l (', 1 +
React in the same manner as in Reference Example 1 in the presence of n, 0°, 13
0°C to 135°C/l) and 1 mmHg were collected. Table 1 shows the physical properties of the obtained compound.

Note that the ketones used in Reference Examples 1 to 4 above were obtained by Friedel-Crafts reaction of 7-talene (or tetralin) and alkyl chloride. Furthermore, Table 1 also lists the physical properties of polybutene, which has been conventionally used as a high viscosity insulating oil.

EXAMPLES AND COMPARATIVE EXAMPLES The electrical properties of the compounds obtained in the above reference examples and of polybutene, which is a typical compound conventionally widely used as a high viscosity insulating oil, were measured as comparative examples and are shown in Table 2.

Claims (1)

[Claims] 1. General formula: % formula %) [In the formula, X contains a compound represented by 1 representing a heptyl group or a tetrahydronaphthyl group and R representing an alkyl group having 1 to 3 carbon atoms. Electrical insulation composition.