JP2741397B2 - Electrolyte for driving electrolytic capacitors - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrolytic solution for driving an electrolytic capacitor. More specifically, the present invention relates to an electrolytic solution for driving an electrolytic capacitor which can be used particularly for an electrolytic capacitor for medium and high pressure and which can reduce the internal resistance and expand the operating temperature range.

2. Description of the Related Art Conventionally, an electrolytic solution obtained by adding boric acid or a salt thereof to a solvent such as ethylene glycol is generally used. However, this type of electrolyte has the drawback that it has a high specific resistance, increases the loss of the capacitor, causes heat generation, and promotes thermal deterioration. In order to improve such a defect, an electrolyte containing a linear saturated dicarboxylic acid such as azelaic acid, sebacic acid, and decane dicarboxylic acid or a salt thereof as a solute or a salt thereof may be used. However, because of its low solubility in solvents such as ethylene glycol, the dicarboxylic acid was liable to precipitate as crystals at low temperatures, and the disadvantage of deteriorating the low-temperature characteristics of the capacitor could not be avoided. Further, in order to solve the above-mentioned disadvantages of the linear saturated dicarboxylic acid, it is also possible to partially use a saturated dibasic acid having a side chain such as butyloctane diacid or 1,6-decane dicarboxylic acid or a salt thereof as a solute. It is made in. However, although the solubility of these dicarboxylic acids or salts thereof in ethylene glycol or the like is improved as compared with the linear saturated dicarboxylic acids or salts thereof,
At present, the properties at low temperatures are still insufficient, and further improvement is desired.

Means for Solving the Problems In view of the current situation, the present invention has made intensive studies to develop an electrolytic solution for driving an electrolytic capacitor free of the above-mentioned drawbacks, and as a result, the following general formula (1) or (2) was obtained. It has been found that when the compound represented by the formula or a salt thereof is used as a solute, it hardly precipitates as a crystal even at a low temperature and can be a desired electrolytic solution for driving an electrolytic capacitor. Thus, the present invention has been completed.

That is, the present invention provides: [Wherein R ³ represents a lower alkyl group. R is a hydrogen atom or a group (R ³ is the same as above). Or a salt thereof, and (B) a compound represented by the general formula: [In the formula, R ⁴ represents a lower alkyl group. R ¹ represents a lower alkyl group. A compound represented by the formula: or a salt thereof, wherein at least one selected from the group consisting of solutes is dissolved in a solvent containing ethylene glycol as a main solvent. .

In the present specification, examples of the lower alkyl group represented by R ¹ , R ² , R ³ and R ⁴ include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-
A linear or branched alkyl group having 1 to 4 carbon atoms such as a butyl group can be exemplified.

The compound represented by the general formula (1) used in the present invention may be, for example, a compound represented by the general formula R ¹ OH (3) wherein R ¹ represents a lower alkyl group in the presence of an acid catalyst. Wherein cyclohexanone is reacted with hydrogen peroxide in a lower alcohol represented by the formula: [Wherein R ² represents a lower alkyl group. R ³ is the same as above. Is reacted in the presence of a metal salt to obtain an acrylate derivative represented by the general formula [Wherein R ¹ , R ² and R ³ are the same as above. R 'is a hydrogen atom or group (R ² and R ³ are the same as described above). ] It hydrolyzes the dibasic acid ester represented by these.

More specifically, first, cyclohexanone and hydrogen peroxide are reacted in a lower alcohol of the general formula (3) in the presence of an acid catalyst to obtain a lower alkoxycyclohexyl peroxide. Here, as the lower alcohol, for example, anhydrous methanol, ethanol, isopropanol, n-
Butanol, tert-butanol and the like can be mentioned. As the acid catalyst, for example, sulfuric acid, hydrochloric acid, phosphoric acid,
Trifluoroacetic acid and the like can be mentioned, and among these, sulfuric acid and phosphoric acid are particularly preferred. In the reaction between cyclohexanone and hydrogen peroxide, the use ratio of both is not particularly limited, but is usually about 80 to 130 parts, preferably about 80 to 130 parts per 100 parts by weight of the former (hereinafter simply referred to as "parts"). It is preferable to use about 100 to 110 parts. The lower alcohol is usually 200 to 700 parts per 100 parts of cyclohexanone.
Parts, preferably about 250 to 350 parts. The acid catalyst is usually 5 to 10 parts per 100 parts of cyclohexanone.
Parts, preferably about 6 to 8 parts. The reaction suitably proceeds usually under cooling, preferably around −20 to 10 ° C., and is completed in a short time.

In the present invention, lower alkoxycyclohexyl peroxide is produced by the above-mentioned reaction. In the present invention, it is preferable that the reaction solution is used for the next reaction without isolation.

As the acrylate derivative of the general formula (4) used in the subsequent reaction, conventionally known ones can be widely used as long as they correspond to the above general formula (4), for example, methyl methacrylate, ethyl methacrylate , N-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methyl 2-ethyl acrylate, 2-
Examples thereof include methyl (n-propyl) acrylate, methyl 2-isopropylacrylate, methyl 2- (n-butyl) acrylate, and methyl 2- (tert-butyl) acrylate.

When reacting the reaction solution with the acrylate derivative of the general formula (4), a metal salt is used as a catalyst. Here, examples of the metal salt include salts, such as sulfates, chlorides, and ammonium salts of metals such as iron, copper, cobalt, titanium, and tin, and hydrates thereof. Of these, ferrous salts are preferred. Examples of the ferrous salt include ferrous sulfate, ferrous chloride, ammonium ferrous sulfate and the like, and hydrates thereof. Among these, ferrous sulfate is particularly preferable, and ferrous sulfate can be advantageously reused by reducing it with sulfuric acid and iron after the reaction to recover ferrous sulfate. The above metal salts are used alone or in combination of two or more. The above reaction solution and the acrylate derivative of the general formula (4) are
The acrylate derivative of the formula (4) is preferably used in an amount of usually about 100 to 270 parts, preferably about 120 to 250 parts per part. In carrying out the reaction, the above-mentioned acrylate derivative is added to the above-mentioned reaction solution, and under stirring, a metal salt is used as it is or a suspension or homogeneous solution obtained by previously dissolving in a lower alcohol as much as possible is used. Drop slowly. Here, the lower alcohol is preferably of the same type as the lower alcohol used in the reaction between cyclohexanone and hydrogen peroxide. The suspension or homogeneous solution of the metal salt in the lower alcohol is preferably prepared by suspending or dissolving the metal salt in a lower alcohol in an amount of 2 to 4 times the amount of the metal salt in nitrogen gas. In suspending or dissolving the metal liquid, the presence of nitrogen gas allows the above reaction to be performed efficiently. The above reaction is usually carried out under cooling at -20.
The reaction suitably proceeds at about -10 ° C, preferably at -10 ° C to about 5 ° C, and the reaction is generally completed in about 0.3 to 2 hours.

The hydrolysis of the compound of the general formula (5) can be carried out according to a conventional method.

The compound of the general formula (2) used in the present invention is, for example, a compound of the general formula (6) instead of the compound of the above general formula (4). Wherein R ⁴ is the same as above. The styrene derivative represented by the above formula is used and the same treatment as above is carried out.

Here, as the styrene derivative of the general formula (6), conventionally known styrene derivatives can be widely used as long as they correspond to the general formula (6). For example, α-methylstyrene, α-ethylstyrene, α- ( n-propyl) styrene, α-isopropylstyrene, α- (n-butyl) styrene, α
-Isobutylstyrene, α- (tert-butyl) styrene and the like.

The thus obtained compound of the general formula (1) or (2) of the present invention can be easily isolated and purified from the reaction mixture by a conventional separation and purification means, for example, distillation or the like.

Examples of the salt of the compound represented by the general formula (1) or (2) include an ammonium salt.

In the present invention, the compound of the general formula (1) or (2) or a salt thereof is used as a solute of an electrolytic solution for driving an electrolytic capacitor.

The proportion of the compound of the general formula (1) or (2) or a salt thereof and ethylene glycol is not particularly limited and can be appropriately selected within a wide range.
Usually, the former is preferably used in a ratio of 5 to 30:95 to 70 (W / W). In the present invention, another solvent such as methyl cellosolve may be appropriately added to ethylene glycol as a solvent, and the compound of the above general formula (1) or (2) or a salt thereof may be added to boric acid or adipic acid as a solute. And the like can be added as appropriate.

Effects of the Invention The compound of the general formula (1) or (2) or a salt thereof used in the present invention has high solubility in ethylene glycol. As a result, according to the present invention, it is possible to provide an electrolytic solution for a medium-to-high pressure electrolytic capacitor which operates stably in a wide temperature range from low to high temperatures and has a high spark starting voltage, and therefore uses the electrolytic solution of the present invention. Thus, the reliability of the electrolytic capacitor for medium and high pressure can be remarkably improved.

Examples Hereinafter, the present invention will be further clarified with reference to Production Examples and Examples.

Production Example 1 A reaction vessel equipped with a stirrer was charged with 460 kg of anhydrous methanol, cooled to 5 ° C., and charged with 160 kg of cyclohexanone and concentrated sulfuric acid.
After adding 0 kg and stirring, 160 kg of 35% aqueous hydrogen peroxide is gradually added, and stirring is continued for 10 minutes while keeping the temperature at 5 ° C. to cause a reaction. In this reaction solution, 200 kg of methyl methacrylate is dissolved, and 480 kg of ferrous sulfate (heptahydrate) is gradually added in a nitrogen gas while keeping the reaction temperature at -20 to -5 ° C to cause a reaction. After the reaction, the mixture is allowed to stand and separated to separate an upper ester layer and a lower ferric salt solution. The ester layer is washed with water, dried, and then distilled at 100 to 120 ° C./1 mmHg to obtain a compound of the general formula (5) wherein R ′ is a hydrogen atom and R ¹ , R ² and R ³ are both methyl groups. Get 263 kg. Yield 70% Elemental analysis value (as C ₁₂ H ₂₂ O ₄ ) Theoretical value of C H (%): 62.58 9.63 Actual value (%): 62.34 9.91 Boiling point: 108-110 ° C./1 mmHg HNMR (CDCl ₃ , 270 MHz, ppm / TMS) 1.14 (d, J = 5.4Hz, 3H, C H 3) 1.25~1.80 (br, 10H, methylene) 2.30 (t, J = 8.1Hz , 2H, -COC H 2 -) 2.43 (sextet, J = 5.4Hz, 1H, C H -CH 3) 3.67 (s, 6H, OC H 3) mass spectrum (m / e): 230 ( P +), 199 (P + -OCH 3), IR spectrum ^{(neat, cm -1): 2930,2850,1740,1430,1360,1200 CNMR (} CDCl 3, 270MHz, ppm / TMS) 17.0 (C H 3), 24.7,27.0,28.7,29.3,33.6,34.0 , 39.3,
_{51.4 (O C H 3),} 51.7 (O C H 3), 174.2 (C = O), 177.
2 (C = O) The compound obtained above was then hydrolyzed according to a conventional method, and further blown with ammonia to obtain an ammonium salt.
This ammonium salt is referred to as Compound A.

Production Example 2 460 kg of anhydrous methanol was placed in a reaction vessel equipped with a stirrer, cooled to 5 ° C., and 160 kg of cyclohexanone and 1% of concentrated sulfuric acid were added.
After adding 0 kg and stirring, 160 kg of 35% aqueous hydrogen peroxide is gradually added, and stirring is continued for 10 minutes while keeping the temperature at 5 ° C. to cause a reaction. 400 kg of methyl methacrylate is dissolved in the reaction solution, and 480 kg of ferrous sulfate (heptahydrate) is gradually added to the reaction solution while keeping the reaction temperature at -20 to -5 ° C in nitrogen gas. After the reaction, the mixture is allowed to stand and separated to separate an upper ester layer and a lower ferric salt solution. The ester layer was washed with water, dried, and then distilled at 140 to 170 ° C./1 mmHg. And 326 kg of a compound of the general formula (5) in which R ¹ , R ² and R ³ are both methyl groups are obtained. Yield 61% Elemental analysis (as C ₁₇ H ₃₀ O ₆ ) Theoretical value of CH (%): 61.79 9.15 Actual value (%): 62.01 8.92 Boiling point: 153 to 155 ° C./1 mmHg HNMR (CDCl ₃ , 270 MHz, ppm / TMS) 1.10 (d, J = 5.4Hz, 3H, C H 3) 1.15 (s, 3H, C H 3) 1.20~1.80 (m, 12H, methylene) 2.27 (t, J = 6.8Hz , 2H, COC _{H 2) 2.40~2.60 (c, 1H} , COC H) 2.63,3.64 and 3.67 (each s, 9H, OCH ₃₎ mass spectrum (m / e): 330 ( P +), 299 (P + -OCH 3) , IR spectrum ^{(neat, cm -1): 2950,2855,1745,1430,1360,1205 CNMR (} CDCl 3, 270MHz, ppm / TMS) 17.1 (C H 3), 19.6 (C H 3), 21.2,24.3, 24.6,28.9,2
_{9.7,33.9,35.8,39.4,43.1,51.5 (O C H 3),} 51.6 (O C H
_{3), 51.7 (O C H} 3), 174.3 (C = O), 177.3 (C =
O), 177.5 (C = O) The compound obtained above was then hydrolyzed according to a conventional method, and further blown with ammonia to give an ammonium salt.
This ammonium salt is referred to as Compound B.

Production Example 3 460 kg of anhydrous methanol was placed in a reaction vessel equipped with a stirrer, cooled to 5 ° C., and 80 kg of cyclohexanone and 5 k of concentrated sulfuric acid were added.
Then, 80 kg of 35% hydrogen peroxide solution is gradually added with stirring, and stirring is continued for 10 minutes while keeping the temperature at 5 ° C. to cause a reaction. In this reaction solution, 120 kg of α-methylstyrene is dissolved, and 240 kg of ferrous sulfate (heptahydrate) is gradually added while keeping the reaction temperature at −20 to −5 ° C. in nitrogen gas to cause a reaction. After the reaction, the mixture is allowed to stand and separated to separate an upper ester layer and a lower ferric salt solution. The ester layer was washed with water, dried, and then distilled at 150 to 175 ° C / 2 mmHg to obtain the formula 137 kg of the compound represented by are obtained. Yield 90% Elemental analysis value (as C ₁₇ H ₂₆ O ₃ ) Theoretical value of C H (%): 73.34 9.41 Observed value (%): 73.37 9.19 Boiling point: 163 to 165 ° C./1 mmHg HNMR (CDCl ₃ , 270 MHz, ppm / TMS) 1.05~1.85 (m, 8H , methylene) 1.51 (s, 3H, C H 3) 1.70 (t, J = 6.8Hz, 2H, C H 2 COCH 3) 2.25 (t, J = 8.1Hz, 2H _{, C H 2 CO) 3.06 (} s, 3H, OC H 3) 3.65 (s, 3H, COOC H 3) 7.15~7.45 (m, 5H, C 6 H 5) mass spectrum (m / e): 278 ( P ⁺ ), 263 (P ⁺ -CH ₃ ), 247 (P ⁺ -OCH ₃ ), 135 (P ⁺ -CH ₃ OOC (CH ₂ ) ₆ ), 105 IR spectrum (neat, cm ^-1 ): 3050, 3020 , 2930,2850,1735,1480,1450,1370,1170,107
_{0,770,680 CNMR (CDCl 3, 270MHz,} ppm / TMS) 22.9 (C H 3), 23.7,24.8,28.9,29.6,33.9,42.8,52.2
_{(O C H 3), 51.4} (COO C H 3), 79.1 (C OCH 3), 126.9, 128.2 ( ortho), 1261 (meth) 124.8 (para), 174.3 (C OOCH ₃₎ The compound obtained in the above Was then hydrolyzed according to a conventional method, and ammonia was further blown into ammonium salts.
This ammonium salt is referred to as Compound C.

Example 1 Compound A 6 parts Ethylene glycol 94 parts Example 2 Compound A 5 parts Ethylene glycol 92 parts Ammonium borate 3 parts Example 3 Compound A 5 parts Ethylene glycol 92 parts Ammonium sebacate 3 parts Example 4 Compound B 6 parts Ethylene Glycol 94 parts Example 5 Compound B 5 parts Ethylene glycol 92 parts Ammonium borate 3 parts Example 6 Compound B 5 parts Ethylene glycol 92 parts Ammonium sebacate 3 parts Example 7 Compound C 10 parts Ethylene glycol 87 parts Ammonium borate 3 parts Execution Example 8 Compound A 5 parts Ethylene glycol 92 parts Ammonium benzoate 3 parts Example 9 Compound B 5 parts Ethylene glycol 92 parts Ammonium benzoate 3 parts Comparative example 1 Ethylene glycol 75 parts Ammonium borate 25 parts Comparative example 2 Ethylene glycol 95 parts Sebacine Acid Moniumu 5 parts Comparative Example 3 Ethylene glycol 95 parts of azelaic acid ammonium 5 parts Examples 1 to 7 and Comparative obtained in Examples 1-3 electrolyte per examined the specific resistance ([Omega] cm) and spark starting voltage (V).
The results are shown in Table 1 below.

Next, an aluminum electrolytic capacitor (400 V, 220 μF) using the electrolytic solution obtained in Examples 1 to 3 and 7 and Comparative Examples 1 to 3
Table 2 below shows the results of a high-temperature load life test after 2500 hours at 110 ° C.

As is clear from Table 2 above, the aluminum electrolytic capacitors using the electrolytic solution of the present invention all have a capacity change rate,
All properties of tan δ, leakage current and appearance change are remarkably excellent.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-277208 (JP, A) JP-A-2-298007 (JP, A) JP-A-2-298008 (JP, A) JP-A-2-298 298009 (JP, A) JP-A-2-14539 (JP, A) JP-A-2-145542 (JP, A)

Claims (1)

(57) [Claims] (1) General formula (A) [Wherein R ³ represents a lower alkyl group. R is a hydrogen atom or a group (R ³ is the same as above). Or a salt thereof, and (B) a compound represented by the general formula: [In the formula, R ⁴ represents a lower alkyl group. R ¹ represents a lower alkyl group. ] An electrolytic solution for driving an electrolytic capacitor, characterized in that at least one selected from the group consisting of a compound represented by the following formula or a salt thereof is dissolved in a solvent containing ethylene glycol as a main solvent.