JP2001253850A - Method for producing ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an ester of an aliphatic polyhydric alcohol containing a small amount of an acid anhydride. SOLUTION: This method for producing the ester is characterized in that the method comprises a step for purifying the ester (full ester) obtained by esterifying the whole hydroxy groups of the aliphatic polyhydric alcohol by subjecting the aliphatic polyhydric alcohol and a saturated aliphatic monocarboxylic acid to an esterification reaction to provide the full ester whose whole hydroxy groups are esterified by using an adsorbent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an ester of an aliphatic polyhydric alcohol.

[0002]

2. Description of the Related Art Reducing friction and wear on sliding surfaces of moving parts of machinery, equipment, equipment, etc. is a basic performance of lubricating oil, and lubricating oil is used in automobiles, ships, aircraft, and various industrial machines. It is used in various fields such as equipment, electric products and the like.

[0003] Ester oil is known as one of lubricating oils, and a typical example thereof is a polyol ester comprising an aliphatic polyhydric alcohol and a saturated aliphatic monocarboxylic acid.

In the production of a polyol ester, usually, the number of moles of the hydroxyl group of the aliphatic polyhydric alcohol is
Although a saturated aliphatic monocarboxylic acid is used in an amount of 1 mol or more, there is a problem that an acid anhydride which is a dehydration condensate of two molecules of a saturated aliphatic monocarboxylic acid is by-produced during the esterification reaction. .

When a polyol ester composition containing a large amount of acid anhydride is used, for example, as a lubricating oil, the acid anhydride is hydrolyzed by the moisture in the ester composition or the moisture in the air, causing an increase in the acid value. Causes metal corrosion.

[0006]

An object of the present invention is to provide a method for producing an ester of an aliphatic polyhydric alcohol having a low acid anhydride content.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to an ester obtained by subjecting an aliphatic polyhydric alcohol and a saturated aliphatic monocarboxylic acid to an esterification reaction, wherein all of the hydroxyl groups of the aliphatic polyhydric alcohol are esterified ( (Furester) with an adsorbent.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The aliphatic polyhydric alcohol which is a raw material of the production method of the present invention is not particularly limited, but is preferably a linear or branched aliphatic polyhydric alcohol having 2 to 20 carbon atoms. Specific examples include ethylene glycol, diethylene glycol, triethylene glycol,
Tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol,
1,3-propanediol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol, 2
-Methyl-1,2-propanediol, 2-methyl-
1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,5-hexanediol, , 6-hexanediol, 2,5-hexanediol, 2-methyl-
2,4-pentanediol, 2,3-dimethyl-2,3
-Butanediol, 1,7-heptanediol, 2-ethyl-1,3-hexanediol, 2,4-dimethyl-
2,4-pentanediol, 1,2-octanediol, 1,8-octanediol, 2,5-dimethyl-
2,5-hexanediol, glycerin, diglycerin, triglycerin, tetraglycerin, neopentyl glycol, 2-ethyl-2-methyl-1,3-propanediol, 2-isopropyl-2-methyl-1,3-
Propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1, 5-pentanediol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol and the like can be mentioned, among which pentaerythritol, trimethylolpropane or 2,4-diethyl-1,5-pentanediol is more preferably used. You. The aliphatic polyhydric alcohols are used alone or in combination of two or more.

The saturated aliphatic monocarboxylic acid is not particularly limited, but is preferably a linear or branched saturated aliphatic monocarboxylic acid having 2 to 36 carbon atoms, specifically, acetic acid, propionic acid, n- Butyric acid, isobutyric acid, n-valeric acid,
Isovaleric acid, n-hexanoic acid, 2-ethylpentanoic acid,
3-ethylpentanoic acid, 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, caprylic acid, 2-ethylhexanoic acid, 3,5
-Dimethylhexanoic acid, 2,2-dimethylhexanoic acid,
2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 2-propylpentanoic acid, 3,4-dimethylhexanoic acid, pelargonic acid, 2,2-dimethylheptanoic acid, 3,5,5-trimethyl Hexanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid, 3-methyloctanoic acid, n-decanoic acid, isodecanoic acid, isotridecanoic acid, isohexadecanoic acid, etc., among which 2-
Ethylhexanoic acid or 3,5,5-trimethylhexanoic acid is preferably used. The above saturated aliphatic monocarboxylic acids are used alone or in combination of two or more.

An adsorbent is a substance that provides an interface that causes positive adsorption, and is not particularly limited.
For example, magnesium, aluminum, silicon, sodium, iron, manganese, at least one metal selected from the group consisting of calcium and potassium oxides or hydroxides or those containing at least one metal containing clay minerals and the like, and the like. Among them, preferred are those containing an oxide or hydroxide of at least one metal selected from aluminum and silicon or clay minerals containing at least one of the above metals, and further include oxides or hydroxides of magnesium or magnesium. Those containing clay minerals are more preferably used.
Specific examples of the adsorbent containing an oxide or hydroxide of at least one metal selected from magnesium, aluminum, and silicon or a clay mineral containing at least one of the above metals include silica-alumina, activated alumina, magnesia, and activated carbon. Clay, bentonite, kaolin,
Zeolite, magnesia-silica, magnesia-alumina and the like can be mentioned. The above adsorbents are used alone or in combination of two or more.

The esterification reaction between an aliphatic polyhydric alcohol and a saturated aliphatic monocarboxylic acid is usually carried out at 150 to 300.
C., preferably at 200-250.degree. The reaction time is not particularly limited because it varies depending on the scale of the reaction and the like, but is preferably 1 to 10 hours. The pressure is carried out at normal pressure or reduced pressure.
It is 80 kPa. In the esterification reaction, a catalyst may be used. In this case, the amount of the catalyst used is 0.01 to 0 of the raw material charged amount (total charged amount of the aliphatic polyhydric alcohol and the saturated aliphatic monocarboxylic acid). It is preferably 0.5% by weight, and more preferably 0.05 to 0.3% by weight. As the catalyst in this case, for example, sulfuric acid, p-
Examples thereof include toluenesulfonic acid, tin oxide, and alkyl titanate.

The ratio of the saturated aliphatic monocarboxylic acid to the number of moles of the hydroxyl group of the aliphatic polyhydric alcohol is usually 1.0.
It is 2.0 to 2.0 times, preferably 1.1 to 1.6 times.

The timing of stopping the esterification reaction is not particularly limited.

[0014]

(Equation 1)

The production rate of the full ester of the aliphatic polyhydric alcohol calculated by the above is preferably 70% or more,
It is more preferably at least 90%, further preferably at least 98%. Further, the esterification reaction can be stopped, for example, by cooling the reaction solution to room temperature.

After the esterification reaction, the reaction solution may be treated, if necessary, by a purification method generally used in organic synthetic chemistry, for example, neutralization, washing, or distillation.

In the present invention, the full ester obtained as described above is purified (treated) with an adsorbent.

As a purification method using an adsorbent, the adsorbent is usually used in an amount of 0.1 to 20% by weight based on the full ester.
A method in which 1 to 10% by weight is preferably used and the solution is passed through a column filled with an adsorbent at 0 to 100 ° C., preferably 10 to 80 ° C., and a method of contacting by agitation or the like in a batch system.

The purification (treatment) time with the adsorbent is not particularly limited, but is usually 10 minutes to 8 hours, preferably 3 minutes.
0 minutes to 5 hours.

When the full ester purified by the adsorbent is used for, for example, lubricating oil, the acid anhydride content is preferably 0.7% by weight or less. Since the acid anhydride produced as a by-product during the esterification reaction is adsorbed on the adsorbent, the full ester treated with the agent has an acid anhydride content of 0.7% by weight or less and contains almost no acid anhydride. Absent. Therefore, the acid value does not increase due to storage or the like without causing hydrolysis of the acid anhydride.

The full ester purified by the adsorbent is
By adding additives such as antioxidants, extreme pressure agents, oiliness improvers, defoamers, metal deactivators, etc. as necessary, jet engine oils, engine oils, lubricating oils, flame-retardant hydraulic oils And biodegradable hydraulic oils.
Antioxidants include 2,6-di (t-butyl) -p-
Phenolic antioxidants such as cresol; amine antioxidants such as phenothiazine; sulfur antioxidants such as benzothiazole; and the like. Extreme pressure agents and oiliness improvers include zinc compounds such as zinc dialkylthiophosphate. , Phosphorus compounds such as tricresyl phosphate, sulfur compounds such as dibenzothiophene, etc., and examples of the antifoaming agents include silicone oils such as dimethylpolysiloxane, and organosilicates such as diethyl silicate. Examples of the agent include quinizarin, mercaptobenzothiazole and the like.

Further, depending on the use, if necessary, the full ester purified by an adsorbent may be further treated by a purification method usually used in organic synthetic chemistry, for example, neutralization, washing, distillation or the like. Is also good.

[0023]

Example 1 (1) Production of full ester A 1 L flask equipped with a stirrer, a thermometer, a nitrogen blowing tube, and a dehydrating tube equipped with a cooling tube was prepared, and 136.2 g (1 mol) of pentaerythritol was prepared. And 331.7 g (2.3 mol) of 2-ethylhexanoic acid and 363.9 g (2.3 mol) of 3,5,5-trimethylhexanoic acid, and reacted at 230 ° C. under normal pressure for 9 hours. Was. Subsequently, the excess fatty acid is distilled off under reduced pressure (0.4 kPa).
After washing by adding 5.5 g of a 5% aqueous sodium hydroxide solution and 62 g of water, further washing with water (4 times with 600 ml of water), dehydration under reduced pressure (200 kC or less, 1.3 kPa).
Below) for one hour. The acid anhydride content of the full ester thus obtained was 0.90% by weight. (2) Purification treatment of full ester with adsorbent 300 g of full ester obtained in the above (1) was stirred,
The mixture was placed in a 500 ml flask equipped with a thermometer and a nitrogen blowing tube, and heated to 60 ° C. While stirring, magnesia (Kyowa Mag 150 manufactured by Kyowa Chemical Industry Co., Ltd.)
15 g was added and heated at 60 ° C. for 1 hour. Subsequently, the mixture was filtered, and the filtrate was used as a full ester (acid anhydride content 0.0
1% by weight).

The acid anhydride content was measured by the following method. Measurement of acid anhydride content: aniline 0.002 to 5 g of sample
Mole was added and stirred at room temperature for 30 minutes. Subsequently, 50 ml of a mixed solution of ethylene glycol / isopropyl alcohol = 1/1 (volume ratio) was added, and 0.1 ml of the solvent was prepared.
The acid anhydride content was measured by titration with 2 mol / l hydrochloric acid.

Examples 2 to 6 Full esters were obtained in the same manner as in Example 1 except that the adsorbent shown in Table 1 was used instead of magnesia.

[0026]

[Table 1]

Example 7 (1) Production of full ester A 1 L four-necked flask equipped with a stirrer, a thermometer, a nitrogen blowing tube, and a dehydrating tube equipped with a cooling tube was prepared, and 136.2 g of pentaerythritol (16.2 g) was prepared. Mol) and 663.3 g (4.6 mol) of 2-ethylhexanoic acid, and reacted at 230 ° C. for 35 hours under normal pressure. Subsequently, the excess fatty acid was distilled off under reduced pressure (0.4 kPa).
A 5.5% aqueous sodium hydroxide solution and 62 g of water were added for washing, followed by washing with water (4 times with 600 ml of water), followed by dehydration (200 ° C. or less, 1.3 kPa or less) under reduced pressure. Time went. The acid anhydride content of the full ester thus obtained was 2.10% by weight. (2) Treatment of full ester with adsorbent 300 g of full ester obtained in the above (1),
The mixture was placed in a 500 ml flask equipped with a thermometer and a nitrogen blowing tube, and heated to 60 ° C. While stirring, magnesia (Kyowa Mag 150 manufactured by Kyowa Chemical Industry Co., Ltd.)
And heated at 60 ° C. for 1 hour. Subsequently, the mixture was filtered and the filtrate was used as a full ester (acid anhydride content 0.0
4% by weight).

Examples 8 to 12 Full esters were obtained in the same manner as in Example 7 except that the adsorbent shown in Table 1 was used instead of magnesia. Table 2 shows the acid anhydride contents before and after the adsorption treatment in each Example.

[0029]

[Table 2]

As shown in Table 2, the production method of the present invention can produce a full ester having a low acid anhydride content.

Comparative Example 1 A full ester was obtained in the same manner as in Example 1 except that the treatment with the adsorbent was not performed. The acid anhydride content of the full ester was 0.90% by weight.

Comparative Example 2 A full ester was obtained in the same manner as in Example 7 except that the treatment with the adsorbent was not performed. The acid anhydride content of the full ester was 2.10% by weight.

Test Example 1 The full esters obtained in Examples 1 to 12 and Comparative Examples 1 and 2 were tested under the following conditions to examine the storage stability. Storage stability test: 100 ml
A 50 g sample was placed in a vial, sealed, and left at 60 ° C. for 60 days to examine the acid value. Measurement of acid value is based on JIS
Performed in accordance with K-2501. Table 3 shows the results.

[0034]

[Table 3]

Table 3 shows that the full ester obtained by the production method of the present invention has a low acid value after the storage stability test.

[0036]

According to the present invention, there is provided a process for producing an ester of an aliphatic polyhydric alcohol having a low acid anhydride content.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C10M 105/38 C10M 105/38 C10N 30:12 C10N 30:12 (72) Inventor Takashi Kondo Mie 2-3-3, Daikyocho, Yokkaichi-shi Kyowa Yuka Co., Ltd. Yokkaichi Research Laboratory (72) Inventor Mitsuru Kokubu 2-3-3, Daikyocho, Yokkaichi-shi, Mie Prefecture Kyowa Yuka Co., Ltd. Yokkaichi Research Laboratory F-term (reference) 4H006 AA02 AB60 AC48 AD17 4H104 BB34A LA06 LA20

Claims (8)

[Claims] 1. An ester (full ester) obtained by subjecting an aliphatic polyhydric alcohol and a saturated aliphatic monocarboxylic acid to an esterification reaction, wherein all of the hydroxyl groups of the aliphatic polyhydric alcohol are esterified (full ester) are purified by an adsorbent. A process for producing an ester. 2. The adsorbent comprises an oxide or hydroxide of at least one metal selected from magnesium, aluminum, silicon, sodium, iron, manganese, calcium and potassium, or a clay mineral containing at least one of the aforementioned metals. 2. The method according to claim 1, wherein the method comprises: 3. The production method according to claim 1, wherein the adsorbent contains an oxide or hydroxide of at least one metal selected from magnesium, aluminum and silicon, or a clay mineral containing at least one metal. 4. The method according to claim 1, wherein the adsorbent contains an oxide or hydroxide of magnesium or a clay mineral containing magnesium. 5. The saturated aliphatic monocarboxylic acid having 2 to 2 carbon atoms.
The method according to any one of claims 1 to 4, wherein the saturated aliphatic monocarboxylic acid is 36. 6. The method according to claim 5, wherein the saturated aliphatic monocarboxylic acid having 2 to 36 carbon atoms is 2-ethylhexanoic acid or 3,5,5-trimethylhexanoic acid. 7. An aliphatic polyhydric alcohol having 2 to 20 carbon atoms.
The method according to any one of claims 1 to 6, which is an aliphatic polyhydric alcohol. 8. The method according to claim 7, wherein the aliphatic polyhydric alcohol having 2 to 20 carbon atoms is pentaerythritol, trimethylolpropane or 2,4-diethyl-1,5-pentanediol.