JP2002293769A - Method for producing sulfurated hydroxyfatty acid dimer and salt thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sulfurated hydroxyfatty acid dimer or its salt in higher yield. SOLUTION: This method for producing a sulfurated hydroxyfatty acid dimer comprises saponifying a sulfurated hydroxyfatty acid dimer alkyl ester with an alkali metal hydroxide and neutralizing the saponified product with an acid. This method for producing a sulfurated ricinoleic acid dimer salt comprises converting the sulfurated ricinoleic acid dimer obtained by the above method to a salt thereof by using a base different from a base used in the above method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a sulfurized hydroxy fatty acid dimer and a salt thereof.

[0002]

2. Description of the Related Art Sulfurized hydroxy fatty acid dimers can be obtained by, for example, heating and hydrolyzing an alkyl sulfided hydroxy fatty acid in the presence of an inorganic acid such as hydrochloric acid or sulfuric acid or an organic acid such as acetic acid. . As a method of this hydrolysis, for example, there is a method of directly obtaining a sulfurated hydroxy fatty acid dimer using hydrogen halide as an acid catalyst.

[0003]

However, the above method has a drawback that a sulfurated hydroxy fatty acid dimer cannot be obtained in a yield as high as expected.

[0004]

Means for Solving the Problems In view of the above situation, the present inventors have conducted intensive studies and found that saponification of a dimer alkyl sulfide of a hydroxy fatty acid with an alkali metal hydroxide followed by neutralization with an acid. The present inventors have found that a sulfurated hydroxy fatty acid dimer can be obtained at a higher yield than before, and have completed the present invention. That is, the present invention provides a method for producing a sulfurized hydroxy fatty acid dimer in which alkylated sulfurated hydroxy fatty acid dimer is saponified with an alkali metal hydroxide and then neutralized with an acid.

[0005] In the production method of the present invention, the first method for performing a saponification reaction is described.
This is a production method including at least a step and a second step of neutralizing the saponified product obtained in the first step in this order.

[0006] The sulfurated hydroxy fatty acid dimer alkyl in the present invention means that the carbon unsaturated double bond contained in the hydroxy unsaturated fatty acid monoalkyl is cleaved and at least one hydroxy unsaturated fatty acid monoalkyl molecule is formed.
Refers to an organic compound having a structure linked through two sulfur atoms (not including a carbon-carbon unsaturated double bond).

[0007] Sulfurized hydroxy fatty acid dimer alkyl is
It can be produced by a known and commonly used method, for example, adding hydrogen sulfide and
And / or by reacting with sulfur.

[0008] By this sulfuration, the carbon-carbon unsaturated double bond of each of the hydroxyunsaturated fatty acid alkyls is cleaved, and the two molecules have various sulfur chain lengths, for example, -S-,
-SS-,-SSS-,-SSSS-,-SSSSS-,
Crosslinked with -SSSSSS- or the like (1 to 6 sulfur atoms) to obtain a sulfurized hydroxy fatty acid dimer alkyl containing no carbon-carbon unsaturated double bond.

[0009] Sulfurized hydroxy fatty acid dimer alkyl is
It may be obtained by performing the reaction in any order, but it is preferable to obtain a hydroxyunsaturated fatty acid alkyl in advance and sulfide it. The advantage of using a hydroxyunsaturated fatty acid alkyl as a raw material for obtaining the corresponding dimer alkyl is that, due to its chemical structure, polycondensation between a hydroxyl group and a carboxyl group does not theoretically occur, and sulfur It is easy to cause a cross-linking reaction selectively.

In the hydroxy-unsaturated fatty acid alkyl, the chain length of the carbon is preferably long, for example, 12 to 30, including carbon of carbon-carbon unsaturated double bond.
Preferably it is 14-20. The carbon chain length of this alkyl group is preferably from 1 to 4.

Examples of such hydroxyunsaturated fatty acid alkyls include monohydroxy unsaturated fatty acid alkyls such as methyl 12-hydroxyoleate (ricinoleate), methyl 13-hydroxyoleate, and methyl 15-hydroxyoleate. Methyl 9,10-dihydroxy oleate, methyl 9,10-dihydroxy linoleate, methyl 12,13-dihydroxy oleate, methyl 15,16-dihydroxy linoleate,
Examples include methyl dihydroxy unsaturated fatty acids such as methyl 10-dihydroxypalmitoleate. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, i
Examples thereof include a so-propyl group, and a methyl group is preferred from the viewpoint of reactivity. These compounds may be used alone or in combination of two or more.

Sulfurized hydroxy fatty acid dimer alkyl is
The selection is made in consideration of the sulfur content of the sulfurized hydroxy fatty acid dimer or its salt. The sulfur content of the sulfurized hydroxy fatty acid dimer or a salt thereof used in the present invention is, for example, 8
１５15% by weight (mass). 9 to 11% by weight (mass) is preferable in that it has both excellent extreme pressure performance and low corrosiveness.

If the salt of the sulfurized hydroxy fatty acid dimer needs to be water-soluble or water-dispersible, it is selected in consideration of the acid value of the sulfurized hydroxy fatty acid dimer. In such a case, the sulfur content of the sulfurized hydroxy fatty acid dimer is not limited to 9 to 11% by weight (mass)%, but also the acid value is 100 to 200 m
gKOH / g provides excellent lubrication performance,
In addition, it is preferable that stable water solubility can be obtained only by neutralization with a base without using a surfactant, and it is preferable to select dimer dialkyl as a raw material so as to have both of them. The most preferred is methyl 12-hydroxyoleate (ricinoleate) in consideration of performance as an extreme pressure additive, economy, and the like.

In the present invention, as the hydroxyunsaturated fatty acid alkyl and hydrogen sulfide, those which are generally commercially available can be used. As the sulfur, either solid or molten sulfur may be used.

The catalyst used in the production method of the present invention is usually a basic catalyst. As the basic catalyst, an amine is suitable, and an alkylamine, an arylamine, a polyamine, or an alkanolamine having good reactivity is used.

Sulfated hydroxy fatty acid dimer alkyl is
Either a method in which hydrogen sulfide gas is blown into the hydroxyunsaturated fatty acid alkyl, sulfur, or the catalyst, or a method in which the hydroxyunsaturated fatty acid, sulfur, liquefied hydrogen sulfide, or the catalyst is temporarily charged and reacted, but the reaction is performed under a relatively low pressure. Is possible,
The former method is preferred.

The raw material charge ratio (in terms of weight (mass)) can be freely changed depending on the required sulfur content of the final product and the like, but the sulfur content is 9 to 11% by weight (mass). 0.5 to 0.7 mol of sulfur, 0.4 to 0.5 mol of hydrogen sulfide gas,
The catalyst is selected from the range of 0.01 to 0.1 mole.

The former method is preferred because it is easier to control the reaction, including the sulfur content, and the resulting product is less colored and has less odor. . The reaction temperature is over 100 ° C and 15
It is preferable to select at 0 ° C. and a reaction time in the range of 1 to 20 hours. The fact that the reaction can be carried out at a relatively low pressure and a relatively low temperature is preferable because the energy consumption per unit production can be reduced and the reaction can be carried out in a general pressure-resistant reactor.

The pressure condition of the reaction is not particularly limited, and may be selected, for example, from 98 to 2940 kPa (1 to 30 kg / cm ² ). / Cm ² )
The reaction can be carried out at a lower temperature, which is more preferable from the viewpoint of safety.

The end point of the sulfurization reaction can be determined by eliminating the precipitation of sulfur. When dimerized alkyl sulfurated hydroxy fatty acid is obtained by synthesis, there are two types such as mass spectrum (FD-MS), nuclear magnetic resonance spectrum (proton NMR, carbon-13 NMR), gel permeation chromatography (GPC), and elemental analysis. By combining the above, it is possible to identify the chemical structure of the target substance, the length of the sulfur chain involved in crosslinking, and the like.

The dimer alkyl sulfurated hydroxy fatty acid thus obtained is saponified with an alkali metal hydroxide,
Sulfated hydroxy fatty acid dimer alkali metal salt. The amount of the alkali metal hydroxide to be used can usually be 0.8 to 1.2 mol per 1 mol of alkyl dimer of sulfurized hydroxy fatty acid.

This saponification can be carried out using a known and commonly used solvent and an alkali metal hydroxide. This saponification may be carried out by heating the dimer alkyl sulfide of a hydroxy fatty acid in a solvent and an alkali metal hydroxide in a solvent.
It is preferable to carry out the reaction at 0 to 120 ° C. by refluxing the inside of the reaction system for 1 to 10 hours.

As the solvent in this case, various organic solvents can be used in addition to water. For example, methanol, ethanol,
It is preferable to use a monoalcohol such as iso-propanol, and particularly ethanol. As the alkali metal hydroxide, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide and the like can be used, but potassium hydroxide is preferable. The optimal combination of the solvent and the alkali metal hydroxide during the saponification is a combination of ethanol and potassium hydroxide.

The end point of the saponification reaction is that no unsaponifiable substance, that is, alkyl dimer of sulfurized hydroxy fatty acid in the present invention is detected. This point can be determined by various methods, for example, infrared absorption spectrum (IR)
The end point may be determined based on the peak intensity derived from the ester bond using the method described above.

Next, the alkali metal salt of a sulfurized hydroxy fatty acid dimer as a saponified product is at least neutralized with an acid to obtain a sulfurized hydroxy fatty acid dimer. It is preferable in terms of operation that the solvent be distilled off before the neutralization.

This neutralization can be carried out using a known and commonly used acid. This neutralization may be carried out, for example, by sufficiently stirring and mixing an alkali metal salt of a sulfurized hydroxy fatty acid dimer with an acid capable of converting a group consisting of the metal salt into a carboxyl group. The amount of the acid used is usually 0.8 to 1.2 per mole of the dimerized alkali metal salt of sulfurized hydroxy fatty acid.
It can be mole. In order to easily finely adjust the degree of neutralization and to perform gentle neutralization, it is preferable to use an aqueous acid solution. The temperature of each of the alkali metal salt and the acid is usually set to more than 0 ° C. and 40 ° C., and it is preferable to mix them gradually so as not to generate remarkable heat generation, or to cool them with an external refrigerant.

As the acid at this time, for example, an inorganic acid such as hydrochloric acid (aqueous hydrogen chloride) and sulfuric acid, and an organic acid such as acetic acid can be used. As the water, for example, tap water, industrial water, ion-exchanged water, distilled water, ultrapure water and the like can be used.

A solvent for saponification and an alkali metal hydroxide,
The optimal combination with an acid during neutralization is a combination of ethanol, potassium hydroxide and hydrogen chloride.

The sulfurized hydroxy fatty acid dimer obtained by the production method of the present invention can be identified by the above-mentioned identification method and the above-mentioned measurement methods such as IR and acid value. The sulfurized hydroxy fatty acid dimer obtained by the production method of the present invention can be used as it is as an extreme pressure additive, but the carboxyl group in the dimer is neutralized with a base different from that used in the previous saponification. By using a salt, the affinity with water can be improved.

The sulfurized hydroxy fatty acid dimer is, for example,
The ion dissociated state of this salt greatly contributes to stable water solubility. As a result, in the past, the use of a surfactant, which was necessary to provide stable solubility and dispersibility, was not necessary, or even if it was used, only a very small amount was required. The disadvantages can be greatly improved.

The sulfided hydroxy fatty acid dimer can be made into a salt to make it water-dispersible instead of water-soluble. However, the stability is better when it is water-soluble.

Examples of the base for converting the dimer into a salt include inorganic bases such as metal hydroxides, metal carbonates, and ammonia, aliphatic primary amines, aliphatic secondary amines, and aliphatic tertiary amines. Examples thereof include organic amines such as secondary amines, and preferred are alkali metal hydroxides and alkanolamines. However, when a base different from that used in the previous saponification is used, the effect of purification can be expected, but it is preferable to select a base different from that used in the previous saponification.

Examples of the alkali metal hydroxide include sodium hydroxide and potassium hydroxide. Examples of the alkanolamine include mono-, di- or tri-type ethanolamine, propanolamine, butanolamine and octanolamine. I can do it. These can be used alone or in combination of two or more. As the base, mono-, di- or tri-type ethanolamine is particularly preferred.

The salt of a sulfurized hydroxy fatty acid dimer can be converted into the salt by mixing with the alkali metal hydroxide or alkanolamine.
Water solubility and defoaming properties are better when the value is increased to 3 or more. If a smaller amount is added than is required for carboxyl group neutralization, the sulfurized hydroxy fatty acid dimer will be partially contained in the dimer of the present invention in a free state. On the other hand, if a larger amount is added than is required for neutralization of the carboxyl group, the base will be partially contained in the dimer of the present invention in a free state. The dimer salt thus obtained is
Like the dimer before salting, it can be used as an extreme pressure additive.

In order to produce a cutting fluid or a grinding fluid from a dimer of a sulfurized hydroxy fatty acid or a salt of the dimer obtained by the production method of the present invention, a known oil, rust preventive, bactericide, and defoamer can be used. May be used in combination. The dimer of a sulfurized hydroxy fatty acid or the salt of the dimer obtained in the present invention may be used by adding to a known and commonly used water-soluble cutting oil or water-soluble grinding oil.

The dimer or salt of the sulfurized hydroxy fatty acid obtained by the production method of the present invention includes, for example, sulfided ricinoleic acid condensate, its alkali metal salt, its alkanolamine salt, and its condensation with ricinoleic acid. And condensates of hydroxyunsaturated long-chain fatty acids such as alkali metal salts or alkanolamine salts.

From the salt of the sulfurized hydroxy fatty acid dimer of the present invention, a cutting fluid or a grinding fluid containing the dimer and water can be obtained.

In this invention, the effective blending ratio (in terms of weight (mass)) of the salt of the sulfurized hydroxy fatty acid dimer obtained in the present invention is appropriately selected depending on the purpose of use and the situation. 1 to 50% by weight (mass), preferably 1%, in an aqueous solution (cutting fluid or grinding fluid) to be applied
To 10% by weight (mass).

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments.

Example 1 In a preliminary experiment, under reflux conditions, methyl sulfide ricinoleate was converted to 56.1 g of potassium hydroxide equivalent to an equimolar amount.
The reaction was carried out in 453.5 g of ethanol containing, and the end point of the reaction (reflux time) was determined. Instead of the above-mentioned methyl sulfide ricinoleate, methyl sulfide ricinoleate obtained by reacting sulfur and hydrogen sulfide with methyl ricinoleate in the presence of an amine catalyst (the sulfur chain length as determined by MS is 4.5) is used. And 553 g of the same were mixed with 453.5 g of ethanol containing 56.1 g of potassium hydroxide, and the mixture was refluxed at 80 ° C. for 6 hours to obtain a reaction mixture containing potassium dimers of ricinoleic sulfide.

Next, ethanol was removed from the reaction mixture.
After distillation, add an equimolar amount to the alkali metal salt.
Hydrochloric acid-containing hydrochloric acid (concentration 35% by mass) is added under stirring.
Neutralized. The product here is carboxyl by IR.
Group (1600-1700cm ^-1) Has been confirmed,
Comparison between theoretical acid value (about 145) and measured acid value, GPC
Is a sulphided ricinoleic acid dimer by peaks in MS and MS
It was confirmed that. The yield from raw materials was 96.8%.
Was. These results are summarized in Table 1.

Examples 2 to 3 The same procedures as in Example 1 were carried out except that the amounts of the alkali metal hydroxide and the monoalcohol used in the saponification reaction and the inorganic acid used in the neutralization were changed so that the equivalents were equal. The operation was performed. These results are summarized in Table 1.

[0043]

[Table 1] Table 1

COMPARATIVE EXAMPLE 1 The same methyl sulphide ricinoleate 55 used in Example 1
77 g of sulfuric acid equivalent to equimolar amount (concentration 98 mass%)
And reacted at 80 ° C. for 6 hours (acid hydrolysis). The reaction mixture was centrifuged to separate two layers, and then the organic layer was washed with water and water was distilled off to obtain a product. When identification was performed in the same manner as in Example 1, the presence of the dimer was confirmed, but the hydrolysis reaction did not easily occur. As a result, a large amount of the raw material remained, and the yield from the raw material was large. Was 43.7%. The same operation was carried out using hydrochloric acid and acetic acid in place of sulfuric acid so as to be equivalent to the raw materials, but the dimer yield was still lower than in this comparative example.

Example 4 An amine salt (a salt of a sulfurized hydroxy fatty acid dimer) was mixed with 1 equivalent of the sulfided ricinoleic acid dimer obtained in Example 1 and 1.2 equivalents of triethanolamine. -10%
It was adjusted to a mass aqueous solution to obtain a grinding cutting fluid.

Grinding cutting fluids of various concentrations have load-bearing performance (fusion load, average Hertz load), wear-resistant performance (wear scar),
Performance such as lubrication performance (coefficient of friction), water solubility, defoaming,
The metal corrosion property can be measured by the following evaluation method.

The load-bearing performance was measured at room temperature at 1770 r using a high-speed 4-ball EP tester based on ASTM D2783.
The welding load and the average Hertz load were measured under the conditions of pm and 10 seconds.

The abrasion resistance was measured using a high-speed 4-ball WEAR tester at 75 ° C., 120 ° C. based on ASTM D4172.
The wear scar diameter was measured under the conditions of 0 rpm, 40 kg, and 60 minutes.

The lubrication performance was measured by using a Soda pendulum friction tester at a room temperature and a 0.5 radian condition.

The solubility in water was determined by dissolving an amine salt sample in 10% by weight of water and determining the transparency on a five-point scale. The criteria were: ◎ is completely transparent, ○ is transparent, △ is slightly turbid, × is turbid, ×
× indicates two-layer separation.

The defoaming property was measured by taking 200 ml of a 1% aqueous solution of an amine salt sample in a 500 ml measuring cylinder, shaking for 30 seconds, and measuring the residual foam amount (ml) after 60 minutes.

The metal corrosivity was determined by immersing an iron piece in 100 ml of a 1% by weight aqueous solution of an amine salt sample for one and a half months, and determining the degree of rust generation in three stages. The judgment criteria were as follows: ○: no rust at all;
Indicates that several points of rust were generated, and x indicates that several tens of points of rust were generated.

The grinding fluid and the cutting fluid obtained from the salt of sulfided ricinoleic acid dimer of Example 4 obtained by the production method of the present invention all showed excellent evaluation results by the above evaluation methods.

Comparative Example 2 An amine salt was prepared by mixing 1.2 equivalents of triethanolamine with 1 equivalent of the acid value of the product obtained in Comparative Example 1. Originally, the product of Comparative Example 1 had a low yield of the sulfurized ricinoleic acid dimer, and thus the yield of the corresponding salt was also low. Then, this was adjusted to a 1% by mass to 10% by mass aqueous solution,
A grinding cutting fluid was used. This grinding fluid was significantly inferior to that of Example 4.

[0055]

According to the present invention, the alkylated sulfurated fatty acid dimer is saponified with an alkali metal hydroxide and then neutralized with an acid to obtain a sulfurized hydroxyfatty acid dimer. As compared with the conventional production method in which heating and hydrolysis are performed under heating, as a result, the residual unreacted raw material can be reduced. As a result, an extremely remarkable effect that a sulfurized hydroxy fatty acid dimer can be produced in a higher yield can be obtained. Similarly, as a result of producing a sulfurized hydroxy fatty acid dimer in high yield, the corresponding salt can be produced in high yield. Thus, the sulfurized hydroxy fatty acid dimer or a salt thereof is useful as an extreme pressure additive, and is useful for preparing a cutting fluid or a grinding fluid.

Claims (4)

[Claims] 1. A method for producing a sulfurized hydroxy fatty acid dimer, wherein saponification of an alkyl sulfurated hydroxy fatty acid dimer with an alkali metal hydroxide and neutralization with an acid. 2. The method according to claim 1, wherein a monoalcohol is used as a solvent for the saponification, and the saponification is carried out under reflux. 3. The method according to claim 1, wherein the alkali metal hydroxide is potassium hydroxide and the acid is hydrogen chloride. 4. A method for producing a salt of a sulfided ricinoleic acid dimer obtained by converting the sulfided ricinoleic acid dimer obtained in claim 1 into a salt with a base different from that previously used.