JPH02104553A - Higher carboxylic acid triester of adamantanetriol and synthetic lubricating oil containing the same triester - Google Patents

Abstract

NEW MATERIAL:A higher carboxylic acid triester of adamantanetriol expressed by formula I (Z is H or OH; R<1>-R<3> are 4-30C alkyl or cycloalkyl). EXAMPLE:Caprylic acid triester of adamantane-1,3,5-triol. USE:Used for high-performance synthetic lubricating oil. Useful as engine oil, gear oil, hydraulic oil, grease, vacuum pump oil, bearing impregnating oil or gas turbine oil, etc., as having excellent heat stability and respectively excellent low-temperature properties and high-temperature properties such as high kinematic viscosity at high-temperature in spite of low pour point. PREPARATION:1mol of adamantane-1,3,5-triol expressed by formula II and 3-6mol of higher carboxylic acid expressed by the formula R-COOH or reactive derivative of said acid are subjected to esterification reaction at 50-150 deg.C to obtain the compound expressed by formula I for the case of Z is H.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel higher carboxylic acid triester of adamanetriol and a synthetic lubricating oil containing the same. More specifically, the present invention relates to a novel higher carboxylic acid triester of adamantane triol that is useful as a high-performance synthetic lubricant having excellent both low-temperature properties and high-temperature properties, and an engine oil containing the same. The present invention relates to high-performance synthetic lubricating oils suitable for use as gear oils, hydraulic oils, breathers, vacuum pump oils, impregnated bearing oils, gas turbine oils, and the like.

[Prior Art] Conventionally, synthetic lubricating oils include polyolefins such as a-olefin oligomers and polyisobutylene, and organic esters such as diesters such as di-2-ethylhexyl sebacate and polyol esters such as pentaerythritol alkyl esters. kind, m-t'su(m-
Known examples include polyphenyl ethers such as phenoxyphenoxy)benzene, phosphoric acid esters such as tricresyl phosphate, polyalkylene glycols such as polypropylene glycol, silicone oil, and perfluoroalkyl ethers.

These synthetic lubricating oils have properties that mineral oil-based lubricating oils do not have, and are used for a variety of purposes depending on their properties. Not only that, but it is also related to resource conservation and environmental protection.
The demand for synthetic lubricating oils is expected to increase further in the future, and in conjunction with this, the development of synthetic lubricating oils with even better properties is being actively carried out.

By the way, as an ester compound of adamancune, for example, the general formula (R6 in the formula is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl group, R1 and R6 are 1 to 20 carbon atoms)
The diester of adamantane-1,3-diol represented by
.

Such adamantane ester compounds, when used as synthetic lubricating oils, have excellent heat resistance stability, but have the drawback of insufficient viscosity-temperature characteristics. For example, in the general formula (I), R6 and R
In the diester of adamantane-1,3-diol in which 8 is a methyl group and R1 is an octyl group, the temperature is 10
Kinematic viscosity at 0°C is 7.1 cSt, viscosity index is 95
, the pour point is 150° C. or less, and in order to use the diester as a high-performance synthetic lubricating oil, higher values are required for the viscosity and viscosity index at high temperatures, respectively.

[Problems to be Solved by the Invention] The present invention provides a novel adamantane compound that is excellent in both low-temperature properties and high-temperature properties and is useful for high-performance synthetic lubricating oils, and a synthetic lubricating oil containing this adamantane compound. It was done for the purpose of

[Means for Solving the Problem] As a result of extensive research to achieve the above object, the present inventors have found that a higher carboxylic acid triester of adamantane triol having a specific structure can be adapted to the object. Based on this finding, we have completed the present invention.

That is, the present invention relates to the general formula (2 in the formula is a hydrogen atom or a hydroxyl group, R'%R1
and R3 are each an alkyl group or a cycloalkyl group having 4 to 30 carbon atoms, and they may be the same or different from each other. , and a synthetic lubricating oil containing the same.

The present invention will be explained in detail below.

The higher carboxylic acid triester of adamantanetriol represented by the general formula (II) of the present invention is a novel compound that has not been described in any literature. R1 in the general formula (If),
R2 and Rs are each an alkyl group or a cycloalkyl group having 4 to 30 carbon atoms, and they may be the same or different from each other, but are the same for ease of production. Preferably. Moreover, 2 is a hydrogen atom or a hydroxyl group.

The higher carboxylic acid triester of adamantane-1,3,5-triol in which 2 in the general formula (II) is a hydrogen atom is, for example, adamantane-1,3,5-triol combined with a corresponding higher carboxylic acid or a reaction thereof. It can be produced by esterifying a chemical derivative. On the other hand, higher carboxylic acid triesters of 7-hydroxyadamantane-1,3,5-triol in which 2 is a hydroxyl group are, for example, adamantone-1,3,5,7
-Titraol can be produced by esterifying it with the corresponding higher carboxylic acid or its reactive derivative.

The above-mentioned adamantane-1,3,5-) diol and adamantane-1,3,5,7-titraol can be produced by oxidizing adamantane (m), for example, as shown in the next step (A). After obtaining IV), further oxidation produces adamantane-1,3,5-1
-diol (V) and adamantane-1,3,5,7-titraol (Vl) can be obtained.

Steps (A) (V) (VI) There are no particular limitations on the method of oxidizing adamantune (I[I) to adamantanediol (mV), and a known method may be used, for example, air oxidation in the presence of a metal salt oxidation catalyst. Although a method of oxidizing with chromium trioxide in an acetic acid solvent can be used, the latter method of oxidizing with chromium dioxide is preferable from the viewpoint of yield.

Next, to explain the method of oxidizing adamantane to adamantanediol using chromium trioxide, first, adamantane is added to acetic acid, and oxidation is performed by dropping an aqueous solution of chromium dioxide into this slurry liquid. ,
The molar ratio of acetic acid to adamantane is preferably from 3 to
7, while chromium trioxide is used in a proportion such that the molar ratio of chromium dioxide to adamantane is preferably between 4 and 8. If the molar ratio of chromium dioxide to adamantane is less than 4, the amount of adamantune monool produced will increase, which is undesirable, and if it exceeds 8, the amount of undesirable by-products will increase.
Undesirable. Further, the higher the concentration of the chromium trioxide aqueous solution, the better, and a saturated aqueous solution is usually used.

The reaction temperature is usually selected within the range of 80 to 120°C. If this temperature is less than 80°C, the reaction rate is too slow to be practical, and if it exceeds 120°C, many undesirable side reactions will occur.

The reaction time depends on the reaction temperature and the amount of chromium trioxide used, and cannot be determined generally, but it is usually 1~
It takes about 20 hours.

After the reaction is complete, the acetic acid in the reaction solution is usually distilled off under reduced pressure, the remaining solution is neutralized with an alkali, and the product is extracted using an appropriate organic solvent. The crude adamantane diol (IV) is obtained by recovering the product from the above by known means.

The crude adamantane diol thus obtained is usually not purified, but is directly oxidized with chromium trioxide under the same conditions as described above, and then subjected to the same post-treatment. At this time, the production ratio of adamantane-1,3,5-)diol (V) and adamantane-1,3,5,7-titraol (Vl) can be changed by appropriately selecting the oxidation conditions using chromium trioxide. Can be done. The crude reaction product obtained by the above-mentioned post-treatment may be esterified as it is, or if necessary, it may be purified by appropriate means to obtain pure adamantane-1,3,5-triol or adamantane-1, It may be used as a raw material for esterification reaction as 3,5,7-titraol.

In addition, the adamantane diol (fV) is obtained by a method other than oxidation of adamantane, for example, by brominating adamantane to obtain dibromoadamantane, and then treating this with an aqueous solution of silver sulfate.
It may also be oxidized with chromium trioxide as described above.

Furthermore, adamancune-1,3,5-1liol and adamantane-1,3,5,7-titraol can be produced in accordance with the following step (B) or step (C) in addition to the above step (A). Can be done.

Process (B) (■) (■)(,V)(
Vl) In this step (B), adamancune (I[[) is brominated in the presence of an aluminum tribromide catalyst to give 1
, 3.5-tribromoadamantane (■) and 1,3,
5.7- After obtaining Chitrabromoadamankun (■),
By reacting these with an aqueous silver sulfate solution, adamantane-1,3,5-triol (V) and adamantane-1,3,5,7-titraol (Vl) can be obtained.

Step (C) A a H(I[[) A d (OH)++(-0') s--(I Ad(O
H)s (V) In this step (C), adamantane (III) is added to co! In the presence of a +catalyst, an adamancune compound (I) into which a hydroxyl group and an oxo group have been introduced by autooxidation with air or oxygen is obtained, and then the oxo group is reduced with hydrogen to form adamancune-1,3, 5-triol (V) can be obtained.

Adamantane-1,3,5-) thus obtained
Diol (V) and adamantane-1,3,5,7-titraol (VI) are triesterified with higher carboxylic acids or reactive derivatives thereof, respectively, to form higher carboxylic triols of adamantane-1,3,5-triol. Esters and 7-hydroxyadamantane-1.3.5-
This leads to higher carboxylic acid triesters of triols.

The higher carboxylic acid has the general formula R-COOH (however,
R is an alkyl group or a cycloalkyl group having 4 to 30 carbon atoms, such as caproic acid, isovaleric acid, n-heptylic acid, caprylic acid,
Examples include pelargonic acid, capric acid, n-undecylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, eicoic acid, behenic acid, cyclohexanecarboxylic acid, decalincarboxylic acid, and the like. Examples of reactive derivatives of higher carboxylic acids include lower alkyl esters, acid chlorides, and acid anhydrides of the carboxylic acids.

The amount of the higher carboxylic acid or its reactive derivative used is:
Usually 3 per mole of adamantane-1,3,5-triol or adamantane-1,3,5,7-tetraol
It is used in a proportion of ~6 moles.

If this amount is less than 3 moles, monoesters and diesters are likely to be produced as by-products, and there is no need to use more than 6 moles.
Moreover, the reaction temperature is usually selected within the range of 50 to 150°C. If this temperature is less than 50°C, the reaction rate is too slow to be practical, and if it exceeds 150°C, undesirable side reactions tend to occur.

From the reaction-completed liquid thus obtained, the adamanthine of the present invention represented by the general formula (R1, R1, R8 and 2 have the same meanings as above) is extracted according to a commonly used method. Higher carboxylic acid triesters of triols can be separated. This compound is a novel compound that has not been described in any literature, and has excellent properties as a lubricating oil. For example, the general formula (II)
In 1ljl, R1 and R3 are both n-heptyl groups, and 2 is a hydrogen atom, adamantane-
As shown in Table 1, the physical properties of the caprylic acid triester of 1,3,5-triol are superior in thermal stability and pour point compared to the caprylic acid diester of adamantane diol and the caprylic acid ester of adamantane monool. Although it has a low viscosity, it has a high kinematic viscosity even at high temperatures, and is excellent in both low-temperature and high-temperature properties.

(Hereinafter, blank spaces) The higher carboxylic acid triester of adamantane triol of the present invention is thus excellent in both low-temperature properties and high-temperature properties, and thus is useful as a high-performance synthetic lubricating oil.

When the higher carboxylic acid triester of adamantune triol is used as a synthetic lubricating oil, it may contain one kind of the ester, or two kinds having different alkyl groups.
7 derived from adamantane-1,3,5,7-titraol, which may contain more than one ester.
- One or more higher carboxylic acid triesters of hydroxyadamantane-1,3,5-1-diol and 1 carboxylic acid triester of adamantane-1,3,5-1-diol
It may contain more than one species.

[Examples] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 2 Adamancune (A d H) 2 was added to a four-L flask.
009 (1,47 mo 1) and acetic acid 15009, and while stirring at 80°C, 736 g (7,36 mo 1) of chromium trioxide was added to the slurry liquid in 400 mft of water.
An aqueous solution of chromic acid dissolved in water was gradually added dropwise so as not to raise the temperature above 120°C (heat generation occurred during the dropping).

After the dropwise addition, stirring was continued for 1 hour at 100°C, most of the water and acetic acid in the reaction-completed solution was removed using a rotary evaporator, and then approximately I
L was added to make the whole solution, and sodium hydroxide crystals (reagent grade) were added with stirring until the pH was 7.

After neutralization, concentrate using an evaporator to bring the total liquid volume to about 111I.

Next, ethyl acetate 11 was added to this concentrated solution, and the reaction product was extracted at 70°C. After performing this extraction five times, ethyl acetate was distilled off from the extract, and white crystals 1309
(Yield: 65% by weight) was obtained. This crystal contained 90% by weight of adamane cundiol. Such operations were repeated to obtain crude adamantane diol for producing adamantane triol.

Next, the crude adamantanediol 2009 (about 1.2 mo 1) obtained in this way and acetic acid 14209 were mixed together.
Pour into a four-bottle flask and stir at 90°C.
Add 480g of chromium trioxide to this slurry and 240ml of water.
An aqueous solution of chromic acid dissolved in No. 1 was gradually added dropwise (there is less heat generation than in the above case).

After the dropwise addition was completed, stirring was continued at 90°C for 2 hours, and then most of the water and acetic acid in the reaction-completed liquid was removed using a rotary evaporator. Next, about 11 parts of water was added thereto, and the mixture was stirred in the same manner as in the previous case. , neutralized to pH 7 with sodium hydroxide.

Next, water was removed from the neutralized solution using a rotary evaporator to obtain a concentrated solution, and extraction was performed with ethyl acetate in the same manner as above to obtain crude adamantane triol 1209 (yield: 60% by weight) as white crystals. Obtained. As a result of gas chromatography (Ov-101) analysis, this product contained 85% by weight of adamantane triol. This crude adamantane triol was purified by recrystallization from ethanol, and as a result, the purity of adamantane triol was 98% by weight.

Caprylic acid chloride (reagent,
Add 316y (manufactured by Tokyo Kasei) (1.95 mol) and add 90
The temperature was raised to 140 °C, and while stirring in a nitrogen stream, adamancoutriol 809 (0.43 mo 1) was added thereto (HCIL gas generation), and then the temperature was raised to 140 °C, and the mixture was stirred at this temperature for 1 hour. did.

Next, 500ml of hexane and a solution of 2009 sodium bicarbonate (reagent grade) dissolved in 2K of water were added to the reaction completed solution, and after stirring was continued at room temperature for 24 hours, the alkaline water was separated using a separatory funnel, and then washed with water. The hexane was removed after drying with anhydrous sodium sulfate. Furthermore, the trace amount of acid chloride remaining was removed at a bottom temperature of 210°C.
The residue was distilled off under a vacuum of 1 mrxHg to obtain liquid material 2409 (yield 98%) as a distillation residue.

The IC-NMR spectrum, proton NMR spectrum and IR spectrum of this product are shown in Figure 81 and 2, respectively.
As shown in FIG. In the IR spectrum, absorption due to stretching of the carbonyl group was observed at 1725 cra-'. Further, the elemental analysis results are shown in Table 2.

From the results shown in Table 2 and above, it was identified that the liquid was a caprylic acid triester of adamantane-1,3,5-)diol represented by the structural formula.

The basic physical properties as a lubricating oil of the caprylic acid triester of adamantane triol obtained as described above were compared with the caprylic acid diester of adamantane diol (Reference Example 1).
) and caprylic acid ester of adamantane monool (
Table 3 shows the basic physical properties of Reference Example 2).

As can be seen from Table 3, Adamankun-1 of the present invention,
The caprylic acid triester of 3,5-1-liol has the following characteristics.

(1) Despite the low pour point of 150℃ or less, 1
The kinematic viscosity at 00°C is as high as 9.55 cSt.

From the relationship between the pour point and kinematic viscosity (100°C) of a hindered ester with excellent heat resistance, the kinematic viscosity (100°C) of a compound exhibiting a pour point of -SO°C or lower is approximately 4 to 5 cSt.
(eg, trimethylolprobancagrilate triester). On the other hand, the caprylic acid triester of adamantane-1,3,5-triol of the present invention has a kinematic viscosity (100"C) higher than that of the above-described one by about 5 to 6 cSt. Such physical properties are similar to those of synthetic lubricating oils. In other words, having a low pour point and high viscosity means that it can be used even in low-temperature environments (e.g., jet engine oil: pour point -53°C or lower) and that it can be used at high temperatures. This means that a thick oil film can be ensured even at low temperatures.

(2) High thermal stability.

As can be seen from the exothermic peak temperature in differential thermal analysis in an air stream, the caprylic acid triester of adamantane triol of the present invention is more stable in an oxidizing atmosphere than the caprylic acid diester of adamantane diol and the caprylic acid ester of adamantane monool. High thermal stability.

[Effects of the Invention] The higher carboxylic acid triester of adamantunetriol of the present invention is a novel compound that has not been published in any literature, and has excellent thermal stability and a low pour point, but exhibits high kinetics at high temperatures. It has excellent low-temperature and high-temperature properties, such as high viscosity, and is useful for high-performance synthetic lubricants.

The synthetic lubricating oil of the present invention containing the higher carboxylic acid triester of adamancoutriol has the above-mentioned excellent properties, so it can be used, for example, in engine oil, gear oil, hydraulic oil, grease, and vacuum pumps. Suitable for use as oil, impregnated bearing oil, gas turbine oil, etc.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are a C-NMR spectrum, a proton NMR spectrum, and an infrared absorption spectrum of an example of a higher carboxylic acid triester of adamantane triol of the present invention, respectively.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (Z in the formula is a hydrogen atom or a hydroxyl group, R^1, R
^2 and R^3 are each an alkyl group or a cycloalkyl group having 4 to 30 carbon atoms, and they may be the same or different from each other). Carboxylic acid triester. 2. A synthetic lubricating oil comprising the higher carboxylic acid triester of adamantane triol according to claim 1.