DEST007192MA - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Registration date: October 23, 1953 ■ Announced on July 19, 1956

GERMAN PATENT OFFICE

In an effort to obtain high-quality lubricating oils with special properties, as they do through The technical developments of the last few years have become necessary, the technology is new synthetic Lubricating oils have been developed. A class of compounds of particular interest as synthetic Lubricating oils are the esters, both the simple and the complex esters. In general, these synthetic lubricating oils are characterized by lower volatility, higher viscosity indices and lower pour points than mineral oils of corresponding viscosity. You are special valuable for the lubrication of moving parts such as combustion turbines, especially propeller nozzles and Turbine jet engines in aviation. Mineral oils with an addition of viscosity index improvers, Pour point depressants or other non-volatile substances are used for lubrication Aggregates disadvantageous because they tend to leave a residue that gradually builds up and gives rise to disturbances. On the other hand, you have to add these additives to the mineral oils so that they Obtain high pressure resistance and the viscosity required for operation at extremely high temperature

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differentiated is required. The synthetic ester-based lubricating oils are for a use under such conditions are particularly suitable because they contain no additives and still the desired Possess combination of low volatility, low pour point and high viscosity index.

With the advancing development of the drive units in aviation, those with top performances and have to work at great heights, there is also the problem of lubricity or the Load capacity added. On this problem of creating the desired viscosity properties with great lubricity or resilience, which is also called the high pressure resistance of the synthetic Oil can be referred to, the present invention is directed. '

According to the invention, synthetic lubricating oils are based on a mixture of a diester of a branched-chain C ₆ - to C ₁₆ -alcohol with a dibasic acid and a dibasic acid with 1 by reaction of 2 moles of a half-ester of a branched C ₆ - to C _{16 -alcohol} Molar of a glycol, in particular polyethylene glycol, complex ester formed from a mixture of 85 to 98 percent by volume of the diester and 2 to 15 percent by volume of the complex ester and 2 to 10 percent by weight of tricresyl phosphate, based on the weight of the total mass.

You can of course incorporate other additives into this base mixture to improve its properties to improve, e.g. by adding known antioxidants such as phenothiazine, and Vl. improvers or pour point lowerers. In general, however, it is desirable to reduce the amount of additives to keep them as low as possible and only incorporate them into the finished product if special Properties are required.

i. The branched chain diester

The dibasic acid that forms the diester component of the lubricating oil is completely esterified, it can be sebacin or adipic acid.

The branched chain alcohol contains 6 to 16 C atoms in branched-chain configuration. It is essential that the carbon chain of the alcohol has a certain degree of branching; Within certain limits, the higher the lubricant, the better is the degree of branching. Alcohols such as ethylbutyl, ethylhexyl, and other known branched chain ones Alcohols, are usable. '

The oxo alcohols obtained by the known "oxo" synthesis by the catalytic conversion of olefins with carbon monoxide and hydrogen, and in particular the oxo _{alcohols obtained by the oxo synthesis of polymers and copolymers of C 3} and C ₄ monoolefins, for example from those in refineries, are preferably used Monoolefins which are available in large quantities can be produced by the "UOP."

Of the oxo alcohols, those with 6 to 16 carbon atoms are preferred. They are made from olefin polymers or copolymers of 5 to 15 carbon atoms obtained.

Particularly preferred are the C ₆ to C ₉ alcohols, ie those oxo alcohols obtained from C ₅ to C ₈ olefins.

2. The complex ester

The second component of the synthetic lubricating oil blends of the invention is generally referred to as g ₀ "complex" ester. This product can be viewed as the reaction product of two or more of the compounds listed below: 1. monohydric alcohols, 2. monobasic acids, 3. dibasic acids, 4. glycols, 5. polyhydric alcohols and 6. polybasic acids.

At least one polyfunctional alcohol and at least one polyfunctional acid are used here used.

These complex esters can be divided into the following groups:

Type I.
Monobasic Acid Glycol Dibasic Acid

Glycolic monobasic acid

The structure of this complex ester can be represented as follows:

R ¹ - C - Ο - R ² - Ο - C - R ³ - C - Ο - R ⁴ - 0 - C - R ⁵ OOO 0

Here, R ¹ and R ^{5 are} the alkyl radicals of the monobasic acids, R ² and R ^{4 are} the alkyl radicals of the glycols, and R ³ is the alkyl radical of the dibasic acid.

Esters of this type can be prepared by taking the calculated amounts of the various compounds mixed together and the esterification carried out directly. The reaction will be occasional Testing of a sample of the product for its acidity continued until the minimum value of Acidity is achieved.

Type II

Alcohol-dibasic acid-glycol-dibasic acid-alcohol

This ester, which is preferred by all complex esters, has the following composition:

R ¹ - O - C - R ² - C - O - R ³ - O - C - R ⁴ - C - O - R ^s

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Here, R ¹ and R ^{5 are} the radicals of the alcohol ^{forming the compound, R 2} and R ^{4 are} the alkyl radicals of the dibasic acid, and R ³ is the alkyl radical of the glycol.

These esters are made as indicated for Type I; but it is advantageous to do so first the half-ester of dibasic acid and des

; Glycol and then sets 2 moles of this half-ester with 2 moles of alcohol.

Type TII

Alcohol - dibasic acid - glycol monobasic acid

¹ ^ This ester has the following composition:

Ri-0 - C - R ² - C - O - R ³ - 0 - C - R ⁴

Here, R ^{1 is} the alkyl radical des _; Alcohol, R ² the alkyl radical of the dibasic acid, R ³ the alkyl radical of the glycol and R ⁴ the alkyl radical of the monobasic acid. This ester can be prepared as described for Type I, but it can also be prepared from a dibasic acid and a glycol under conditions such that a hydroxyl group of the glycol bonds with a carboxyl group of the dibasic acid, in other words that first a half ester is formed. This half-ester is then reacted with one molar proportion each of an aliphatic alcohol and a monobasic acid.

Type IV
Monobasic Acid Glycol Dibasic Acid

Glycol monobasic acid _g

These synthetic complex esters have the following composition:

Ri-C - 0 - R ² - O - C - R ³ - C - 0 - R ⁴ - 0 - C - R ^s O OO O

Here, R ¹ and R ^{5 are} the alkyl radicals of the monobasic acid, R ² and R ^{4 are} the alkyl radicals of the glycol, and R ³ is the alkyl radical of the dibasic acid.

These esters have the same composition as those of Type I, with the exception that this type is made by mixing a monobasic acid with a glycol under such conditions brings to reaction that a half ester is formed, whereupon 2 moles of this ester with 1 mole a dibasic acid.

The following alcohols, for example, are used as the alcohol component: 2-ethylhexyl alcohol, the

Ether alcohols formed by the reaction of ethylene oxide or propylene oxide with aliphatic alcohols and especially the oxo alcohols.

The following monobasic acids, for example, are used as acid components: vinegar, propionic, Butter-, Valerian-, Capron-, Capryl-, Pelargon-, Laurin-, Palmitin-, Stearin-, Oil-, / 3-Methoxypropion-, / 3-Äthoxypropion-, ß-tert.-Octoxypropion-, / 5-Äthylmercaptopropion-, /S-tert.- octylmercaptopropion-, jS-tert-dodecyl mercaptopropionic acid and the various acids produced by oxo synthesis. Among those used to make the complex esters Glycols include ethylene glycol and all paraffin homologues of the same up to about 18 carbon atoms. This subheading includes propylene glycol, butylene glycol, pinacon, trimethylene glycol, tetramethylene glycol, Pentamethylene glycol, etc. Since the glycols also contain oxygen or sulfur atoms can also include compounds such as di-, tri- and polyethylene glycols from the composition

HO (CH ₂ CH ₂ O) _n CH ₂ CH ₂ OH

where η is 1 to 26 can be used. Glycols,

which contain sulfur atoms in thioether bonds are, for. B. thiodiglycol and i, 2-bis- (2-oxyethyl ~ mercapto) ethane. One can also use glycols, which contain both oxygen and sulfur in the appropriate Binding included; an example of this is bis-2- (2-oxyethoxy) -äthylsulnd.

According to the invention, an ester of type II is preferred as the complex ester, for example one which is obtained by reaction of 2 moles of a branched C ₈ - to C ₁₀ alcohol with 2 moles of a half ester of a dibasic acid, such as succinic, glutaric, adipic , Pimelic, cork, azelaic or sebacic acid, and 1 mole of a polyethylene glycol has been obtained. The reaction product of 2 moles of a half ester of adipic or sebacic acid and 2-ethylhexanol with 1 mole of a polyethylene glycol with a molecular weight of about 200 is particularly preferred.

The modern turbine jet and propeller jet engines have high compression ratios and high power. Their operating temperatures are very high, and the load on the gears and bearings is also increased. Oil cooling has also become a problem since bearing temperatures above 232 ^{° are} no longer uncommon. Under these conditions, in addition to the usual requirements at lower temperatures, the lubricating oil is subjected to extremely severe conditions in terms of its behavior at high temperatures and its load capacity. The lubricating oils suitable for these engines must therefore have a superior combination of physical and chemical properties.

Generally, such oils are not intended to have a viscosity of at least 3 cSt at 98.9 °, of at least 11 EST at 37.8 ° and of more than 14,500 cSt at - 54 have ^0th Your loading capacity must

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sufficient kg in the from Shell Development Company developed the four-ball tester, an adhesive loading of about 70 and to provide a welding load of 120 kg, and they are intended to verm'eiden an excessive oil consumption, a flash point of greater than about 200 ⁰ own.

It is under protection to use mixtures of diesters and complex esters as synthetic lubricants, with polyethylene glycol as the glycol component, adipic or sebacic acid as the acid component and branched-chain alcohols as the alcohol component of the complex esters as well as adipic and sebacic acid and branched-chain alcohols as components of the diesters. In these cases, however, the proficiency test does not provide the optimal combination of test values required for use in modern aviation. Either these esters, when used on their own, have too low a viscosity index and too high a pour point, that is, inadequate at very low temperatures, or testing them in the four-ball apparatus reveals too low adhesion and sweat loads.
. In order to obtain the combination of the properties mentioned, the relative proportions of the three components which make up the basic mixture according to the invention must be carefully selected. Compliance with the quantities of the three components is essential. These must be approximately within the following limits: the dibasic acid ester must be present to about 85 to 98 percent by volume and the complex ester must only be present to about 2 to 15 percent by volume. The tricresyl phosphate, the stress-increasing additive, must be present in amounts of about 2 to 10 percent by weight, based on the amount by weight of the total mixture. In particular, a mixture of 90 to 98 percent by volume of the ester of a dibasic acid with a branched-chain C is recommended ₇ or C ₈ alcohol and 10 to 2 percent by volume of the complex ester, which contains 2 to 10 percent by weight of tricresyl phosphate. An increase in the proportion of complex esters and tricresyl phosphate on the specified limits has ^1, the load zusätzliche.Wirkung no noticeable, but on the other hand, increases the viscosity at low temperatures on the value that is required for launching low temperature engines. The decrease in the content of complex ester or tricresyl phosphate leads to an insufficient load capacity.

Various combinations with different contents of the individual components of the lubricating oil mixture according to the invention were produced. The viscosity of these samples and their behavior in the four-ball apparatus were tested. In the first series of experiments, a di-C _8r oxoadipate was used as the diester. The proportion of the complex ester in the mixture consisted of a reaction product of 2 moles of a half ester of sebacic acid and 2 moles of ethylhexanol with 1 mole of a polyethylene glycol with a molecular weight of about 200.

A test of the values given in Table I shows that the addition of the complex ester to the mixture increases the viscosity and the load-bearing capacity of the oil. Further, it is seen that about io ° / ₀ is the maximum amount of a complex ester which can be added for optimum viscosity and load capacity. Larger amounts of complex ester will not improve the mixture. It can be seen that larger amounts of tricresyl io / ₀ necessary than about ° not. It is worth noting that a combination of 5% complex ester and 5 weight percent tricresyl phosphate behaves better in the high pressure test than ₀ these two components would have from the addition of each io ° / can be predicted.

In a second series of tests, combinations of the same complex ester as above was used, made with 2-diethylhexyl sebacate and checked. The results are shown in Table II. They show the overwhelming advantage the admixture of complex ester and tricresyl phosphate within the specified limits.

A third series of blends was made using a di-C ₇ oxoadipate as the base oil. Combinations of this base oil with complex ester and tricresyl phosphate are extremely valuable, as shown in Table III.

The value of the mixtures according to the invention can also be seen from the drawing. This specifies the adhesive and perspiration loads for four mixtures in which the base _{oil consists of C 7} oxoadipate, C ₈ oxo adipate, C ₁₈ oxoadipate or di-2-ethylhexyl sebacate. The illustration shows that mixtures which contain both the complex ester and the tricresyl phosphate within the specified limits behave excellently with regard to both adhesion and perspiration.

The mixtures according to the invention are compatible with additives that improve certain Properties of a lubricant are used. For example, by adding certain Oxidation inhibitors, such as polynuclear phenols, alkylated phenols, phenothiazine, alkylated phenothiazine, in amounts between about 0.1 and 2 percent by weight the resistance to oxidation of the base mixture raise. Sludge inhibitors such as petroleum sulfonates or metal salts can also be added to the mixtures of petroleum sulfonates, such as the Na, Zn, Mg, Ba salts. These inhibitors work best in amounts between about 0.1 and 5 percent by weight. You can also add anti-rust agents to the finished mass add, such as polyoxyesters, e.g. B. sorbitan monooleate and pentaerythritol monooleate, in quantities between 0.1 and 5 percent by weight. 0.1 to 2 percent by weight can also be used as an anti-corrosive agent Add lecithin, and antifoaming agents, such as liquid silicones, can be used in amounts up to add about 0.1 percent by weight.

The mixtures according to the invention can also be reinforced against corrosive effects by small amounts of mineral oil are added to them. In order to achieve this effect, one can manufacture it Add about 5 to 15 percent by weight to the mixture.

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Table I.
Synthetic oil mixtures (basis: Di-C ₈ oxoadipate)

Diester mixture Tricresyl
phosphate Mechanical properties Four-ball apparatus at least Viscosity in cSt at
37.8 °
iften at
- 54 ° / Volume Weight (Shell) at least at most percent composition percent at
98.9 °
special properties 11.0 14 500 No. 100 O Load in kg
Adhesive load welding load
gefoi at least 10.10 6812 100 3 at least 3, o 10.26 7 912 100 5 70 2.88 10.36 8679 I. 100 IO 40 ^; 2.84 10.67 11 282 2 95 0 60 2.87 .11.18 8349 3 95 3 .55 2.87 11.36 10 105 4; 95 5 60 3.03 10 815 5 95 10 45 3.O7 11.91 14114 6th 9 ° 3 70 .-, 3.08 ... ■ 12.23 12 7OO 7th 90 ■ 5. " 70 3.11 12.23 I34OO 8th 65 0 .60 3.28 53.6o ' fixed • .9 35 0 70 3.28 18.78 38 724 IO 35 3 '■ 75 10.26 18.84 42 766 II 35 5 65 - 4.62 ■ 18.99 48 676 12th 35 IO 60 4.63 19.22 50836 13th 0 0 • 75 4.61 53.6o fixed 14th 0 3 85. 4.54 53.10 . fixed 15th 0 5. 80 10.26 52-, 75 fixed l6:. 0 IO 65 120 10.10 52.49 fixed 17th 80 95 10.01 : 18. 125 95 9.76 ^19th 120 95 more complex
Ester 100 Volume 120 'percent 130 O 130 O 130 O 140 O 140 5 140 5 140 5 140 5 · 140 IO 140 IO 140 35 140 65 130 ■ 65 130 65 " ⁶ 5, 100 100 100 100

Table II

Synthetic oil mixtures (basis: di-2-ethylhexyl sebacate) '■■■,.; ■ · Diester more complex
Ester Tricresyl
phosphate Mechanical properties Four-ball apparatus Welding load Viscosity in cSt at at required properties at least at least at least at least /■.'■;1 mixture (Shell) 98.9 ° 37.8 ° 70 120 3, o 11.0 Volume Volume Weight Load in kg 55 100 3.31 12.54 percent 'percent percent Adhesive load 70 100 3.33 12.84 No. 100 O O 85 100 3.32 13.15 at composition 100 O 5 - - 3,6o ' - - 54 ° 100 O IO 80 120 3.60 - 95 5 O 85 120 3.60 - at most 95 5 3 60 14O 3.8o - 14 500 I. 95 5 5 - - 3.8o - 8,450 2 90 IO 0 95 140 3.8o - 14420 3 90 IO 3 60 140 5.2Ö - 17368 4th 90 IO 5 65 140 10.26 53.60 10 800 5 65 35 0 13,000 6th 0 100 .0 13 800 7th 12 500 8th 13 9OO 9. 16 200 IO 33OOO II fixed

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Table III

Synthetic oil mixtures (basis: C ₇ oxoadipate)

mixture Room
Diester iscompositionui
more complex
Ester Tricresyl
phosphate Mechanical properties Four-ball apparatus 311)
ig in kg
Welding load
required Viscosity in cSt at
37.8 °
ften at
-54 °. Volume Volume Weight (Sh
Load
Adhesive load at least at
98.9 °
special property at least at most No. percent percent percent at least 120 at least ΙΙ, Ο 14 500 100 • 0 O 70 100 3, ° 2 290 100 O IO 40 100 2.3 - - I. 95 5 5 70 120 - - 4 100 2 90 IO 5 80 I30 3, i - 4800 3 50 2.8 4th

Claims (5)

Patent claims: ι. Synthetic lubricating oil based on a mixture of a diester of a branched-chain C ₆ - to C ₁₆ -alcohol with a dibasic acid and a dibasic acid by reaction of 2 moles of a half-ester of a branched C ₆ - to C ₁₆ -alcohol of a dibasic acid with ι mol of a Glycol, in particular polyethylene glycol, formed complex ester, characterized in that it consists of a mixture of 85 to 98 percent by volume of the diester and 2 to 15 percent by volume of the complex ester and 2 to 10 percent by weight tricresyl phosphate, based on the weight of the total mass. 2. Synthetic lubricating oil according to claim 1, characterized in that it has a viscosity of at least 3 cSt at 98.9 °, at least 11 cSt at 37.8 ° and not more than 144,500 cSt at -54 ⁰ and that the dibasic acid is adipic acid or sebacic acid. 3. Synthetic lubricating oil according to claim 1 and 2, characterized in that the branched chain alcohols are those alcohols obtained from the oxo synthesis of an olefin. 4. Synthetic - lubricating oil according to claim ι to 3, characterized in that the same a diester of adipic or sebacic acid with a C ₈ alcohol obtained by oxo synthesis in amounts of 92 to 98 percent by volume and a complex ester of 2 moles of a 2-ethylhexyl Half-ester of sebacic acid or adipic acid with ι moles of a polyethylene glycol of a molecular weight of about 200 in amounts of 2 to 8 percent by volume and 2 to 10 percent by weight of tricresyl phosphate, based on the weight of the total mass. 5. Synthetic lubricating oil according to claim 1 to 4, characterized in that the diester is the 2-ethylhexyl diester of sebacic acid or adipic acid. Considered publications:
U.S. Patents Nos. 2,548,493, 2,548,494,
588 194. 1 sheet of drawings © 609 550 / 423.7. 56