DE1444851A1 - Lubricant composition - Google Patents

Description

DK. E. WIEGAND MÖNCHEN 15, 11 March T96O

MÖNCHEN NUSSBAUMSTRASSE 10 ._

DIPL-ING. W. NIEMANN phone : 555476 η 44405

HAMBURG PATENTANWXLTE

W. 19089/60 7 / Ed

Dr. Expl.

Heyden Newport Chemical Corporation Few York, N.Y. (V.St.A.)

Lubricant composition

The invention relates to synthetic lubricants of the Eeter type. In particular, the invention relates to new, synthetic lubricants that are effective over a wide temperature range.

Lubricants for use in aircraft engines and

Instruments in gas turbines and in certain technical

en
Applications must have special properties that conventional lubricants do not have. They must have high viscosity indices and relatively high viscosities at elevated temperatures to ensure adequate lubrication over a wide temperature range. You must also have good oxidation and thermal stability, so that they have their useful properties

Operation "at high temperatures for a long period of time keep. They must have low pour points so that they work at low temperatures, and they must eventually have high flash points to reduce the risk of fire while operating at high temperature and loss to avoid lubricant by evaporation.

A new class of synthetic lubricants has been found which meet these requirements and which are particularly desirable for use in internal combustion engines, which among widely differing Working temperature conditions. The new lubricants are mixed esters that make up the formula

CH ₉ OOCR
AC-CH ₉ OOCR ¹
CH ₂ OOCR ¹¹

to have. In this formula, A represents a hydrogen atom

or an alkyl group having 1 to 5 carbon atoms. R, R and

11
R each represent a straight-chain, saturated alkyl radical with 1 to 11 carbon atoms, and the combination

1 11
tion of R, R and R represents at least two different alkyl radicals.

These mixed esters have viscosity properties, lubricity, and other properties that make them excellent Make lubricants. These mixed esters

QftOOn ¹ ? >

are superior as lubricants to the esters that are derived from a single straight-chain alkanoic acid or a mixture are made from acids, which includes both straight chain and branched chain alkanoic acids »

The mixed esters according to the invention are those in which the hydroxyl groups are trivalent lieopentyl alcohol are replaced by residues of straight-chain alkanoic acids containing 2 to 12 carbon atoms. the mixed esters contain at least 2 different esters in pail Acid residues.

The trivalent neopentyl alcohols that make up the mixed Esters are formed have the formula

CH ₀ OH

AC-CH ₉ OH

CH ₂ OH

in which A represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples of such trihydric alcohols are: 'frimethylo! methane, trimethylolethane, Trimethylol propane, trimethylol butane and trimethylol hexane. -It can be a. the only trivalent neopentyl alcohol or a mixture of two or more of these alcohols in the preparation of the mixed esters according to the invention be used. A purified grade or a technical grade of trihydric alcohol can be used.

BATH

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The term "technical quality" refers to a product that is in addition to the trihydric alcohol contains small amounts of the dimer of alcohol and the formals of alcohol and their dimers.

The acids that are used in the esterification are the straight-chain alkanoic acids with 2 to 12 Carbon atoms. These acids include acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, Capric acid and lauric acid. At least two of these acids are used in making the mixed esters. If desired, as many as four acids can be used reach.

While all of the mixed esters according to the invention have exceptional lubricating properties over one have a wide temperature range, the lubrication applications are at which any mixed ester is most effective, largely dependent on the choice of esterification acids. Esters that are made from relatively short-chain acids, i.e. from those acids that are about 2 to 6 Containing carbon atoms generally have very low levels Flow points and exceptional viscosity properties ten at low temperature. These esters are from Particularly useful in applications at low temperatures, e.g. as a lubricant for cooling and freezing devices. Esters, which are made from relatively long-chain acids, i.e.

809807/0376

made from those acids containing from about 7 to 12 carbon atoms, on the other hand, have excellent stability and viscosity properties at elevated temperatures. These esters are of particular value, for example, in high-pressure lubricants, such as, for example, lubricants for pumps, gearwheel housings and valves, and in various technical lubricants, such as those used in metalworking. Esters which are prepared from at least one relatively short chain acid and at least one relatively long-chain acid, generally have _t _; ute en lubricating property both at high and at low temperatures. Of particular interest is a group of esters in which about two of the hydroxyl groups are esterified with an acid having 4 to 6 carbon atoms and about one of the hydroxyl groups is esterified with an acid having 7 to 10 carbon atoms. Examples of such soters are trimethylolpropandivaleriate monopelargonato. These esters, as well as similar esters of drimethylolethane, have a unique combination of high temperature and low temperature properties which enables them to meet the requirements established for lubricants to be used in jet aircraft.

Any of the mixed esters according to the invention can be used as

BATH ORIGINAL

Lubricant can be used, if necessary, a Mixture of these esters are used. During everyone the ester present in the mixture has the aforementioned structural formula, the mixture can have an average composition that is not in accordance with this formula. For example, contains a mixture of equal amounts of trimethylolpropane dicaprylate monocaprate and Ürimethylolpropane monocaprylate dicaprate on average 1.5 caprylaic esters and 1.5 caprate residues per mole of imethylolpropane. It can be seen that mixtures of "mixed esters within of praising the present invention.

The reaction products contemplated herein can be prepared by any of the conventional teresterification procedures getting produced. For example, the trihydric alcohol can be mixed with the acids at room temperature and the Mixture can be heated until the esterification is substantially complete, or the alcohol can be partially mixed with an or several of the acids can be esterified, and the partial ester can then continue with the other acid or the others Acids are esterified. The total amount of acids used is generally in excess over that which is necessary to react with all hydroxyl groups of the alcohol present in the reaction mixture. However, equivalent amounts of alcohol and acids or an excess of trihydric alcohol can also be used in the

BATH ORIGINAL

Reaction to apply. The reaction can be carried out in the absence of a catalyst or in the presence of one of the customary esterification catalysts, such as p-toluenesulfonic acid or sulfuric acid. A volatile organic solvent such as petroleum ether, benzene or xylene can be added to the reaction mixture to aid in removing the water formed during the esterification. The temperature at which the esterification is carried out is preferably below the distillation temperature of the acids. In general, a temperature between about 115 ° 0 and 18O ⁰ C is applied. The length of the heating time depends on the reaction temperature and other reaction conditions. Heating is generally continued until the product, after removal of the solvent and any unreacted acid, has an acid number below 0.5.

The crude product from the esterification can be cleaned using customary procedures. For example, can't reacted acid can be removed by washing with dilute alkali. Volatile contaminants can by distillation and certain other impurities can be removed by treatment with activated carbon.

The following procedure, which is used for the preparation and purification of Trimethylolpropandivaleriatmonolaurat was applied, iut typical of those used in the manufacture

^BATH

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the mixed esters according to the invention to be used procedures:

A mixture of 268 g of trimethylolpropane, 448.8 g of valeric acid, 440.6 g lauric acid, 23 g activated carbon, and 115.7 g of xylene at 175 ° C Ms ⁰ 180 _t for 2 hours and heated at this temperature for 25.5 hours long held. At the end of this time, the reaction mixture was sprayed or flushed with carbon dioxide to remove the xylene and filtered to remove the charcoal. The crude ester was then diluted with the same volume of petroleum ether. The crude ester solution was washed with enough 5 liters of aqueous sodium hydroxide solution to neutralize the unreacted acid and then washed with 12 liters of sodium chloride solution until neutral. After the addition of about 2 wt. $ Activated carbon, the solution was heated to 160 ° to 18O ⁰ G 2 to 3 mm of absolute pressure to remove water, petroleum ether and volatile impurities. The residue was cooled to 100 ° 0 and filtered. The properties of this ester and other trimethylol propane esters are given in Table I.

8098 07/0376

Table I. Mixed esters of trimethylol propane

viscosity
(Oentistpkes) at

3
(IQO ⁰ P)

54 (-65

Viscosity I index

18.9

fixed

H, 3

16.2 j fixed

11.0 j 5,000!
i19,000

11.6

13.2

i -

] 105 145 96

17,600 {11,300!

firmly fixed

A represents trimethylol propane dibutyrate monolaurate B represents trimethylolpropane dibutyrate monopelargonate G represents trimethylol propane divalerate monolaurate B represents trimethylolpropane divaleriate monocaproXate E represents trimethylolpropane monovalerate dipelargonate F represents trimethylolpropane monovaleriatdicaproate Gr represents trimethylolpropane monovalerate monocaprylate monocaprate represent

ftnQQ (17

- ίο -

H represents trimethylolpropane monovalerate monocaprylate

monocaproat
I represents trimethylolpropane monopelargonate monocaprylate

monocaprat
J represents trimethylolpropanecaprylate reagent (an average of 1.5 moles of each acid per mole of trimethylo! Propane)

Ester

The characteristics of a distinctive group of mixed esters of trimethylol ethane are in table II reproduced.

Table II Mixed esters of trimethylol ethane

Acid i 'paid OH

Fliess-1 (Centistpkes) at j visco-

point ^! 99 ^ 0 I 38 "C ⁰ F 1 (21O ⁰ F); (100 ⁰ F)

-54: 0! sitys- (-65 ι)! index

Dibutyrate monolaurate

Bivalry monolaurate

Divaleriate monocaproate

Bi c aprο atmono pelargonate

Dicaproate monovaleriat

Monovaleriate monocaproate monocaprylate

Pelargonate laurate (average 1.5 moles each Acid per mole of trimethylolpropane)

0.05 0.04 0.01 0.0-3 0.01

0.18

0.28 0.19 0.06 0.02 0.02

2.5 2.8 2.7

3.1

9j7 10.6

10.3 12.4

fixed I j fixed

6 500 j : j , 7 500 ί

\ 7 400

500

120

0.20

fixed

800.80 7/037

The flash points, pour points and viscosities were according to the ASTM test method "determined. The viscosity index, which is a measure of the rate of change in viscosity with temperature, was after the procedure determined by Dean and Davis (Chem. & Met.Eng. 36, (1929), 618) is described.

Any of the mixed esters according to the invention or a combination of two or more of these esters can can be used as a lubricant. If necessary, the esters can be mixed with e.g. mineral oils or other polyvalent ones Alcohol esters are mixed so that many combinations with special lubricating properties are obtained. It it is generally desirable to add at least one of the known lubricant additives to the mixed ester. For example, an antioxidant such as phenyl-tf {-

1
naphthylamine, 2,2-dipyridylamine or phenothiazine, or mixtures of these antioxidants added to the mixed ester

are set. The amount used depends on the particular ester or esters used and on the choice of antioxidant addicted. Generally about 0.5 to 5 weight percent antioxidants are used. Viscosity index improver, Pour point depressants, detergents and corrosion inhibitors can also use the Lubricants are incorporated to improve their properties. The lubricants according to the invention can

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can be mixed with any of the commonly used grease making soaps to create solid or semi-solid lubricants. In any event, the choice of additives and the amount of each additive used will depend on a number of factors, including those
Choice of ester and application for which the lubricant composition is intended. It can be seen, however, that the lubricant compositions according to the invention contain the mixed esters according to the invention in a larger amount as a base and one or more of the aforementioned additives in a smaller amount.

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Claims (6)

Claims 1.) Lubricant composition, characterized in that it is a mixed ester of a trivalent Neopentyl alcohol of the formula GH ₀ OOCR
ι ^ AG-CH ₉ OOCR ¹ CH ₂ OOCR ¹¹ in which A represents a member selected from the group consisting of a hydrogen atom and an alkyl group with 1 to 1 11 5 carbon atoms, and R, R and R each a straight-chain, saturated alkyl radical with 1 to 11 Mean carbon atoms, where the combination of R, 1 11 R and R represent at least two different alkyl radicals. 2.) lubricant composition according to claim 1, characterized in that it contains an antioxidant as a lubricant additive. 3.) Lubricant composition according to claim 2, characterized by a content of about 0.5 to 5 wt. ^ Of an antioxidant from the group of phenyl - # (- naphthylamine, 2
gobble away. naphthylamine, 2,2-dipyridylamine, phenothiazine and mi Λ 'ft Λ Λ Λ M ^ Λ Λ It f ^ -H- 4.) Lubricant composition according to one of the claims 1 to 3, characterized in that A is methyl ". 5.) Lubricant composition according to claim 4, characterized in that it is trimethyloläthandibutyratmonolaurat or trimethyloläthandivaleriatmonocaproate has. · 6.) Lubricant composition according to one of claims 1 Ms 3, characterized in that A is propyl "means. 7,) lubricant composition according to claim 6, characterized in that it contains trimethylolpropandivaleriate monocaproate, Having trimethylolpropane divalerate monolaurate or trimethylolpropane monovalerate monocaproate monocaprylate. Qno.Qn'7