DE2257708A1 - OIL PREPARATIONS - Google Patents

Description

DR. BERG DIPL.-ING. STAPF

PATENT LAWYERS
8 MUNICH 86, POST BOX 860245

Dr. Berg Dipl.-Ing. Stapf, 8 Munich 86, P. O. Box 86 0245

Your sign Your ref.

Our mark Our ref.

8 MONKS 80 OA fJ _niI

Mauerkircherstraße 45 ^fc · '"« »J

Lawyer file 22 Be / Ro

Esso Research and Engineering Company Linden / USA

"Lubricating Oil Preparations"

This invention relates to lubricating oil formulations which Contain amine salts of phosphoric acids.

Lubricating oils usually need additives for improvement their properties against abrasion and their high pressure performance, and this is particularly true of aircraft lubricating oils, e.g., aviation turbine lubricating oils. It so far certain amine salts of phosphorus and thio-

-2-

3098 ^ 2/1090

(0811) 988272 S8 70 43 983310

Telegrams: BERGSTAPFPATENT Munich TELEX: 0524560 BERG d

Banks: Bayerische Vereinsbank Munich 453100 * Hypo-Bank Munich 3892623 Post check Munich 653 43

Phosphoric acids have been suggested as anti-slip additives, but these, although some good, are anti-slip additives Have properties, corrosive and / or incompatible with silicone elastomers. It has now been found that certain amine salts not only have good slip-improving and extreme pressure properties, but also good compatibility with silicone elastomers. They also have good corrosion properties.,

The invention relates to a lubricating oil preparation which contains a lubricating oil and a mixture of certain amine salts. This mixture comprises (a) a quaternary hydrocarbyl ammonium salt of a mono (C 6 -C 8 alkyl dihydrogen phosphate of the general formula
R ⁵ O

R ¹ R ² R ⁵ H ⁴ N (K

and (b) a quaternary hydrocarbylammonium ala of a di- (Cj-C ₁ ,) -alkyl hydrogen phosphate of the general formula

R ⁵ O ^ O

^ ONR ¹ R ² R ⁵ R ⁴ ,

in which the radicals R, R, R ^ and R are identical or different

12 "5 dene hydrocarbyl groups, where the radicals R ₁ R, R

4th
and R contain a total of at least 10 carbon atoms, and R.. and R the same or different C ₁ -C ₁ , -

309822/1098 -3-

Are alkyl groups.

The total number of carbon atoms in the radicals R ,,

2 3 4 ■ "'- ·'

R, R and R must be at least 10 and is preferably higher, e.g. at least 14. This means that although one or more of the groups can be relatively short-chain, e.g., methyl or ethyl, one or more of the other groups can be long-chain, e.g. Must be Dodeeyl, etc. When the mixture of amine salts is added to the mineral oils, the preferred maximum number of carbon atoms in the radicals R ¹ , R ² , R ⁵ and R ⁴ "is 100, while when the mixture is to be added to synthetic ester oils, the preferred maximum number of carbon atoms

1 2 '3 4 is ο Although the groups R, R, R and R can be different, it is preferred when carrying out the invention that at least two of the groups are the same, ie, R ¹ and R ² methyl, R ⁵ ethyl and R ^{4 are} octadecyl, or R ¹ and R are methyl, R and R are octadecyl. The groups R ¹ , R ^2, R and R can be straight or branched chain. The radicals R ¹ , R., R ⁵ and R ⁴ can be alkaryl, aralkyl, cycloalkyl or aryl groups, but are preferably alkyl groups.

12 3 One or more of the groups R, R, R and

A. ■ "'

R methyl, ethyl, n-propyl, iso-butyl, n-hexyl, n-decyl, 2-ethyldecyl, n-octadecyl, m-tolyl, p-ethylphenyl, benxyl, Be Gycloootyl, Phenyl or Kaphthyl, with the proviso that the total number of carbon atoms in the 4 groups at least 10 is. It is particularly preferred that at least 3

-4-309822 / 1098 '

1 O ^ A

the groups R, R, Ir and R are identical alkyl groups, e.g. all the same group as n-butyl, or 5 groups of octyl groups as with the hexyltrioctylammonium salts.

Although each of the groups R, R, R "^ and R al are hydrocarbyl groups but they can be designated by polar substituents, e.g. chlorine or bromine atoms or by keto or ether groups, with the proviso that these substituents are not present in such large proportions are that they substantially change the hydrocarbon character of the group} so, for example, the groups should no more than 10 wt. # of polar substituents, based on the weight of the hydrocarbyl part of the group.

5 6
The groups R and R are alkyl groups with 1, 2, 3 or 4 carbon atoms, ie they are methyl, ethyl, n-propyl iso-propyl, η-butyl, sec-butyl or iso-butyl groups. It

5-6 it is preferred that both R and R are the same, e.g.

are both methyl or both ethyl groups. Particularly preferred salts are mixtures of tetra-n-butylammonium salts of dimethyl hydrogen phosphate and methyl dihydrogen phosphate and mixtures of hexyl trioctyl ammonium salts of methyl dihydrogen phosphate and dimethyl hydrogen phosphate

The mixture of the acidic phosphates from which the juarternary ammonium salts (a) and (b) are derived is best prepared by mixing phosphorus pentoxide with an O ₁ -C ₄ alcohol or mixture of alcohols in a ratio of about

309822/1098 " ⁵ ~

..3 moles of alcohol per mole of pentoxide. The mixture of alkyl phosphates is obtained after the following reaction:

p- + 3R ⁵ OH

R ⁵ O P. / RO O - + \. R ⁵ O HO / P. \ 'r \ OH- \ V OH

When carrying out phosphorus pentoxide can vigorously in dry ether and add the alcohol drop by drop at a sufficient rate that the ether can be kept under moderate reflux. The product can then remove any unreacted iron Phosphorus pentoxide filtered, and the ether by evaporation removed under vacuum. '

The mixture of the alkyl phosphates thus obtained is with a quaternary ammonium hydroxide solution (e.g. 40%, aqueous Solution) implemented, such solutions can expediently be produced by .that one at room temperature tertiary amine with an alkyl halide to form the quaternary ammonium halide such as the following Implements equation:

R-K + RX —— »R-N ^ -

RR

This halide is mixed with a solution of silver oxide in water and stir the reaction mixture. The silver-

3 09822/1098 ~ ⁶ "

Halide is precipitated and a solution is obtained that contains quaternary ammonium cations and hydroxide anions. The quaternary ammonium halide can also be converted into the corresponding hydroxide by a suitable Iontnauataueeher resin, e.g. a polystyrene / divinylbenzene isohpolymer » which is substituted with tertiary amine groups is used.

If you have such quaternary ammonium hydroxide solutions Reacts the mixture of alkyl phosphates, the desired Mixture of the amine salts (a) and (b) formed. The molar ratio of (a) to (b) formed by this method is about 1i1 and this is the preferred ratio.

Mix the amount of amine salt that is added to a lubricating oil , especially a plug turbine oil, is common a minor proportion, preferably 0.001 to 10% by weight, e.g. 0.01 to 5.0 wt% based on the weight of the lubricating oil.

The lubricating oil can be any mineral oil, animal oil, fish oil, Vegetable oil or synthetic oil, for example petroleum oil fractions from spindle oil to lubricating oil up to SAE 30, 40 or 50, castor oil, animal or fish oils, or oxidized Mineral oil, e.g. palm oil, fatty oil, fallow oil, peanut oil or sperm oil.

The preferred lubricating oil is in synthetic esters and in suitable diesters include diesters of the general formula

30 98

.- ■■■■■, ■■ .. .- ..- 7-

wherein R is a Cg to CJ ₂ alkyl group, while R ^ is a C ₄ - Tais G ^ q saturated aliphatic hydrocarbon group or an ether-interrupted saturated aliphatic hydrocarbon group. The types of esters given above can be prepared from alcohols and dicarboxylic acids or glycols and monocarboxylic acids.

Another suitable class of ester lubricants are the polyesters made by polyvalent Alcohols, e.g., those having 2 to 12 hydroxyl groups per molecule and 2 to 40 carbon atoms per molecule, such as Trimethylolpropane, pentaerythritol and di-pentaerythritol with. Mono- and / or dicarboxylic acids, such as butyric acid, caproic acid, oaprylic acid and pelargonic acid or adipic, sebacic acid or azelaic acids.

The complex esters that can be used as base oils, are produced by esterification reactions between a dicarboxylic acid, a glycol and an alcohol and / or a monocarboxylic acid. These esters have the following general formulas;

R ₄ COO-E ₃ - (0OCR ₂ COO-R ₃ ) _n -00CR ₄ R ₁ -OOCR ₂ COO- (R ₃ -OOCR ₂ COO) _n -R ₁

R ₁ -C0OCR ₂ COO-R ₃ ) _n 00CR _4:

wherein R _{1 is derived} from a monohydric alcohol, Rg is derived from a dicarboxylic acid, for example alkanedioic acids.

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- ο -

derived hydrocarbon radicals, R, divalent hydrocarbon or hydrocarbonoxy radicals, such as OH ₂ (OH ₂ ) -,
or CH ₂ OH ₂ (00H ₂ OH ₂ ) _n - or OH ₂ CH (OH ₃ ) (0OH ₂ OH (CH ₅ )) _n ~,
which are derived from an alkylene glycol or polyalkylene glycol, while R, which is the alkyl group derived from a monocarboxylic acid, "n * ¹ in the complex ester molecule is an integer, usually in the range of 1 to 6, depending on the desired viscosity of the product, as controlled by the relative molar ratio of the glycols or polyglycols to the dicarboxylic acid. In the preparation of the complex esters, some simple esters will always be formed,
doh · those in which η = 0, but these will generally only make up a small proportion. In general, these complex esters will have a total of 15 to 80, e.g.
Have 20 to 65 carbon atoms per molecule.

Particularly suitable lubricants are esters of polyhydric alcohols of the formula

CH ₂ OH

RC-CH ₉ OH CH ₂ OH

wherein R is a CH ₂ OH group, or an alkyl group such as a _f
Is an alkyl group of 1 to 6 carbon atoms. Suitable
Esters of this type are therefore the neopentyl polyol esters of
Trimethylolethane, trimethylolpropane, trimethylolbutane and
of pentaerythritol or di-pentaerythritol.

309822/1098

■ - 9 - ■

The preferred comparable for the esterification of ^{trimethylolpropane:} used acids are the C ^ Cp-monocarboxylic acids. Particularly preferred are the C ^ -C ^ Q esters, ζ.B. Cg (caprylic) and Og (pelargonic) acid esters. Mixtures of these CU-CL ₂ -SaUs can be used. When using such a mixture of acids, a mixture having an average of 8 to 9 carbon atoms is preferred. Although more difficult to manufacture, it is even preferred that a methylol group with a neο-heptanoic acid, Z ₀ B. 2 _O 2-dimethylpentanoic acid is esterified, and the other methylol groups with not hindered acids, for example, "esterified Pelargonsäuren. This particular ester is much more thermally stable than the fully hindered ester, but has higher performance and superior low temperature properties.

The preferred acids for the esterification of pentaerythritol are the C.-G.Q-monooarboxylic acids, the particularly preferred esters being those of C ^ to Cg acids, ZoB * n-Valerian- * Isovalerian-, 2-ethylbutter-, Öapron-j n-Heptyi-i n-Octan or 2-ethylhexonic acids or a mixture of Oc-Öq acids are.

Mixtures of diesters with small proportions of one or several thickeners can also be used as lubricants. For example, you can use mixtures, which, up to 50%, are one or more water-insoluble Polyoxyalkylene glycols, for example polyethylene or Polypropylene glycol or mixed oxyethylene / oxypro-

309822 / 109Ö

contain pylene glycol

To formulations! which are suitable for gas turbine lubrication include 65 to 90 YoI, Ji τοη one or more diesters of azelaic acid or sebacic acid and a Cg-G branched-chain alcohol} especially 2-ethylhexanol or "oxo" alcohols, which are predominantly C ₈ , Cg or C 8 ₁ Q contain alcohols or mixtures of such alcohols and 35 bis polyoxyalkylene glycol ethers of the general formula:

RO

CH-O

R,

in which the radicals R ^, R and Rg are hydrogen or Ö ^ ö ^ groups bind and in which no more than two of these groups are hydrogen and η 'is an integer greater than 1 * Particularly valuable compounds are polyoxypropylene glycol monoethers and the corresponding Dieter. '^;"

The thermal stability of such diesters / polyoxyalkylene glycol ethers can be improved if a small percentage Complex ester of three or more carboxylic acids or Alcohols, at least two of which are difunctional Acids or alcohols are, brings in. Such granular esters can be glycolic or dicarboxylic acid centered, where the molecule is terminally a mono-hydroxy or mono-

■ "-T1-309822 / 1098

having carboxylic acid compound. A particularly preferred complex ester of this type is derived from a polyethylene glycol with a molecular weight of 200, 2 molecules of sebacic or azelaic acid and 2 molecules of an Oc-O-jq branched-chain aliphatic monohydric alcohol, especially 2- ^: ethylhexanol. -

Other additives that can be used in the lubricating oil include corrosion inhibitors such as sebacic acid, a metal deactivator, such as quinizarine, a foam inhibitor, ZoB. Silicone polymer, such as dimethyl silicone, an antioxidant such as phenothiazine or dioctyldiphenylamine or a slip enhancing additive such as tricresyl phosphate. It can also be the mixture of amine salts with a liquid fuel oil, e.g. with a diesel oil, be used*

example 1

Tetrabutylammonium salts of mixtures of (1) methyl dihydrogen phosphate and dimethyl hydrogen phosphate (2) ethyl dihydrogen phosphate and diethyl hydrogen phosphate and (.3) n-butyl dihydrogen phosphate and di-n-butyl hydrogen phosphate were produced by the following procedure.

A 10 $ aqueous solution of the acidic phosphate was stirred and gave tetra-n-butylammonium hydroxide solution (40%, aqueous) to adjust the p "value to 7, and evaporated the

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Solution to dryness in the presence of a trace amount of n-octanol to inhibit foaming. Then one gave Toluene and the solution evaporated again to Trooknef this was repeated once more to ensure an anhydrous product.

Tetrabutylammonium salts were also used for comparison the mixtures of 05- »Cg- and C.g - ^ - alkyl dihydrogen and Di-n-alkyl hydrogen phosphates produced.

Each mixture was separately based on a synthetic oil Ester base added, which also contains 1.0% by weight of tricresyl phosphate, 1.6% by weight of dioctyldiphenylamine and 0.4% by weight of phenothiazine contained. The base oil was a mixture of esters obtained by esterifying 90% by weight of pentaerythritol and 10% by weight. Dipentaerythritol obtained with a mixture of (Oc-GgJ fatty acids became. ·

The IAE transmission fracture load at 110 ° C / 2000 rpm and the Rolls-Royce elastomer swelling temperature from the IUIIr point (in ⁰ C) were determined. The standard Rolls- Royse investigation of the silicone elastomer compatibility (method IOO9) involves immersing a standard test specimen in 50 ml of the Versuoh for 192 hours. Lubricant at a temperature of 175 ° C. Oils with extreme pressure properties cannot be produced in such a way that they are still compatible with elastomers under these conditions, and a modification has therefore been made

309822/1098 -13-,

tion of this procedure series of tests with different Temperatures performed and the percentage of swelling of the elastomer plotted against the temperature «The extrapolated temperature at which the swelling '* occurs from the zero level is used as the index of the elastomer compatibility of the oil. The results are shown in the table below. It can be seen that the best Results in terms of the extreme pressure properties then obtained when tetrabutylammonium salts of the dimethylhydrogen and methyl dihydrogen phosphates are used, and that the high pressure properties decrease rapidly as the chain length of the groups R and R in that Phosphate increases-.

309822/1098

Tabel: Tabel

Carbon chain layer in that
acidic phosphate mixture

Concentration of IAE transmission

Weight # P Weight $ (Arcin salt) breaking load - 2000 rpm / 110 ° 0

10

'10

10

10

10

7 x 10

5 x 10

-2 -2 -2 -2 -2 -3 -3

0.19 0.17 0.1.5 0.10 0.07

Ib leg 50 22.7 60 27.2 65 29.4 63 28.6 73 33.1 108 49.0 90 40.8

RE silicone elastomer Hull filling according to rc) '

135 132 125

120 125 130

AJl

Example 2 ■ .. "-_ ■ -.".

Hexyl trio et ylammonium salts of mixtures of methyldi ^ hydrogen phosphate and dimethyl hydrogen phosphate are added prepared according to the procedure of Example T, except that Hexyltrioctylaimaoniumhydroxidlösung (4® $, aqueous) instead of tetra-n-liutylammonium hydroxide was used.

0.125 wt.% ( "Weight <äes lubricating oil) were mixed Hexyltrioctylammoniumsalzen · added, using the same base oil as used in Example Ί containing the same amounts as Tricresylphosjphat, dioctyldiphenylamine and phenothiazine.

V / hen this Sciniierölpreparation the liE gear and Subjected to Eolls-Royce silicone elastomer sub-rods the following results were obtained: IAE gear breakage load 2000 rpm / 10 ^ C - 4.309 kg

Rolls-Hoyce-silicone-elastomer-lfiall-:

aufquellraag. - 125 ° G

Claims; 309022/1098 -16-

Claims (7)

Patent claims " 1 ο lubricating oil preparation, gekennzeiohne t by the content of a lubricating oil and a mixture of (a) a quaternary hydrocarbylammonium _{salt of the mono- (C 1} -C.) - alkyl dihydrogen phosphate of the formula R ⁵ O R ¹ R ² R ³ R ⁴ IKK ^ ONR ¹ R ² R ⁵ R ⁴ and (b) a quaternary hydrocarbylammonium al of the di- (0 ^ - 0,) - alkyl hydrogen phosphate of the formula ^ ONR ¹ R ² R ⁵ R ⁴ wherein the radicals R, R, R ^ and R are the same or different Are hydrocarbon groups, and contain a total of at least 10 carbon atoms, and R and R the same or different and are C. to C. alkyl groups. 2. Preparation according to claim 1, characterized in that the total number of carbon atoms in the radicals R ¹ , R ² , R ³ and R is at least 14. 3. Preparation according to one of claims 1 and 2 d a - 309822/1098 " ¹⁷ " ~ I (- ■ d u r .c h marked that the remains R, R, R and R are the same and are preferably n-butyl groups are. 4 ο preparation according to one of the preceding claims through this . marked that the 5 6
R and R residues are the same and preferably both methyl groups pen or ethyl groups sindo 5. Preparation according to one of the preceding claims, characterized in that the molar ratio from (a) to (b) is about 1: 1. 6. Preparation according to one of the preceding claims characterized in that the Lubricating oil is a synthetic ester, preferably one Polyhydric alcohol ester of the formula GH ₂ OH R: - 0 GH ₂ OH CH ₂ OH - 'where R is an alkyl group or the group GH ₂ OH. 7. Preparation according to one of claims -1, 2, 4 and 6 characterized in that the mixture d, the salts are a mixture of hexyltrioctylammonium salts 309822 / Ί 098 of methyl dihydrogen phosphate and dimethyl hydrogen phosphate 309822/1098