DE1225161B - Process for the production of polyol fatty acid esters serving as high-performance lubricants - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 'MTTWt PATENT OFFICE

EDITORIAL

Int. α .:

Number:
File number:
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C 07 c

German class: 12 ο -11

C 25865 IV b / 12 ο
December 29, 1961
September 22, 1966

The invention relates to the production of polyol fatty acid esters which are used as lubricants in the Continuous operation at high temperatures can be used.

Fatty acid esters of polyols with two or more methylol groups on a single quaternary Carbon atom such as trimethylolpropane, trimethylolethane and pentaerythritol can be known as Lubricants are used at high temperatures. So is z. B. from the French patent

1 239 027 a lubricant for jet engines known, which by mixing an alkanol diester one Alkanedicarboxylic acid with the ester of a polyol with two or more methylol groups on a quaternary Carbon and an alkanoic acid having at least 5 carbon atoms or more alkanoic acids is made with an average of at least 5 carbon atoms. In the case of the However, the processes used to prepare these esters result in products falling under the extremely harsh oxidizing conditions encountered by lubricants in high performance jet turbines for aircraft are exposed to failure as lubricants. Furthermore, yields are in the order of magnitude of only got 87 to 89%.

The process according to the invention for the production of fatty acid polyol esters serving as high-performance lubricants by reacting polyols which contain at least two, preferably three methylol groups bonded to a single quaternary carbon atom, with saturated fatty acids having 4 to 12 carbon atoms is characterized in that the esterification catalysts used are phosphorus compounds general formula O = P (OR) ₃ used, in which R denotes hydrogen atoms, alkyl, alkylene or aryl radicals, but not more than

2 oxygen atoms are bonded to aryl radicals. A yield of, for example, is obtained

greater than 93% of an ester with exceptional resistance to oxidizing conditions at high temperatures. The phosphorus compounds used for the purpose of the invention include z. B. phosphoric acid, its partial alkyl esters, trialkyl, Alkylene alkyl, alkylene bis (dialkyl), monoaryldialkyl and diaryl monoalkyl phosphates. To the Compounds that can preferably be used include, besides phosphoric acid, butyl phosphoric acid, Dipropyl phosphoric acid, tripropyl phosphate, tributyl phosphate, triamyl phosphate, phenyl dibutyl phosphate, Diphenylmethyl phosphate, ethylene butyl phosphate and ethylene bis (dibutyl phosphate). Preferred are trialkyl phosphates whose alkyl radicals 1 to

Process for the production of as a high-performance lubricant serving polyol fatty acid esters

Applicant:

Celanese Corporation of America,

New York, N.Y. (V. St. A.)

Representative:

Dr.-Ing. A. ν. Kreisler, Dr.-Ing. K. Schönwald,
Dr.-Ing. Th. Meyer and Dr. JF Fues,
Patent attorneys, Cologne 1, Deichmannhaus

Named as inventor:

James D. Atwood,

Ronald H. WiIe, Gallipolis Ferry, W. Va .;

Paul C. Pearson, Newark, N.J. (V. St. A.)

Claimed priority:

V. St. ν. America January 3, 1961 (80 046)

Contain carbon atoms, especially tributyl phosphate. The phosphorus compound is usually used in an amount of about 0.2 to 1.0 percent by weight, based on the weight of the polyol ester, which can be formed theoretically. 0.3 to 0.6 percent by weight is preferred.

The saturated fatty acids used to produce the polyol esters preferably contain straight chains with a length of 5 to 9 carbon atoms, or they are mixtures of such acids with an average chain length of 5 to 9 carbon atoms. When mixtures are used, the individual acids can contain carbon chains of 2 to 18 atoms. Straight-chain acids are preferred, but branched fatty acids can also be used, especially those with no more than 2 carbon atoms in the side chains. When using trimethylolpropane as the polyol, C ₆ -C ₉ acids are usually used, with pure heptanoic acid (= enanthic acid, C ₇ H ₁₄ O ₂ ) being preferred.

The polyols used are those with at least two, preferably three, methylol groups on a quaternary Carbon atom used. Suitable polyols include trimethylolpropane, trimethylolethane, Neopentyl glycol, pentaerythritol, 2-butyl-2-ethyl-1,3-propanediol and 2,2,4-trimethyl-1,3-pentanediol.

609 667/427

3 4

The polyol esters are generally made and boil at 250 ° C. at 1 mm Hg. It looks like,

by the polyol with a small excess of that also the poorer yields of the known

Fatty acid with removal of the water by ab- process due to the stabilizing effect of the re-

distill, preferably in the presence of an agent, action products _ of phosphorus are improved,

which forms an azeotropic mixture with water, e.g. B. 5 It also seems that usually first

a volatile hydrocarbon. entire polyol - esterification in the presence of one

In the case of trimethylolpropane, for example, 3.3 to excess acid can be converted into the ester, which

However, 3.6 moles of fatty acid per mole of trimethylolpropane used in part during the esterification and the

will. The subsequent heating under the applied water forms an azeotropic mixture

the connection, e.g. B. xylene, can be broken down again in a lot in harsh conditions. The arrival

from 2 to about 12 parts by weight per 100 parts of Reak essence of one of the inventive phosphorus

tion mixture are added. Preferably it appears to compounds or their reaction products

a boiling to reduce this, between 80 and 15O ⁰ C degradation and thus allows

Used hydrocarbon. In addition to xylene, there will be an increase in yield.

Toluene, cyclohexane, benzene and mixtures of ali- 15 The esters prepared according to the invention can

Phatic hydrocarbons, such as suitable soil, are mixed with additives, of which are known

oil fractions, preferred. is that it enhances thermal stability, oxidation

The esterification reaction will usually improve durability and lubricity, m

Deactivate normal pressure under reflux at a temperature and prevent lead corrosion,

carried out between about 140 and 350 ° C. The 20 particularly advantageous as an anti-oxidant

Water is added to the extent to which it is formed, an additive of 0.5 to 3 percent by weight

distilled off together with the entrainer. That of a secondary amine, such as phenyl-a-naphthylamine,

The reaction is carried out until the hydro and 0.5 to 3 percent by weight of a phenosilazine

xyl content of the reaction mixture no more than compound, ζ. B. N-ethylphenodiphenylsilazine.

0.1 weight percent. This requires habitual 25

borrowed 4 to 20 hours. Example!.

After completion of the esterification reaction can

the pressure can be reduced to 5 to 10 mm Hg, with 250 parts by weight of trimethylolpropane, 800 parts by weight

the end product up to a temperature of 240 ° C parts heptanoic acid and 4 parts by weight tributylphosphorus

is heated to the as an entrainer for water 30 phat were placed in a still, the

used hydrocarbon and the excess was provided with a 5-tray column, and below

Remove acid. The acidity is heated to nitrogen until reflux began. After addition

Lower the value of not more than 2 percent by weight, of 120 parts by weight of a petroleum fraction dated

An emulsion formation during the subsequent boiling range 115 to 130 ° C was about 4 hours

to avoid washing out. 35 heated until all the water was removed. then

After heating, the ester can be washed with sodium for 1 hour at a flask temperature of hydroxide and then with sodium chloride solution 280 ° C and a slight excess pressure (0.21 to 0.42 kg / cm ^a ) and finally to remove the Water further heated. Entrainer and excess acid are reheated in vacuo. It can also were then / 5 to 10 mm Hg abgetriebeü other methods for reducing the acidity present at 240 ° C 40, and the mixture extracted with 3% strength aqueous sodium ^he be turned, z. B. Wash washed with a sodium carbonate solution. The oil layer was separated from carbonate solution, stirring with an aqueous solution, completely dehydrated at 100 to 105 ° C./10 mm Hg, slurry of an alkaline substance of less than carbon was treated and finally filtered. The off solubility, e.g. B. calcium oxide, or treatment with loot of trimethylolpropane triheptyl ester was an ion exchange resin. 45 96.5%> based on trimethylolpropane.

The dehydrated product can then be used in a comparative experiment based on the same

treated carbon and finally carried out by diatoms, the tributylphosphorus was

earth filtered, phat omitted. The yield in this case was

The phosphorus compound used as a catalyst only 87%> based on trimethylpropane.

must during at least part of the esterification 50 samples obtained in the two experiments

<■ reaction, but preferably during the entire ester, were each with 1 percent by weight of phenyl

Reaction time as such. A finished a-naphthylamine and 1 percent by weight of N-ethyl

Trialkyl phosphate added to ester does not increase its phenodiphenylsilazine mixed. The mixtures were

Resistance to oxidation. Triaryl phosphates, such as tridene in one with thermostat and heating device

cresyl phosphate, are not available as an additive to the finished aluminum block with six holes

Esters can still be used as esterification catalysts. their resistance to oxidation checked. The exams

It is assumed that the phosphorus compounds were according to the specification "Revised MÜ-L-9236A"

is not itself effective as a stabilizing substance, carried out with 961 air hourly through the at

^{but rather that they were passed 250 cm 3} samples held at 218 ° C. during the esterification process. Of the

of a product with a stabilizing effect. 60 volatile weight loss during

It was found that the finished ester was stripped from the samples even after testing,

the distillation and other purification measures were carried out at intervals of 5 hours by the same about half of the volume of a fresh sample originally in the reaction mixture is replaced. The exams

Contains existing phosphorus. This phosphorus has continued until a sharp rise in

obviously constituent of compounds whose viscosity, acidity and weight loss break down

Boiling point at 1 mm Hg up to about 20 ° C above that of the sample tested. The received

Boiling point of the polyol ester, which is z. B. in the results are listed in the following tables;

Case of trimethylol propane heptanoate between 230 in which (a) that prepared according to the invention

Ester and (b) is the ester prepared in the comparative experiment.

sample 0 Time (p
25th hours)
30th 35 Viscosity (cSt at 37.8 ⁰ C) 31.80
17.39 17.49 19.09 Acidity (mg KOH / g) 0.02
0.04 2.49
0.23 0.30 1.10 Weight Loss Supplement (g) 10 Time
15th t (hour
20th en)
25th 30th 35 15.78
15.90 5 10.6
9.6 15.6
6.2 21.2
9.2 19.7
8.6 11.5 * (b)
(a) 11.0
8.5 (b)
(a) sample (b)
(a)

Total volatile acidity (mg KOH / g)

(b) 54.2

(a) 9.10

Example2

335 parts by weight of trimethylolpropane, 1072.5 parts by weight of heptanoic acid and 7.0 parts by weight of phosphoric acid was heated to 24O ⁰ C and held for 22 hours at this temperature. During this time

ίο the water was distilled off using xylene as an entrainer. Then, at a temperature of 230 ° C and a pressure of 1 mm Hg volatiles were removed, cooled and washed five times with l ° / _o igeva. aqueous sodium carbonate and washed twice with water. Finally, the product was freed from water at 100 ° C. and a pressure of 1 mm Hg, treated with charcoal and filtered.

The ester obtained in the manner described

was with 1 weight percent phenyl-a-naphthylamine

ao and 1 percent by weight of N-ethylphenodiphenylsilazine and mixed in the manner described above Oxidation resistance tested. The results are given below:

test

25th hours 35 0 19.42 30th 18.99 16.01 0.33 19.40 0.47 0.49 8th 0.43 10 10

Viscosity (cSt at 37.8 ° C)

Acidity (mg KOH / g)

Supplement of volatile substances (g)

Total volatile acidity (mg KOH / g).

Claims (5)

Claims: 35 1. A process for the production of fatty acid polyol esters serving as high-performance lubricants by reacting polyols which contain at least two, preferably three methylol groups bonded to a single quaternary carbon atom, with saturated fatty acids having 4 to 12 carbon atoms, characterized in that the esterification catalysts are phosphorus compounds general formula O = P (OR) ₃ used, in which R denotes hydrogen atoms, alkyl, alkylene or aryl radicals, but not more than 2 oxygen atoms are bonded to aryl radicals. 2. The method according to claim 1, characterized in that the catalyst used is a trialkyl phosphate, preferably tributyl phosphate is used. 19.51
0.43
8th
5.8 3. The method according to claim 1 and 2, characterized in that the phosphorus compound in an amount between 0.2 and 1.0 percent by weight, preferably 0.3 to 0.6 percent by weight, based on the theoretically available polyester. 4. The method according to claim 1 to 3, characterized in that the polyol is trimethylolpropane used. 5. The method according to claim 1 to 4, characterized in that one is a fatty acid or a Fatty acid mixture used whose straight chain or average chain length 5 to 9 carbon atoms contains or amounts to. Considered publications:
U.S. Patent No. 2,798,083;
French patent specification No. 1251027,1251028. 609 667/427 9.66 © Bundesdruckerei Berlin