DE1225628B - Process for the production of mixed esters serving as lubricating oils - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN # f # PATENTAMT Int. Cl .:

C07c

EDITORIAL

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German class: 12 ο-11

E12652IVb / 12o

July 9, 1956

September 29, 1966

The invention relates to a process for the production of mixed esters serving as lubricating oils. From mixed stars Lubricating oils consisting of mixed esters and diesters are known. You show one Better viscosity temperature behavior than lubricants based on mineral oil and can be achieved by using the appropriate Selection of starting materials with numerous desirable properties can be produced.

Such mixed esters can by reacting dicarboxylic acids, glycols, monocarboxylic acids and optionally monohydric alcohols can be prepared and can be determined by the general formulas

R ¹ COO - R ^a - OOC - R ³ - COOR ⁴
R ¹ COO - (- R ² OOC - R ³ - ■ COO -) - R ² - OOCR ¹ R ⁴ - (OOC - R ³ - COOR ² -) - OOC-R ³ - COOR ⁴

represent, in which R ¹ , R ² , R ³ and R ^{4 represent} hydrocarbon radicals.

These mixed esters can be obtained by converting the corresponding starting materials in one or more stages under esterification conditions. All reactants should be saturated; H. contain no polymerizable double bonds.

The saturated aliphatic hydrocarbon on which the glycol radical R ^{2 is} based can be straight or branched-chain and contain 2 to 18 carbon atoms or consist of a chain of saturated aliphatic hydrocarbon radicals linked by oxygen and / or sulfur atoms, provided there are at least 2 carbon atoms between each Carboxyl group and the next oxygen or sulfur atom and at least 2 carbon atoms between each pair of oxygen or sulfur atoms in the chain and provided that the total number of carbon, oxygen and sulfur atoms in the whole remainder is 5 to 80 and the number of Sulfur atoms is not larger than 2.

The remainder of the monohydric alcohol R ⁴ can be a straight or branched chain saturated aliphatic hydrocarbon radical with 1 to 20 carbon atoms or contain a number of straight or branched chain saturated aliphatic hydrocarbon radicals which are linked by oxygen and / or sulfur atoms, the total number being the carbon, oxygen and sulfur atoms is 4 to 20. The maximum number of oxygen and / or sulfur atoms in the remainder is not greater than 5, the number of sulfur atoms is not greater than 2; between the acid residue and the first oxygen or sulfur atom is a chain of at least 2 carbon Processes for the production of as lubricating oils
serving mixed star

Applicant:

Esso Research and Engineering Company,

Elizabeth, N. J. (V. St. A.)

Representative:

Dr. K. Th. Hegel, patent attorney,

Hamburg 36, Esplanade 36 a

Claimed priority:

Great Britain 11 July 1955 (19 967)

atoms; a similar chain of at least 2 carbon atoms is located between each pair of the Oxygen or sulfur atoms in the remainder.

The radical of the monocarboxylic acid R ¹ can be a branched or straight-chain saturated aliphatic hydrocarbon radical having 1 to 22 carbon atoms or contain a number of aliphatic hydrocarbon radicals which are linked by 1 to 5 oxygen atoms; there are at least 2 carbon atoms between each pair of oxygen atoms and at least 1 carbon atom between the carboxyl group and the closest oxygen atom; the total number of carbon and oxygen atoms in the remainder is 3 to 22; the remainder can also consist of an aliphatic hydrocarbon chain with a single sulfur atom, which is separated from the carboxyl group by at least 1 carbon atom; the total number of carbon and sulfur atoms in the remainder is 3 to 22.

The remainder of the dicarboxylic acid R ³ can be a straight or branched chain saturated aliphatic hydrocarbon residue with up to 26 carbon atoms or a residue which consists of a series of saturated aliphatic hydrocarbon residues which are connected by one or more oxygen or sulfur atoms, provided at least 2 carbon atoms are between each pair of oxygen or sulfur atoms and provided that the total number of carbon, oxygen and sulfur atoms is 3 to 80 and the total number of sulfur atoms is not greater than 2. That. The molecular weight of the ester is expediently at least 300; it is preferably saturated; the viscosity is desirably no greater than 32cSt at 98.9 ° C in order to provide a product with lubricating oil properties.

609 668/454

3 4

Among the various components of the mixing series with 6 to. 10 carbon atoms, e.g. B. adipic esters are some preferred because they give the optimum of the acid, azelaic acid, sebacic acid, suberic acid, desired properties in terms of performance melic acid and the corresponding mixtures of isomers of the lubricating oil. The preferred monobasic dicarboxylic acids ("Isq acids").
Alcohols are the straight or branched chain ali- 5 The mixed esters can either be phatic primary alcohols that do not contain oxygen via the monohydric alcohol or or sulfur atoms and 6 to 10 carbon atoms by heating all components together. under reflux in the presence of an esterification

The preferred monocarboxylic acids are saturated catalysts and a water entrainer.

Fatty acids with 2 to 10 carbon atoms. io places be. The esterification preferably proceeds

The preferred dicarboxylic acids are straight in two stages over the glycol half ester according to the

or branched chain dicarboxylic acids of the paraffin equations

j OH COOH

R / + 2R "^ > HOOC-R" —COO-R - OOC - R "—COOH (1)

^ XOOH

HOOC - R "- COO - R - 0OC - R" - COOH + 2 ROH

> R'OOC - R "—COO —R - OOC - R" —COOR '

The esterification is expediently under reflux, diisobutylene and C 1 -C olefins are suitable for this; at higher temperatures, for example from 150 to 200 ° C, in 25 even higher molecular weight olefins are sometimes present an esterification catalyst, such as Schwewendet. The alcohols obtained in this way are usually acidic acid, sodium bisulfate or an arylsulfonic acid branched chain.

and a water entrainer, e.g. an aroma

table hydrocarbon. So that the additives are added to their properties

The end product is as effective a lubricating oil as possible to be improved as lubricating oils, e.g. B. Oxidation

the unreacted remainder of the retarders, viscosity index improvers, thickeners,

participants by stripping in a vacuum, pour point depressants, dyes,

A disadvantage of the mixed esters is their thixotropy

remain. low temperatures: if the mixed

As glycols for the production of mixed esters 35 ester is kept at a low temperature, it becomes

include ethylene glycol and all paraffi- increasingly thicker. This behavior is for lubricating oils,

frilled homologues of the same with up to 18 charcoal- mobility at low temperatures of

To name material atoms, as z. B. Ethylene Glycol, Pro- is crucial, very disadvantageous. Thixo-

pylene glycol, butylene glycols, pinacon, trimethylene entropy at low temperatures show particularly ali-

glycol, tetramethylene glycol, pentamethylene glycol. 40 phatic mixed esters, which due to the small change

Suitable monohydric alcohols are, for. B. the following: their viscosity with the temperature itself is methyl alcohol, Ethyl alcohol, n-butyl alcohol, n-hexyl are preferred.

alcohol, n-octyl alcohol, 2-ethylhexyl alcohol, cetyl It has now been found that by introducing

alcohol, oleyl alcohol, ethylene glycol mono-n-butyl- a small proportion of aromatic groups in ali-

ether, ethylene glycol mono-2-äthylbutyläther, ethylenic mixed ester 45 gets a lubricating oil whose

Glycol mono - 2 - ethylhexyl ether, ethylene glycol mono - viscosity also increases over time with longer storage

tert.octylätherj ^ -n-Butylmercaptoethanol ^ -tert.Octyl- changes very little at very low temperatures,

mercaptoethanol, / 3-n-dodecylmercaptoethanol, di- The process according to the invention for the preparation

Ethylene glycol mono - η - butyl ether, diethylene glycol of mixed esters used as lubricating oils by conversion

mono-2-ethylbutyl ether, diethylene glycol mono-2-ätb.yl- 50 deposition of more than 2 moles of 6 to 10 carbon

hexyl ether, propylene glycol monobutyl thioether, dicarboxylic acids containing pro atoms or their

pylenglykohnono-tert.octylthioäther, propylene glycol hydrides and more than 2 moles of a 6 to 10 carbon

mono-n-dodecylthioether, n-butyl mercaptoethoxy material atoms containing monovalent aliphatic

ethanol, tert-octylmercaptoethoxyethanol, n-dodecyl alcohol with 1 mole of 2 to 18 carbon atoms

mercaptoethoxyethanol, n-butylmercaptopropoxypro- 55 containing glycol is that as dicarbon

panoUertOctylmercaptopropoxypropanol, n-dodecyl acid component a mixture is used, which

mercaptopropoxypropanol, Propyleneglykohnono-n-bu- to 90 to 98 mole percent from aliphatic and to

tyl ether, dipropylene glycol monomethyl ether, C ₈ - to 2 to 10 mol percent from aromatic dicarboxylic acids

Qo-oxo alcohols, dipropylene glycol monoethyl ether, or their anhydrides.

Dipropylene glycol mono-n-butyl ether, tripropylene glycol is preferably used as in the process

kolmonomethyläther, Tripropyleneglykolmonoäthyl- dicarboxylic acid component, a mixture which to

ether, tripropylene glycol mono-n-butyl ether, propylene - about 95 mole percent from aliphatic and about

glycol monoisopropyl ether, dipropylene glycol mono- 5 mole percent from aromatic dicarboxylic acids or

isopropyl ether, tripropylene glycol monoisopropyl ether. whose anhydrides consists.

Particularly suitable monohydric alcohols are the 65. It is known that mixed esters can be prepared by reacting

"Oxo" alcohols obtained by reacting 2 mol of carbon of an aliphatic monocarboxylic acid, 2 mol

oxide and hydrogen with a glycol and 1 mol of an aromatic dicarbonate from petroleum products

available olefins are produced. For example acid or through. Implementation of 2 moles of one off

equimolecular amounts of an aliphatic monocarboxylic acid and to prepare a glycol formed half ester with 1 mole of an aromatic dicarboxylic acid. In the case of these known mixed esters, the one condensed into the molecule during the esterification reaction is therefore Dicarboxylic acid radical of a completely aromatic nature, and aliphatic reactants with extremely high molecular weights would have to be used be in order to arrive at mixed esters in which the proportion of aromatic dicarboxylic acid residues is not greater than 10 mole percent. Aliphatic reactants with such high molecular weights but are by definition not suitable for carrying out the process according to the invention.

On the other hand, it is also known to produce lubricating oils by mixing mixed esters and diesters. In this way it is possible, when using the known mixed esters, which are the remainder of an aromatic Containing dicarboxylic acid as a component by mixing with aliphatic diesters to form lubricating oil mixtures arrive in which the dicarboxylic acid residues to less than 10 mole percent from aromatic dicarboxylic acid residues exist. Such mixtures would, however, meet the requirements placed on the low-temperature behavior here not sufficient, since the proportion of aromatic dicarboxylic acid residues in the mixed ester itself is more than 10 mole percent of the total dicarboxylic acid residues and therefore regardless of the admixture of a diester still experience the undesirable phenomenon of low temperature thixotropy would.

Contains a lubricant mixture of a diester and a mixed ester according to an older proposal a reaction product as a mixed ester

a) an aliphatic dicarboxylic acid or its anhydride and / or an aromatic one Dicarboxylic acid or its anhydride (at least one residue of an aromatic dicarboxylic acid per molecule),

b) a glycol or polyglycol and

c) an aliphatic alcohol,

where the molecular fraction of c) is smaller than that of a) and the fraction of b) is greater than half, z. B. is at least two thirds of the molecular fraction of a). With these mixed stars, however, the

35

The proportion of aromatic dicarboxylic acid residues in the total amount of dicarboxylic acid residues is 20 mol percent, so that these lubricating oils also do not meet the requirements with regard to the low-temperature thixotropy of the mixed ester.

In general, the viscosity temperature behavior of the mixed ester is determined by the aromatic dicarboxylic acid residues adversely affected. According to the invention, therefore, there are only so many aromatic dicarboxylic acid residues condensed in, as required to achieve the desired low temperature resistance is. The method according to the invention can achieve the desired resistance without serious impairment the viscosity temperature behavior can be achieved.

Examples of suitable aromatic dicarboxylic acids are phthalic acid, isophthalic acid, terephthalic acid, Homophthalic acid, o-, m- or p-phenylenediacetic acid and corresponding higher molecular weight acids, e.g. B. Phenylacetic - /? - propionic acid, and alkyl-substituted aromatic Dicarboxylic acids.

example

A mixture of a mixed ester and a diester is made by reacting 1 mole of tetraethylene glycol ("Polyglycol 200") with more than 2 moles of sebacic acid and twice the molar excess of 2-ethylhexanol prepared in the usual way. The esterification reaction produces a mixture of one Mixed esters and di-2-ethylhexyl sebacate. The bigger the The proportion of di-2-ethylhexyl sebacate in the mixture, the less viscous the lubricating oil. If you have the Carefully controls working conditions, e.g. B. keeps the local glycol concentration low, can Produce mixtures which, if they are sufficiently low in viscosity, no longer have low temperature thixotropy exhibit. As the table shows, the more viscous the mixture, the greater the low-temperature thixotropy (i.e. the higher the proportion of mixed ester). It is not through direct implementation of these starting materials possible to produce a mixture of mixed ester and diester with a viscosity of over 6.5 cSt at 98.9 ° C, which has no significant low temperature thixotropy. The table also contains the Values for mixtures in which 5 mol percent of sebacic acid has been replaced by phthalic anhydride; these show at most a slight thixotropic.

Properties of mixtures of mixed esters and diesters, produced by reacting 2-ethylhexanol, Polyglycol 200 and sebacic acid

2 Attempt no. 6.64 7.34 4th I 5 Phthalic acid 6.10 7.08 1 3 30.81 34.14 5 mole percent sebacic acid anhydride 28.07 33.72 8240 9990 replaced by 7320 10400 Without phthalic anhydride 8920 14170 7160 10410 +680 +4180 -160 +10 6.09 0.613 0.594 0.627 0.608 27.9 0.660 0.653 0.666 0.659 7350 0.640 0.630 0.650 0.640 7300 -50 0.625 0.668 0.646

Kinematic viscosity cSt

at 98.9 ° C

at 37.8 ° C

at -4O ⁰ C

at -4O ⁰ C after storage at -53.9 ⁰ C

Kinematic viscosity increase at —40 ⁰ C, cSt ... Slope of the ASTM curve:
98.9 to 37.8 ° C

37.8 to -40 ° C

98.9 to -40 ° C

The experiments of the first series (No. 1, 2 and 3) as well as those of the second series (No. 4 and 5) were with in the order given, increasing amounts of sebacic acid and 2-ethylhexanol are carried out, so that the corresponding products in each series of experiments increasing proportions of di-2-ethylhexyl sebacate contained.

Claims (2)

Patent claims: 1. Process for the production of mixed esters serving as lubricating oils by reacting dicarboxylic acids containing more than 2 moles of 6 to 10 carbon atoms or their anhydrides and more than 2 moles of a monohydric aliphatic alcohol containing 6 to 10 carbon atoms with 1 mole of a 2 to 18 carbon atoms holding glycol, characterized that a mixture is used as the dicarboxylic acid component, which is 90 to 98 mol percent of aliphatic and 2 to 10 mole percent consists of aromatic dicarboxylic acids or their anhydrides. 2. The method according to claim 1, characterized in that a dicarboxylic acid component is used Mixture is used which is about 95 mole percent aliphatic and about 5 mol percent of aromatic dicarboxylic acids or their Anhydrides. Considered publications:
French patent specification No. 1 046 800,
334, 1058 878;
British Patent No. 659 103. 609 668/454 9.66 © Bundesdruckerei Berlin