DE2306668A1 - HYDROLYSIS-RESISTANT ESTER LUBRICATION OIL - Google Patents

Description

Hydrolysis- resistant ester lubricating oil e

The invention relates to the production of hydrolysis-resistant esters and their use as lubricants and lubricant components .

Due to the ever increasing demands placed on lubricants are made, the common mineral oil fractions are less and less able to achieve the desired properties to be presented in sufficient quantities. Efforts are therefore made to replace mineral oils with synthetic lubricants as much as possible substitute. For example, ester lubricants for use in aircraft turbines have proven themselves in the aviation industry. Farther Mixtures of mineral oils and synthetic components for the lubrication of automotive engines and industrial engines were also used (DT-PS 933 650, DT-AS 1 021 211).

According to their chemical structure, carboxylic acid esters are substances that in principle have to be viewed as hydrolyzable. the The resulting hydrolysis products lead to corrosion and contamination of the lubricating oil. A disadvantage of the The ester lubricating oils used consists in the fact that they have a more or less pronounced sensitivity to hydrolysis. A process has now been found by means of which esters can be synthesized, which the conventional ester lubricating oils considerably excel in resistance to hydrolysis. In addition, the esters of the present invention stand out over mineral ones Lubricating oil components that cannot deliver harmful hydrolysis products have various advantages.

409833/0587

105/72

O.Z.2695 9.2.1973

So are mineral products because of the unfavorable viscosity-temperature dependence not to be used as multigrade lubricating oils without suitable additives. To have good low-temperature behavior To achieve this, mixtures of low-viscosity mineral oils with a relatively high proportion of polymer additives are produced. Of the Content of low-viscosity mineral oils has, inter alia, the disadvantage that a relatively high evaporation loss occurs during use, which leads to an undesirable thickening of the Lube oil leads. It has now been found that these disadvantages of the prior art can be avoided by using hydrolysis-resistant -Carboxylic acid ester as a lubricant or lubricant component, prepared by linear in the first stage Olefins with 13 to 18 carbon atoms, the double bond isomers of which are distributed in the sense of a thermodynamic equilibrium are subjected to a hydroformylation reaction and the obtained Aldehydes are converted to esters in a second stage in a Tishchenko reaction.

The n-olefins required for hydroformylation and their double bond isomers are distributed in the sense of a thermodynamic equilibrium, one obtains in such a way that any n-01efin or a mixture of n-olefins of the relevant carbon number subject to the conditions necessary for double bond migration. In a particularly simple embodiment of the Isomerization v / ground linear C ^ olefins with metal carbonyls Carbon monoxide heated. It is preferred to use one made from a simple rhodium compound in the step of the oxo synthesis and triphenylphosphine.

In a further embodiment, it is used in the second reaction stage a mixture of aldehydes with different numbers of carbon atoms.

409833/0587

O.Z.2695 9.2.1973

Hydroformylation reactions are basically started. The rhodium-catalyzed hydroformylation rectifications are described, for example, by Craddock et al. / Xnä. and Engng. formerly Product Research Devel. 8, No. 3, page 291 (1969} _7 described in more detail.

Simple rhodium compounds such as RhCl ₃ · 3H-O, R ^ -O or the Rh salts derived from carboxylic acids and organic phosphines such as tributylphosphine or triphenylphosphine can be used as catalysts. The rhodium concentrations in the reactor

- 3 - 1

tion solution are 1 · lo to 1 · Io percent by weight. the Reaction temperatures are between 100 and 130 ° C. The reaction is preferably carried out in the presence of triphenylphosphine by working in the presence of about 3 to 10 g of triphenylphosphine per liter of olefin.

By the hydroformylation carried out in the context of the invention isomer mixtures of aldehydes and their components are obtained by the position of the methyl group in a linear paraffin chain differentiate (Formula 1):

2 P ^{B = O} 4

3 \ 5 CH = O

Formula picture 1

It is also characteristic of these oxoaldehydes that the proportion of unbranched isomers is low and that all others possible isomers are not only present, but also occur in an even distribution. In a final step you lead with the so characterized aldehyde isomer mixture a Tishchenko reaction by. In an ester synthesized in this way, the number of isomers is significantly greater than in the one in question.

409833/0587

O.Z.2695 9.2.1973

the starting aldehyde, because during ester formation, aldehyde components with differently branched carbon skeletons are also linked. In addition, there is the possibility of increasing the number of ester components considerably by converting mixtures of aldehydes with different carbon numbers according to "Tischtschenko ¹ ".

The Tishchenko reaction is known in principle and is described in Houben-Weyl, Methods of the organ. Chemistry, Volume VUH / ΪΙΙ / Saite 557 (1952) but η described. It is about disproportionation of the aldehydes with simultaneous esterification. In the present case, aluminum alcoholates of alcohols or carbon are used as catalysts number 2 to 6, with advantage aluminum tris-2-methylbutanolate used. The reaction is carried out at 10 to 30 ° C.

For the synthesis of the Tishchenko esters according to the invention come essentially aldehydes in the C number range 14 to 19 in question. The products made from aldehydes with a carbon number ^ 14 have too low a viscosity and show too high evaporation losses in the Noack test, while esters from the higher aldehydes (C number> 19) have crystallization points above 0 ° C.

The very special hydrolysis resistance of the according to the invention Products used in relation to carboxylic acid esters, which are used according to the prior art, should be compared with the information in Table 1 can be demonstrated. Then the compounds used for comparison are di- (2-ethylhexyl) sebacate and diisotridecyl adipoate, about a factor of 4 times faster and the 2.2.4-trimethyladipic acid-Alfol-8/10-diester by a factor Saponified 1.5 times faster than those to be used according to the invention Substances *

409833/0587

O.Z.2695 9.2.1973

Table 1: Alkaline hydrolysis of lubricating oil esters with 0.5 η alcoholic KOH according to DIN 51 559

Type of hydrolyzable saponified ester in % according to the reaction j

Try! Ester

times (min.) 15

for ver-j di- (2-ethyl equals shexyl) sebacate

i

to Ver-jDi-isotridecyl- j equal to adipoat j

compared to 2.24-trimethyl equivalents jadipic acid

JAlfol-8/10-di-

\ ester

according to the invention

according to the invention

according to the invention

: Esters from pen-

jtadecanal

1 (according to example

j 3a)

jester made of hepta-I decanal (according to example 3b)

jEster from hepta-;

decanal and no-;

nadecanal |

Example 3c)

'240

50

36

37

i -

j 66

The esters to be used according to the invention should be used as hydrolysis-resistant lubricating oils or as lubricating oil components. In the latter case, they can partially replace the low-viscosity mineral oil components customary for multigrade oils, namely in amounts of 5 to 50 , preferably 10 to 30 percent by weight, based on the total mixture of carboxylic acid ester and mineral oil. The esters of the present invention

409833/0587

0.2.2695 9.2.1973

sit opposite mineral oil components, e.g. in engine oils can be used, various advantages. Table 2 shows a comparison with three paraffin-based mineral oils (oil A, oil B, and oil C) employed. Due to its properties, the product designated with Oil A can practically only be used for single-grade oils, while oils B and C are suitable for the production of multigrade oils.

From Table 2 it can be seen that the Noack evaporation test only provides a value for oil A which is not quite achieved by the esters to be used according to the invention. Regarding the viscosity index however, the substances to be used according to the invention are also the mineral ones intended for multigrade oils Clearly superior to base oils B and C. The pour points of the from, which are lower than that of mineral oils, should also be emphasized Pentadecanal (Example 3a) or esters obtained according to the invention from the mixture of heptadecanal and nonadecanal (Example 3c). To further test the lubricating properties, pentadecyl pentadecanoate. Test runs on the FZG transmission test bench (A / 8.3 / 90) according to DIN 51 354. It could as well as Damage load level 7 can be achieved with oil A (Table 2).

409833/0587

23U6668

OZ2695 9.2.1973

Table 2ί Test values for esters to be used according to the invention in comparison with paraffin-based mineral oils

«Kind and method
The examination (zuir
Oil A t cf.
Oil B .eich);
Oil Ci (according to the invention)
Ester ausjEster aus Ester aus;
Pentad- ί heptad- heptad- j
canal ί canal '■ canal and \
! j Nonaαε
ί I canal j j
^; 4.40 i
4.73 jViscosityfcSt]
at 98. "9 ⁰ C 11.4 5.2 3.9 ^l 3.48 j 19.7
I. 22.0 at 37.8 ° C 113 32.3 20.2; 14.4 155 151
I.
! Viscous index
(ASTM-D 567-53) 95 99 93 ■
> ■ 138 ■
5.1 i
5.0
I. Evaporation test
according to Noack [%}
(DIN 51 581) 3.0 15th f
j
I ³³ j 11 -15 t
-19 Pour point F ⁰ Cf
(DIN 51 583) -15 -14 -15 y
i -35 266 f
237 Flash point ^l Ci
(DIN 51 584) ' 268 226 ²¹⁴ I: 242

Examples 1 to 3 Production of the esters to be used according to the invention Example la-c

The n-olefins required for the hydroformylation were on won in the following way. 100 g of a defined one were heated in each case λ-olefins under carbon monoxide pressure (100 to 140 atm) in a 2 1-stroke autoclave with 5 g of co-naphthenate for 10 hours 180 ° C. The results are summarized in Table 3.

409833/0587

OZ2695 9.2.1973

Table 3

Isomerized
n-olefin g distillate 20th
ⁿ D Boiling temp./Torr % <£ -olefin * ^ retradocs
Hexadecene
Octadecene 989
985
990 1.4389
1.4429
1.4466 93-96 ° / 0.5
1O5-1O9 ° / O.3
116-119 ° / O.2 2
1
1
I.

Determined by IR spectroscopy.

Example 2a-c

Oxygenation of the olefins isomerized according to Example 1 (100 g each) was carried out at 120 ° C. and 200-270 atm synthesis gas pressure
(COiHp = 1: 1) in a 2 1-stroke autoclave. 76 mg of rhodium (used as RhCl .3H ₀ O) and 6.0 g of triphenylphosphine were used as the catalyst. After completion of the reaction (7 to 19
Hours of synthesis gas uptake), the autoclave discharges were subjected to fractional distillation in vacuo, the
The distillation residue in all cases was only 1 to 2 percent by weight (based on the distillate). The results are given in Table 4 *

Table 4

aldehyde g distillate "20th
ⁿ D Boiling temp./Torr Pentadecanal
Heptadecanal
Wonadecanal 1068
1024
lon 1.4405
1.4442
•
1.4472 110-112 ° / O.2
128-132 ° / O.2
141-143 ° / Ol

409833/0587

23U6668

OZ2695 9.2.1973

The isomer distribution was determined in each case by 20 g of the alcohol obtained from the aldehyde in question by hydrogenation stirred with 20 to 30 g of acetic anhydride for 2.5 hours at 80 and the alkyl acetates prepared in this way after the distillation analyzed by gas chromatography.

a) 20.1 g of pentadecyl acetate were isolated, boiling point _, = 105 - 3.07 ° C,

n ^ ° = 1.4387. Ber. C 75.48 H 12.67 0 11.83

Found C 75.41 H 12.78 0 11.95

Gas chromatographic analysis

17.1 % 6- and 7-acetoxymethyl-tetradecane

13.2% 5-acetoxymethyl-tetradecane 17.5 % 4-acetoxymethyl-tetradecane

22.5% 3-acetoxymethyl-tetradecane

24.4% 2-acetoxymethyl-tetradecane 2.1% n-pentadecyl acetate

b) There were 21.5 g of heptadecyl acetate, boiling point - = 132-135 C, n ~ = 1.4420, won.

Gas chromatographic analysis

24.6 % 7- and 8-acetoxyinethyl hexadecane

11.0 % 6-acetoxymethyl-hexadecane

13.5 % 5-acetoxymethyl-hexadecane

12.1 % 4-acetoxymethyl-hexadecane

10.6% 3-acetoxymethyl-hexadecane 17.0% 2-acetoxymethyl-hexadecane 4.0% n-heptadecyl acetate

A09833 / 0587

OZ2695 9.2.1973

c) During the esterification, 21.9 g of nanadecyl acetate fell.

Sdp.

0.1

- 130 - 132 ° C,

= 1.4449, an.

Gas chromatographic analysis

35.5 % 7-, 8- and 9-acetoxymethyl-octadecane

δ-acetoxymethyl octadecane

12.9 %

15.5 % 14.2 %

11.6 % 7.7.%

Example 3a-c

S-acetoxymethyl octadecane 4-acetoxymethyl octadecane S-acetoxymethyl octadecane 2-acetoxymethyl-ocfcadecane n -conadecyl acetate

To carry out the Tishchenko reaction were those according to Example 2 obtained aldehydes with 0.5 to 1.0 percent by weight of aluminum tris-2-methylbutylate stirred at 22 to 30 ° C for 24 hours. The products were left to stand for a further 24 hours at room temperature and then cleaned thoroughly. Distillation {table 5)

Table 5

Ver
search-
be ~
drawing
tion \
\ g initial
;aldehyde
¹ r
- product
: g distill
; lat Boiling temp./Torr 20 \
ⁿ D j
I. 3a 470 penta
decanal Pentad
cyl-pen-
tadeca-
noat 414 203-206 ° / O -2 1.4510 3b 733 hepta-
decanal Heptad
cyl-hep-
tadeca-
noat 660 225-227 ° / o -1 1.4538 3c 570 nonad
canal
400 hepta-
decanal four ver
divorced
Ester i 801 24O-248 ° / O.2 1.4550

409833/0587

Claims (3)

11 ~ 0.2.2695 9.2.1973 claims 1. Use of hydrolysis-resistant carboxylic acid esters as lubricants or lubricant component prepared by in the first stage linear olefins with 13 to 18 carbon atoms, their double bond isomers in the sense of a thermodynamic Are equilibrium distributed, subjected to a hydroformylation reaction and the aldehydes obtained in a second stage converts to esters in a Tishchenko reaction. 2. Use of hydrolysis-resistant carboxylic acid esters according to claim 1,. * through this characterized in that a rhodium triphenylphosphine catalyst is used in the first stage begins. 3. Use of hydrolysis-resistant carboxylic acid esters according to claim 1, characterized> characterized in that a mixture of different aldehydes is used in the second stage Uses carbon atom numbers. 409833/0587