DE1235938B - Stabilizing polyphenyl ethers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

LEGAL LETTERING

Int. .CL:

C 07c

German KL: 12 q- 14/04

Number: 1 235 938

File number: M 56666 IV b / 12 q

Filing date: April 30, 1963

Opened on: March 9, 1967

The invention relates to the stabilization of polyphenyl ether against oxidation.

The polyphenyl ethers are known compounds. It is further known to these as polyphenyl ethers Lubricants for gas turbines, as hydraulic fluids, as coolants for electronic systems, to use as a coolant for nuclear reactors and as diffusion pump fluids because they high and low temperature stability, foaming resistance and good storage stability, even at temperatures ranging up to about 370 ° C and higher. The polyphenyl ethers come because of their well-balanced properties Recently, it has also been increasingly considered as a lubricant for jet engines. To the extent that the speed and working height of the devices containing jet engines increases, the lubrication problems also increase because of the increased working temperature and the higher bearing pressures, which result from the increased thrust that is necessary to achieve higher speeds and to reach greater heights result. As the associated working conditions are increasing As the degree of hardness increases, the useful life of the polyphenyl ethers is shortened, in particular due to their lack of oxidation stability above 260 ° C.

The life of a lubricant can be judged on the basis of many criteria, such as The amount of viscosity increase, the amount of corrosion on metal surfaces that are exposed to contact with the lubricant and the extent of deposit formation. Many procedures are known that serve to improve lubricants and increase their service life. It is common practice to add small amounts of additives to lubricants in order to improve their properties to influence. However, it is difficult to add additives, especially for high working temperatures find which work as intended, without other disadvantages, such as the increase corrosion and deposits in the machine.

The invention is based on the knowledge that the oxidation stability and thus the service life of the polyphenyl ethers can be largely increased by adding certain organic lead compounds, even under the difficult conditions that exist in jet engines and similar devices, which are at temperatures in the order of magnitude of over 300 ⁰ C and higher work.

The invention accordingly relates to stabilizing stabilizing polyphenyl ethers

Applicant:

Monsanto Company, St. Louis, Mo. (V. St. A.)

Representative:

Dr. M. Owl, Dr. W. J. Berg

and Dipl.-Ing. O. F. Stapf, patent attorneys,

Munich 2, Hilblestr. 20th

Named as inventor:

Roger Eugene Hatton, Kirkwood, Mo .;

Louis Rodhouse Stark,

East St. Louis, JIl. (V. St. A.)

Claimed priority:

V. St. v. America April 30, 1962 (191337)

of polyphenyl ethers of the general formula

in which η is an integer from 2 to 5, against oxidation, by adding a lead compound of the general formulas to the polyphenyl ethers

(Ph) _m PbX4-m or Pb (OOC-R) ₂ ,

in which Ph is a phenyl radical, X is a halogen atom, m is an integer from 1 to 4, R is an alkyl or phenyl radical and y is 2 or 4, in an amount of at least 0.01 to at most about 5 percent by weight, preferably 0, 05 to 1 percent by weight, added.

The invention makes it possible to obtain polyphenyl ethers with increased resistance to oxidation with better viscosity stability, increased color stability and lower corrosion effect create.

Examples of compounds falling under the aforementioned general formulas are Tetraphenyl lead, triphenyl lead chloride, triphenyl lead

709 518/518

fluoride, diphenyl lead dichloride, diphenyl lead diiodide, Phenyl lead trichloride and diphenyl lead dibromide, lead benzoate, lead vanillate, lead tetraacetate, lead acetate, Lead - ethyl caproate, lead - ethyl hexoate, lead - 2 - ethyl ethyl caproate, Lead - ethyl hexoate, lead - 2 - ethyl hexanoate, lead octoate, lead palmitate, lead salicylate and lead stearate.

The phenyl-lead compounds used according to the invention can in a known manner by reacting a Grignard compound with lead chloride and the lead salts of carboxylic acids by salt exchange or neutralization, e.g. B. by implementing of sodium benzoate or acetate with lead chloride.

Polyphenyl ethers in which all ether bonds are in the m-position to one another are preferably stabilized stand because the m-bonded ethers are used for many purposes because of their wide fluid range and are best suited for their high thermal stability. However, mixtures of polyphenyl ethers, for example, either isomeric mixtures or mixtures of homologous ethers are used to achieve certain properties; for example lower solidification points. Polyphenyl ethers that can be stabilized according to the invention are, for. B. bis (phenoxyphenyl) ether, like bis- (m-phenoxyphenyl) -ether, bis- (phenoxyphenoxy) -benzenes, like m-bis-m- (phenoxyphenoxy) -benzene, m-bis- (p-phenoxyphenoxy) -benzene, o-bis- (o-phenoxyph en oxy) -benzene, bis- (phenoxyphenoxyphenyl) -ether, Bis - [m - (m - phenoxyphenoxy) phenyl] ether, bis [p- (p-phenoxyphenoxy> phenyl] ether, m - [(m-phenoxyphenoxy) - (o-phenoxyphenoxy)] ether and bis (phenoxyphenoxyphenoxy) benzenes, e.g. B. m - bis- [m- (mphenoxyphenoxy) -phenoxy] -benzene, ρ-bis- [p - (m-phenoxyphenoxy) -phenoxy] -benzene, m-bis- [m- (p-phenoxyphenoxy) -phenoxy] -benzene. It is also possible to stabilize mixtures of the polyphenyl ethers. For example, mixtures of polyphenyl ethers, in which the non-terminal phenylene rings, d. H. those rings that are in the above general formula enclosed in brackets, by oxygen atoms, in the m- and p-positions are bound, especially proven as a lubricant, because such mixtures have lower solidification points own, d. H. have a wider range of fluids. Of the mixtures that have only m or p bonds have, mixtures of polyphenyl ether with five phenyl rings are preferred, in which the non-terminal phenylene rings linked to one another by oxygen atoms in the m- and o-positions are and from 65 percent by weight of m-bis (m - phenoxyphenoxy) - benzene, 30 percent by weight m - [(m-phenoxyphenoxy) - (p-phenoxyphenoxy)] benzene and 5 percent by weight of m-bis (phenoxyphenoxy) benzene exist. This mixture solidifies at about -23 ° C, whereas the three components each solidify at temperatures above normal room temperature.

The Federal Specification procedure is used to determine the oxidative stability of a lubricant 791, method 5308.4, according to which the lubricant to be tested is at a certain temperature is heated in the presence of certain metals and oxygen and the viscosity increase of the Lubricant is determined. In addition, the corrosion ability of a lubricant can oppose Metals are determined.

Various polyphenyl ethers were tested by this procedure, with the exception that the Temperature held at 316 ° C instead of 121 ° C and the metal samples used were steel, copper, silver, titanium, magnesium alloy and Aluminum alloy were. The examined polyphenyl ethers had almost no effect on steel, Titanium and aluminum alloy and generally showed a small increase in copper corrosion. In some tests only the increase in viscosity was measured. The results are in the following Table reproduced. Viscosity measurements were made according to ASTM - Method D-445-53 T, using a Ostwald viscometer modified according to Cannon - Fenske. The percentage increase in viscosity was determined by looking at the difference in viscosity before and after heating determines, divides the difference amount by the original viscosity and the quotient with 100 multiplied. The corrosive effect on metals was determined by weighing the metal samples and determined after trying. The polyphenyl ether used consisted of about 65 percent by weight m - bis - (m-phenoxyphenoxy) benzene, about 30 weight percent m - [(m - phenoxyphenoxy) - (p-phenoxyphenoxy) J-benzene and about 5 weight percent m-bis (p-phenoxyphenoxy) benzene.

attempt Lead compound 1.0 Viscosity increase, ° / o 99 C Change in weight, mg / cm ² No Ag No. Weight percent 1.0 37.8 "C 38 * Mg 0.10 0.41 * 1 None (control attempt) 1.0 100 * 414 ** 0.38 ° No Metals 2 None (control attempt) 0.5 663 ** 18th No 0.01 3 Lead vanillate 0.2 44 17th 0.14 No 4th Lead tetraacetate 0.5 45 11 0.47 5 Lead acetate 0.5 30th 12th 1.6 0.34 6th Lead acetate 0.2 35 16 0.39 7th Lead benzoate 44 12th 0.02 8th Lead benzoate 33 16 Metals 9 Tetraphenyl lead 44 11 10 Tetraphenyl lead 34 0.16 Metals I 0.12 Metals

Average of sixteen different experiments using three lots of polyphenyl ether base fluid. Average value from seven different experiments using three batches of polyphenyl ether base liquid.

continuation

attempt

No.

Lead compound
Weight percent viscosity increase,%
37.8 ^: C 99C

Weight change, mg / cm '

Mg

Ag

11
12th
13th
14th

Triphenyl lead chloride
Triphenyl lead chloride
Diphenyl lead dichloride
Diphenyl lead dichloride

0.5
0.5
0.5
0.5

23
16
17th
12th

-0.78

-0.12

No metals -2.02 I -0.34

No metals

The addition of metal salts of aromatic carboxylic acids to polyphenyl ethers is already known from French patent specification 1 242 463 and German Auslegeschrift 1 128 068. However, the lead salts used according to the invention show considerable advantages over the known and closest zinc salts, both due to their greater antioxidant effect at higher temperatures (approx. 02 g / cm ² versus -1.24 g / cm ² when using a corresponding zinc salt).

The addition of the lead compound also leads to polyphenyl ethers with significantly reduced corrosion towards certain metals and a reduced tendency to form varnish-like products. Already the visual inspection revealed significantly less sludge than unstabilized Polyphenyl ethers.

Claims (1)

Claim: Stabilizing polyphenyl ethers in general formula in which η is an integer from 2 to 5, against oxidation, characterized in that the polyphenyl ethers are a lead compound of the general formulas ₄ -, * or Pb (OQC-R) ₂ , in which Ph is a phenyl radical, X is a halogen atom, m is an integer from 1 to 4, R is an alkyl or phenyl radical and y is 2 or 4, in an amount of at least about 0.01 to at most about 5 percent by weight, preferably 0 , 05 to 1 percent by weight, added. Considered publications: German Auslegeschriften No. 1 020 750, 128 068;
French patents nos. 1 022 055, 643, 1242 463.