DE748244C - Prevention of the oxidation of lubricants - Google Patents

Description

It has been found that one can prevent or at least prevent the oxidation of lubricants can be significantly reduced if you give them small amounts of metal compounds of phenol sulfides or the corresponding selenium or tellurium compounds. This measure is particularly suitable for improving the resistance to oxidation of lubricating oils, preferably mineral lubricating oils.

The added metal salts of the phenol sulfides correspond to the general formula

MO

Ar —Z _v —R '.
R ^x

Herein Ar means any cyclic group that contains one or more benzene rings, in the latter case z. B. in the form of a condensed ring system may contain. M represents a metal, e.g. lithium, sodium, potassium, magnesium, barium, calcium, aluminum, Copper, zinc, cadmium, tin, lead, chromium, manganese, iron, cobalt or nickel. If M is a polyvalent metal, it can with its other valences to other inorganic ones or organic groups, for example to halogen, sulfur, oxygen or to alkyl or aromatic groups, alcoholic residues, phenolic compounds, mercaptans or organic or inorganic Acids. R 'can be an aryl, alkyl, aralkyl or alkylated aryl group, which also has other substituents, such as halogen, in particular Chlorine, or the nitro, nitroso, amino,

May contain oxy, carboxy, alkoxy, aroxy or mercapto groups. R likewise denotes an organic group which can belong to the same class as R ′, but preferably an alkyl group with about 4 to 5 carbon atoms. Z denotes sulfur, selenium or tellurium, χ is an integer from 1 to 5, preferably 1 or 2.

Metal salts of • 10 alkylphenol sulfides or polysulfides are particularly effective !! and their Polymepen z. B. can correspond to the following formulas:

i. Alkyl phenol thioether

OH OH

R,

OH 2, "S. 3- R. Alky lphenoltli su 1 fide OH or - ■ s - OH R. O: S ' > <A S. OH R A ■ A, « Chains made from alkylphenol sulfides OH OH A .R OH OH 1 I.

OH

or S /

S /

OH OH

R S \, R

Symmetrical connections of this type are expediently used, but can one or more of the benzene nuclei also contain other substituents, such as. B. in the is shown in the following formula:

OH

NO.,

y S ' ~ -s "NO ₂

(Dinitrophenylalkylphenol sulfide)

In all of these formulas, R preferably denotes an alkyl group having 4 to 6 carbon atoms. In the compounds mentioned, the hydrogen in one or more hydroxyl groups can be replaced by a metal. If polyvalent metals are used, these can be linked to two hydroxyl groups of the same molecule or else two identical or different molecules, of which at least one is a phenol sulfide, can be linked to one another. F ^- For example, the following formulas result for the metal compounds:

0 —Na 0 —Ca —0 0 —Ni-OR "

R, A R. A, A, RR / ,

V - S _x -R 'V-' ■

Here, OR "preferably means the same group that is connected to the other valence of the nickel atom. The production / ■

S _x - R '

such metal compounds will be described in more detail with reference to the following examples will.

Example ι

ι mol tert. Amylphenol thioether (the after the process of French patent 824 600 can be produced) about i ^ times the absolute amount of space Ethyl alcohol and then dissolved into a solution of sodium ethylate, which consists of 2 moles of metallic Sodium and an excess of absolute ethyl alcohol is prepared, added. The sodium salt of is formed tert. Amylphenol thioether, which is dissolved from the excess ethyl alcohol. It can can be obtained by evaporating the alcohol, or one can also use the alcoholic Add the solution immediately to a lubricating oil and then when the lubricating oil has a high Should have a flash point, remove the alcohol by evaporation.

Salts of other metals can be derived from the sodium salt by double conversion of the following example.

Example 2

A slight excess over the calculated amount of an anhydrous halide of the desired Metal (it is advisable to use the chloride or bromide), for example calcium chloride, is in absolute ethyl alcohol dissolved and with stirring the alcoholic solution of the obtained according to Example 1 Sodium salt added. On the one hand, the calcium salt of tert is formed. ΑΠ13Ί-phenol thioether, on the other hand sodium chloride, which is insoluble in the absolute alcohol and is therefore precipitated. The sodium chloride is filtered off and the alcohol is removed from the filtrate by evaporation, wherein it is advisable to work in a vacuum towards the end. If not all of the sodium chloride is present due to the presence of small amounts of water should be removed, the product can be freed from it in any way, for example by removing the dried Product dissolves in gasoline in the absence of water, the sodium chloride being undissolved remains and is removed by filtration.

The salts of barium, aluminum, zinc and manganese can also be used in an analogous manner or make cobalts. In most cases the chlorides of these metals are well suited to however, in the case of barium, it is advisable to work with the bromide, as this is more soluble in absolute alcohol *

A certain amount of the sodium chloride may also be used together with the sodium chloride Metal salt of phenol thioether precipitated. It can then come from the dried precipitate by extraction with gasoline (54 ° Be).

fio Instead of absolute ethyl alcohol, you can also use absolute methyl alcohol as a solvent use. This is recommended. in the manufacture of nickel salts, as nickel chloride is only sparingly soluble in ethyl alcohol.

Example 3

Salts of such metals, which form sufficient basic oxides, can also be obtained by direct Reaction of the phenol thioether and the metal oxide in the following manner obtained: A mixture of 107 "parts of tert. amylphenol thioether, 214 parts Xylene, 10.8 parts of water and 16.8 parts Calcium hydroxide is heated to boiling under a reflux condenser, which is equipped with a Device for separating water from the reflux condensate is provided. One heats until all water initially present and formed during the reaction (16.5 Parts) is removed. A solution of the calcium salt of thioether in xylene is obtained, from which the excess calcium hydroxide can be removed by filtration.

One can work in a similar way with the oxides or hydroxides of barium and sodium or potassium work.

Example 4

A suspension of magnesium ethylate is made by stirring metallic Magnesium with an excess of absolute ethyl alcohol in the presence of mercury chloride and iodine as catalysts and then gives a solution of tert. Amyl phenol thioether in absolute ethyl alcohol too. The mass is heated to boiling under a reflux condenser for 24 hours and then filtered hot. When the filtrate is evaporated to dryness, the residue is obtained Magnesium salt.

Example 5

¹ To a solution of 1 part of anhydrous sodium hydroxide ° _/ isopropyl alcohol is added the theoretical amount of tert in 3 parts 98th Amylphenol thioether and heat the mixture to the boil until 2 parts of alcohol have distilled off. At the same time, the water passes over, since the distillate is 91% strength isopropyl alcohol, and a practically anhydrous distillation residue is obtained, which can be reacted directly with metal halides in the manner described in Example 2.

Example 6

To a mixture of 25 parts tert. Amylphenol thioether, which is needed for salt formation 100 parts of benzene are added to the amount of sodium hydroxide and 100 parts of 95% alcohol and heats the mass to a boil. The water formed is called constant boiling

Mixture of benzene, water and alcohol distilled off. Then you give anhydrous calcium chloride and proceed as described in Example 2.

Instead of anhydrous calcium chloride you can also use a solution of calcium chloride Use in 95 "% ethyl alcohol, with the water contained in alcohol through azeotropic distillation is removed. ίο In a corresponding way one can also the metal salts of alkylphenol polysulides and of chain-like alkylphenol thioethers or polysulphides. The same applies to the extraction of the metal salts the corresponding selenium or tellurium compounds.

If desired, the raw products can be subjected to further purification, for example by fractional crystallization or extraction or precipitation with selective solvents. Also through Treatment with adsorbent] !, such as fuller's earth, can remove impurities will.

To improve the lubricant, the metal compounds can be used in any concentration, insofar as they are at all soluble, can be used. Amounts of 0.05 or 0.1 to 0.25% are preferably used When using relatively large amounts of about 5% or more, the Increased lubricity of the oils.

As already mentioned, the metal compounds are particularly suitable for improving hydrocarbon lubricating oils, which can be of any type. The oils may be unpurified or subjected to refining, for example by distillation, voltolization or treatment with chemical or adsorbents, and may or may not contain paraffin. For example, coal tars, oil shale distillates, residual oils, fractions of fission residues or oils obtained by condensation or polymerization are suitable. In particular, highly refined oils come into question, as they are, for. B. by extraction with solvents such as phenol. Dichlorodiethyl ether. Furfural, propane, xitrobenzene, crotonaldehyde or mixtures of propane and cresol, or by treatment with fuller's earth or acids or aluminum chloride, and also oils obtained or synthetically produced by hydrogenation. The additives can be used both with relatively light oils, such as spindle or textile oils, and with any other oils such as cutting oils, turbine oils, transformer oils, engine sealing oils, steam cylinder oils and lubricating greases 6u. They are particularly suitable for Kurbehvellensehmierölen and other lubricants that are used at elevated temperatures above about 150 to 200 ^c .

The lubricants can also contain other additives, such as. B. dyes, Soaps, pour point depressants. Sludge distributing agents, antioxidants, thickening agents, Means for increasing the viscosity index, also resins, rubber, fatty oils, fatty oils thickened by heating. sulphurized fatty oils, agents to increase pressure, organometallic compounds. Residual oils, voltolization products from. fatty or mineral oils or paraffin, also colloidal solid disturbances, like graphite or zinc oxide.

The application of the metal compounds to lubricants is illustrated in the following examples explained.

Example 7

It is a naphthenisehen mineral lubricating oil having a viscosity of 1.729 ³ E 1% at 99 ° d ^e - ^s described in Example 2 to Caleiumsalzes. The following comparative values result from the diesel oil oxidation test:

Treatment time 48 hours 72 hours ui '< hours

Oil without additives 1 2 4

Oil + ι% calcium salt

according to example 2 ... 1 1 1

In this test, the oil is at 149 'the oxidized for the specified time, whereupon an io-g sample nitrated through filter paper and the amount of residue remaining on the paper is estimated. The means Rating number 1 is the smallest and number 10 is the largest amount of precipitation.

For example S.

Mixing a sample of the oil described in Example 7 with 0.5 ° / ₀ of the Caleiumsalzes described in Example 2 or 0.5 ° / ₀ of the corresponding aluminum salt, and compares the thus obtained mixtures with the original oil in verlx? Sserten Sligh -Test (this is carried out according to the information in Proc. ASTM 24, 964, TI (1924), but for 24 hours), whereby the following values result:

Schlummi ücksuind in milligrams

Oil with no added Oi

oil 4- 0.5% calcium salt

according to example 2 32.7

Oil J- 0.5% aluminum salt

according to example 2 21.9

Example 9 _lao

One sets a refined paniflhiisehen Mineral lubricating oil with a viscosity of

2.31 ° E at 99 ⁰ in an amount of 0.25% different salts obtainable according to Example 2 and compares the mixtures obtained in this way with the oil without addition by comparing the oils under comparable conditions in a CFR (Cooperative Fuel Research -) Motor used. Each sample lasts 14 hours and is carried out ^{at a jacket temperature of 190 0.} After each test, the machine is dismantled and the condition of the pistons, valves and cylinders is assessed, the rating number being higher the worse the individual machine parts look. If the rating for the oil without additives is set equal to 100, lower numbers result for the oils with -the additives, and the ratio then results as

Evaluation of the mix
Evaluation of the oil without additives

Xioo

Oil without additives .. '

Oil + aluminum salt according to the example:
Oil + barium salt
Oil + calcium salt
Oil + nickel salt
Oil + cobalt salt

Ratio

100
24
10

17th
12th

Compared to the known use of phenol sulfides with free hydroxyl groups, the metal salts of phenol sulfides described above have the advantage that they are significantly more effective. So z. B. with a lubricating oil without additive in a gasoline engine a permissible running time of the engine of 22 hours, with the addition of 0.2% diisobutylphenol sulfide one such of 24 hours and with the addition of the aluminum or lead or copper salt of diisobutylphenol sulfide, likewise in quantities of 0.2%) ^Z 'U the same oil a running time of 28.5 or 33 or 35.5 hours. Also in. The appearance of the engine results in advantages, since the contamination of the piston ring grooves and the underside of the piston as well as the amount of carbon precipitated from the oil is significantly less in the case of the metal compounds of the phenol sulfides than when the phenol sulfides with free hydroxyl groups are used.

Claims (1)

Claim: The use of metal compounds of phenol sulfides, especially those which contain an alkyl group with 4 to 8 carbon atoms in the phenol radical to reduce the oxidation of Lubricants. BERLIN. GKDRlICKr IN THE