DE1618713A1 - Process for the preparation of tertiary alkyl polysulphides - Google Patents

Description

DR. E. WIEGAND DIPL-ING. W. NIEMANN 1618713

TELEPHONE: 555476 * 8000 MÖNCHEN 15, 3Λ. June 1967

TELEGRAMS: KARPATENT NUSSBAUMSTRASSE 10

Where 15 O8O / 67 13 / never

Mobil Oil Corporation New Yoifc, N.Y. (V.St.A.)

Process for the preparation of tertiary alkyl polysulphides

The invention relates to a process for the preparation of polysulphide compounds and in particular of Alkyl trisulfides. Furthermore, the invention also relates to a novel reaction mass that is obtained with this order will.

It is well known that oil-soluble organic

• -

Sulfur compounds high pressure properties (extremepressure properties) for lubricating oil masses, especially under conditions of high speed and vibrations or bumps. Examples of such compounds are the alkyl polysulfides. The alkyl polysulfides are produced according to a

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Arbeltswelse by reacting an alkyl mercaptan and with sulfur. Preferred mercaptans are tertiary alkyl mercaptans, since they are widely available and accordingly are cheaper reactants. • Primary and secondary alkyl mercaptans for use are suitable in the manufacture of lubricating oil additives are much more expensive.

However, the reaction of sulfur and a tertiary alkyl mercaptan usually leads to reaction products which contain 50% to over 90 γ> of the tetrasulfide. A disadvantage is that, although the alkyl tetra. sulfides contain a substantial amount of sulfur, they cannot be used in systems in which sulfur-corrodible metals such as copper and silver are present. The trisulphide contains the highest percentage of sulfur that is not yet corrosive to sensitive metals. There is therefore a great technical interest in the preparation of reaction products which

contain a high percentage of the trisulfide.

present
According to the / Krrind a method of manufacture

of a tertiary alkyl polysulfide that is more than 65 mol # of a tertiary alkyl trl sulfide. The procedure according to the invention is characterized in that a tertiary alkyl mercaptan with sulfur is present a basic catalyst and a neutral, organic,

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is converted to polar solvent. In particular / at the The method according to the invention uses a tertiary alkyl mercaptan having 4 to 20 carbon atoms per molecule, wherein the reaction in the presence of the catalyst and the solvent mentioned with up to 20 carbon atoms per molecule, the one sulfur, oxygen or nitrogen substituent contains, is executed.

The yields of trisulfide in the process according to FIG Invention are on the order of above 65 MoI-Ji and even above 95 mol # of the total reaction product, being the maximum amount of byproduct formed Tetrasulfide can be kept below .35 mol #. the reaction products obtained in the process according to the invention contain the sufficient amount of sulfur necessary for creating the desired extreme pressure properties is required for use in lubricating oil masses, where they also have such a small amount of the tetrasulfide contained, uni their corrosive effect to a negligible Extent "attributed.

Bas affects the solvent used in the reaction unexpectedly the extent of the formation of the trisulfide

in derivatives "Bie polarity of the carrier or solvent, Reaktionsmisehung is critical for the type of products · formed Sun nonpolar solvent at the same reactants in the formation of more than $ 90> Tetra sulfide compound may result. Such reaction

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products cannot be used in the lubrication of certain Types of machines or motors are used because the lubricant masses they contain damage the Metal surfaces of the machines or motors. Accordingly, organic solvents with 1 to 20 carbon atoms, which have a sulfur, Contain oxygen or nitrogen substitution, preferably.

suitable solvents include liquid alcohols of up to 20 carbon atoms, e.g., methanol, ethanol, propanol, isopropanol, butanol, cyclohexanol, or the like. Other solvents which have been found to be satisfactory are liquid carboxylic acids including allyl acetate, isobutyl acetate and arnyl acetate. Further suitable compounds are liquid alkylene glycols, for example ethylene glycol, liquid aldehydes and ketones, for example benzaldehyde, acetaldehyde, acetone and methyl ethyl ketone. Further suitable neutral solvent, the organo-sulfur compounds, such as sulfoxides and sulfones, such as dimethyl sulfoxide, heterocyclic compounds such as Pyridinoxyd, tetrahydrofuran and 1,4-Boxyn and Organos / Kitickstoffverbindungen, for example cyano or amino compounds \ Le acetonitrile and dimethylformamide. The total number of carbon atoms of each of these compounds can be up to 20 carbon atoms.

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The tertiary alkyl mercaptans used according to the invention JÜegen in the range from C ₂ to CgQ compounds. The tertiary groups include butyl, amyl, nonyl, dodecyl and hexadecyl. The compounds listed above are of particular interest because of their technical adequacy.

The reaction takes place in the presence of a basic catalyst executed. Preferred catalysts include aliphatic and cycloaliphatic primary, secondary and tertiary Amines. Other amine catalysts include alkanolamines such as diethanolamine, alkylene polyamines such as ethylenediamine and Tetraethylene pentamine, and heterocyclic amines such as piperidines. The alkyl, alkylene or present in the amines cyclic groups can contain up to 10 carbon atoms. The amount of catalyst in the reaction mixture can in the range from 2 to 20 wt .- ^, based on the amount of Schwefelj lie.

The reaction can be carried out by gradually adding the mercaptan reactant to the sulfur and base. The solvent other than the mercaptan solvent is also initially present in the reactor. As shown in Example 5 below, an excess of a tertiary alkyl mercaptan can be used to serve as a solvent. The reaction can. be carried out at temperatures ranging from room temperatures up to 130 ⁰ G. Preferably a temperature of

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Maintain 25 to 80 ⁰ C with stirring before removing the solvent.

The invention is explained in more detail below with the aid of examples, in which the stated percentages or parts are based on weight. Analyzes of the product mixtures of the examples were determined by temperature controlled or temperature programmed gas chromatography using a silicone gum rubber column of approximately 1.2 m (4 feet). In a typical analysis, the temperature was increased from 50 ° to 275 ° C at a rate of 11 ° per minute. The temperature of the injector or injector was kept at 215 ° C with a block temperature of 3 (X) ⁰ C.

example 1

In a 1 liter flask equipped with a condenser, stirrer, thermometer and dropping funnel were charged 64 g (2 gram atoms) of sulfur, 3 × 5 6 n-propylamine and 225 ml of methanol. With this mixture stirred, 188 g (2.1 mol ·) of tertiary butyl mercaptan were added at room temperature over 3/4 hours. The temperature rose from 26 ° C to 3I ⁰ C with the evolution of some hydrogen sulfide. The reaction mixture "formed a homogeneous solution" within 1 hour.

Stirring was continued for an additional 4 hours and the mixture was left to stand overnight.

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mass was ^{topped to 7O 0} C at 5 mm. The yield was 196 pounds (93.0 yield) of a yellowish product. This product resulted in the following analysis:
Analysis;

sulfur 1.2 i-tol-J » Di- (tert-butyl) -
disulfide Di- (tert-butyl) -
trisulfide 19.5 "ίίοΐ-ji Di- (tert-butyl) -
teti ^ asulfide Examples 2 to 7

The reaction described above was used repeated by υ different types of polar solvents. The results obtained are in compiled in the table below.

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Tabel

example ο
O
33
c>.
Z solvent i » yield * S A η a 1 y
Diaulfide, Mol- # Trisuc se
lifid • 7th Tetrasulfide , Mol- # CD II Dimethylformamide 87 47.5 1.2 66 3 31.9 III Tetrahydrofuran 88 48.4 1.3 70 7th 28.4 IV acetone 84 48.7 23.3 69 0 17.0 V tert-butyl mercaptan 95 45.9 1st, 9th 88 0 10.1 VI Ethyl acetate 88 0 66 0 34.0 VII 1,4-dioxane 88 0 67, • 33.0 009852> f
■ to

Comparative example A.

As an example of a non-polar solvent, carbon tetrachloride was used in the reaction with the same amounts of reactants and catalyst and under similar working conditions.The following results were obtained:
Analysis ι

Sulfur 52.2 #

Disulfide 0.8 #

Trisulfide 10.0

Tetrasulfide 89.2

It can be seen that this is when using carbon tetrachloride received • "■ reaction product for use in facilities or systems that use metals that are sensitive to the corrosive effects of sulfur included, is not suitable. Although such reaction products Extreme pressure properties can impart to a lubricating oil, they are due to their limitation with regard to their corrosive effect as additives in lubricant technology is less desirable.

The reaction products according to the invention have been found to be useful in lubricant compositions as well not corrosive in the normal additional concentrations. The additives can be used in amounts from 0.01 wt .- # to 10 Sew.-9 £ come into use.

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Suitable lubricating oils include mineral oils of suitable viscosity for lubricants and synthetic ones oils, and especially synthetic ester oils derived from dicarboxylic acids and monohydric alcohols, e.g. di- (2-ethylhexyl) sebacate, and from monocarboxylic acids and polyhydric acids Alcohols, e.g. esters of trimethylolpropane and of pentaerythritol and of acids with up to 30 carbon atoms other synthetic lubricants include flowable, polyolefinic media, e.g., polydecene, Polyalkylene oxide fluids, organosubstituted silicone fluids, and polyacetals. Furthermore, lubricating oil masses include other additives which provide other desirable properties, e.g., detergents, pour point depressants Agents, (pour point depressants), antioxidants and other known additives.

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Claims (4)

Claims 1. Process for the production of tertiary alkyl polysulphides «, the at least 65 mole # of a tertiary alkyl trisulfide contain, by reaction of a tertiary alkyl mercaptan with sulfur, characterized in that the mercaptan with sulfur in the presence of a basic catalyst and a neutral, organic, polar solvent. 2 * Process according to claim 1, characterized in that a C, - Cp ₀ mercaptan is used as the mercaptan. 3. The method according to claim 1 or 2, characterized in that, daii one the reaction in the presence of a primary, secondary or tertiary amine, especially an aliphatic Runs amine as a catalyst. 4. The method according to any one of claims 1 to 3, characterized in that there is a neutral, organic, polar solvent (a) an alcohol, especially methyl alcohol, (b) a ~ ter _f egg in particular ethyl acetate, or a ketone
(cj an aldehyde / especially acetone, (d) an amide, especially pormamide (e) a heterocyclic oxygen compound, in particular tetrahydrofuran or 1,4-dioxane, or (f) a tertiary alkyl mercaptan, in particular tert-butyl siercaptan used. 009852 / 21B4 BADOR ₁ GiNAk