US2214379A - Extreme pressure lubricant - Google Patents

Description

Patented Sept. 10, 1940 UNITED STATES PATENT OFFICE EXTREME PRESSURE LUBRICANT of Delaware No Drawing; Application November 22, 1937, Se-

rial No. 175,882.

8 Claims.

This invention relates to lubricants suitable for lubrication under extreme pressure conditions, dealing more particularly with mineral lubricating oils containing small amounts of organic sulfonyl halides produced from aromatic mineral oils. The present invention is a continuation-in-part of that disclosed in our application Serial No. 69,163, filed March 16, 1936, in which we disclosed mineral lubricants containing small amounts of said sulfonyl halides, i. e., compounds containing the radical SO2X attached to an organic grouping where X is a halide, such as methylene sulfonyl chloride, benzene sulfonyl bromide, naphthalene sulfonyl chloride, etc. It was shown that these organic sulfonyl halides are powerful extreme pressure compounds, superior in their effect in the matter of raising the load carrying capacities of lubricating oils to which they are added, over other compounds containing the same number of the same elements in diflerent configurations. It was also shown that many of the organic sulfonyl halides are very resistant to hydrolysis so that the danger of corrosion may be exceedingly small, if at all existing.

Now we have discovered that sulfonyl halide mixtures prepared from normally liquid asphaltfree aromatic mineral oil fractions which are soluble in so-called naphthenic solvents, such as furfural, at a temperature below 50 C. and boil substantially above gasoline range (50% or less distilling below 400 F. by A. S. T. M. method), are in many respects superior extreme pressure compounds than the sulfonyl halides heretofore proposed. We have found that such mixtures not only possess equal or superior extreme pressure properties and greater resistance to hydrolysis than the best of the sulfonyl halides disclosed in said application Serial No. 69,163, flied March 16, 1936, but in addition possess the unique property of positively inhibiting corrosion of normally corrosive lubricating oils.

Suitable aromatic mineral oil fractions used in the preparation of the mixed sulfonyl halides of this invention may be obtained for instance from highly aromatic mineral oils such as Borneo crude oil, cracking recycle oil, or coal tar oils by suitable distillation to remove gasoline, asphalts and tar; or from naphthenic petroleum oil fractions of the proper boiling range such as kero- 50 sene, gas oil, lubricating oil distillate, by extrac- In the Netherlands March 19,

tion with a selective solvent for aromatic hydrocarbons such as liquid S02, furfural, phenol, nitrobenzene, BB dichlorethyl ether, croton aldehyde, etc. For instance a fraction which was excellently suited for our purposes was prepared by extracting a kerosene obtained by distillation from a naphthenic crude oil, with liquid S02 and removing the S02 from the extract. This particular fraction had a-boiling range of 385 to 575 F. and proved to contain 50% aromatic rings, naphthene rings and 40% alkyl radicals, most of which were saturated. The presence of relatively large percentages of olefines as found in cracking recycle oils, however, is not objectionable.

The suitable aromatic mineral oil fractions are then converted to the sulfonyl halides by any of the conventional methods used for producing such sulfonyl halides. Probably the most convenient procedure comprises treating the aromatic fraction with an excess of chlorsulfonic acid having the formula ClSOsH, at about normal room temperature, preferably in the presence of a substantial amount of carbon tetrachloride or other substantially inert mutual solvent for the reactants.

For example a solution of 200 grams carbon tetrachloride containing 25 grams chlorsulfonic acid was cooled to 50 F. A solution of 14 grams of an aromatic kerosene extract in one-third its own volume of carbon tetrachloride was slowly admixed to the chlorsulfonic acid solution while stirring and cooling, approximately to maintain the original temperature. After completed admixture stirring was continued for one hour at the same temperature and thereafter the reaction mixture was allowed to stand for 24 hours without further cooling. Two layers formed, a bottom sludge layer and a larger top layer comprising the carbon tetrachloride solution. The layers were separated and the carbon tetrachloride solution was poured on ice to effect hydrolysis and separation of unreacted chlorsulfonic acid. The aqueous acid layer was removed and the remaining carbon tetrachloride solution was twice washed with water. During the washing further products of hydrolysis separated in the form of a dark brown liquid which was allowed to settle and was then removed. The purified carbon tetrachloride solution was dried and distilled to remove the solvent and to recover the mineral sulfonyl chlorides in substantially pure form. Last traces of solvent were expelled by passing mtrogen through the distillation residue for 1 hour at about 260 F. A light yellow mobile liquid was obtained which consisted essentially of the desired sulfonyl chloride mixture and had the following properties:

Saponiflcation number 328 Chlorine content per cent" 10.4 Unsaponifiable matter do 6.0

Other methods for producing the petroleum sulfonyl halides comprise preparing the sulfonic acids first by sulfonation of suitable mineral oil fractions and then treating the sulfonic acid so produced with a halogenating reagent capable of replacing acidic hydroxyl radicals with halides, such as PCls, SbCls, etc.

Solutions of 2% of the yellow liquid obtained above in mineral lubricating oils were prepared and tested for extreme pressure properties in several of the recognized extreme pressure testing machines, and for anti-corrosiveness in the Underwood corrosion testing apparatus, as shown in the following examples. For the purpose of comparison, data for similar solutions of B naphthalene sulfonyl chloride are also given.

In the Boerlage four-ball apparatus described in Engineering vol. 136 (1933) page 46, the results were as follows:

'AKE aromatic kerosene extract.

The Floyd tester imitates to some extent the condition of a journal in a sliding bearing. A steel shaft M; inch in diameter is driven by a motor by way of a retarder, so that the shaft revolves at the rate of 100 R. P. M. By means of an hydraulic plunger, an upper bearing cap is pressed upon this shaft with a known force.

There is another bearing cap underneath which supports the journal. The bearings and the shaft are made of S. A.-E. 1112 "screw stock. The oil pressure is measured on the plunger by a pressure gauge in lbs. per sq. inch and this reading has to be multiplied by the factor 76.97 to find the pressure in lbs. per sq. inch of the projected bearing surfaces.

In this tester the straight mineral oil permitted a load of 200 pounds only, before the shearing pin broke. 2% B naphthalene sulfonyl chloride raised the permissible load to 300 pounds, and with 2% aromatic kerosene extract sulfonyl chloride in the lubricating oil, the pressure could be raised to 600 pounds.

Anti-corrosion properties. were evaluated by the Underwood corrosion test which consists of pumping the test oil for 5 hours at 320 F. in the presence of oxygen and a small amount of lead naphthenate as corrosion accelerator over a set of four half bearings, two of cadmium silver alloy and two of copper-lead alloy. At the end of this time the loss in weight of the bearings and the acid number of the oil are measured. V

The oil used in these tests was a solvent refined West Texas lubricating distillate which had a neutralization number. of .1 and proved to be quite corrosive in actual iulerication service. Results of the tests were as follows:

'AKE=aromstio kerosene extract.

The anti-corrosive action of our sulfonyl halides appears to be independent of the nature of the corrosiveness of the lubricating oil. In other words it is immaterial whether the corresiveness is due-merely to the absence of natural corrosion inhibitors, as the result of which metals receive insuiiicient protection from oxygen, moisture and acidic gases contained in the surrounding atmosphere; or whether it is due to the presence of corrosive substances such as corrosive sulfur compounds, acids, etc.; or whether it is of a galvanic nature. In all cases a substantial reduction of corrosiveness has been observed upon addition of the sulfonyl halides of this invention to corrosive lubricating oils.

The amounts of sulfonyl halides to be added to lubricating oils vary with the requirements which the oils must meet. In general the amounts added are well below 5% and preferably are between .1 and 2%.

While in the foregoing examples we have shown the efiect of sulfonyl chlorides only, it shall be understood that other aromatic mineral oils sulfonyl halides, namely, the fluorides, bromides and iodides are also suitable although the chlorides are preferred as being in general the most effective and the most stable.

Moreover, the sulfonyl halides of this invention may be used in combination with other compounds such as oiliness compounds or thickeners capable of producing greases, or ring sticking inhibitors for Diesel engine lubricating oils such as the salts of polyvalent light metals and aromatic fatty acids, naphthenic acids, etc.

We claim as our invention:

1. A substantially non-corrosive lubricant comprising a predominating quantity of a mineral lubricating oil and a small quantity of mixed organic sulfonyl halides prepared from an aromatic normally liquid mineral oil fraction soluble in liquid S02 and boiling substantially above gasoline boiling range.

2. A substantially non-corrosive lubricant comprising a predominating quantity of a mineral lubricating oil and a small quantity of mixed organic sulfonyl halides prepared from an aromatic mineral oil fraction soluble in liquid SO: and free from asphalt and boiling substantially above gasoline boiling range.

3. A substantially non-corrosive lubricant comprising a predominating quantity of a mineral lubricating oil and a small quantity of mixed organic sulfonyl halides prepared from a mineral oil extract obtained by extraction of the oil with a preferential solvent for aromatic hydrocarbons.

which extract is free from asphalt and boils substantially above gasoline boiling range.

4. A substantiallynon-corrosive lubricant comprising a predominating quantity of a mineral lubricating oil and a small quantity of mixed organic sulfonyl halides prepared from an aromatic kerosene extract which is soluble in liquid S02. 1

5. A substantially non-corrosive lubricant comprising a mineral lubricating oil containing less than 5% mixed organic sulfonyl halides prepared from an aromatic normally liquid mineral oil fraction soluble in liquid S02 and boiling substantially above gasoline boiling range.

6. A substantially non-corrosive lubricant comprising a mineral lubricating oil containing between .1 and 2% of a mixture of organic sulionyl halides prepared from an aromatic normally liquid mineral oil fraction soluble in liquid 80: and boiling substantially above gasoline boiling range.

'7. A substantially non-corrosive lubricant comprising a predominating quantity of a mineral lubricating oil and a small quantity of a mixture of sulfonyl chlorides obtained by treating an aro-' matic normally liquid mineral oil fraction soluble in liquid SO: and boiling substantially above gasoline boiling range with chlorsulfonic acid.

8. A substantially non-corrosive lubricant comprising a predominating amount of a corrosive mineral lubricating oil and a small quantity of a mixture 01' organic sulfonyl halides prepared from an aromatic normally liquid mineral oil fraction soluble in liquid SO: and-boiling substantially above gasoline boiling range.

FRANZ RUDOLF MOSER. MARINUS CORNELIS TUYN.