US2246059A - Composition of matter - Google Patents

Description

Patented June 17, 1941 UNITED STATES PATENT OFFICE COMPOSITION OF MATTER No Drawing. Application February 1, 1940, Serial No. 316,778

4Claims.

This invention is directed to the stabilization of hydrocarbon oils of higher boiling points against the deteriorating effects of oxidation. Highly refined oils of the non-sludging types, such as the white oils, turbine ofls, and the like, must be able to withstand the conditions of their use without the formation of acidic constituents of a corrosive or otherwise damaging nature.

This invention contemplates the stabilization of such oils. Moderately refined oils of the nature of many lubricant fractions must likewise be able to withstand the conditions of their use without the formation of sludges, loss of color, or development of oxidation products corrosive to commonly used metals, as for instance to copper. This invention likewise contemplates the stabilization of such moderately refined oils. In short, this invention is directed to the stabilization against deterioration due to oxidation reactions of any petroleum fractions of a light lubricant nature or heavier, from the lightest spindle oils, through the various classes of moderately refined oils of higher viscosity, and inclusive of the highly relilkned oils such as turbine ofls, white oils, and the This invention has for an important object the preparation of oils falling within the above classes which are stable against oxidation and capable of meeting the normal conditions of their use without the formation of gummy material, sludges, materials of an acidic or corrosive nature, and/or darker color. It also has for an object the provision of a class of stabilizing materials not heretofore known to be effective for that purpose. a

Recent changes in automotive engine design, tending toward higher bearing pressures, higher rotative speeds, higher engine temperatures, and the like, have occasioned departure from the use of the usual bearing metals such as Babbitt. The newer bearing metals ar"fdii!erent nature, and, while harder, are in general more susceptible to destructive agencies of a corrosive nature. Typical of these newer bearings are those composed of a cadmium-silver alloy supported upon a steel back, which are now widely installed in certain makes of automobiles. Others of these relatively new bearing metals which may be mentioned are" cadmium-nic eL and copper-lead alloys.

These changes in engine design have been concurrent with marked advances in methods of refining lubricant oils for automotive use. The demand for oils having lesser changes in viscosity with temperature change: i. e., higher viscosity index (V. 1.), has been met by refining lubricants intended for motor oils by certain solvent-refining or solvent-extraction processes, wherein advantage is taken of the selective solvent power i'or hydrocarbons of various types which is possesed by certain liquid reagents-for example, dichlorodiethvi ether, cresylic acid, phenol, ichioraniline, chlorophenol, phenetidine, benzyl alcohol, nitrobenzene, benzonitrile, furrural, aniline, benzi acetate, liquid sulfur dioxide, mixtures of liquid sulfur dioxide or aniline with benzoi, and the like. These solvent-refining proceses are operated to concentrate in the desired lubricant fraction those compounds of a paraiiinid' nature mof the ability to suffer only 8) small change of viscosity upon change of temperature, and to reject the compounds of "naphthenic" nature which do suii'er such change of viscosity toa more marked degree. These refining proceses have enabled supply of an oil of quite desirable general characteristics, definitely far superior to any oil previously produced from mixed base or asphaltic crudes, and superior to a like, though lesser, degree over oils previously produced from paraffin base crudes.

It has been found that the solvent-refined motor oils referred to above are for some reason definitelyvcorrosive to the newer bearing metals under normal conditions of automotive use, sometimes resulting in bearing failure after only a few thousand miles of normal driving. It is further known that the same reaction, viz., corrosion of alloy bearing metals such as cadmiumsilver, occurs in good paraiilnic base oils which have not been subjected to solvent-refining. The higher the V. I. of the hbricatlm oil, the more mnoimced is the tendency to corrosion of the kind referred to above: generally speaking, the problem is encountered in oils having a V. I. of or higher, and becomes important in oils havingaV.I.ofto85orhigher. and very important in oils of V. I. or higher.

It is an important object oi this invention to provide means for satisfactorily inhibiting or preventing this corrosion from taking place to a serious degree. It is an object of this invention to alter or modify a highly refined motor oil, normally corrosive, by the use of an additive ingredient capable of substantially inhibiting this corrosion. It is an object to provide a substantially non-corrosive motor oil of high V. I. An object of this invention is to provide an additive reagent or ingredient. capable of inhibiting the corrosive properties of these oils. The production of solvent-refined oils of low corrosive properties under conditions of automotive use is a major object of this invention, as well as the method of production of such oils which couple high viscosity index with low tendency to corrosion.

We have found that hydrocarbon oils of the classes defined above can be stabilized in the respects above indicated by the additionthereto of small amounts of compounds selected from the class of aryl phosphites having the general formula (ArO):P, in which Ar designates an aryl radical, as for instance CaHa or CHaCsI-Is. The aryl phosphites which are suitable for the uses of this invention are as follows: Compounds of the general formula where one or more of the Rs is a radical selected from the group consisting of where the R"s are radicals selected from the group consisting of hydrogen, alkyl, hydroxy', halogen, aryl (such as phenyl and hydroxyphenyl), alkaryl, aikoxy, nitro, and amino and substituted amino (as phenyl or benzyl substituted).

,Of the above-defined classes of compounds, those at present preferred for the uses of this inven-.

tion are those wherein all three Rs are radicals of either type (a) or (b) defined above, and wherein the R"s are either hydrogen or alkyl. Examples of specific materials which we have found especially suitable for the uses of this invention are triphenyl phosphite, tricresyl phosphltes, and tribeta-naphthyl phosphite; Where R is alkyl, it may range from a short alkyl such as methyl to very long alkyls corresponding, for example, to paraflin wax.

The general inventive concept as set forth in the preceding paragraph is embodied in our copending application Serial No. 106,227, of which the present application is a continuation in part. This application is specifically directed to that class of the aforesaid compounds in which R. is a long chain alkyl group corresponding to aliphatic hydrocarbons of the type characterizing paraflin wax, These compounds, which we may designate as wax-aryl phosphites, distinguish over the general class of phosphites described above in that they are efi'ective to reduce the pour point of viscous mineral oil fractions in addition to P improving the oil in the aforesaid respects. Thus, the wax or heavy alkyl-substituted aryl phosphites are multifunctional oil-addition agents, functioning as pour depressants and oxidation inhibitors while the aforesaid general class of aryl phosphites possess as their common property that of corrosion or oxidation inhibition.

The specific compounds contemplated herein may be represented by the general formula in which R represents a radical selected from the group consisting of hydrogen and the radicals wherein at least one R is a long chain alkyl radical corresponding to paraffin wax and the remaining R"s are radicals selected from the group consisting of hydrogen, alkyl, hydroxy, aryl, alkaryl, alkoxy, nitro, amino, and substituted amino radicals, at least one of the Rs being selected from the aforesaid group of radicals (a) (b) and (c). Of the compounds corresponding to the foregoing general formula preference is.

given to compounds of the type in which all of the R"s are substituted with aryl radicals, at least one of which has a long chain alkyl substituent corresponding to an aliphatic hydrocarbon group of the type characerizing paraflln wax. Such preferred compounds may be identified as triaryl phosphites in which at least one of the aryl radicals has at least one relatively long alkyl substituent of the general order corresponding to parafiin wax.

Triaryl phosphites of the character discussed above in which the aryl radical is derived from phenol may be represented by the general formula wherein at least one R" is a long chain alkyl radical corresponding to the alkyl radicals characterizing paramn wax and the remaining R"s are radicals selected from the group consisting oi hydrogen and alkyl.

.. blends are set forth in Table I below, wherein None- These wax-aryl phosphites may be formed by first reacting a chlorinated paraflin wax or similar long chain aliphatic compound or predominantly aliphatic material with a hydroxyaromatic compound, such as phenol, naphthol, and the like, in the presence of a Friedel-Crafts catalyst to form a wax-substituted phenol" or waxphenol" and then reacting the wax-phenol thus obtained with phosphorus trichloride.

For example, a so-called "monowax". phenol may be obtained by reacting a quantity of chlorinated paraflin wax (about 14 per cent chlorine content) with phenol in the presence of aluminum chloride, the reaction mixture being proportioned so that there is one atomic proportion of chlorine present for each mol of phenol. By changing the ratio of the chlorwax to phenol in the reaction mixture so that there are two, three or four atomic proportions of chlorine to one mol of phenol, the so-called di-, tri-, and tetra-wax phenols are obtained. The Friedel-Crafts reaction for obtaining the wax-phenol is carried out at elevated temperature, preferably not to exceed 350 F.

The wax-phenol reacts with the PC13 at elevated temperature (from 103 F. to 205 F.) with the evolution of HCl gas. The use of a solvent such as ethylene dichloride is desirable to reduce foaming. Following the reaction the mixture may be taken up in benzene containing a. little fusel oil and washed with hot water, thereby hydrolizing any chlorine of the PC13 which has not been substituted with thewax-aryl nucleus.

EXAMPLE ONE Pom: POINT DEPRESSION The oil used in this test was an S. A. E. 30 motor oil having an A. S. T. M. pour point of +20 F. Several blends of this oil were prepared with wax-phenyl phosphites of the type contemplated herein and the pour points of such.

60 the various wax-phenyl phosphi-tes are identified Per Addition agent can Monowax-phenok-PCP compound l. 0

EXAMPLE Two Gonnosron Inmnmon The oil usedinthistestwasan S.A.E.20-' motor oil having a specific gravity of 0.872, a flash point of 435 F., and a Saybolt viscosity of 318 seconds at 100 F. The test involved placing a section of a. bearing containing a cadmiumsilver alloy surface and weighing about 6 grams inasampleof the oil andheatingtheoiltoa temperature of 175 C. for 22 hours while bubbling a stream of air against the surface of the bearing. The loss in weight of the bearing is a measure of the amount of corrosion which has From the foregoing examples it will be seen that the wax-aryl phosphites contemplated herein are effective to reduce the pour point and retard the deleterious effects of oxidation when added in minor proportions to viscous mineral oil fractions.

The amount of addition agent to be used will vary with the nature of the oil to be stabilized and with the use to which it will be put. In general, efiective stabilization and pour point depression will be obtained in the oils of the class herein discussed with not more than 2% of the wax-aryl phosphites, usually not more than 1%. For more common uses, effective stabilization and pour point depression may be obtained with amounts in the neighborhood of 0.05 per cent to 0.50 per cent of these compounds.

In the claims, where the term hydrocarbonoils of relatively high boiling point or the equivalent thereof is used, it is intended to mean any and include all hydrocarbon mineral oil products normally used as lubricants or for electrical insulating purposes. It includes oils with an S. U. V. of 50 seconds at F. or higher or a flash point greater than 200 F. (Cleveland open cup). This term, in efiect, is in contradistinction to gasolines, kerosenes, and the like.

,As aforesaid, this application is a continuation in part of our copending application Serial No. 106,227, filed October 17, 1936, which application is, in turn, a division of application Serial No. 46,870, filed October 26, 1935, now issued as Patent No. 2,058,343 of October 20, 1936.

We claim:

1. As an antioxidant for petroleum hydrocarbon oil of boiling point higher than that of gasoline and kerosene, a triaryl phosphite in which at least one of the aryl radicals has at least one relatively long alkyl substituent of the general order corresponding to paraflin wax.

2. An improved mineral oil composition comprising a petroleum oil of relatively high boiling point normally tending to deteriorate by oxidation when heated and in admixture therewith a small proportion, suflicient to retard said deterioration and depress the pour point of the oil, of a triaryl phosphite in which at least one of the aryl radicals has at least one relatively long chain alkyl substituent of the general order corresponding to paraflln wax.

3. An improved mineral oil composition comprising a petroleum oil of relatively high boiling point, having added thereto a minor proportion of a compound or the general formula /-R P-O-R in which R. represents a. radical selected from the group consisting of hydrogen and the radicals point having added thereto a minor proportion of a compound of the general formula wherein at least one R. is along chain alkyl radical corresponding to the aliphatic groups characterizing paraflin wax and the remaining R"s are radicals selected from the group consisting of hydrogen, alkyl, hydroxy. halogen, aryl, alkaryl, alkoxy, nitro, amino, and substituted amino radicals.

ROBERT C. MORAN.

WILLIAM L. EVERB. EVEREI'I W. FULLER.

CERTIFICATE OF CORRECTION. Patent No. 2,2h6,059. June 17, 19in.

ROBERT C. MORAN, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 55, and second column, lines 514. and 59, for "R s" read -Rs;

pageLp, first column, line 27, claim 5, for "R s" read -Rs-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

.Signed and sealed this 6th day of January, A. D. l9b,2.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,21%,059. June 17, 19M.

ROBERT c. MORAN, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 55, and second column, lines 514. and 59, for "B s". read -Rs-;

pagelp, first column, line 27, claim 5, for "R s" read R s-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. .Signed and sealed'this 6th day of January, A. D. 19m.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.