US2033543A - Lubricating oils - Google Patents

Description

Patented Mar. 10, 1936 g UNITED STATES mnmca'rmc oms Anderson W. Balaton and Carl W. Christensen,

Chicago, Ill., assignors to Armour and Company, Chicago, 111., a corporation of Illinois No Drawing. Application May 4, 1935,

Serial No. 19,906

9Claims. (c1. s x-s) This invention relates to lubricating oils and it comprises an improved lubricating oil composed of a hydrocarbon lubricating oil to which has been added a mixed ketone in quantities of the order of 0.1 to 1 percent.

Within recent years eflorts have been made to improve mineral lubricating oils by adding various ingredients thereto. In many cases such additions have been made for the purpose of improving that characteristic of the oil commonly referred to as oiliness. These added substances have mostly been fatty acids such as oleic acid, various glycerides, lard, and the like. The property of oiliness has not been clearly defined, but the term has a rather definite meaning to those skilled in the art. Some have defined it as that property which an oil must possess to a sufiicient degree to enable the oil to lubricate adequately under all conditions of use. In more practical terms, an oily oil is one which will forma film between bearing surfaces of such strength that the film will withstand rupture under extreme conditions of pressure or temperature. To put it another way, an oily oil is one which has high film strength and as a result will give better engine performance under all conditions of use. At'the same time, however, such oils should have low internal friction and should also have the property of clinging tometal surfaces. It used to be considered that viscosity was a good criterion of the oiliness in oil 0 higher the viscosity the stronger would be the oil film. However, it has now been pretty well acknowledged that viscosity alone does not explain oiliness in an oil.

As stated, the prior art has hitherto ,added small quantities of vegetable oils such as oleic acid to hydrocarbon lubricating oils. Undoubtedly such additions have proved beneficial, in

part because of the high "polar" characteristics of the higherfatty acids. That is to say. the carboxyllc acidgroup of the fatty acid tends to cling to the'metal surfaces of a bearing and thus aids in the development of a persistent film.

5 However, in many instances, the internal friction of the compounded oil has been increased and this .is a distinct disadvantage. Many oi the added substances hitherto used increase the viscosity of the oil and hence such oils necessarily cause increased power losses in engines lubricated with them. This is because of the internal friction in the oil itself.

Another serious objection to the addition or substances like oleic acid and fats is that these added substances do not have very much resistance to high temperatures. In a gasoline engine the crank-case temperature may on the average be about 210 F. and bearing temperatures may run as high as 400 F. Bearing pressures may o occasionally be as high as 600 pounds per square n the theory that the inch which means that a satisfactory oil must have high film strength and heat resistance if it is to function continuously under these conditions. 1

Substances like oleic acid are notsufiiciently 5 heat resistant to operate satisfactorily over long periods of time at the relatively high temperatures in a rapidly rotating bearing. These substances, although they initially contribute oiliness to an oil, tend to break down and decompose at 10 high temperatures. This action may beoxidizing, or it may in part be instituted by the presence of traces of moisture. Fatty esters are readily hydrolyzed at the high operating temperatures in the presence of moisture and free 15 fatty acids thus liberated tend to decompose. All ofwhich means that such substances, althoughthey may initially improve a mineral lubricant very soon lose their effectiveness and actually prove detrimental. 20

' We have now discovered a-class of substances which can be addedto mineral lubricating oils in small amounts, of the order of 0.1 to 1 percent, and which markedly improve the oiliness of the oil but do not have the many disadvan- 25 tages unavoidably present in substances hitherto suggested. We have discovered that compounds known as "mixed ketones satisfy the require ments in this art. These mixed ketones can be generically described-as ketones in which aryl 30 or heterocyclic groups, and alkyl groups are linked to a carbonyl. -'And we have further dis covered that of the many substances which can be designated as mixed ketones we find that those in which the alkyl group contains eleven 5 or more carbon atoms are best. In our invention aryl or heterocyclic groupsmay be varied over a wide range as will be described. Structurally then, the compounds we add to a mineral lubricant oil can be generically illustrated as 40 wherein R is a ring compound either of the car- 'bocyclic or heterocyclic series and R. is an alkyl .in lubrication. We find that ,.they contribute oiliness to a high degree and thus function to 55 maintain high film strength under all conditions of pressure.

Moreover the compounds of our invention have a. beneficial efiecton viscosity. Many compounds hitherto added to mineral lubricating oils 00 In.contrast thereto many of the compounds which we add to a lubricating oil raise the viscosity index several points. For example. stearophenone is one very advantageous substance toaddtoanoilinthepracticeoi'ourinvention. Whenweaddlpercentoistearophenonetoa number 30 (SAE) Mid-Continent lubricating oil the viscosity index is increased from 86.7 to 92. At 100 F. the viscosity (Saybolt) is 493 seconds whereas the untreated oil has a viscosity of 514 seconds. At 210 F. both the compounded oil and the untreated oil have the same viscosity.

Hence it is apparent that the addition of the aralkyl ketone has decreased the viscosity at 100 F. and thus increased the viscosity index. This is a marked advantage because it means that oilines is increased without increasing the internal iriction in the 011. As stated almost all substances hitherto added to oils for increasing oiliness have increased internal friction whereas, in our invention, the internal friction is either decreased or remains substantially unchanged. Such a result has long been desired.

In addition, many 01' the substances which we use for increasing oiliness pronouncedly lower the cloud point of the mineral lubricating oil. In the example given above the original oil has a cloud point of 52 F. The addition 01' 0.1 percent oi. stearophenone lowers the cloud point to 30 F..

We shall now describe numerous examples oi compounds falling within the generic disclosure given above. It .is tobe understood 0! course that these compounds are simply admixed and blended in the mineral lubricating oil in proportion of from about 0.1 to 1 percent based on the weight of the oil. This quantity can be increased somewhat but to no substantial advantage. All or the compounds we add are. of course, soluble in lubricating oil, and it is to be understood that we can treat lubricating oils from any source and 01' any viscosity. We can add our improving substances to mixed lubricating oils and to lubricating oils composed oi. both mineral and vegetable oils such as castor oil, but in the ordinary practice of our invention the ketones are generally added to an ordinary mineral lubricating oil. We do not however wish to be restricted to lubricants composed entirely of mineral oils.

We shall now describe our invention with relerence to the treatment of a Mid-Continent lubricating oil having an (SAE) viscosity of 30 it being understood however that this is merely illustrative and not limiting.

There are many mixed ketones we can use. It the generic formula for our compolmds be written as R can be any alkyl group having eleven or more carbon atoms. It can also be a substituted alkyl group. Thus R can be undecyl CuHn, tridecyl CnHrr, pentadecyl 01031:. and heptacecyl C11HJs.

R can be any one of a number of closed ring radicals. The following are examples thereof; phenyl, xyiyi, tolyi, anisyl and chlorphenyl, these being typical examples of phenyl and substituted phenyl radicals. R can also be phenoxyphenyl, diphenyl, naphthyl and anthracyl or substitution products thereof, as further examples of carbocylic ring compounds. R can also be Iuryi, fluoryl, carbazoyl, dibenzoturyl, thiophenyl and dibenzothiophenyl, as examples of heterocyclic radicals.

We shall now give examples of many compounds ialiing under our generic invention.

In the following table, from 0.1 to 1 percent of various aralkyl ketones are added to a No. 30 Mid-Continent lubricating oil which has a cloud point of 52 F., a pour point of 20 F. a Saybolt viscosity at F. oi 514 seconds and at 210' I". 01 62 seconds, and a viscosity index of 86.7.

Table 1 v Ho o vkcoaisti mt Cloud Pour m vim-n was Mm point point mm 'r. 'r'. .1 12 10 m 04 000 .0 u so 000 04 0a: 1.0 so so 400 00 01o .1 as 10 no 01 014 .s :2 1s m 01 an 1.0 a0 :0 400 0: 00.0 .1 a an s11 00 01.1 .0 so 10 000 02 an 1.0 a so 400 00 no .1 10 Y 10 m 0: 001 .o :0 10 m 02 as: 1.0 40 as 100 01 on .1 11 so 114 01 01.0 .0 u 10 000 a 00.0 1.0 as 11 000 0: 0110 .1 n 10 on 00 04.0 .0 11m -u m 02 00.0

dark 1.0 T00 --10 no 0: 01.0

dark .1 s4 10 on as 01.4 .0 :0 10 000 02 00.1 1.0 :0 :0 m 01 00.1 .1 00 10 us 01 au .1 u 10 an as 00.1 1.0 u 10 001 01 00.0 .1 a a 00 as: .0 as an 010 01 01.0 1.0 no :0 00s a. as: .1 I4 ll Ill 03, n0 .0 a 10 000 n as: 1.0 ---..do a 0 40s 0: no CcatnHtah-alkfiwmphbd) Is a m 00 00.1

' One of the best ketonic substances to add is that aosaus The compound from dimethyl aniline and stearoyl chloride is probably a mixture of ketones which can be generically described as dimethyl aminophenyl heptadecyl ketones. The aralkyl phenones (lard fatty acids) were made by reacting acid chlorides obtained from lard fatty acids with benzene in the presence of aluminum chloride as will be explained. It is a mixture of ketones in which oleyl phenone probably predominates. Anthracyl heptadecyl ketone colors the oil somewhat when used in percentages of 0.5 and 1.0 which makes the cloud pointdetermination diflicult. These amounts do not however deleteriously affect oiliness and they actually reduce the pour point markedly.

Itis to be noted that most of the above compounds tabulated increase the viscosity index. In some instances the index is slightly reduced but the reduction is markedly less than that commonly met with when adding many of the substances hitherto used for increasing oiliness.

It is of course obvious that we can use mixtures of ketones and thus obtain the desirable advantages of individual substances. For exam- I pie we can add a mixture of phenyl heptadecyl ketone and anthracyl heptadecyl ketone in this way obtaining the advantageous increase in viscosity index contributed by phenyl heptadecyl and the marked reduction in pour point contributed by anthracyl heptadecyl' ketone. Both of these compounds markedly increase oiliness in the oils. 1

Curiously, in some instances, impure ketones work better. This may be due to the fact that the impure ketone really contains a mixture of ketonic compounds and this effect is especially noticeable in the case 'of the anthracyl ketones.

obtained from reacting anthracene oil or fractions thereof with higher fatty acid chlorides by the Friedel-Crafts synthesis as will be explained.

This gives us a mixture of ketones which arev difficult to isolate separately but which markedly contribute oiliness to the lubricating oil.

In Table 2 which follows we describe the effect of adding various other mixed ketones among which are ketones in which the alkyl radical is undecyl. This table also shows the effect of ketones inwhich the aryl group is substituted by chlorine and by methoxy. The character of the lubricating oil treated is indicated at the bottom of the table. It was a Number 30 Mid-Con- In the above table, cloudpoints and pour points were not determined in every instance. In the case of dibenzofuryl heptadecyl ketone it is to be noted that 0.5 percent thereof lowers the viscosity index somewhat. When using this substance we therefore find it best to keep the quantity at about 0.1 percent. Many of the ketones given above are not ordinarily used in the commercial. practice of our invention because they are more expensive than substances like stearophenone and the anthracyl derivatives, but we have described these compounds to illustrate the generic characteristics of our invention.

Many of these mixed ketones or aralkyl ketones are new materials and, in copending applications, we have so claimed them as new compounds. All of these aralkyl ketones can be made by a simple Friedel-Crafts synthesis. This can be illustrated inconnection with the preparation of diphenyl tridecyl ketone. Thirty-five grams of diphenyl are admixed with fifty grams of myristyl chloride and 100 cubic centimeters of carbon disul-ge fide. This mixture is cooled in an ice bath and then to it fifty grams of aluminum chloride are slowly added with stirring untiLthere is no further evolution of hydrochloric acid. Then dilute hydrochloric acid solution is added and the contents of the mixture steam-distilled. This removes disulflde. The ketone can then be decanted from the aqueous solution of aluminum chloride and crystallized from carbon tetrachloride.

All of the many aralkyl ketones described herein can be made by this general procedure as w be apparent to those skilled in the art.

Thus when we wish to make the correspond-,- ing anthracyl compound we start with anthracyl or fractions of anthracyl oil. When we wish to makethe corresponding furyl compound we start with furane.

In the appended claims we generically define radicals of the carbocyclic series and heterocyclic series, as closed ring radicals, and we generically define our alkyl radicals as those comprising the alkyl residue of a fatty .acid containing at least twelve carbon atoms. To illustrate, CrzHasCOOH is the formula of steariq' acid and CnHaa is the alkyl residue of said acid.

As stated, many of the ketones which we use are. new materials. In our copending applications we have described and claimed them as such. In our copending application Serial Number tinent lubricating oil. 17,873; filed April 23. 1935. we have claimed the Table 2 ren s Percent Cloud Pour 1 Viscosity added Mam point point index v "F. F.

.1 Flu lhe tadec lketone. 611 02 87.3 .5 r 38 10 511 62 87.3

. l Dibcnzoiuryl heptadecyl ketone 614 62 86. 7

.5 44 20' 638 01 74.8 1.0 do 524 01 78.6 .1 p-Bi henyl undecyl ketone 510 02 86.1 .5 o a2 20 mo 02 88.7 v 1 Phenyl undecyl keton 51B 02 86. l

. 1 p-Ohlorphenyl undecyl ketone 507 62 88. 5

32 2%. iii s2 et 0 an e a so e no..

.5 :--do... .?.?.-.-i.u nuf 32 20 617 61.5 83.1 l p-Methoxyphenyl undecyl ketone 617 01. 5 83. l

Control 42 20 518 62 86.2

mixed phenoxy phenyl alkyl ketones, in our co.- pending application Serial Number 17,874, filed April 23, 1935, we have claimed the mixed diphenyl alkyl ketones, in our copending application Serial Number 17,875, flied April 23, 1935, we have claimed the mixed furyl alkyl ketones, and in our application Serial Number 48,940, flied November 8, 1935 as a division of Serial Number 17,875, we have claimed the' benzofuryl alkyl ketones.

Having thus described our invention, what we claim is:

1. A lubricating oil comprising a mineral lubricating oil containing a small amount of the order of 0.1 to 1.0 percent, of a ketone having the structural formula R-g-R wherein R is a closed ring radical and R' is an alkyl radical having at least eleven carbon atoms.

2. A lubricating oil comprising a mineral lubricating oil containing a small amount, of the order of 0.1 to 1.0 percent, of a ketone having the struc tural formula wherein R is an aryl radical and R is an alkyl radical having at least eleven carbon atoms.

3. A lubricating oil comprising a mineral lubricating oil containing a small amount, of the order of 0.1 to 1.0 percent, of a ketone having the structural formula wherein R is an aryl radical and R is the alkyl residue of a fatty acid containing at least twelve carbon atoms. a

4. A lubricating oil comprising a mineral lubricating oil containing a small amount, of the order of 0.1 to 1.0 percent, 0! a ketone having the struc' tural formula wherein R is a radical choan from the group consisting, of phenyl, naphthyl, diphenyl, anthracyl, fury], fluoryl, thiophenyl, carbozoyl and dibenrofury], and R is an alkyl residue of a higher fatty acid containing at least twelv'e carbon atoms.

5. A lubricating oil comprising a mineral lubricating oil containing a small amount, of the order of 0.1 to 1.0 percent, of a ketone having the structural formula eleven carbon atoms.

"I. A lubricating oil comprising a mineral lubricating oil containing a small amount, of the order of 0.1 to 1.0 percent, of a mixed anthracyl alkyl ketone wherein the alkyl radical contains at least eleven carbon atoms.

8. The lubricating oil as in claim 6 wherein the ketone is a phenyl heptadecyl ketone.

9. The lubricating oil as in claim 7 wherein the ketone is an anthracyl heptadecyl ketone.

ANDERSON W. RALSTON. CARL W. CHRISTENSEN.