US2375516A

US2375516A - Lubricating oil

Info

Publication number: US2375516A
Application number: US523350A
Authority: US
Inventors: Jr Charles M Blair
Original assignee: Petrolite Corp
Current assignee: Baker Petrolite LLC
Priority date: 1944-02-21
Filing date: 1944-02-21
Publication date: 1945-05-08
Anticipated expiration: 1962-05-08

Description

UNITED STATES PATENT OFFICE LUBRIGATING on.

Charles M. Blair, Jr., Webster Groves, Mo., assignor to Petrolite Corporation, Ltd., Wilmington, Del., a corporation of Delaware No Drawing. Original application May 31, 1944,

Serial No. 489,238. Divided and this application February 2-1, 1944, Serial No. 523,350

Claims.

This application is a division of my pending application Serial No. 489,238, filed May 31, 1943,

and relates to an improved lubricating oil.

In my parent application for patent above recontaining less than 10 carbon atoms, such as the examples just recited. Because of their availability, relatively low cost, and marked reactivity, maleic anhydride, fumaric acid, and

ferred to I have disclosed a new type of polyester 5 citraconic anhydride, are especially useful, and products of high molecular weight-consisting of products obtained with these reactants will be polyesters of a resinous or semi-resinous charused below to illustrate the present invention. acter, that can be produced or prepared by an Alcohol reactants of class (2), above, which esterification reaction in which two different are suitable for use in preparing the present types of alcohols enter into combination with a 1 products, are the aliphatic and cycloaliphatic polybasic afi unsaturated, carboxylic acid or anmonohydric alcohols in which the ethylenic carhydride. The two types of alcohols consist of: hen atom nearest to the hydroxyl group is sepa- (a) Unsaturated aliphatic or cyclo-aliphatic rated from the carbon atom attached to said alcohols; and hydrcxyl group by at least three singly bonded (b) Saturated long chain aliphatic alcohols. carbon atoms. Such alcohols may contain one My present invention consists of a new comor more carbon-to-carbon double bonds, but all position composed of or comprising a relatively must satisfy the above requirement as to proxsmall amount of a condensation polymer of the imity to the hydroxyl group. When the alcohol kind described in my parent application above contains two or more. double bonds, these may referred to, andalubricating oil. be either conjugated or non-conjugated. My In my co-pending application Serial No, preferred class of unsaturated aliphatic and 489,237, filed May 31, 1943, there are described cycloaliphatic alcohols is composed of those havcertain new polymerized esters which are preins 8 Or mo e a bo t s a e s than 32 pared from unsaturated aliphatic or cyclecarbon atoms), and are exemplified by the folaliphatic alcohols and of! unsaturated, carboxylic lowing: Octene-3-ol-8, decene-1-ol-10, oleyl alcoacidsin approximately equimolal quantities. The hol, erucylalcohol, linoleyl alcohol, eicosene-lO- compounds used in the new composition of matol-l, p-vinyl cyclohexanol, citronellal, rhodinol, ter constituting my present invention may be abietyl alcohol, dihydroabietyl alcohol, crude looked upon as being derived from certain of the 'spefln oil alcohols, crude jojoba oil alcohols, and compounds of my said co-pending application the like. Serial No. 489,237. Specifically, they may be Alcohol reactants of class (3), above, which looked upon as being the most complete esters are suitable for preparing products of the presof polymerized acidic fractional esters derived by ent invention, are the saturated aliphatic or condensing a 'polybasic afi unsaturated acid (or alkylcycloaliphatic alcohols containing 8 or more anhydride) with approximately an equimolal carbonatoms and less than 32 carbon atoms, and quantity of an unsaturated aliphatic or cyclopreferably, the normal, primary alcohols conaliphatic alcohol, the alcohol used to form the e taining 8 or more carbon atoms. Examples of final esters being a saturated aliphatic alcohol. suitable alcohols are: 2-ethyl hexanol, S-ethyl- The compounds employed in my herein denon'anol-2, 7-ethyl-2-methylundecanol, 3,9-discribed new composition may, perhaps, be best 40 ethyltridecanol-fi, and the like. Examples of the described in terms of a method of preparation. most preferred alcohols are: n-octanol, n-deca- The required reactants are: n01, lauryl alcohol, myristic alcohol, cetyl alcohol, (1) A polybasic (including dibasic) as unsatstearyl alcohol, l-eicosanol, l-docosanol. Other urated, carboxylic acid or anhydride; useable alcohols include propylcyclohexanol, oc-

(2) An unsaturated aliphatic or cyclo-aliphatic 4r) tylcyclohexanol, decylcyclohexanol, etc. alcohol; and One method of preparingthe new products used (3) A saturated, long chain aliphatic or alkyl i the m osition constituting my present in- W phatic alcohol. vention, is to mix the three desired reactants The total mo s of v( d d u of the kinds described above in the desired proappr im t y equal the quivalents of (1) with portions, keeping these proportions within the respect to carboxylic acid g p Whi e the ratio limitspreviously specified. This mixture is then of moles of (2) to moles of (3'). y v ry from heated and stirred at a temperature in the range about 0.2 to 5.0. y from about 100 C. to about 250 C. for a period Examples of suitable reactants of class (1), of several hours. The-exact temperatures and above, are up unsaturated, carboxylic acids and heating periods employed will depend upon the anhydrides, such as: maleic acid, fumaric acid, specific reactants employed. as well-as upon the citraconic acid, aconitic acid, itaconic acid, mesuse to whichthe product is to be'put. During aconic acid, maleic anhydride, citraconic anhythe heating period the viscosity and average modride, itaconic anhydride, and the like. Thepre lecular weight of the product increase. For cerferred class of acids and anhydrides are those tain purposes, as for use as a pour point depressant for lubricating oils, a material 'of average molecular weight in the range of 1,200 t 5,000 may be desirable; so the reaction may be stopped 1 'Although the present compounds may be prepared by reacting at temperatures of from about 100 C. to about 250 0., I- generally prefer to carry out the reaction in the temperature range from about 150 C. to about 210 C. The reaction.

involved is notcompletely understood, but appears to involve both esteriflcation and addition of the unsaturated constituents. Conventional esteriflcation catalysts such as sulfuric acid, beta camphor sulfonic acid, para toluene sulfonic acid,

hydrochloric acid, etc., may be employed. Alsoolefine condensation catalysts such as sulfuric acid, benzoyl peroxide, hydrogen peroxide, etc., may also be employed. However, none of these catalysts is necessary for preparation of the compounds,'as appreciable reaction and polymerization may, be obtained simply by heating the reactants at the proper temperature for a period of several hours. To obtain the highest rate of reaction and polymerization, I have found that certain conditions of reaction are particularly desirable. The-discovery of these reaction conditions actually constitutes an invention within an invention, in that it makes possible the preparation of the most desirable products with the minimum of time and effort. In particular, I have found that reaction is promoted by passing through'the mixture, during reaction, a slow stream of oxygen or oxygencontainlng gas, such as air. The beneficial effect of this operation appears to arise directly from the oxygen in the gas used. If nitrogen, hydrogen, or other inert oxygen-free gas is passed through. the reactionmixture, the rate of reaction appears not to be appreciably increased.

J Whenoxygen or an oxygen-containing gas is passed through the reaction mixture, temperature may be maintained at any point over a rather wide limit; but as remarked above, I obtain best results using a temperature of reaction in the range from about 150 C. to about 210. With reactants that boil within the temperature range, it is desirable that the materials be reacted under pressure, or that the reaction be conducted for a while at a lower temperature until esterification of the reactants has produced an intermediate of higher boiling point. The temperature may then be gradually increased to a higher value, in order to increase the rate of the reaction At extremely high temperatures, however, de-

composition and oxidation of the product may occur to an-objectionable degree.

The time of reaction will depend, of course;

upon the reactants themselves and upon the temperature at which the reaction is carried 1 out, as well as upon the use to which the material j is to be put. Ordinarily this time of reaction will 1 be several hours, and perhaps as much as 48-72 hours. To prepare pour point depressants'I-have found that a typical set of conditions may involve 1 a reaction temperature of about 200 C. and a 1 reaction time of about 24 hours.

is to be used as a viscosity index improver, a

; materialof higher molecular weight is required example,

45 hours.

If the product .75 iodine No. (Wiis) of 16.9.

scribed in terms of their .preparation from three. 0 classes of reactants, it should be pointed out that the reaction may be carried out in a series 'of steps. The first step might involve reacting only two, of the reactants; and this product then may be further reacted with the third material. For in preparing a pour point depressant from reactants such as maleic anhydride, abietyl alcohol, and stearyl alcohol, the maleic anhydride and abietyl alcohol may be condensed first to give a semiresinous polmer ester of the type disclosed s in my aforementioned co-pending application Serial No. 489,237. This product may then be mixed with stearyl alcohol about equivalent to the free carboxylic acid content of the polymer,

.and further heated and esterifled to complete es- 2 'terification. Ordinarily, however, it is more convenient and simpler to. combine all of the reactants at once to prepare the desired compound.

The following examples will serve to illustrate the methods of preparation which may be em- 25 played. The parts are by weight Example 1 17 parts of maleic anhydride, 45 parts of commercial oleyl alcohol (iodine No. 67) and 45 gms.

of commercial stearyl alcohol were heated and room temperature. It had an average'molecular weight, as determined in benzol, of 1820. It was clearly soluble in lubricating oil. The product had a finite, but low, acid value. 1

Example 2 v 14 parts of maleic anhydride and parts of commercial oleyl alcohol were heated and stirred in a flask attached to a reflux condenser. The temperature was held at 200 C. to 225 C. for 11 The mixture was then cooled and to it were added 26 parts of stearyl alcohol. A water trap was placed between the flask and condenser and heating was resumed. The temperature was raised to 240 C. and held for three 50 hours, after which time, water evolution had 0 ceased.

The product was a red, opaque syrup at room temperature. It apparently contained some unreacted stearyl alcohol. Its average molecular weight in benzol was 945,

Example .3 14.0 parts of maleic anhyride, 37.5 parts of commercial oleyl alcohol and 37.5 parts of comso mercial stearyl alcohol were placed in a glass vessel equipped with stirrer, gas inlet tube, water trap, and condenser. The mixture was heated while stirring t 175 C. and held for two hours. After that time, a slow stream of air was introduced through the, gas inlet. tube under the surwater were collected in the trap. Some water was probably lost in the air stream. I v

The product was a light red, transparent,

waxyfsolid at room temperature. It was clear-' ly soluble in lubricating oil. The product had an Example 4 14 parts of maleic anhydride, 37.5 parts of commercial oleyl alcohol and 25 parts of com- 12.5 parts of commercial lauryl alcohol, 18.8 parts of commercial stearyl alcohol, 37.5 parts of commercial oleyl alcohol, and 14.0 parts of maleic anhydride were reacted, using the apparatus and procedure of Example 3. I

The product was a viscous red oil having an iodine No. (Wijs) of 24.8.

Example 6 16.5 parts of fumaric acid were substituted for themaleic anhydride of Example 5. The product was substantially identical with that of Example 5.

Example 7 20 parts of dihydroabietyl alcohol, 29 parts of commercial stearyl alcohol, 20 parts of commercial lauryl alcohol and 14 parts of maleic anhydride were reacted, using the apparatus and procedure of Example 3.

The product was a viscous red oil.

Example 8 16.5 parts of fumaric acid were substituted for the maleic anhydride of Example '7. v

Example 9 Linoleyl alcohol was substituted for the oleyl alcohol in Example 5.

Example 10 16 parts of citraconic anhydride were substituted for the maleic anhydride of Example 5, and heating and stirring in the presence. of an air stream and at a temperature of 190,-195 C. was continued for 36 hours.

It will be noted that in some of the above examples mixtures of saturated alcohol have been employed instead of a single species of saturated aliphatic alcohol. The use of such mixtures is considered the equivalent of using a single species of alcohol. If desired, mixtures of unsaturated alcohol may also be employed, instead of one unsaturated alcohol; and the same analogous condition applies to the use of the ccfl unsaturated polycarboxylic acid,

Although it has been stated that the presen compounds are made from a mixture of up unsaturated polycarboxylic acid and certain saturated aliphatic alcohols and certain unsaturated aliphatic or alkylcycloaliphatic alcohols, in which the modes of alcohol are equivalent to the number of carboxylic acid groups present, it is not absolutely necessary that the hydroxyl and carboxyl groups be exactly equivalent. In fact, in some instances, it may be desirable to use a small excess of unsaturated acid over that required to esterify all of the alcoholic hydroxyl groups. When this is done, the final product may mercial lauryl alcohol were heated and stirred of such reagent may be neutralized with alkalies or. amines or heavy metal oxides to yield polymeric salts which have useful properties in addition to those of the polymers alone. For example, salts such as the sodium salts may be used as sludge dispersers or detergents in lubricating oils. to inhibit the oxidation of lubricating oils. By theproper balance of carboxyl groups to molecular weight, it is possible to prepare poly-functional lubricating oil additives, i. e., materials which have more than one function; for example, they may be both pour point depressants and antioxidants. In general, however, it is desirable that the number of residual carboxyls in the polymer product not be sufficient to give the product a neutralization equivalent of less than about 3,000.

Th nature of the reaction which results in the formation of the present products is not clearly understood, but it is believed that the 043 unsaturated polycarboxylic acid esterifies the hydroxyl groups of the alcohols and also adds, by proton transfer, to th unsaturated alcohol at an ethylenic carbon atom of same, or

at a carbon atom near the double bond. The

unsaturated alcohol undergoing condensation with a molecule of ethylenic acid is probably esterified by a different'molecule of ethylenic acid; so a type of linear polyester is formed. The saturated alcohol employed in the reaction mixture is also esterified by carboxyl groups of the polybasic acid; the final product thus being a complicated type of polyester. When the double bond of the unsaturated alcohol is nearer to the hydroxyl group than allowed by the conditions previously given, good yields of the desired products do not seem to be obtainable. It is believed that this may result from the formation of stable cyclic inner esters, rather than linear polyesters. This postulated reaction may be exemplified, in part, by the reaction between oleyl alcohol, stearyl alcohol and maleic acid. With these reactants it is believed that the product may b a polymerized, substituted, succinic acid ester, or possibly, a polymerized, substituted, fumaric acid ester. Conceivable reactions are as follows:

' mHatOH nCmHmOH nolmo.

0 0 1sHa1 In the above formulae, no attempt has been made to define the carbon atom of the oleyl alcohol residue to which the maleic acid residue becomes attached. Probably, a carbon atom near the double bond, or a double bonded carbon atom itself, is involved. It becomes impractical to attempt to show in detail all of the conceivable reactions of the above types which may occur.

The present products will be referred to herein and in the claims as condensation polymers, this term being used in the sense as defined in-Gilman Organic Chemistry, 2nd edition, page 702. However, as pointed out above, their formation is believed also to involve addition of one oleflnic molecule to another olefinic have a small acid number; and for certain uses,

moleculathus, in the strictest sense, the result-.

ant compounds may be looked upon as being both condensation and addition polymers.

Certain amine salts may be used I and, in fact, is an objectionable the preparation reactions are carried out, as depounds contemplated have molecular weights larger than the simple monomeric ester formed by esterification of the ethylenic polycarboxy acid with the alcohol reactants. As prepared, the crude products, in many instances, undoubt edly contain some monomeric ester as impurity. but such monomer is not contemplated herein,=

scribed, the amount of monomer present is us- 1 f ually quite negligible.

Because of the uncertainty as to the mecha- 1 nism of the reaction, as well as to the large 1 variety of possible reactions which could be postulated, no eifort will be made to describe j the present products in terms of conventional 5 chemical formula.

My present invention consists in using prod- 1 nets of the kind previously described, to lower the pour point or increase the viscosity or vis- 1 cosity index of lubricating oils, or consists of 1 a new composition of matter, composed of a rel- .atively small amount of such a condensation Qpolymer and a lubricating oil. are examples of my new composition.

Example I 0.25 gm. of the product of Example l was dissolved in 100 ml. of a 20 S. A. E. viscosity Gulf Coast lubricating oil- This mixture had a pour point of 25 F., in comparison with a pour point of 20 for the original oil.

Example 11 The product of Example 3 was dissolved in varying proportions in the lubricating oil of Example I. Pour points of the various mixtures are shown in the table below:

blends are shown below:

Concentra tion of 5232 prodliiilct in on Per cent F.

+20 it M2 -20 30 K; -30

Example III diluent. When The following 1 to an aliphatic alc saturated alcohol densation polyme 1 taining at least 8 I Example IV The product of Example 3 Wasadded in the amount of 2% to 9. Gulf Coast lubricating oil having a viscosity index of 55, The resulting blend was clear and light in color and was found to have a viscosity index of 85.

In general,the percentage of the present compounds which will be required to depress the pour point of oils sufiiciently to be of practical interest, will vary from as little as 0.025% to as much as 1%,'or even 2%. The amounts required to increase the viscosity index by appreciable amounts will vary from as little as 0.25% to as much as 5%, or even more, depending upon the compound and the character of the oil to which it is added.

Thus, one object of my invention is the preparation of improved lubricating oils or lubricating oil compositions a 0.025% or more than about 5% of the herein described compounds to lubricating oils which are used in an internal combustion engine or as lubricants for moving machinery.

The present products are in general unsaturated, as reaction does not remove all of the olefinic groups of the unsaturated reactants. If desired, these products may be hydrogenated to remove olefinic double bonds. Other chemical reactions may also be employed to modify the properties of the polymers. For example, they may be treated with sulfur at elevated temperatures to form sulfurizecl polymers; or they may be treated with chlorine to remove the unsaturation and otherwise modify their properties; or they may be treated with sulfur chloride to give products of somewhat different properties. The introduction of sulfur into the present compounds does not appear to change their pour point depressant properties, while at the same time it improves their resistance to oxidation and also imparts to them film strength improving properties.

Previous reference has been made to the fact that one may employ either aliphatic or cycloaliphatic alcohols of the kind described. Although, ordinarily speakin aliphatic alcohols and alkylcycloaliphatic alcohols are not necessarily the obvious equivalent of each other, yet in light of what has been said above, it is obvious that they are the functional equivalent in the present instance. In the hereto appended claims reference ohol is intended to include the alkylcycloaliphatic alcohols. Reference to a straight chain alcohol must, of course, contemplate only the acyclic type.

Having thus described my invention, what I claim as new and desire to secure by Letters Patentis:

l. A composition of matter, comprising a lubricating oil and a relativelysmallamount of a (:13 unsaturated polybasic carturated aliphatic alcohol conr;' said saturated alcohol conand not more than 32 carbon having less than 10 carbon atoms boxylic acid-unsa atoms; said acid and said unsaturated alcohol containing less than i 32 carbon atoms the hydroxyl gr ent in an amo and having at least 3 intervening tween the carbon atom to which oup was attached and the nearest ethylenic carbon atom; said polymer being presunt varying from 0.025% to about carbon atoms be it is admixed.

2. A composition of brlcating oil and a re] matter, comprising a 111- atively small amount of a dding not less than abouton the basis of the lubricating oil with which saturated alcohol-up unsaturated polybasic carboxylic acid-unsaturated aliphatic alcoholcondensation polymer; said saturated alcohol containing at least 8 and not more than 32 carbon atoms; said acid having less than 10 carbon atoms and said unsaturated alcohol containing at least 8 carbon atoms and having at least 3 intervening carbon atoms between the carbon atom to which the hydroxyl group was attached and the-nearest ethylenic carbon atom; said polymer being present in an amount varying from 0.025% to about 5% n the basis of the lubricating-oil with which it is admixed.

3. A composition of matter, comprising a, lubricating oil-anda relatively small amount of a straight chain saturated alcohol-ac unsaturated polybasic carboxylic acid-unsaturated aliphatic alcohol condensation polymer; said saturated alcohol containing at least 8 and not more than 32 carbon atoms; said acid having less than 10 carbon atoms and said unsaturated alcohol containing at least 8 carbon atoms and having at least 3 intervening carbon atoms between the carbon atom to which the hydroxyl group was attached and the nearest ethylenic carbon atom; said polymer being present in an amount varying from 0.025% to about 5%, on the basis of the lubricating oil with which it is admixed. I

4. Acomposition of matter, comprising a 111-- bricating oil and a relatively small amount of a straight chain saturated aICOhOI-afi unsaturated polybasic carboxylic acid-unsaturated straight chain aliphatic alcohol condensation polymer; said saturated alcohol containing at least 8 and not more than'32 carbon atoms; said acid having less than 10 carbon atoms and said unsaturated alcohol containing at least 8 carbon atoms and having at least 3 intervening carbon atoms between the carbon atom to which the hydroxyl groupwas attached and the nearest ethylenic carbon atom; said polymer being present in an amount varying from 0.025% to about 5%, on the basis ofv the lubricating oil with which it is admixed. i

5. A composition or matter, comprising a lubricating oil and a relatively small amount of a straight chain saturated alcohol-mp monoethylenic polybasic carboxylic acid-unsaturated straight chain aliphatic alcohol condensation polymer; said saturated alcohol containing at least 8 and not more than 32 carbon atoms; said acid having less than 10 carbon. atoms and said unsaturated alcohol containing at least 8 carbon atoms and having at least 3 intervening carbon atoms between the carbon atom to which the hydroxyl group was attached and the nearest ethylenic carbon atom; said polymer being present in an amount varying from 0.025% to about 5%, on the basis oi the lubricating oil with which it is admixed.

6. A composition of matter, comprising a lubricating oil and a relatively small amount or a straight chain saturated alcoholp monoethylenic dibasic carboxylic acid-unsaturated straight chain aliphatic alcohol condensation polymer; said saturated alcohol containing at least 8 and not more than 32 carbon atoms; said acid having less than 10 carbon atoms and said unsaturated alcohol containing at least 8 carbon atoms and having at least 3intervening carbon atoms between the carbon atoms to which thehydroxyl group was attached and the nearest ethylenic carbon atom; said polymer being present in an amount varying from 0.025% to about 5%, on the least 8 and not more than 32 carbon atoms; said acid having less than 10 carbon atoms and said unsaturated alcohol containing at least 8 carbon atoms and having at least 3 intervening carbon atoms between the carbon atom to which the hydroxyl group was attached and the nearest ethylenic carbon atom; said polymer being present in an amount varying from 0.025% to about 5%, on the basis of the lubricating oil with which it is admixed.

8. A composition of matter, comprising a lubricating oil and a relatively small amount or a straight chain saturated alcohol-maleic acid monoethylenic straight chain aliphatic alcohol condensation polymer; said saturated alcohol containing at least 12 and not over 22 carbon atoms, and said unsaturated alcohol containing at least 12 and not over 22 carbon atoms and having atleast 3 intervening carbon atoms between the carbon atom to which the hydroxyl group is attached and the nearest ethylenic carbon atom;

said polymer being present in an amount varying from 0.025% to about 5%, on the basis or the lubricating oil with which it is admixed.

9. A composition of matter, comprising a lubricating oil and a relatively small amount of a straight chain saturated alcohol-fumaric acid monoethylenic straight chain aliphatic alcohol condensation polymer; said saturated alcohol containing at least 12 and not over 22 carbon atoms, and said unsaturated alcohol containing at least 12 and not over 22 carbon atoms and having at least 12 and not over 22 carbon atoms and having at least 3 intervening carbon atoms between the carbon atom to which the hydroxyl group is attached and the nearer ethylenic carbon atom; said polymer being present in an amount varying from 0.025% to about 5%, on the basis of the lubricating oil with which it is admixed.

CHARLES M. ma.