GB1578667A

GB1578667A - Hydrolysed ethylene copolymer/ethylenically unsaturated nitrogen reactant adducts useful as multifunctional vi improvers for lubricating oil

Info

Publication number: GB1578667A
Application number: GB6947/77A
Authority: GB
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1976-03-19
Filing date: 1977-02-18
Publication date: 1980-11-05
Also published as: CA1099841A; FR2351134A1; DE2711960A1; FR2351134B1; JPS6139322B2; JPS52112689A; DE2711960C2

Description

(54) HYDROLYSED ETHYLENE COPOLYMER/ ETHYLENICALLY UNSATURATED NITROGEN REACTANT ADDUCTS USEFUL AS MULTIFUNCTIONAL V.I. IMPROVERS FOR LUBRICATING OILS (71) We, EXXON RESEARCH AND ENGINEERING COMPANY, a Corporation duly organised and existing under the laws of the State of Delaware.

United States of America, of Linden, New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to the preparation of nitrogen-containing polymeric adducts, the polymeric adducts and to lubricating oil compositions containing said adducts as multifunctional additives, especially those adducts derived from copolymers which have a substantially saturated hydrocarbon backbone-chain with side-chain unsaturation and unsaturated, polar, nitrogen-containing organic reactants.

The literature abounds with discussions of multifunctional viscosity index (V.I.) improvers containing nitrogen to enhance their dispersant activity. Included therein are polymeric nitrile-containing substances as lubricating oil additives with detergent-dispersant and other properties.

The incorporation of any nitrile moiety in said V.I.-improving polymeric substances according to the prior art was generally by conventional means including copolymerization of one or more olefins with a nitrile containing monomer (U.S. Patent 3,445,387), free radical grafting as by hydroperoxidation of an ethylene copolymer directly with a polar vinylidene monomer, such as acrylonitrile (see U.S. Patent 3,404,091), and reacting a nitrile-containing compound with a reactive copolymer such as is obtained from a free radical grafting of maleic anhydride to polyisobutylene (see U.S. Patent 3,448,049).

These processes which utilize free radicals, either generated by shearing stresses during mastication or by heating organic compounds, such as peroxides, to prepare a polymeric adduct have certain disadvantages, including irreversible crosslinking of the copolymer and homopolymerization of monomeric components. One of such disadvantages is shown in U.S. Patent No. 3,236,917 which discloses adducts prepared by heating a mixture of ethylene/propylene copolymer and maleic anhydride in the presence of an organic peroxide which initiates the addition reaction by the generation of free radicals. Unfortunately, among other reactions generated therein, a molecule of maleic anhydride grafts into two copolymer chains thereby irreversibly crosslinking the copolymer and markedly decreasing its solubility in oil. One approach to overcoming this disadvantage is shown in U.S. Patent 3,378,492 which teaches lubricating oil compositions which comprise a major proportion of a lubricating oil and a minor, but V.1. improving proportion of a reaction product of an unsaturated hydrocarbon polymeric compound, e.g. polybutadiene, with an unsaturated, polar, nitrogen-containing organic compound, e.g. acrylonitrile, which is grafted onto said polymeric compound by a free radical initiated reaction.

Another approach to preparing an oil-soluble nitrogeneous ashless dispersant involves reacting a polyolefin with acrylonitrile and chlorine or bromine at elevated temperatures, followed by reacting the product with enough aliphatic amine to replace the halogen atoms and thereafter with maleic anhydride and finally with an aliphatic amine or polyamine (see U.S. Patent 3,914,203).

It has now been found that multifunctional V.I. improvers of enhanced dispersancy can be obtained by thermally incorporating a C3-C24 ethylenically unsaturated nitrogen-containing reactant onto a carbon-to-carbon double bond which is pendant from a substantially saturated hydrocarbon polymer backbone by a thermal ("ene") addition, The ene reaction, as reported in the literature, has been defined as the indirect substituting addition of a compound with a double bond (enophile) to an olefin with an allylic hydrogen (ene) and involves allylic shift of one double bond, transfer of the allylic hydrogen to the enophile and bonding between the two unsaturated termini. (See Hoffman, "The Ene Reaction", Angew Chemie, International Edition, Vol. 8, 556-578 (1969)).

The ene adducts are readily distinguished from other function-alized adducts, such as epoxide functionalized adducts reported in U.S. Patent 3,842,010, since ene adducts maintain a site of olefinic unsaturation and are characterized by an olefin to olefin i.e. carbon to carbon bond formation.

The present invention therefore provides a method for preparing a hydrolysis product of an oil-soluble ene adduct, said adduct having a polar group and containing 0.02 to 0.5 wt.% nitrogen as pendant nitrogen-containing groups and having a number average molecular weight ranging from 10,000 to 200,000, which comprises mixing a copolymer which has a substantially saturated hydrocarbon polymer backbone having pendant carbon-to-carbon double bonds, said copolymer comprising 30 to 85 mole % ethylene, 15 to 70 mole% C3 to C,0 alphamonoolefin, and 0.5 to 20 mole % C5 to C24 non-conjugated diolefin which furnishes said carbon-to-carbon double bonds, with a C3 to C24 ethylenicallyunsaturated nitrogen-containing reactant having an electron withdrawing group in such proximity to its unsaturation whereby its olefinic bond is activated by at least one electron-attracting group, heating said admixture under a substantially oxygen4?ee atmosphere at a temperature in the range of from 1000C to 2500C for a time sufficient to thermally add said nitrogen-containing reactant at said carbonto-carbon double bonds of said copolymer and then hydrolyzing said ene adduct The invention also provides hydrolyzed oil-soluble ene adducts obtained by the above process and lubricating compositions containing them.

The adducts of the invention are suited for lubricating oil applications when they possess sufficient oil-solubility, i.e. at least 10 wt % at 200C based on the total weight of the lubricating oil composition; however, when oil-insoluble, these adducts of the invention have application as oil-resistant rubbers in seals and gaskets, such as for automobile automatic transmissions.

The lubricating oil compositions of this invention comprise a major proportion of a lubricating oil and a minor, but V.I.-improving proportion of said adducts.

Copolymers of ethylene, at least one C3 to C50 alpha-monoolefin, and at least one non-conjugated diene prepared by means of Ziegler-Natta catalysis are well known. These copolymers have a substantially saturated hydrocarbon backbone chain which causes the copolymer to be relatively inert to ozone attack and oxidative degration and side chain unsaturation available for adduct formation by means of the ene addition.

Propylene is normally selected as the C3-C50 alpha-monoolefin in preparing such copolymers because of its availability and for reasons of economics. Other alpha-monoolefins, such a l-butene, l-pentene, I-hexene, l-decene, l-dodecene, and l-hexadecene, can be selected in place of or in addition to propylene in preparing such copolymers. The term EPDM as used herein refers to the copolymers of ethylene, propylene, and at least one non-conjugated diene useful for this invention; said diene is a C5-Cu, preferably C6-C34, diene.

An especially preferred class of EPDM is that in which the non-conjugated diene is monoreactive. Monoreactive non-conjugated dienes have one double bond which readily enters the copolymerization reaction with the ethylene and the C3-C50 alpha-monoolefin, and a second double bond which does not, to any appreciable extent, i.e. less than about 20 percent, enter the copolymerization reaction. Copolymers of this class have maximum pendant group unsaturation for a given diene content, which unsaturation is available for adduct formation.

Monoreactive non-conjugated dienes which can be selected for preparing the preferred class of oil-soluble EPDM copolymers include linear aliphatic dienes of at least six carbon atoms which have one terminal double bond and one internal double bond, e.g. l,4-hexadiene, and cyclic dienes wherein one or both of the carbon-to-carbon double bonds are part of a carbocyclic ring, e.g. 5 - ethylidene 2 - norbornene.

Other suitable nonconjugated dienes include straight chain acyclic dienes such as 1,5 - heptadiene, 1,6 - octadiene; branched chain acyclic dienes such as 5 methyl - 1,4 - hexadiene, single ring alicyclic dienes such as 1,4 - cyclohexadiene, multi-single ring alicyclic dienes and multi-ring alicyclic fused and bridged ring dienes such as dicyclopentadiene, 5 - methylene - 2- norbornene, 5 methylene - 6 - methyl - 2 - norbornene, 5 - methylene - 6,6 - dimethyl - 2 norbornene, 5 - propenyl - 2 - norbornene, 5 - (3 - cyclopentenyl) - 2 norbornene and 5 - cyclohexylidene - 2 - norbornene.

The copolymers which are to be reacted with the ethyienicaiiy unsaturated nitrogen-containing reactant, e.g. the nitrile monomers, to form the ene adducts, comprise 30 to 85 mole /n ethylene; 15 to 70 mole Vn of the C3-C50, e.g. C3 to C,, optimally C3 to Cs, alpha-monoolefin, and 0.5 to 20 mole % of the diene. Preferred are polymers consisting of ethylene, said higher alpha-olefin and said diene containing 40 to 70 mole % ethylene and 2 to 15 mole % dienes, the remainder being propylene. On a weight basis usually at least 2 or 3 wt % of the polymer will be the non-conjugated diene. Mixtures of monoolefins and/or mixtures of nonconjugated dienes can be used.

In general, the catalyst compositions used to prepare these copolymers comprise a principal catalyst consisting of a transition metal compound from Groups IVb, Vb and VIb of the Periodic Table of the Elements, particularly compounds of titanium and vanadium, e.g. VOCl3, and organometallic reducing compounds from Groups IIa, IIb and IIIa, particularly organo-aluminium compounds, e.g. (C2H5)3 Al2CI3, which are designated as cocatalysts. Examples of suitable catalysts and preferred reaction conditions are shown in U.S. Patent 3,551,336.

The copolymers have molecular weights (Mn) of 10,000 to 200,000; and usually about 20,000 to 100,000. In general, polymers having a narrow range of molecular weight, as determined by the ratio of weight average molecular weight (3.v) to number average molecular weight (Mn) are preferred. Polymers having a MdM, of less than 10, preferably less than 7, and most preferably 4 or less are most desirable. Polymers in this range may be obtained by a choice of synthesis conditions, such as choice of principal catalyst and cocatalyst combination, addition of hydrogen during the synthesis, or post synthesis treatment, such as extrusion at elevated temperatures and under high shear through small orifices.

While these copolymers are essentially amorphous in character by superficial inspection, they may contain up to 25 percent by weight of crystalline segments as determined by X-ray or differential scanning calorimetry.

Broadly, the ethylenically unsaturated nitrogen-containing reactants comtemplated by the present invention generally consist of carbon, hydrogen and nitrogen and may also contain oxygen. These nitrogen-containing reactants may also contain substituent groups such as keto, hydroxyl, ether, mercapto, sulfide, sulfoxide, sulfonyl, etc. These nitrogen-containing reactants contain 3 to 24 carbon atoms and must contain an electron withdrawing group in such proximity to the unsaturation whereby the olefinic bond is activated by at least one electronattracting group. The terms "electron-withdrawing and "electron-attracting" are used as synonyms herein.

Thus, in its broadest form, the ethylenically unsaturated nitrogen-containing reactant may be selected from a broad group of tetra-substituted olefins. Thus, the reactant can be represented by the general formula:

wherein Rl, R2, R3 and R4 may be the same or different at least one being an electron-attracting group, N represents a nitrogen moiety and x ranges from 1 to 50. Thus, the only restriction placed upon said groups is that the final reactant contains at least one nitrogen atom. In this manner, the ethylenically unsaturated nitrogen-containing reactant may be represented by the above general formula where R1, R2, R3 and R4 are independently selected from the groups consisting of hydrogen and Cl to C30 straight and branched chain alkyl, arylalkyl, cycloalkyl, alkenyl, arylalkenyl and cycloalkenyl moieties and/or one or more reactive groups of the class consisting of alkyl unsaturation, cyano, carboxyl, epoxide, thiol, carbonyl, isocyanate, thionyl, amido, hydroxy, imino, acylhalide, halo, lactamo, lactono, dicarboxylic acid anhydride, thiolic anhydride, thionic anhydride, dithionic anhydride, disubstituted amino, trisubstituted amino, ureido, isourea and dicarboxylamic acid anhydride or one-half of cyclic dicarboxylic acid anhydrides as in maleic anhydride or one-half of cyclic thionic anhydride or onehalf of cyclic dithionic anhydride or one-half of cyclic dicarboxylic amic acid anhydride or one-half of cyclic N Cm 18 hydrocarbyl imides such as N dodecylmaleimide and pyrrotidine.

The term "N", as used in the above formula, is designed to indicate that the nitrogen-containing group or moiety is present in one or more of the "R" groups and/or several nitrogen-containing groups may be present in the same "R" group; however, there must be at least one N-containing moiety in the reactant with a preferred range of X of 1 to 10, more preferably 1 to 5. Thus, in acrylonitrile, R1, R2 and R3 are hydrogen atoms while X=l; that is, R4 is a "CN" group. Examples of these groups include alpha-chloroacrylonitrile; N,N - dibutyl acrylamide; acrylamide; N - t - octyl acrylamide; thioacrylamide; N - a - octylacrylamide; N- acryloyl - morphiline, thioacrylamide; ammonium acrylate; vinylidene cyanide; N,N - dimethylamino ethyl methacrylate; t- dodecylaminoethyl acrylate; N- octyl maleimide; N- vinyl - 5-methyl- 2 - pyrrolidone; pyrrolidinyloctyl vinyl sulfide; N - vinylethyleneurea; N - vinyl - 1,2 propyleneurea; N- vinylcarbazole; butanamido - decyl vinyl ether; acetamidooctadecyl vinyl ether; ureidoethyl vinyl ether; and 2 - vinyl - 5 methylpyridine; and tetracyanoethylene. One preferred type of nitrogen-containing reactants, i.e. unsaturated, polar nitrogen-containing enophiles, to which the present invention is directed, has the formula

wherein X is oxygen, or an NR group, n is a whole number from 1 to 5, preferably 2 to 5, R and R' are either hydrogen or a Cl to C4 alkyl group, R" and R"' are each Cl to Cl2, preferably Cl to C4, hydrocarbyl groups, e.g. alkyl groups. The various R groups may be the same or different.

Specific examples of compounds which may be employed as the preferred nitrogen-containing emophiles include dimethylaminoethyl methacrylate, diethylamino-propyl methacrylamide, di(isobutyl) aminoethyl methacrylate, methylisobutyl-aminopropyl acrylate, 4-vinyl pyridine, ethylene imine, N-vinyl pyrrolidone etc. Mixtures of various nitrogen-containing enophiles may be used.

Another preferred type of nitrogen-containing enophiles, i.e. unsaturated, polar, nitrogen-containing organic compounds, to which the present invention is particularly directed are nitriles having the formula:

wherein R is a hydrogen atom or a lower alkyl, e.g., methyl, ethyl, and the like, X is a hydrogen atom, a halogen atom, a cyano or a lower alkyl group, e.g. methyl, ethyl, propyl, butyl and the like. Examples of nitrile monomers which are contemplated by the aforedescribed structure include, acrylonitrile, methacrylonitrile, alphabromoacrylonitrile, alpha-chloroacrylonitrile, vinylidene cyanide, allyl cyanide, and the like.

The thermal ene addition of the ethylenically unsaturated nitrogen-containing reactant to the saturated ethylene backbone copolymer having pendant group carbon-to-carbon unsaturation is theorized to occur by the following reaction (using a copolymer of ethylene, propylene and 5 - ethylidene - 2 - norbornene and acrylonitrile as the thermal ene reactants) equation:

Polymer Bockbone 3 + H2HC=C-CN CH3 heot + ' CH3 CH3 I I /H2c1/CFIc/NCH 2+; CF' CN HC1 CH3 A molecule of acrylonitrile adds to the polymer at the site of pendant group unsaturation and involves allylic shift of one double bond, transfer of the allylic hydrogen to the acrylonitrile and thus bonding between the two unsaturated groups. It is understood that the exocyclic olefin, i.e. of the 5 - ethylidine - 2 norbornene, can only shift away from the bridgehead to the C5-C6 position. A shift of the double bond toward the bridgehead, i.e. C4-C5, is forbidden by Bredt's rule.

Ene adducts of this invention can be prepared by any process which intimately mixes the nitrogen-containing reactant or reactants with the copolymer and concurrently or subsequently heats the mixture to a temperature where thermal ene addition occurs without appreciable generation of free radicals. Reaction temperatures will be at least 1000C to obtain adduct formation at acceptable rates and less than 250"C to avoid any significant copolymer breakdown and/or homopolymerization of the ethylenically unsaturated nitrogen-containing reactant. Although preferred temperature ranges will vary with the particular copolymer and reactant and can readily be determined by one skilled in the art; optimally, it ranges from 1500C to 2250C, e.g. 1700C. Mixing of the reactant and copolymer can be by blending together neat or with a solvent in an internal mixer or extruder. Preferably the blending and subsequent "ene" reaction is carried out in a hydrocarbon solvent at elevated temperatures.

Thus in the preferred process, the ethylene backbone copolymer is dissolved in a hot solvent such as benzene, heptane, cyclohexane, optimally, mineral oil, and the reactant e.g. acrylonitrile, is introduced into the solution. The solution is heated at from 1500C to 2250C for several hours in the substantial absence of air or oxygen and, preferably under a blanket of inert gas, e.g., nitrogen. Modest elevated pressures of the inert gas can be used to maintain the reactant in solution.

Should a solvent other than mineral oil be used, diluent oil may be added and the light solvent and unreacted ethylenically unsaturated nitrogen-containing reactant are then removed. The remaining residue is a solution of ene adduct in diluent oil.

particularly useful as an additive package for lubricating oils.

For said reactants which readily homopolymerize under free radical conditions, the following method may be utilized in order to moderate the generation of free radicals: Dissolve said copolymer, said reactant and up to about 1 wt % (based on weight of said reactant) of a free radical scavenger (inhibitor such as hydroquinone to eliminate homopolymerization of said reactant) in a hot solvent, such as mineral oil, heptane, benzene, or cyclohexane; and, heat to reaction temperatures, e.g.

from 150"C to 2250C for several hours in the substantial absence of oxygen (flushed several times with nitrogen prior to starting the reaction) and under a blanket of modestly pressurized inert gas, such as nitrogen. If the solvent is not oil, then diluent oil may be added and the light solvent and unreacted nitrile monomer can be readily removed. The remaining residue is a mixture of ene adduct of the ethylene copolymer and said reactant in diluent oil.

The proportions in which the above-described nitrogen-containing reactants are to be used may range widely according to the ability of said ethylene copolymer and said nitrogen-containing reactant to react with each other, but normally should range from 0.1 to 400, preferably 10 to 200 parts by weight of said nitrogencontaining reactant to 100 parts by weight of said ethylene backbone copolymer.

Adducts containing 0.02 to 0.50 % by weight nitrogen (all of said % by weight nitrogen values in this specification determined by the Kjeldahl method have sufficient dispersancy sites for additive applications, to enhance lubricating oil performance. To achieve a desired degree of adduct formation within a resonable time, high concentrations of reactants (usually a substantial excess of nitrogencontaining reactant) are helpful. One will generally select an ethylene copolymer having about thrice the amount of pendant group unsaturation as is stoichiometrically (based on nitrogen equivalent) required for the desired amount of nitrogen incorporation. Similarly, about two to five times as much nitrogencontaining reactant (based on equivalent nitrogen) is added as is desired in the oilsoluble adduct. Conversion of 20 to 50 % of the nitrogen containing reactant will result in copolymer adduct having the desired composition. For example, if one desires to obtain an adduct derived from an ethylene/propylene/5 - ethylidene 2 - norbornene copolymer having 0.15 wt % nitrogen content, he could conveniently mix said copolymer having 0.08 moles pendant group unsaturation per kilogram of copolymer with 0.2 moles of acrylonitrile as said reactant and heat the mixture for a time sufficient to convert 25 % of the nitrile reactant thereby obtaining the desired product. If desired, two or more different ethylene backbone copolymers and/or two or more different types of nitrogen-containing reactants can be reacted.

These hydrolysed ene adducts can be used per se as a dispersant and/or V.I.

improver or which can be used as an intermediate for the preparation of other novel polymers. They are particularly useful as multifunctional V.I. improvers for mineral oil lubricants. When used as intermediates, these hydrolyzed ene adducts of the invention can be tailored to provide varying functional groups requisite for a given application. For example, as in the case of an adduct produced with acrylonitrile, the resultant ene adduct can be readily hydrolized to provide sites for reaction with alkylene polyamines to provide enhanced lube oil dispersancy.

The hydrolysis of these ene adducts is readily carried out under alkaline (base hydrolysis) or acidic (acid hydrolysis) conditions. Suitable bases include alkali metal and alkaline earth metal bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide and the like. Suitable acids are mineral acids such as sulfuric acid, nitric acid, hydrochloric acid and the like.

Both the base and acid hydrolysis can be carried out at a temperature ranging from about 0 C to about 225"C, preferably from about 20"C to about 125"C. The hydrolysis is usefully carried out at relatively mild conditions, i.e. only a catalytic amount of the hydrolyzing agent is employed.

The corresponding carboxyl containing adducts either in their original solution or after isolation and redissolving in suitable hydrocarbon solvents of the type mentioned are contacted with approximately equimolar amounts of nucleophilic reagents to convert the carboxyl derivatives into the new nucleophilic derivatives.

Examples of suitable functional nucleophilic reagents include water, Cl to C13 alcohols, C, to C,8 preferably C2 to C,2 monobasic acids, C, to C,8 amines, C2 to C,8 amides, phenol, thiophenol, alkyl phenols or thiophenol with 1 to 4 alkyl groups of ! to 12 carbons each, Cl to C18 alkyl mercaptans, dialkylaminophenols, N,N dialkylaminoarylene diamines, alkyl imidazolines, aryl ether alcohols, alkyl ether alkylene amines and the like.

Further descriptions of preferred forms of some of these functional agents follow: The C, to C13 alcohols can be branched or unbranched saturated, aliphatic, aromatic, primary, secondary, or tertiary alcohols, preferably monohydric alcohols, but including other alcohols. Particularly preferred are polyhydric alcohols of 2 to 6 hydroxy groups as well as amino alcohols. Examples include methanol, isopropanol, C8 Oxo alcohol, lauryl alcohol, benzyl alcohol, ethylene glycol, monododecyl ether of triethylene glycol, glycerol, pentaerythritol, glucose,dipentaery-thritol, sorbitol, Cellosolvesx Carbitole, diethanolamine, etc.

The Cl to Cl8, preferably C2 to C,2 monobasic acids, can be branched or unbranched, saturated, aliphatic, monocarboxylic acids, preferably the saturated fatty acids, such as acetic acid, butyric acid, caproic acid, lauric acid, etc.

The Cl to C18 amines can be branched or unbranched saturated, aliphatic, primary or secondary amines, containing 1 to 8 nitrogens, preferably mono-or diamines, such as ethylamine, butylamine, sec. butylamine, diethylamine, etc., but including higher polyamines such as alkylene polyamines, wherein pairs of nitrogen atoms are joined by alkylene groups of 2 to 4 carbon atoms. Thus, polyamines of the formula: NH2(CH2)nlNH(CH2)nlrnNH2 are included where n is 2 to 4 and m is 0 to 6. Preferably the polyamines have from 3 to 20 total carbon atoms and from 2 to 6 total nitrogen. Examples of such polyamines include tetraethylene pentamine, tripropylene tetramine, Naminoalkyl piperazines, e.g., N - (2 - aminoethyl) piperazine, N,N' - di(2 aminoethyl) piperazine, etc. Particularly preferred are the C4 to C13 N,N dialkylamino alkylene diamines such as N,N - dimethyl - 1,3 - propylene diamine, etc. Also, preferred is tetraethylene pentamine, as well as corresponding commercial mixtures such as "Polyamine H," and "Polyamine 500".

The alkyl phenols or thiophenols are those with 1 to 4 alkyl groups, preferably averaging I to 2 alkyl - groups, wherein the alkyl groups each contain I to 12 carbon atoms which can be straight chain or branched chain such as cresol, n-octyl phenol, di-n-octyl phenol, monoisobutyl thiophenol, etc.

The above-discussed reactions with the hydrolyzed adduct can be carried by procedures well known in the art. For the preferred amine functionalization the amination of the carboxylate groups is usefully carried out in a solution by reaction with the hydrolyzed ene adduct dissolved in a solvent such as mineral oil.

The formation of the amide dispersants in high yield can be effected by adding from 0.1 to 1, preferably 0.7 to 1, molar proportions of alkylene polyamine per molar proportion of carboxylate groups per kilogram of the hydrolyzed adduct to said solution and heating the mixture at 1400C to 1650C until the appropriate amount of water of reaction is evolved.

In some applications, it is useful to modify the aminated hydrolyzed ene adduct dispersant by subsequent boration as generally taught in U.S. Patents 3,087,936 and 3,254,025. This is readily accomplished by treating said aminated ene adduct with a boron compound selected from the class consisting of boron oxide, boron halides, boron acids and esters of boron acids in an amount to provide from about 0.3 to 0.9 wt % boron, based on the total weight of said borated, aminated, hydrolysed ene adduct.

When the adduct additives of the present invention are employed in lubricating oils, they are added in proportions of 0.1 to 10.0 %, and more preferably about 0.5 to 5.0 percent by weight. The proportions giving the best results will vary somewhat according to the nature of the adduct additive, the nature of the lubricating oil base stock to which it is added and the specific purpose which the lubricant is to serve in a given case. For commercial purposes, it is convenient to prepare concentrated oil solutions in which the amount of adduct additive in the composition ranges from 10 to about 49 % by weight, and to transport and store them in such form. naphthenic, asphaltic, or mixed base crudes, or, if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed. Hydrogenated oils, white oils, or shale oil may be employed as well as synthetic oils prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products or one may use esters of mono- or dibasic acids, esters of glycols, or complex esters, etc. Mixtures of any of the above or with mineral, animal or vegetable oils in any proportions may also be used.

EXAMPLE 1 The starting copolymer was an ethylene copolymer consisting of about 50 wt % (61 mol %) ethylene, 45 wt % (37 mol 0/ propylene and 5 wt % (2 mol %) of 5 ethylidene - 2 - norbornene having a Mn of about 45,000.

200 grams of this copolymer, 2200 ml of heptane, 11 grams (0.21 moles) of acrylonitrile and 1 gram of hydroquinone were introduced into a 3 litre rocker bomb. The contained air was replaced with nitrogen and then the reactor was pressurized with nitrogen to about 400 psi at room temperature. The bomb was sealed and rocked at a temperature of 1700 for 15 hours. The reactor was next cooled, 200 cc of sample taken, then 100 grams (1.88 moles) of additional acrylonitrile added, and the above procedure repeated at a temperature of 1500 for 12 hours. The reactor was cooled and the product filtered and recovered by precipitation from methanol the resulting yield after drying in a vacuum oven was 130.7 g of an ene adduct which contained 0.075 wt % nitrogen.

5 g. of this adduct in toluene (100 ml) were placed in a dry flask under a nitrogen atmosphere and refluxed with 3 g. potassium hydroxide dissolved in 15 cc distilled water. The refluxing took place at 90--940C for 6.0 hours. The solution was cooled to ambient temperature and the hydrolyzed copolymer recovered by precipitation from methanol (2 liter). The resulting copolymer was washed with methanol (500 ml) then dried in a vacuum oven at 1000C for about 15 hours, after which 4.05 g of copolymer was recovered. The nitrogen level of the resulting copolymer was 0.03 wt %.

The following illustrates amination of the hydrolyzed ene adduct. 2 g of the atom copolymer was dissolved in toluene (100 ml) then carefully refluxed (110"C) under a nitrogen atmosphere with a solution of 0.5 g diethylene triamine for 5 hours. The solution was cooled to ambient temperature and the aminated copolymer recovered by precipitation from methanol to yield 1.9 g of product (95% yield). The nitrogen level of the resulting product was 0.09 wt %.

EXAMPLE 2 In this example the efficacy ofthe adduct of Example 1, particularly with regard to its unusual dispersancy properties in lubricating oil applications, is illustrated by comparison with a commercially available multifunctional V.I. improver, sold as Lz 3702 by Lubrizol Corporation of Cleveland, Ohio, in a Sludge Inhibition Bench Test (hereinafter designated SIB). The SIB test has been found, after a large number of evaluations, to be an excellent test for assessing the dispersing power of lubricating oil dispersant additives.

The medium chosen for the SIB test was a used crankcase mineral lubricating oil composition having an original viscosity of about 325 SUS at 38"C that had been used in a taxicab that was driven generally for short trips only, thereby causing a buildup of a high concentration of sludge precursors. The oil that was used contained only a refined base mineral lubricating oil, a viscosity index improver, a pour point depressant and zinc dialkyldithiophosphate antiwear additive. The oil contained no sludge dispersant. A quantity of such used oil was acquired by draining and refilling the taxicab crankcase at 100 > 2000 mile intervals.

The Sludge Inhibition Bench Test is conducted in the following manner. The aforesaid used crankcase oil, which is milky brown in color, is freed of sludge by centrifuging for 1 hour at about 39,000 gravities (gs.). The resulting clear bright red supernatant oil is then decanted from the insoluble sludge particles thereby separated out. However, the supernatant oil still contains oil-soluble sludge precursors which on heating under the conditions employed by this test will tend to form additional oil-insoluble deposits of sludge. The sludge inhibiting properties of the additives being tested are determined by adding to portions of the supernatant used oil, a small amount, such as 0.5, 1 or 2 weight percent, on an active ingredient basis, of the particular additive being tested. Ten grams of each blend being tested is placed in a stainless steel centrifuge tube and is heated at 280"F for 16 hours in the presence of air. Following the heating, the tube containing the oil being tested is cooled and then centrifuged for 30 minutes at about 39,000 gs. Any deposits of new sludge that form in this step are separated from the oil by decanting the supernatant oil and then carefully washing the sludge deposits with 25 ml. of pentane to remove all remaining oil from the sludge.

Then the weight of the new solid sludge that has been formed in the test, in milligrams, is determined by drying the residue and weighing it. The results are reported as % of sludge dispersed by comparison with a blank not containing any additional additive. The less new sludge formed, the larger the value of percent sludge dispersant, and the more effective is the additive as a sludge dispersant. In other words, if the additive is effective, it will hold at least a portion of the new sludge that forms on heating and oxidation, stably suspended in the oil so it does not precipitate down during the centrifuging. Using the above-described test, the dispersant action of the adduct prepared in accordance with this invention were compared with the dispersing power of a dialyzed product obtained from dialysis of a commercial dispersant previously referred to as Lz 3702. Sufficient dialyzed residue which analyzed about 0.4 wt % nitrogen, was dissolved in S--150N mineral oil to provide a 10% active ingredient concentrate. The dialyzed residue and adduct of the invention were appropriately diluted in mineral oil to furnish the 0.05 and .1 wt % of added additive test samples. The test results are as follows.

Concn.gms.

polymer/l0 gms. %sludge Polymer Used Oil dispersed Lz 3702 .1 88.7 .05 73.3 Example 1 0.1 78 0.05 79 WHAT WE CLAIM IS: 1. A method for preparing a hydrolysis product of an oil-soluble ene adduct, said adduct having a polar group and containing 0.02 to 0.5 wt /O nitrogen as pendant nitrogen-containing groups and having a number average molecular weight ranging from 10,000 to 200,000, which comprises mixing a copolymer which has a substantially saturated hydrocarbon polymer backbone having pendant carbon-tocarbon double bonds, said copolymer comprising 30 to 85 mole /^ ethylene, 15 to 70 mole % C3 to C50 alpha-monoolefin, and 0.5 to 20 mole % C5 to C24 nonconjugated diolefin which furnishes said carbon-to-carbon double bonds, with a C3 to C24 ethylenically-unsaturated nitrogen-containing reactant having an electron withdrawing group in such proximity to its unsaturation whereby its olefinic bond is activated by at least one electron-attracting group, heating said admixture under a substantially oxygen-free atmosphere at a temperature in the range of from 100"C to 2500C for a time sufficient to thermally add said nitrogen-containing reactant at said carbon-to-carbon double bonds of said copolymer and then hydrolyzing said ene adduct.

2. The method of claim 1 wherein said temperature ranges from 1500C to 2250C and said reaction is carried out in the presence of mineral oil and an inert gas.

3. The method of claim 1 or claim 2 wherein a scavenging amount of a free-radical scavenger is present during said heating step.

4. The method of claims 1--3 wherein said reactant is acrylonitrile and said ene adduct is subjected to a hydrolyzing agent at a temperature of from 0 C to 2250C whereby a hydrolyzed ene adduct having carboxylate groups is obtained.

5. The method of claims 14 wherein said hydrolyzed ene adduct is subjected to amination with an alkylene polyamine having from 3 to 20 total carbon atoms and from 2 to 6 total nitrogens.

6. A method according to claim I substantially as hereinbefore described with reference to the accompanying Example 1.

7. Hydrolyzed oil-soluble ene adduct of a C3 to C24 ethylenically-unsaturated nitrogen-containing reactant having at least one electron withdrawing group and a copolymer of 3085 mole /O ethylene, 15 to 70 mole /^ of at least one C3 to C50 alpha-monoolefin and 0.5 to 20 mole % of at least one C8 to C,4 non-conjugated diene said oil-soluble ene adduct containing 0.02 to 0.5 wt / > nitrogen and said hydrolyzed ene adduct containing carboxylate groups in molar concentration

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. active ingredient basis, of the particular additive being tested. Ten grams of each blend being tested is placed in a stainless steel centrifuge tube and is heated at 280"F for 16 hours in the presence of air. Following the heating, the tube containing the oil being tested is cooled and then centrifuged for 30 minutes at about 39,000 gs. Any deposits of new sludge that form in this step are separated from the oil by decanting the supernatant oil and then carefully washing the sludge deposits with 25 ml. of pentane to remove all remaining oil from the sludge. Then the weight of the new solid sludge that has been formed in the test, in milligrams, is determined by drying the residue and weighing it. The results are reported as % of sludge dispersed by comparison with a blank not containing any additional additive. The less new sludge formed, the larger the value of percent sludge dispersant, and the more effective is the additive as a sludge dispersant. In other words, if the additive is effective, it will hold at least a portion of the new sludge that forms on heating and oxidation, stably suspended in the oil so it does not precipitate down during the centrifuging. Using the above-described test, the dispersant action of the adduct prepared in accordance with this invention were compared with the dispersing power of a dialyzed product obtained from dialysis of a commercial dispersant previously referred to as Lz 3702. Sufficient dialyzed residue which analyzed about 0.4 wt % nitrogen, was dissolved in S--150N mineral oil to provide a 10% active ingredient concentrate. The dialyzed residue and adduct of the invention were appropriately diluted in mineral oil to furnish the 0.05 and .1 wt % of added additive test samples. The test results are as follows. Concn.gms. polymer/l0 gms. %sludge Polymer Used Oil dispersed Lz 3702 .1 88.7 .05 73.3 Example 1 0.1 78 0.05 79 WHAT WE CLAIM IS:

1. A method for preparing a hydrolysis product of an oil-soluble ene adduct, said adduct having a polar group and containing 0.02 to 0.5 wt /O nitrogen as pendant nitrogen-containing groups and having a number average molecular weight ranging from 10,000 to 200,000, which comprises mixing a copolymer which has a substantially saturated hydrocarbon polymer backbone having pendant carbon-tocarbon double bonds, said copolymer comprising 30 to 85 mole /^ ethylene, 15 to 70 mole % C3 to C50 alpha-monoolefin, and 0.5 to 20 mole % C5 to C24 nonconjugated diolefin which furnishes said carbon-to-carbon double bonds, with a C3 to C24 ethylenically-unsaturated nitrogen-containing reactant having an electron withdrawing group in such proximity to its unsaturation whereby its olefinic bond is activated by at least one electron-attracting group, heating said admixture under a substantially oxygen-free atmosphere at a temperature in the range of from 100"C to 2500C for a time sufficient to thermally add said nitrogen-containing reactant at said carbon-to-carbon double bonds of said copolymer and then hydrolyzing said ene adduct.

ranging up to the molar concentration of said reactant and having a number average molecular weight of from 10,000 to 200,000.

8. The hydrolyzed ene adduct of claim 7 wherein said nitrogen-containing reactant is acrylonitrile.

9. The hydrolyzed ene adduct of claim 7 substantially as hereinbefore described with reference to the accompanying Example 1.

10. An oil-soluble amide suitable as a lubricating oil sludge dispersing additive, of a hydrolyzed ene adduct of a C3 to C24 ethylenically-unsaturated nitrogencontaining reactant having at least one electron withdrawing group and a copolymer of 3085 mole % ethylene, 15 to 70 mole /O of at least one C3 to C00 alpha-monoolefin and 0.5 to 20 mole jO of at least one C8 to C24 non-conjugated dienes, said ene adduct containing 0.02 to 0.5 wt /O nitrogen and said amide having a number average molecular weight of from 10,000 to 200,000.

11. The oil-soluble amide of claim 10, wherein said nitrogen-containing reactant is acrylonitrile, and wherein said amide is formed by reacting said hydrolyzed ene adduct with a C, to C18 amine.

12. The oil-soluble amide according to claims 10 or 11 wherein said amine is an alkylene polyamine.

13. The oil-soluble amide of claim 10 substantially as hereinbefore described with particular reference to the accompanying Example 1.

14. A lubricating oil composition comprising a major proportion of lubricating oil and in the range of 0.1 to 10 wt /^ of the oil-soluble amide of claims 10 to 13.