CA1079709A - Lithium salts of hydrocarbon substituted amic acids as low ash rust inhibitors - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A lithium salt of a reaction product of a hydrocarbon-substituted amic acid in which the hydrocarbon substituent contains about 12 to 20 carbon atoms and an amine or ammonic, is effective as rust and corrosion inhibitors in lubricating oil compositions.

Description

31 ~7~'7~9 1 This invention relates to a novel class of

2 chemical compositions which act as rust and corrosion

3 inhibitors in lubricating oils and to lubricating oil

4 compositions containing these compositions.
Certaln alkyl and alkenyl dicarboxylic anhydrides, 6 acids, and various salts thereof have been proposed as 7 ashless or low ash rust inhibitors for motor lubrlcants.
8 In ashless or low ash formulations, however, these 9 anhydrides and acids can cause considerable copper-lead bearing weight loss. The prior art has generally tcLught 11 that when using a salt of a hydrocarbon-substituted 12 dicarboxylic acid, t~e size of the hydrocarbon subs~ituent 13 of the dicarboxylic compound appears to d~te~m~ne the 1~ e~ectiveness of the additive in lubrlcating oils. Thus, the prlor art is repl2te with statements to the efect 16 that it is critically important that the substituent be 17 large; that is, that it have at least about 50 aliphatic 18 carbon atoms in its structure and the molecular weight of 19 the hydrocarbon substituent should be with the range o about 700 to about lO,000. Because such salts have high 21 molecular weight hydrocarbon substituents, a relatively 22 h~gh weight per cen~ active ingredient oE salts ls required 23 in the oil. The shorter chain aliphatlc-hydrocarbon-24 substituted dicarboxylic anhydrides and acids, andtheir salts while having rust inhibiting properties, are generally 26 insoluble in oil) and thus present special problems to 27 their success~ul incorporatibn as rust inhibitors in 28 lubricating compositions. The rust inhibitors also must be compatible with other additives conventionally used in motor lubricants and sometimes this has also proved to be 31 a problem.
32 It has now been discovered that a nitrogen-~J~

~97~)9 1 containing lithium salt composition comprlsing a lithium 2 salt o~ C12 to C20 aliphatic-hydrocarbon substituted amic 3 acid (amides of dicarboxylic acids) can be added to a 4 lubricating oil composition as a low ash antirust additive that provides improved corrosion resistance and which is 6 compatible with a variety of antiwear agents.
7 The salts used in this invention can be prepared 8 by either of two methods. The first method comprises 9 reacting the hydrocarbon substituted amic acid with a lo lithium compound to provide the half-lithium salt and 11 then reacting the half-lithium salt with an amine or 12 ammonia. The second method comprises reactlng the hydro-13 carbon substituted dlcarbo~yllc acld with an amitle or 14 ammonla and then reacting the resultlng amide wlth a lithium compound~ The irst method is, however, preerred 16 when using either an amine or ammonia and) indeed, will 17 generally result in higher yields of the desired product 18 with both reactants.
19 The salt composition used in the present inven-tion is obtained from C12 to C20 aliphatic-hydrocarbon-21 ~ubstituted dicarboxyllc anhydrides and acids. Generally, 22 the hydrocarbon substitueTIts may be either alkyl or alkenyl 23 groups or mixtures thereof. Similarly, the diearboxylic 24 anhydride and/or acid is generally succinic anhydride and/or succinic acid.
26 Alkenyl-substituted acids and anhydrides can 27 be straight chained or branch chained and are obtained by 28 conventional methods known in the art which involve 29 heating maleic anhydride and an olefinic material together~
usually in about equal molar portions. For example~ a C12 31 alkenyl succinic acid anhydride can be prepared by the 32 condensation of maleic acid anhydride and a C12 raction o 79 ~ ~g 1 propylene polymer. The reactants are heated with agitation 2 for 20 hours under pressure at a temperature of about 350 3 to 390~F under gentle reflux. The reaction product is then 4 allowed to cool and is fractionated under diminished pressure to remove unreacted polymer and low-boiling 6 reaction products. The resulting alken~yl succinic acid 7 anhydride can then be employed directly to produce the 8 half-lithium salts hereinafter described. In the present 9 invention, either alkenyl succinic anhydrides or the lo corresp~nding acids can be used and it is to be understood 11 that any general description involvlng the use of the 12 anhydride is intended to encompass the use of the equivalent 13 acid as well. Similarly, any general description lnvolving 1~ the use o the acid i~ intended to encompass th~ use o the equivalent anhydrlde.
16 Among the alkenyl-substituted succinic acids and 17 anhydrides which can be used according to the present 18 invention are tetradecenylJ hexadecenyl, octadecenyl, 19 eicosenyl, hexaeicosenyl and octaelcosenyl succ~nic anhydride or acid, and mixtures thereof. A partlculnrly 21 pre~erred material is dodecenyl succinic anhydride or acid 22 (hereina~er re~erred to as DDSA) which can readily be 23 prepared by the addition of tetrapropylene to maleic 24 anhydride. The tetramer of propane, as opposed to the trimer of butene is preferred in preparing DDSA.
26 In place of the alkenyl succinic acid or 27 anhydride, the corresponding saturated acid or anhydride, 28 or mixtures of saturated and unsaturated materials, can 29 be used. Conversion of the alkenyl group to the alkyl group is usually accomplished by hydrogenation to saturate 31 the double bond, using procedures well known in the art.
32 See, for example, U.S. Pat. 2,682,489.

~0797a9 l The lithium compounds used in preparing the salts 2 used in the present invPntion arP lithium ba~es such as 3 lithium oxide, lithium hydroxide~ lithi.um carbonate or 4 lithium alkoxide.
The amines useful in ~his in~ention have the 6 general formula X - N - H, and those wherein at least one 8 of X and Y provide a polar group which can attach to ~he 9 surface to be protected are preferredO Simple, primary amines, then, which do not provide such a polar group are ll not preferredO
12 It is believed that effective rust inhibition iR
13 obtained by providing an inhibitor which i5 bondled to the 14 ~urace to be protectedO In the pre~ent invention~ it is believed that the hal~-lithlum dicarboxylic acid salt 16 portion of the additlve provides the rust inhibition whlle 17 the amine portion of the additive provides a polar group 18 which can attach to the surface to be protectedO
19 The amines useful in this invention include alkylene polyamines and hydroxyalkyl;substituted alkylene 21 polyamines, such as ethylene diamine, triethylene tetramine, 22 propylene dlamine, ~ecamethylene diamine, octamethylene 23 diamine, di(hept~-methylene~ ~riamine, tripropylene tetra-24 mine, tetraethylene pentamine, trimethylene diamine, tetra-ethylene hexamine, di(trimethylene) triamine, 2-heptyl~3-26 (2-aminopropyl)imidazoline, 1,3-bis(2-aminoethyl~ imidazo-27 line, pyrimidine, 1-(2-amino-propyl) piperazine~ 1,4-bis 28 (2-aminoethyl) piperazine, and 2-methyl~1(2-aminobutyl) 29 piperazine. Higher homologues such as are obtained by condensing two or more of the above-illustrated alkylene 31 amines are likewise usefulO
32 Hydroxyalkyl-substituted alkylene polyamimes, 1~;)79~)9 1 i.e., alkylene polyamines having l or more hydroxyalkyl 2 substituents on a nitrogen atom, are likewise contemplated 3 for use within this in~ention. 'rhe hydroxyalkyl-substituted 4 alkylene polyamines are preerably those in which the alkyl group ls a l~wer alkyl group, i.e., having less than about 6 6 carbon atoms. Examples of such amines include N-(2-7 hydroxyethyl)ethylene diamineJ N,N'-bis(2-hydroxyethyl) 8 ethylene diamine, l-(2-hydroxyethyl~-piperazine, lower 9 hydroxypropyl-substituted diethylene triamine, dl-hydroxy-propyl-substituted tetraethylene pentamine, and 11 N-(3-hydroxypropyl) tetramethylene diamine.
12 Higher homologues such as are obtained by 13 condensa~ion of the above-illustrated alkylene amines with 1~ hydroxy-alkyl-~ubst~tuted alkylene amines throu~h amino radlcals or through hydroxy radicals are likewise useEul.
16 It will be appreciated that condensation through amino 17 radicals results in a higher polyamine accompanied by 18 removal of ammonia and that condensation to the hydroxyl 19 radicals resul~s in products containing ether linkages accompanied by removal of water.
21 The ethylene polyamines are especially useEul 22 ln thls invention. Such compounds are prepared by the 23 reaction of an alkylene chloride with ammonia which 24 results in the production of complex mixtures of alkylene 2s polyamines, including cyclic condensation products such as 26 piperazines. These mixtures find use in the processes of 27 this invention. On the other hand, quite satisactory 28 products may be obtained also by the use of pure alkylene 29 polyamines. An especially useful alkylene polyamine for reasons of economy as well as the effectiveness of the 31 products derived therefrom~ is a mixture o ethylene 3~ polyamines prepared by the reaction of ethylene dichloride ~1)79709 1 and ammonia and having a ccmposition which, in it~ elemental 2 analysis~ corresponds to that of tetraethylene pentamine.
3 Another especially useful am-Lne for reasons of 4 economy as well as the effectiveness of thP products der~ved therefrom is a mixture of poly(trimethylene) 6 polyamines and the l,3-trimethylene diamine derived ~rom 7 the reaction of acrolein and ammonia.
8 As will be readily appreciated, each of the above 9 described polyamines provides at least one polar group ln addition to a nitrogen atom it contains. When ammonia is 11 used, it is believed that the ammonia reacts with thle 12 dicarboxylic acid portion of two molecules to lirlk these 13 two molecules by an imlno group -NH which acts to provide a 14 good surace bond. This product i8 lllustrated by the following formula:
16 R - CHCOOLi R - CHCOOLi 21 where R and R' are either the same or a different alkyl or 22 alken~l group ha~lng 12 to 20 carbon atoms.
23 The process o this invention can be carried out 24 either by (l) irst preparing the acylated amine of the hydrocarbon-substi~uted dicarboxylic compound and then 26 reacting the acylated amine with the lithium compound, or 27 by (2) first preparing the mono-lithium salt of the 28 hydrocarbon-substitu~ed dicarboxylic compound and then 29 reacting the mono-li~hium salt with ammonia or an amine such as an alkylene polyamine or hydroxyalkyl-substituted 31 alkylene polyamine. In the second method, it is preerred 32 that the dicarboxylic compound be succlnic acld. In all ~97~

1 cases, it is preferred that nitrogen or some such inert 2 gas be bubbled through the reactlon mixture to remove any 3 water formed as a result of the acylat:Lon reaction.
4 The first method is illustralted by the following equations:
6 NH N~
7 5 RCHCO ~ R" ~ ' ~ R""
~ ¦ \0 ~ / \N/ N~2 J, ., --CH2 --CH~

12 /N ~ N
13 RCHCOOH / R' ~'' R " R'~

CO HOOC-CH

17 5Li 19LiOOC CO CO COOLi 21 RCHCOOL~ R' ~'' /R~ ' R""

23 LiOOC CO LiOOCCH

wherein R is an alkyl or alkenyl group having 12 to 20 26 carbon atoms or a mixture of two or more such groups and 27 R' - R"" are the same or different substituted or unsub-28 stituted divalent hydrocarbon radicals corresponding to 29 those of the particular amine or amines actually employed.

~ O ~ 9 7C~9 1 The second method, on the other hand, ls more 2 simply illustrated by the following equation:
3 NH ~H
45R-CHCOOLi + R~ Rl' / R~" R"' 5CH2COOH NH~ NH N~2 6 R~CH-CH2 CH -CH-R
. . , 2 , 7 LiOOC C~ CO COOLi /\ / ~
9LiOOC-CH R' R" R'l' Rl"' ' / \N' \ NH
11 CH CO~I ' I
12 2 C~ CO
13 R-Ct~-C~2 R-GH~CH2 16, C C

17 Li Li 18 wherein R, R', R", R~', and R"" are as previously indicated 19 in the equations illustrating the first method.
With respect to the aforeme~tloned methods, it 21 should be noted that a rather broad range of products is 22 possible, ranging from those wherein one amine ~itro~en is 23 converted to an amide to those wherein all amine groups are 24 80 converted. Similarly, the ultimate product may contain from only one lithium atom per molecule to one lithium atom 26 per amine nitrogen in the amine actually used.
27 The first method above involved (A) mixing a di-28 car~oxylic compound that can be selected from the class con-29 sisting of hydrocarbon~substituted succinic acids and hydro-carbon-substituted succinic anhydrides wherein the hydro-31 carbon substituent has between 12 to 20 aliphatic carbon 32 atomsJ with at least one equivalent of an amine that can be _ g _ 1~97a)9 l selected from the class consisting of alkylene polyamines 2 and hydroxyalkyl-substituted alkylene polyamines, and heating 3 the resulting mixture to effect acylati.on and to form an 4 acylated amine, and to remove the water formed thereby, and then (B) mixing said acylated amine with about one equiv-6 alent of a lithium compound from the cl.a~s consisting of 7 lithium oxide, hydroxide9 carbonate ancl lower alcoholates, 8 and heating the resulting mixture at a temperature within 9 the range of from about 20C to about 250C.
The second variant of the process comprises react-ll ing at a temperature within the range of from about 50F to 12 about 350F ~A) one equivalent of a half-lithium salt of a 13 hydrocarbon~substituted succinic acid in which the hydro-14 carbon substituent has from 12 to 20 aliphatic carbon atom8 with (B) at least about one equivalent of am~lonia or an am~ne 16 selected from the class consisting of alkylene polyamines 17 and hydroxyalkyl~substituted alkylene polyaminesO
18 The half-lithium salt can be prepared by heating 19 at a temperature with the range of from about 80C to about 130C, one mole of a hydrocarbon substituted succinic acid 21 with about one mole of a lithium compound such as lithlum 22 oxide, lithium hydroxide, lithium carbonate and lower alco~
23 holates of lithium, or a period of time from about 1 hour 2~ to about 5 hoursO The temperature can be as low as 20C
although usually it should be within the range aboveO Also~
26 it is preferred that the reaction of the half~lithium suc;-27 cinate with the amine is best carried out at a temperature 28 within the range of from about 80C to about 160Co It 29 usually requires from about 3 to about 5 hoursO
The use of a solvent such as toluene; mineral oil 31 and the like is sometimes desirable.
32 The lithium succinates are illustrated by the ; 1 0 7970~

1 structural formula:

"
3 R ~ C - C - O - Li 4 H - C - C ~ OH
H O
6 where R is a hydrocarbon substituent having from 12 to 20 7 carbon atoms.
8 The lower alcoholates referred to in this inven-9 tion are alcoholates containing from one to about 16 carbon atoms. Examples of these alcoholates include methylates, ll ethylates, propylates, butylates, hexylates and the liken 12 The low molecular weight lithium salts of this l3 invention are derlved from hydrocarbon substituted amic l4 aclds containing 12 to 20 carbon atoms in the hydrocarbon 8ubstituent and are not especially soluble ~n lubricatlng 16 oil compositions. As a result~ a dispersing agent or solu-17 bilizing agent is generally employed~ Suitable dispersing l8 agents include amide condensates of polyisobutenyl propionic 19 acid and tetraethylene pentamine (see British Patent ~oO
1,075,121), as well as high molecular welght polyisobutenyl 2l succinic acid and tetraethylene pentamine, and hlgh molec-22 ular weight polyisobutenyl amic acid and tetraethylene pen~
23 ~amine.
24 There are a number of oxygenwcontaining compounds which will solubilize the lithium salts of the aliphatic 26 hydrocarbon-substituted dicarboxylic acids or anhydrides 27 (ASA) of the present invention Among these are tall oll 28 fatty acids and alcohols such as isooctanol and nonanolO
29 f all the oxygen~containing materials that can be used as solubilizers, the alkyl phenols are preferred because they 31 make the salts soluble in lubricating oils without: destroying 32 the copper-lead corrosion inhibiting properties of- the salts ,. . , :.
, ~ ~ 7 9 7 ~g 1 and allow the preparation o a sta~le liquld concentrate.
2 The phenols that can be used include alkyl phenols having a 3 total of 5 to 30 and preferably 8 to 26 carbon atoms in 4 their alkyl side chains and may be polyhydric phenols co~- ;
taining more than one ring structure The so-called bls 6 phenols may be used, also acyl phenols, amino phenols, 7 acetyl phenols and dialkyl phenols. Thus, typical compounds 8 include 2,2-bis-(2-hydroxy-3-tert-bu~yl-5-methylphenyl) -9 propane, diethylamino p'nenols, benzyl amino phenols, acyl amino phenols, for example, N~propionyl~p-aminophenol, acetyl 11 phenol, and their homologues. Condensation products of such 12 phenols with aldehydes or ketones~ eOgO, formaldehyde and l3 acetone, n~ay al~o be usedO
1~ The phenol that i5 used to solubllize the lithium lS salts of this invention can be present when the salt i8 made, 16 or can be added later. Reaction time of combining these 17 components is not criticalO The only requirement is that 18 the phenol be present while the temperature of the m~xture 19 is at least as high as the melting point of the salt. Thus, the solubilization which must be carried out while the salt 21 i8 in liquid phase can be effected at a temperature range o~
22 about 300F to about S00F.
23 It i8 to be understood that the exact nature of 24 the compositions formed upon the addition of the alkyl phenol has not been determined and, while they have been referret 26 to as solubilized lithium salts, it is possible that a 27 lithlum phenate complex has been formed between the ASA, 28 the lithium base, and the alkyl phenol or that some other 2q undetermined compositional structure has resultedO
Experiments indicate that the mole ratio of salt 31 to phenol may range from about 15 1 to about 0.5:1.
32 This invention contemplates the use of 0l01 to 50 ~ 12 -1 weight percent of the products o~ the present invention in 2 oil compositions. As ststed above, the lithi~m salts of the 3 present invention, in combination with an alkyl phenol, are 4 useful as antirust additives in lubricating oils and when combined with a lubricating oil will form homogeneous liquid 6 lubricating oil compositions which are stable at ambient 7 temperatures~ When used as antirust additives, they can be 8 incorporated in lubricating oil composiLtions in concentrations 9 within the range of from about 0.2 to about lO weight per-cent active ingredient, but will ordinarily be used in con 11 centrations of from about 0.2 to about 400 weight percentO
12 The lubricating oils to which the additives of the 13 inventlon can be added include not only mineral lubricating 14 oils, but synthetLc oil9 also. The mlneral lubricatlng oils may be of any pre;Eerred types, lncludlng those derlved from 16 the ordinary paraffinic, naphthenic, asphaltic, or mixed 17 base mlneral crude oils by suitable refining methodsO The 18 synthetic oils include synthetic hydrocarbon lubricating 19 oils, as well as dibasic acid esters such as di 2~ethyl hexyl sebacate, carbonate esters, phosphate esters halogen~
21 ated hydrocarbons, polysilicones, polyglycols9 glycol esters ~2 such as Cl3 OX0 acid diesters o tetraethylene glycol, and 23 complex esters, as for e~ample the complex ester formed by 24 the reaction of l mole of sebacic acid with 2 moles of ~:
tetraethylene glycol and 2 moles of 2-ethyl hexanoic acid.
26 While the lubrlcant compositions herein described 27 are primarily designated as internal combustion engine 28 crankcase lubricants, the additives of the invention may 29 also be employed in other oil composltionsg inclulding tur-bine oils, various industrial oils~ gear oils9 hydraulic 31 fluids, transmission fluids and the likeO
32 It is within the contemplation of this invention ;

797~9 l to prepare easily handled liquid additive concentrates in 2 whlch the concentration of additives is greater than would 3 normally be employed in a finished lubricant. These concen-4 trates may contain in the range of from lO to 50~/O of addi-tive on an active ingredient basis3 the balance being min;
6 eral oil. S~ch concentrates are conveniLent for handling the 7 additive in the ultimate blending operation into a finished 8 lubricating oil compositionO The additive concentrates can 9 be made up simply by combining the lithium salts and alkyl phenol of the present invention in a suitable mineral oil 11 mediumO The additive package can also include other addi-12 tives, for example, detergents and dispersants of the ash~
13 contaLning or ashless type3 o~idatlon inhlbiting agents, l~ vlsco~lty index improving agen~s, pour polnt depressantq, extreme pressure agents~ color stabilizers and antifoam l6 agents~
17 Alternatively9 although not preferably9 the alkyl 18 phenol and the lithium salt can be combined in any aliphatic l9 or aromatic hydrocarbon with a boiling point of about 400F
or higher, e gO9 ortho~cresol or cetane~ which9 can then be 21 boiled off to leave a readily soluble additlve in so:Lid 22 form.
23 Whereas mentioned previously~ the lithium amine 24 salts of the instan~ invention may be prepared via either of two methodsg the first method which comprises reacting 26 the hydrocarbon~substituted amic acid with a lithium com~
27 pound to provide the hal~ llthium salt and then reacting 28 the half-lithium salt with an amine or ammonia is preferredO
29 This method generally will result in higher yields of the desired product with both reactantsO
31 Similarly, with respect to this first method, it 32 is preferred that the dicarboxylic compound be succi.nlc ~ 14 ~

~ ~79 ~ ~ 9 1 anhydride and that trace amounts o water5 iOeO 9 Up to about 2 2.5% by weight, be present when the basic lithlum compound 3 is an oxideO Nitrogen or some other such inert gas i4 bub 4 bled through the reaction mixture to remove any water formed as a result of the acylation reactionO
6 With respect to the preferred embodiment, it 7 should be noted that a ratner broad range of products is 8 possible ranging from those wherein one amine nitrogen is 9 converted to an amide to those wherein all ~mine groups are lo so convertedO Similarly9 the ultimate product may contain 11 only one lithium atom per molecule to one llthium atom per 12 amine nitrogen in the ~mine actually usedO Although such a 13 range of products is possible~ the products having one amlde 14 group and one lithium atom Eor each nltrogen are preferred.
When the reaction condltlons are controlled as aet ~orth 16 below, the preferred products are dominantO
17 The preferred amines useful in this invention have 18 the general formula X ~ N ~ Ha wherein at least one of X and Y provide a polar group whlch can attach to the surface to 21 be protected 22 Another p~erred source of the amine group consists 23 of alkylene polyamlnes con~ormlng for the most part to the 24 formula H ~ ~N o alkyleneooN~ ~ H ~ `
25 ~A AJn ~
26 wherein n is an integer preferably less than about 103 A is ~ ~ -27 a hydrocarbon radical or hydrogen or an amino hydrocarbon 28 radlcal, and the alkylene radical is preferably a lower 29 alkylene radical having less ~han about 8 carbon atomsO
The most preferred of such amines is tetraethylene pentamlne 31 (TEPA).
32 The acylation reaction is preferably carrted out ~ 15 ~

~ O 7 9 ~ 9 l at a temperature within the range of from about 80C to 2 about 160C and for a period of time wi~hin the range of 3 from about 3 hours to about 5 hoursO The acylates amine 4 preferably is formed by having one mole o succinic acid present for each ni~rogen atom in the amineO For example, 6 when using the preferred tetraethylene pentamine, a mole 7 ratio of succinic compound to amine of 5ul is preferably 8 used.
9 The low molecular weight lithium salts of this 0 invention are derived from hydrocarbon~substituted amic ll acids containing 12 to ~0 carbon atoms in the hydrocarbon 12 substituentO The lithium salts are not particularly soluble 13 Ln lubricating oil compositionsO ~ccordlngly~ a dispersing 14 agent or solubilizing agent i5 generally employedO The pre-ferred dispersing agent is the amide condensate of polyiso-16 butenyl propionic acid and tetraethylene pentamineO
17 Where dispersing agents are not u~e~g it is pre~
18 ferred to work with oil soluble additives as opposed to oil 19 dispersible additivesO
Furthermore9 as a practical matter~ it is preerred 21 and predominantly the practice to blend additives into lub-22 ricating compositions in concentrate formO Usually in a 23 concentrate, the weight percent of active ingredient ranges 2~ from about 10 to about 80 weight p~rcentg for there is no economic advantage in using concentrates having less than 26 10 weight percent active ingredientO How~ver~ if one 27 attempts to prepare concentrates wherein the weight percen-28 tage of oil insoluble lithlum salt of ASA is greater than 10, 29 using dispersants t such concentrates will form solid gels at ambient temperatures9 thus presenting a number of dis~
31 advantages in thelr handling in subsequent blendillg opera-32 tions.

~ 16 ~L~7 The invention pref ers as o~ygen containing com~
2 pounds which will solubilize the lithiu~n salts cf the inven~
3 tion, monoalkylated monohydroxy phenols who~e molecular 4 weights are between 150 and 700O ~spec:ial.ly preferred are monoalkylated phenols having 8 to 12 alkyl carbon atoms, 6 More specificallyg effective compoun~s :include p~octyl 7 phenol, mixed nonyl phenolsS mlxed dodecyl phenols~ and 8 dihexyl phen~lO
q As expressed previcuslyg the reaction time of o combining the phenol that it is used to sol.ubilize the ll lithium salts of this lnventlon is nct criticalO However9 12 this solubilization is pr~ferably carried out at a tempera~
13 ture range o about 350F to abou~ 450~ Slmilarly~ the 14 preferred mole ratio o salt to phenol will range from abou~
lS 8:1 to about 1,1~ When the produc~ of ~he pre8ent i.nven 16 tion are used as additives in oil compositions9 the pre~
17 ferred concentrations range from about 0O4 to about 20 0 18 weight percent actlve ingredientO

~he half~llthium salt of dodecenyl succinic acid 21 i9 prepared by diluting five msles of dodecenyl succinic 22 acld with an equal volume of a solvent refinedD hydroinished 23 Western Canadian paraffinlc distillate h~ving a nominal Volo 24 (viscosity index~ of 90 and a viscosity cf 150 SUS ~Saybolt Universal seconds~ at 100Fo The mixture is heated to 260F
26 to 280F in a Hobart mixerg and an aqueous solution contain~
27 ing five moles of lithium hydroxide m~nohydrate in 1500 gms 28 of hot water is added dropwise over a period of 120 minutes 29 at a rate sufficient to avoid foamingO At this temperature9 all of the water flashes off ~nd is rapidly evapor,atedO
31 Upon completion of the addition of the lithium hydroxide 32 solutiong the temperature is raised to 300F and vne mole ~ 17 3L ~ 97 ~ 9 l of tetraethylene pentamine is added gradually over 60 min~
2 utes. The reaction is carried out for 5 hours at 300Fo 3 The resulting product is maintained at 300F and 150 grams 4 of nonyl phenol is added wlth mixing to provide a composi-tion which upon cooling to room tempera~ure will not solidify 6 and will remain a liquid. The cooled composition is an addi-7 tive concentrate suitable for lubricating oil blending 8 operationsD

-0 Two blended oil compositions are prepared contain-ll ing 2.0 weight percent active ingredient of the additive of 12 Example 1. The irst oil composition9 in addition to the 13 additive of Example 1, contalnsg on a weight percent ba~is, l~ (1) 4.~/~ o~ a di9persant obtalned by reacting a hi~h molecw ular wcight polyi~obutene succlnic acld ~molecular weight 16 of polyisobutene 900~ with tetraethylPne pentamine in a 2,8:1 17 molar ratio; ~2~ loO~Io of an oil composition consisting of 18 26 weight percent of a hydrocarbon lubricating oil ~nd 74 19 weight percent of a zinc dialkyl dithiophosphate prepared from a mixture oE acids derived from 65% isobutyl alcohol 21 and 35V/o primary amyl alcohol; (3~ 00 025% of a silicone type 22 antifoam agent; and (4~ 92.975Vlo of a SAE 30 base oil having 23 a viscosity of about 69 SUS at 210Fo The ~econd oil com~
24 position, in addition to the additive o Example 1, contains (1) 4.0% oi a dispersant obtained by reacting a high molec~
26 ular weight polyisobutene succinic acid (molecuLar weight of 27 polyisobutene is 900) with tetraethylene pentamine in a 208~
28 molar ratio; (2~ 1.2% of an oil composition consisting of 26 ~ weight percent of a hydrocarbon lubricating oil and 74 weight percent of a zinc dialkyl dithiophosphate prepared from a 31 mix~ure of acids derived from 65~/o isobutyl alcohol and 35/0 ~ 18 ~079709 1 primary amyl alcohol~ and ~3~ 92~775~/o of the same SAE 30 2 base oil.
3 A third oil composition i5 prepared containing 4 ~1~ 6~/~ active rust inhibitor of the reaction product of the half~lithium salt of a high molecular weight polyisobutylene 6 succinic acid (molecular weight of polyisobutylene substit~
7 uent is 900) with tetraethylenepentamine in a molar ratio of 8 5:1; (2) 102% of an oil composition con~sisting of 26 weight 9 percent of a hydrocarbon lubricating oil and 74 weight per~
cent of a zinc dialkyl dithiophosphate prepared from a mix~
ll ture of acids derived from 65~/o isobutyl alcohol and 35V/~
12 primary amyl alcohol; (3~ 0002~/o Of a sillcone type antifoam 13 agent; and ~4) 920775% of the same S~E 30 base oil~
l4 Each o the abova three oil compo~itions are tested or rust performanceO To determine ru~t lnhibitlon9 16 the General Motors MS series test is used~ employing a 17 sequential MSIIB engine merit testO The MSIIB engine test 18 entails running the regular MSIIB low temperature cycle, 19 then disassembling only the parts to be rust ratedO The engine crankcase is then drained~ filled with new test oLl 21 (plus dummy rust test parts~ and run to flu~h the system of 22 all the oll and re~idue rom the first runO Then new parSs 23 and fresh test oil. are placed in the engine or the next 24 runO The MSIIB series of tests is described in ASTM Special Technical Publicaticn 315Do 26 The MSIIB rust rsting varies from around 300 to 27 10 with higher values indicating better results, Values of 28 8.4~809 are common for present day crankcase oilsO
29 The first and second oil compositions containing the xust inhibitors of ~he present invention each have a 3l rust rating of 807 as does the third oil compositionO The 32 additives o~ the present invention9 however9 are present at ~ 19 ~

, . .

~ ~7 9 ~ ~ ~

l a 2 weight percent active ingredient level whereas the active 2 ingredient of the third composition is present at the mu~h 3 higher level of 60~/
4 EX~MPLE 3 The half~lithium salt of dodecenyl succinic acid 6 is prepared by first diluting 19000 gr~s of dodecenyl suc~
7 cinic acid with 19000 grams of an SAE 10 grade oil which was 8 solvent and having a typical VoI~ of 90 and a viscosity of 9 150 SUS at 100F extracted and/or hydrofinished in a Hobart lo mixer equipped with a heating mantLeO The mixture becomes ll homogeneous and the temperature is raised to 260Fo A solu~
12 tion of 158 grams oE lithium hydroxide monohydrate in 1000 l3 grams of hot water is added dropwlse to the stlrred hot l~ DDSA/oil mi~tureO The wa~er ~lashes ofE rapldl.y and the lS addition is complete in 60 mlnutes~ A Eurther .~0 mi.nute 16 perlod of heatsoak at 260F tc 270F gives a clearD viscous l7 anhydrous productO The temperature of the anhydrous product 18 i5 raised to 300F and tetraethylenepentamine ls added in an 19 amount of 142 gramsO The reaction is complete in 5Q7 hoursO
A rust inhibitcr additive of this invention was 21 used in a fully fonmulated lOW~30 crankcase motor oil conW
22 talning an ashless dispersant which is the reaction product 23 of polyisobutenyl succinic anhydride with a polyamine9 a 24 zinc dialkyl dithiophosphate an oxidation inhibitorD an ethylene~propylene copolymer~ a non~alkylated naphthalene 26 dispersant and a silicone antifoæmantO
27 The rust inhibitor additive9 identical to that o:E
28 Example 3g is added ~o this blended base oil in an ~mount of 29 0O5 weight percent active ingredient and the resulting com~
position is tested in the MSIIB rust engine test in ac~or~
31 dance with the procedure in Example 2 aboveO The MSIIB rust 32 rating for this composition is 9O4O

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An oil composition comprising a major proportion of lubricating oil, and a minor rust inhibiting proportion, in the range of about 0.2 to 4.0 weight percent, of lithium salt of an amide of a hydrocarbon-substituted succinic acid; said hydrocarbon substituent containing 12 to 20 carbon atoms and being selected from the group consisting of alkenyl and alkyl groups;
said amide being the reaction product of said acid with a nitrogen material selected from the group consisting of ammonia, alkylene polyamines of the general formula:
wherein n is an integer less than about 10 and A is selected from the group consisting of hydrogen and a lower alkylene radical having less than about 8 carbon atoms, and said alkylene polyamines substituted with one or more hydroxy alkyl substituents on a nitrogen atom, in which the hydroxy alkyl group has less than about six carbon atoms.

2. An oil composition according to Claim 1, wherein said nitrogen material is a polyethyleneamine.

3. An oil composition according to Claim 1, wherein said nitrogen material is tetraethylene pentamine.

4. An oil composition according to Claims 1 - 3, wherein about five molar proportions of said succinic acid is reacted per about one molar proportion of said tetraethylene pentamine, and there is about one lithium atom per amine nitrogen.

5. An oil composition according to Claims 1 - 3, wherein said succinic acid is dodecenyl succinic acid.

6. An oil composition according to Claims 1 - 3, including an alkyl phenol having a total of about 5 to about 30 alkyl carbon atoms, in an amount sufficient to solubilize said lithium salt in said lubricating oil.

7. A rust inhibiting oil concentrate comprising a mineral oil and about 10 to 50 wt. % of the lithium salt of the amide of dodecenyl succinic acid and tetraethylene pentamine.

8. An oil concentrate according to Claim 7, which contains alkyl phenol as a solubilizing agent for said lithium salt in a mole ratio of about 15 to 0.5 moles of said lithium salt per mole of said alkyl phenol, and wherein said alkyl groups of said alkyl phenol contain 8 to 12 carbon atoms.