CA1199318A

CA1199318A - Borated lube oil additive

Info

Publication number: CA1199318A
Application number: CA000422728A
Authority: CA
Inventors: Ronald L. Anderson
Original assignee: BP Corp North America Inc
Current assignee: BP Corp North America Inc
Priority date: 1982-03-29
Filing date: 1983-03-02
Publication date: 1986-01-14
Also published as: ATE29732T1; EP0090629A2; DE3373672D1; JPH0672232B2; JPS58176296A; EP0090629A3; AU560164B2; ES521059A0; EP0090629B1; AU1260183A; ES8405061A1

Abstract

ABSTRACT
Borated reaction product of a long chain aliphatic succinic acid compound and alkylene diamine having an average of at least about 2 N-substituted hydroxyalkyl groups.

Description

BORATED LUBE OIL ADDITIVE
This invention relates to a borated reaction product of a long chain aliphatic succinic acid compound and alkylene diamine having an average of at least about 2 N-subs~ituted hydroxyalkyl groups and lube oil additives containiny said borated reac-tion products.
The patent literature is replete with disclosures of the use of various long chain aliphatic succinic acid compounds in lubricating oil compositions.
For example, Lubrizol discloses in U.S. Patents 3,219,666 of Norman e~ al; 3,381,022 oE Le Suer, 3,630,904 of Musser et al; 3,836,471 of Miller;
3,533,945 of Vogel; 3,28~,955 of Le Suer; etc. that foreign particles in lubricating oils is a particular problemO U~S. Patent 3l282,955 explains the problem at Column 1, lines 19 to 37 as follows: "One of the principal problems associated with present day automobile crankcase lubricants is that posed by the inevitable pre~ence in the lubricant of foreign particles such as dirt, soot, water, and decomposi-tion products resulting from breakdown of the lubri-cating oil. Even if there were none of this latter contaminant present the very nature of the design of the modern internal combustion engine is such that a significant amount of foreign matter will accumulate in the crankcaseD Perhaps the most impor-tant of these contaminants is water because it seems to be responsible for the deposition of a mayonnaise~
like sludge. It appears that if there were no water present the solid components of the mayonnaise-like sludge would circulate with the oil and be removed by the oil filter. It will be readily appreciated that the deposition of the sludge presents a serious problem with respect to the efficient operation of the engine and that it is desirable to prevent such deposition of sludge-like material." Subsequently, '~

U.S~ Pa~ent 3,630,904 points out at Column 1, lines 42 et seq. that high molecular weight acylated nitro-gen composi~ions have achieved wldespread use as ashless dispersants in crankcases and filters.
Generally, these ashless dispersants are prepared by reacting high molecular weight mono- or polyc~r~
boxylic acid acylating agents with a suitable amine or hydroxy compound. While the patentee indicates that the commercial success of these acylated nitro-gen compositions as ashless dispersants is conclusive evidence of their effectiveness as sludge-dispersants, the patentee points out that sludge can and does form on metal surfaces in areas of the engine where water vapor condenses at places such as rocker arms, oil-fill caps, etc.
As indica~ed above, numerous patents disclose various long chain aliphatic succinic acid deriva-tives. In somewhat greater detail, U.S~ Patents 3,219,666 and 3,640,904 disclose that hydroxyalkyl subst~tuted amines and polyamines can be reacted with long chain aliphatic succinic acid compounds and formulated into lubricating oil compositions.
U.S. Patent 3,282,955 discloses the formation of lubricating oil additives based upon borated reac-Z5 tion products of long chain succinic acid compounds and mono-amines, including N-substituted hydroxy-alkylated amines. U.S. Patent 3,533~945 discloses lube oil additives based upon borated reaction products of long chain aliphatic succinic acid com-pounds and polyols. U.S. Patent 3,836,471 discloses lube oil compositions containing the reaction product of long chain aliphatic succ.nic acid compounds and at least one polyoxyalkylene alcohol demulsifier with the possibility of utilizing amines such as polyalkylene polyamines or hydroxyalkylated poly-amines together with the polyoxyalkylene alcohol demulsifier~ U.S. Patent 3,630,904 discloses lube , , . .

oil compositions containing additives formed by reacting adducts of a hydroxyalkylamine and an acylating agent with a long chain aliphatic succinic acid compound. U.S. Patent 4,097,389 of Andress discloses lube oil compositions containing borated oxazoline additives wherein the oxazoline component is a cyclized reaction product of a long chain succinic acid compound and a tris(hydroxymethyl)aminomethane.
UOS. Patent 4,071,548 of Okamoto discloses lube oil co~positions comprising borated reaction products of long chain aliphatic succinic acid esters and/or amides con~aining oxyalkylene chains of at least 5 oxyalkylene units. All of the~e patents are hereby incorporated by reference. However, none of these references discloses borated reaction products of a long chain succinic acid compoùnd and an alkylene diamine having an average of at least abou~ 2-N-hydroxyalkyl groups and lube oil groups containing these borated reaction products.
While additives prepared from the reaction product of long chain aliphatic succinic acid compounds and alkylene polyamines are excellent lube oil additives, they are inferior to additives where the alkylene polyamine is hydroxyalkylated. In generall tlle more hydroxyalkyl moieties the greater the dispersancy.
However, the products based on hydroxyalkylated polyamines have the drawback that they tend to attack engine seals particularly those of the fluorocarbon polymer type thereby limiting the use of lubricating oils containing these dispersants. Accordingly, there is a need for high dispersancy lube oil addi-tives tha~ do not attack engine seals based on fluoro-carbon polymers.
The general object of this invention is to provide a lube oil additive having high dispersancy which is compatible with fluorocarbon engine seals.
Other objects appear hereinafter.
' :~

33~

We have now found that the objects of this inven-tion can be attained with borated reaction products of long chain aliphatic succinic acid compounds and alkylene diamines having on an average at least about 2 N-hydroxyalkyl groups. The additive of this invention is a particularly well balanced prod-uct. While we have found that it is generally desir-able to use long chain succinic acid amides and esters based on polyalkylene polyamines having a relatively high concentration of N-hydroxyalkyl moieties because the more N-hydroxyalkyl ~ubstituents the cleaner the engine, we have also found that the more amino groups in the polyamine the greater the degradation of fluorocarbon polymer seals. This means that while it is desirable ~o have a high level of hydroxyalkyl moie~ies in the additive to enhance engine cleanl;ness and reduce sludge forma-tion, alkylene amines containing more than 2 amino groups cannot be utilized in this invention. Hydroxy-alkylated monoamines do not provide adequate dis-persancy. At the same time, it is imperative ~hat the diamine have at least about 2 N-hydroxyalkyl groups, preferably 2.5 to 4-N-hydroxyalkyl groups, in order to provide acceptable levels of engine ~S cleanlinessO Boration is necessary in order to stabilize the additive and reduce engine seal attack.
Other things being equal, omission of boration leads to unacceptably high levels of fluorocarbon engine seal attack~ However, boration of additives prepared from N-unsubstituted diamines does not reduce fluoro-carbon engine seal attack. Accordingly, the lube oil additives of ~his invention are particularly well balanced.
Briefly the lube oil additives of this invention can be prepared by borating react;on products of an alpha long chain succinic acid compound and an alkylene diamine having on an average at least about 2 N-a~

hydroxyalkyl groups. In somewhat greater detail, the dispersants of this inven~ion can be prepared by (1) reacting an unsubstituted alkylene diamine with at least 2 mols of hydroxyalkylating reagent per mol of alkylene diamine, (2) reacting the result-ing N-hydroxyalkyl alkylene diamine with an alpha long chain aliphatic succinic acid compound and (3) borating the reaction product of step 2.
The alkylene diamines useful in khis invention have the structure NH2-R-NH~ wherein R is an alkylene group of from 2 to 24 carbon atoms, such as ethylene, 1,2-propylene, trimethylene, hexamethylene, dodecam-ethylene, tetracosene, etc. In general, alkylene diamines containing from about 6 to 12 methylene units are preferred, in order to provide a dispersant having the most advantageous properties, particularly compatibility with the lubricating oil. Hexa methylenediamine is preferred because of its relatively low cost and compatibility of additives ?O prepared from it with lube oils.
Suitable hydroxyalkylating reactants include halohydrins and vicinal epoxies (olefin oxides) con~aining from 2 to 4 carbon atoms in the alkylating agent, such as ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 2-chloro-1 ethanol, 2-chloro-1-propanol, 3-bromo-1-propanol, 4-chloro-butanol, etc. The vicinal epoxies are preferred because of their relatively high reactivity with the amine groups in the alkylene diamine. Of the various olefin oxides, propylene oxide is preferredO
Hydroxyethylated alkylene diamines tend to yield borated dispersants which are slightly incompatible with lubricating oils in the sense tha~ they yield hazy borated products. E~hylene oxide also has the disadvantage that it has a tendency to hydroxyethylate N-hydroxyethylated groups on the diamine thereby reducing the efficiency of the reaction. In contrast D3 ~3 propylene oxide yields borated additives which are fully compatible with the lubricating oils and has a reduced tendenc~- to react with N-hydroxypropylated amines. Butylene oxide tends to be less reactive than either ethylene oxide or propylene oxide and is substantially more expensive. ~he hydroxyalkylat-ing agents can be used in a concentration of about

2 to 6 mols per mol of alkylene diamine. In general approximately 2.5 to 4.5 mols of alkylene oxides per mol of diamine is preferred since the final products have about 2.5 to 4 N~hydroxyalkyl groups which provides the best properties at the lowest cost.
The alk.ylene diamine can be hydroxyalkylated under conventional conditions f i.e. by reaction at 50 to 300C from 1 to 10 hours.
The long chain aliphatic succinic acid compounds useful in this invention can be prepared by any of the techni~ues described in the aforesaid patents, which have been incorporated by reference. For examplel an acid compound, particularly an ethylenical-ly unsaturated dicarboxylic acid compound (acid or anhydride), such as maleic acid, maleic anhydride, fumaric acid, etc., can be reacted with a suitable olefin or halogenated olefin at a temperature of about 100 to 300C yielding an alkenyl or alkyl substituted succinic anhydride, If desired the unsaturated groups in the alkenyl group can be removed by standard hydrcgenation procedures. Typically, the olefins or halo substituted olefins contain from about 8 to 500 carbon atoms or more and can include homopolymers and copolymers of mono olefins such as ethylenel propyleneS l-butene, isobutene, etc. How~ver, as indicated above any of the tech-niques utilized in this art can be employed to pro-duce the long chain succinic acid compound.

The long chain aliphatlc succinic acid compounds are then reacted with the N-substituted hydroxyalkyl diamine under conditions normally employed i.n this art at a temperature of from 0 to 250C. If desired a solvent such as benzene, toluene, naphtha, lube oil, xylene and n-hexane or the like can be used to facilitate the control of the reaction. From about .5 to 2 mols of long chain aliphatic succinic acid compounds can be reacted per mol of N-substituted hydroxyalkyl alkylene diamine~ It will be noted that the long chain aliphatic succinic acid compound for purposes of this reaction is difunctional while the N-substituted hydroxy alkylene diamine is tetrafunctional irrespective of the degree of substitution of the alkylene diamine.
The boron compounds useful in this invention include boron oxide, boron dihalides (boron trifluoride, boron tribromide, boron trichloride~ boron acids, such as tetraboric acid, metaboric acid and simple esters of the boron acids (trialkyl borates containing 1 to 8 carbon alkyl groups such as methyl, ethyl, n~octyl, 2-ethylhexyl, etc.).
The boron compounds can be reacted with the long chain succinic acid-hydroxy alkylene diamine product at a temperature of from about 50 to 250C
preferably from about 100 to 170C with a sufficient concentration o boron compound to yield a long chain succinic acid product containing at least .15 percent by weight boron (excluding lu~e oil). The boron compound can be reacted in a ratio OL from 0.1 to 10 moles of boron compound per equivalent of starting long chain succinic acid compound ln s~ep lo This step can be carried out in the preserlce of diluen~ or solvent. In general, the more boron incorporated, the lower the seal attack.

3:~

Unless specified in the examples follvwing, percent boron content is always based on lube oil and additive concentration.

Example I
Four hundred fifteen grams of propylene oxide (7.15 moles) was added dropwise to two hundred sixty-two grams of hexamethylenediamine (2.26 moles) at 150C in a two liter, 3-necked, round bottom flask fitted with an overhead stirrer 9 condenser and tem-perature controller attached to a heating mantle through the top of the condenser over a four hour period while stirring. After the reaction was com-plete the reaction mass was found to have gained three hundred ninety-five grams ~6.81 moles propylene oxide, 95~ incorporation) or 3 moles propylene oxide per mole of hexamethylenediamine. The pale yellow N-hydroxypropylated hexamethylenediamine having on an average about 3 hydroxypropyl groups per hexamethy-lenediamine moiety remained a liquid at room tempera-ture for several days but sl~wly crystallized to a low melting solid.
One hundred sixty-six grams of the hydroxypropy~
lated hexamethylenediamine ~0~571 moles), sixteen hundred grams of a 50% active solution in oil of polybutenyl-succinic anhydride (0.571 moles~ having a molecular weight of fourteen hundred, and six hundred forty-nine grams SX-5 base oil were heated at 190C for two hours in a 3 liter, round bottom, 3-necked flask under a mild nitrogen purge.
The reaction mass was cooled to 130C and treated with 250 ml xylene and 35.3 grams of boric acid (00571 moles). The mixture was then refluxed at 140C with azeotropic removal of water and finally heated to 180C with a nitrogen purge to remove the xylene. The product (including base oil) was filtered with celite and contained 0023% boron (0.25%

33~&~

g B theoretical) and 0.63 nitrogen (0.66% nitrogen theoretical).
Example II
This Example illustrates the production of a borated reaction product of a long chain aliphat;c succinic acid compound and an unsubstituted alkylene diamine. Twelve hundred grams of a 40.5 percent active solution lin oil) of polybutenyl~succinic anhydride (0.217 moles) having a molecular wei~ht of 2240 and 50.4 grams hexamethylenediamine (0.43 mvles~ was heated at 100C for two hours in a 3 liter, 3-necked, round bottom flask~ The tempera-ture was then raised to 150~C and nitrogen was blown through the solution to remove excess hexamethylene-diamine. The resultant product h~as treated with ninety-seven grams of boric acid suspended in a Mannich condensation product of polybutylphenol, tetraethylenepentamine and formaldehyde (2.72% boron) overnight at 95C to yield a product containing 0~20% by weight boron and 0.47% nitrogen.
Example III
This Example illustrates the production of a borated reaction product of a long chain aliphatic succinic acid compound and alkylene diamine having an average of about 2 N-substituted hydroxypropyl groups. Twenty-four and nine-tenth grams of hydroxy-propylated hexamethylenediamine prepared by the method of Example I except that a two to one ~ole ratio of propylene oxide to diamine (0.107 molesj was used, three hundred grams of a 50~ active solution (in oil) of polybutenyl-succinic anhydride ~0.107 moles) combined with one hundred twelve grams SX-5 base oil were heated at 190C for two hours in the manner described in Example XI. Two hundred grams of this reaction product (0.0490 moles) were treated with 15.2 grams boric acid (0~246 moles~ and eight ~rams of water at 82C for ninety minutes and then '3;~

at 170C for two hours followed by ~ilkr~tion through celite. The final product was shown to be primarily amide and imide by infrared spectroscopy and contained 1.11~ B (1.31 theoretical).
Example IV
This Example illustrates the production of an unborated reaction product of polybutenyl succinlc anhydride and hydroxypropylated hexamethylenediamine having approximately khree hydroxypropyl groups per hexamethylenediamine moiety~ Sixty two grams of the hexamethylenediamine prop~lene oxide reaction product of Example I, twelve hundred grams of a 40%
active oil solution of polybutenyl-succinic anhydride havin~ a molecular weight of 22~0 (0.214 moles) and ninety-three grams SX-5 base oil were heated at 150nC for five hours with a mild nitrogen purge in a 3 liter, 3-necked flask. The resultant product contained 0.456~ nitrogen (0~44 ~heore~ical~ and was shown by infrared spectroscopy to be a mixture of ester (1740 cm~l) and amide (1650 cm~l).
Example V
This Example illustrates the preparation of a borated reaction product of polybutenyl-succinic anhydride and hydroxypropylated hexamethyl2nediamine having approximately three hydroxypropyl groups per hexamethylenediamine moiety and a relatively high boron content~ One hundred nineteen grams of the hexamethylenediamine propylene oxide reaction product of Example I, one thousand forty-five grams of a 55% active oil solution of polybutenyl-succinic anhydride having a molecular weight of fou~teen hun-dred (.41 moles) and five hundred seventy-one grams SX-5 base oil were heated at 190C for two hours with a nitrogen purge in a 5 liter, 3-neck~d flask.
After the reaction mass was cooled ko 82C, one hundred twenty seven grams boric acid (2.05 moles) and six~y-three grams of water were added~ The ,~;

-,g~

reaction mixture was slowly hea~ed to 170C and held at 170C for two hours and filtered. The final product contained 0.99% boron.
Example VI
This ~xample illustrates a comparison of sequence VD engine test of dispersants made according to Example~ I, II, IV and V.
Sequence V~ Results (wt. Oil Avg.
Dispersant ~) Type Sludge (9.4)*

Example I (4.15) SF/CC 9.66 Example I (4.00) SF/CD 9.45 Example II (5.00) SF/CC 8.99 Example IV (5.00~ SF/CC 9.52 Example ~T t4.50) SF/CC 9.57 DispersantAvg. Vaxnish Piston Varnish (6.6)* (6.7)*

Example I 7~70 7-54 Example I 7.85 7~38 Example II 7.44 6.98 Example IV 7.72 7.60 Example V 6.39 6.39 *Minimum rating needed to pass (10 = clean) The above data shows that a borated unpropoxylated adduct failed the sequence VD test whereas the propoxylated and borated propoxylated adducts of Examples I, II and IV passed the above test. The borated propoxylated adduct of Example V passed the average sludge and piston varish tests and would pass ~he average varish test at a higher concentra-tion.

3~

Example VII
Dispersants prepared in accordance wi~h the preceding Examples were tested by suspending a fluoro~
carbon seal in oil solution at 300~F for seven days and the change in physical properties ~tensile strength percent elongation) was then measured.

Type %BWt.~ in SF/CC Blend HMDA-2PO 0.00 4.0 HMDA-2PO 0.23 4.0 HMDA-2PO (Ex. III) 1.11 4.0 HMDA-3PO 0~00 4.0 HMDA-3PO (Ex. I) 0.23 4.0 HMDA-3PO 5Ex. V) 0.99 4.5 HMDA-4PO 0.00 4,0 HMDA-4PO 0.23 4.0 HMDA 0.00 4~0 HMDA (Ex. II) 0~20 4.0 ~ Tensile Type% Elongation** Strength**

HMDA-2PO (Ex. III) -21 -15 HMDA-3PO (Exo I) -40 -45 HMDA-3PO (Ex. V) ~25 -21 HMDA ~24 -25 HMDA (Ex. II) -27 -28 ~:~t~3 --~3--** These values indicate the change in the indicated physical property as a result of aging khe test specimen in the hot oil blend. ~ value of zero is ideal~
The above data clearly shows that boration of an unpropoxylated adduct has no substantial effect upon fluorocarbon seal test results whereas boration of hydroxypropylated dispersants reduces fluorocaxbon seal attack as the concentration of boron in the dispersant increases.
Example VIII
'his Example illustrates the production of a borated reaction product of polybutenyl-succinic anhydride and hydroxyethylated hexamethylenediamine having approximately four hydroxyethyl groups per hexam~thylenediamine moietyO Three hundred seventy grams hexamethylenediamine (3.19 moles) were heated to 180C in a one liter, 3-necked round bottom flask fitted with an overhead stirrer fritted glass gas dispersion tube, thermometer and heating mantle.
While stirring vigorously, ethylene oxide was added through the gas dispersion tube for six and one-half hours until ~he product gained five hundred sixty-two grams, corresponding to reaction of 12O77 moles of ethylene oxide (4:1 ratio of ethylene oxide to hexamethylenediamine).
Thirty-five grams of the hydroxyethylated hexamethylenediamine (.120 moles), four hundred fifty grams of a 50~ active oil solution of poly-butenyl-succinic anhydride (.161 moles) having a molecular weight of 1400, and one hundred sixty-five grams SX-S base oil were heated at 190C for two hours with a mild nitrogen purge in the manner described in Example I.
A portion of this product (three hundred eighty-nine grams) was cooled to 100C and treated with ;~ L~3~

fifty milliliters of xylene and 5.9 grams of horic acid. The mixture was then refluxed at 140C with azeotropic removal of water and finally heated to 180C with a nitrogen purge to remove the xylene.
The product (including ba~e oil) was filtered with celite and the final product con~ained 0.11% boron.

Claims

I claim:

1. A borated reaction product of a long chain aliphatic succinic acid compound and alkylene diamine having an average of at least about 2 N-substituted hydroxyalkyl groups.

2. The borated reaction product of Claim 1 wherein said alkylene diamine has on an average from about 2.5 to 4 N-substituted hydroxyalkyl groups.

3. The borated reaction product of Claim 1 wherein the hydroxyalkyl groups are hydroxypropyl groups.

4. The borated product of Claim 1 wherein the alkylene diamine contains from 2 to 24 carbon atoms.

5. A borated reaction product of a long chain aliphatic succinic acid compound and alkylene diamine containing from 6 to 12 methylene units having an average of about 2.5 to 4 N-substituted hydroxypropyl groups.

6. A lubricating oil composition comprising a lube oil and the borated reaction product of Claim 1.

7. A lubricating oil composition comprising a lube oil and the borated reaction product of Claim 5.

8. The method of producing a lube oil additive, which comprises the steps of (1) reacting an unsub-stituted alkylene diamine with at least 2 mols of hydroxyalkylating reagent per mol of alkylene diamine (2) reacting the resulting N-hydroxyalkyl alkylene diamine with an alpha long chain aliphatic succinic acid compound and (3) borating the reaction product of step 2 with sufficient concentration of boron compound to yield a long chain succinic acid product containing at least .15% by weight boron.

9. The process of Claim 8 wherein the hydroxy-alkylating reagent is propylene oxide in a concentra-tion of about 2.5 to 4.5 mols per mol of diamine.

10. The process of Claim 9 wherein the alkylene diamine contains from 6 to 12 methylene units.

11. The process of Claim 9 wherein the alkylene diamine comprises hexamethylenediamine.