GB2307685A - Seal compatible diesel dispersants - Google Patents

Abstract

An oil-soluble dispersant obtainable by boronating and acylating the product formed by reacting (1) a polyalkenyl succinic acylating agent, (2) a polyamine and (3) a nitrogen-containing compound of formula R 1 [N(R 1 )R] q -Y in which: Y is -N(R 1 ) 2 , piperazinyl optionally N-substituted by a group R 1 or a group R 1 [N(R 1 )R] q - or is a 4-morpholinyl group; q is from 0 to 10; R is an alkylene group having from 2 to 6 carbon atoms; and R 1 is independently selected from hydrogen and a group of formula (R 2 O) r R 3 in which r is 0 to 6, R 2 is an alkylene group having 2 to 6 carbon atoms and R 3 is an hydroxyalkyl group having 2 to 6 carbon atoms, provided that when Y is - N(R 1 ) 2 or optionally substituted 1-piperazinyl the nitrogen-containing compound has on average from 1 to less than 3 free hydroxyl groups per molecule.

Description

SILL COMPATIBLE DIESEL DISPERSAMTS This invention relates to dispersants useful as additives in lubricating oils, especially lubricating oils for diesel engines and vehicles driven by such engines. More particularly, the present invention provides novel ashless dispersants which have reduced reactivity towards fluoroelastomers and which impart excellent soot handling capability to lubricating oils in which they are included.

A continuing problem in the art of lubrication is to provide lubricant compositions which meet the requirements of original equipment manufacturers. One such requirement is that the lubricant does not cause or contribute to premature deterioration of seals, clutch face plates or other parts made from fluoroelastomers. Many currently used dispersants contain basic nitrogen, and it is known that such dispersants, including more particularly the commonly used succinimide dispersants, tend to have an adverse effect upon fluoroelastomers which causes them to lose flexibility and tensile strength, to become brittle, and, in severe cases, to disintegrate.Standard test methods for evaluating fluoroelastomer compatibility of lubricant compositions include the Volkswagen PV-3334 Seal Test and the CCMC Viton Seal Test (CEC L-39-T-87 oil/elastomer compatibility test).

However, there now exists a more severe fluoroelastomer comparability test procedure called the Volkswagen PV-3344 Seal Test. A variety of commercially available premium dispersant-containing diesel oils from various manufacturers fail to meet the requirements of the PV-3344 test. There is therefore a continuing need for novel dispersants which satisfy current requirements for compatibility with fluoroelastomers while at the same time meeting the other requirements for ashless dispersants to be used in lubricant oils.

It is a further requirement of the automotive industry that engine exhaust emissions, such as NO, and particulates, be minimised. In diesel engines methods for doing this include recirculating exhaust gas and retarding fuel injection timing. However, while achieving the desired reduction in exhaust emissions, this also causes an increase in the carbon/soot content of the engine oil. In turn this leads to an increase in oil viscosity. At high soot loading the increase in viscosity of the oil becomes unacceptable.

It is thus also desirable to provide a lubricant oil additive which reduces or even negates the effect of soot loading on oil viscosity, thereby minimizing or preventing viscosity increase. Lubricating oils which exhibit this beneficial effect are said to show improved soot handling capability.

The present invention provides novel oil-soluble ashless dispersants which have improved compatibility with fluoroelastomers and which impart improved soot handling capability to lubricating oils in which they are included.

The oil-soluble dispersants of the present invention are made by boronating and acylating the product formed by reacting (1) a polyalkenyl succinic acylating agent, (2) a polyamine and (3) a nitrogen-containing compound of formula R1(N(R1)R] qY in which: Y is -N(R)2, piperazinyl optionally N-substituted by a group R1 or a group R1[N(R1)R]q or is a 4-morpholinyl group; q is from 0 to 10; R is an alkylene group having from 2 to 6 carbon atoms; and RX is independently selected from hydrogen and a group of formula (R20),R3 in which r is 0 to 6, R2 is an alkylene group having 2 to 6 carbon atoms and R3 is an hydroxyalkyl group having 2 to 6 carbon atoms, provided that when Y is -N(R1)2 or optionally substituted 1-piperazinyl the nitrogen-containing compound (3) has on average from 1 to less than 3 free hydroxyl groups per molecule.

Polyalkenes which may be used in making the succinic acylating agent (1) are described for example in EP-A-0460309 and USP 4,234,435. The polyalkene is typically one having a number average molecular weight of between about 800 and about 5000, preferably between about 900 and about 2500 and more preferably still between about 900 and about 1500.

Polyalkenes having a number average molecular weight of about 1300 are especially preferred.

Specific examples of polyalkenes which may be used include polypropylenes, polybutenes, ethylene-propylene copolymers, styrene-isobutene copolymers, isobutene-1,3-butadiene copolymers, propene-isoprene copolymers, isobutene-chloroprene copolymers, isobutene-4-methylstyrene copolymers, copolymers of l-hexene with 1,3-hexadiene, copolymers of l-octene with 1-hexene, copolymers of l-heptene with 1-pentene, copolymers of 3-methyl-l-butene with l-octene, copolymers of 3,3-dimethyl-l-pentene with 1-hexene, and terpolymers of isobutene, styrene and piperylene.More specific examples of such interpolymers include copolymer of 95% (by weight) of isobutene with 5% (by weight) of styrene, terpolymer of 98% of isobutene with 1% of piperylene and 1% of chloroprene; terpolymer of 95% of isobutene with 2% of l-butene and 3% of l-hexene, terpolymer of 60% of isobutene with 20% of l-pentene and 20% of 1-octene, copolymer of 80% of 1-hexene and 20% of l-heptene, terpolymer of 90% of isobutene with 2% of cyclohexene and 8% of propylene, and copolymer of 80% of ethylene and 20% of propylene. Preferred sources of polyalkenes are the polyisobutenes, such as those obtained by polymerisation of C4 refinery streams which contain both nbutene and isobutene in various proportions using a Lewis acid catalyst such as aluminum trichloride or boron trifluoride.These polybutenes usually contain predominantly (for example, greater than about 80% of the total repeating units) of repeating units of the configuration

In forming the polyalkenyl succinic acylating agent the polyalkene is reacted with an unsaturated acid, i.e. monomer or derivative thereof which is responsible for the presence of acidic groups in the acylating agent. Such unsatyrated acids and their derivatives may be represented by the formula: X-CO-CH=CH-CO-X' where X and X' are such that at least one of them is capable of reacting with a polyamine. These acids are described in greater detail in EP-A-0460309. Especially preferred acids which may be used include maleic and fumaric acids and their derivatives, particularly their anhydrides. The preparation of polyalkenyl succinic acylating agents as used in the present invention is well known in the art, for example from USP 3,912,764 and USP 3,215,707.

According to a preferred feature of the invention the polyalkenyl succinic acylating agent is polyisobutenyl succinic anhydride derived from a polyisobutene having a number average molecular weight of about 1300.

The polyamine (2) used in making the oil-soluble dispersant of this invention is one or a mixture of polyamines which preferably has at least one primary amino group in the molecule and which additionally contains an average of at least two other amino nitrogen atoms in the molecule.

One preferred type of polyamine is represented by the formula: H2N (CH2) D (NH ( CH2) n) mNH2 wherein n is 2 to about 10 (preferably 2 to 4, more preferably 2 or 3, and most preferably 2) and m is 0 to 10, (preferably 1 to about 6). Illustrative are ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, spermine, pentaethylene hexamine, propylene diamine (1,3-propanediamine), butylene diamine (1,4-butanediamine), hexamethylene diamine (1,6-hexanediamine), decamethylene diamine (1,10-decanediamine), and the like. Typically polyamines containing 3 to 6 nitrogen atoms in the molecule are used.

Preferred for use is tetraethylene pentamine (TEPA) or a polyamine mixture which approximates tetraethylene pentamine.

These mixtures are commercially available (e.g. S-1107 available from Dow Chemical Company). Cyclic polyamines such an aminoalkyl-piperazines, e.g. ss-aminoethyl-piperazine, can also be used in the invention.

Another preferred type of polyamine is comprised of hydrocarbyl polyamines containing from 10 to 50 weight percent acyclic alkylene polyamines and 50 to 90 weight percent cyclic alkylene polyamines. Preferably such mixture is a mixture consisting essentially of polyethylene polyamines, as described in EP-A-0460309.

In the nitrogen-containing compound (3) q is 0 to 10, preferably 0 to 5 and r is 0 to 15, preferably 0 to 10. R is an alkylene group having from 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms. R2 is an alkylene group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms. R3 is an hydroxyalkyl group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms.

The values q and r take are selected independently.

This means for example that when Y is bonded to two groups Rl[N(Rl)R]q~ the value q takes need not be the same in each substituent group. Also, when r is greater than zero, R2 may be the same or different in each ether repeat unit.

The nitrogen-containing compounds (3) which may be used in the present invention are commercially available or may be the made by the application or adaptation of known techniques. For example, the compounds in which r is 1 or more, i.e. those containing an ether or polyether linkage, can be prepared by reaction of a suitable amine, morpholine or piperazine compound with a molar excess of one or more alkylene oxides. When the same kind of alkylene oxide is used R2 and R3 contain the same alkylene moiety. When different kinds of alkylene oxide are used R2 and R3 may contain the same or different alkylene groups.

In one aspect of the invention, when Y is -N(R) 2 or optionally substituted l-piperazinyl, the nitrogen-containing compound (3) contains on average from 1 to 2 free hydroxyl groups per molecule.

According to a preferred embodiment, in the nitrogencontaining compound (3) Y is -N(R)2 or optionally substituted l-piperazinyl, q is 0 to 4, R is ethylene and Rl is hydrogen or a group of formula (R2O),R3 in which r is 0 and R3 is an hydroxyalkyl group having from 2 to 4 carbon atoms, the proviso described above applying. More particularly, the nitrogen-containing compound is diethanolamine or ethylene diamine, diethylene triamine, triethylene tetramine, piperazine or aminoethylpiperazine N-substituted by on average 1 to 2 hydroxyethyl or hydroxypropyl groups per molecule. Preferably, the latter are ss-hydroxyethyl or ss-hydroxypropyl groups.

In another preferred aspect of the invention, Rl is hydrogen or a group of formula (R2O),R3 in which r is 1 to 3, R2 is an alkylene group having 2 or 3 carbon atoms and R3 is an hydroxyalkyl group having 2 or 3 carbon atoms, the proviso described above applying. In such compounds q is preferably 0 and Y is -N(R) 2. An example of such is the compound formed by reacting 1 mole of diethanolamine with 4 moles of propylene oxide. In this reaction the diethanolamine is propoxylated on the oxygen atoms.

According to a further preferred embodiment, in the nitrogen-containing compound (3), Y is 4-morpholinyl, q is 0 to 2 and R is an alkylene group having 2 to 4 carbon atoms, for example morpholine or N-(2-(4-morpholinyl)ethyl-1,2ethane diamine.

In accordance with the present invention, the oil soluble dispersant composition is prepared by reacting, concurrently or sequentially in any order, the polyalkenyl succinic acylating agent (1), the polyamine (2) and the nitrogen-containing compound (3), and then boronating and acylating, concurrently or in any order, the reaction product obtained.

In the reaction the mole ratio of polyamine (2) to nitrogen-containing compound (3) is typically 95:5 to 1:1, but is usually in the range of 9:1 to 2:1.

Usually in making the dispersants of the present invention the mole ratio of polyalkenyl succinic acylating agent (1) to the total of polyamine (2) and nitrogencontaining compound (3) is in the range of 1.2:1 to 4:1, preferably in the range from 1.5:1 to 3:1.

The ashless dispersants of the present invention may be prepared by reacting the polyalkenyl succinic acylating agent (1), polyamine (2) and alkoxylated polyamine (3) in the desired mole ratio at a temperature in the range of 140 to 190 C. However, it is preferable to carry out the reaction at a temperature of between 150 and 170 C. Generally, the reaction is complete within 3 to 4 hours.

The product obtained from reacting the components (1), (2) and (3) is then subjected to post-treatment, in known manner, with a boronating agent and an acylating agent.

Suitable post-treating agents are known in the art. Here reference may be made, for example, to USP 5241003 and the United States Patents referred to therein, to USP 4857214 and USP 5164103 and to EP-A-0460309. As described above, posttreatment may be performed simultaneously or consecutively with the chosen boronating and acylating post-treatment agents. The most preferred post-treating agent for use in the practice of this invention is maleic anhydride. In the overall reaction the mole ratio of total succinic acylating agent and acylating agent to total of polyamine (2) and nitrogen-containing compound (3) is 1.6 or greater.

Boronation of the dispersants is accomplished using a boron compound or mixture of boron compounds capable of introducing boron-containing species into the dispersant undergoing the reaction. Any boron compound, organic or inorganic, capable of undergoing such reaction can be used.

Accordingly use can be made of boron oxide, boron oxide hydrate, boron trifluoride, boron tribromide, boron trichloride, HBF4, boron acids such as boronic acid (e.g.

alkyl-B(OH)2 or aryl-B(OH)2), boric acid (i.e. H3BO3), tetraboric acid (i.e. H2B5O7), metaboric acid (i.e. HBO2), ammonium salts of boron acids, and esters of such boron acids. The use of complexes of a boron trihalide with ethers, organic acids, inorganic acids, or hydrocarbons is a convenient means of introducing the boron reactant into the reaction mixture. Such complexes are known and are exemplified by boron trifluoride-diethyl ether, boron trifluoride-phenol, boron trifluoride-phosphoric acid, boron trichloride-chloroacetic acid, boron tribromide-dioxane, and boron trifluoride-methyl ethyl ether. The use of boric acid is preferred.

Specific examples of boronic acids include methyl boronic acid, phenyl boronic acid, cyclohexyl boronic acid, p-heptylphenyl boronic acid and dodecyl boronic acid.

The boron acid esters include especially mono, di-, and tri-organic esters of boric acid with alcohols or phenols such as, e.g. methanol, ethanol, isopropanol, cyclohexanol, cyclopentanol, l-octanol, 2-octanol, dodecanol, behenyl alcohol, oleyl alcohol, stearyl alcohol, benzyl alcohol, 2butyl cyclohexanol, ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 2,4-hexanediol, 1,2cyclohexanediol, 1,3-octanediol, glycerol, pentaerythritol, diethylene glycol, carbitol, Cellosolve, triethylene glycol, tripropylene glycol, phenol, naphthol, p-butylphenol, o,pdiheptylphenol, n-cyclohexylphenol, 2,2-bis-(p-hydroxyphenyl) propane, polyisobutene (molecular weight of 1500)-substituted phenol, ethylene chlorohydrin, o-chlorophenol, m-nitrophenol, 6-bromo-octanol, and 7-keto-decanol.Lower alcohols, 1,2glycols, and 1,3-glycols, i.e. those having less than about 8 carbon atoms are especially useful for preparing the boric acid esters for the purpose of this invention.

In accordance with the invention the oil-soluble dispersant may be provided as an additive concentrate.

Typically, the concentrate comprises the oil-soluble dispersant of the invention in combination with a diluent oil and/or other liquid inert diluent(s). Such concentrates typically comprise from 1 to 99% by weight of the diluent oil and/or inert diluent and from 99 to 1% by weight of the dispersant of the invention.

The invention also includes within its scope compositions, especially lubricant compositions, comprising an oil of lubricating viscosity and a dispersant as described above. The dispersants can be used in a wide variety of conventionally used lubricating oils. The concentration at which the dispersant is used generally falls in the range of up to about 10% by weight, for example 1 to 9% by weight.

Amounts of up to about 2 to 7% by weight are preferred.

The concentrates and lubricant compositions of the invention typically contain other additives commonly found in lubricant formulations. Such additives include viscosity index improvers, antiwear agents, antioxidants, rust inhibitors, antifoams and color stabilizers. Of course, these additives are only used provided they are compatible with the dispersants of the present invention and the other component(s) used. When present the other additive(s) are used in conventional amounts.

A further embodiment of the invention is the use of the above described dispersants in a lubricant composition for lubricating an engine, e.g. a diesel engine, or other device.

The invention thus includes within its scope a method of lubricating mechanical parts using a lubricating oil or functional fluid comprising a dispersant of the invention.

As noted above, the dispersants of the invention show a remarkably reduced tendency to degrade or otherwise adversely effect fluoroelastomers. Such composition is thus particularly suitable when in use it comes into contact with a fluoroelastomer.

The invention further provides a method of improving the soot handling capability of an oil of lubricating viscosity which comprises incorporating therein an oil-soluble dispersant as described above.

The following examples illustrate the present invention.

Example 1 Polyisobutylenylsuccinic anhydride (PIBSA) prepared from polyisobutylene with a number average molecular weight of 1300 (1000g; 0.69mole) was stirred and heated to 16700 and a vacuum applied. Tetraethylene pentamine (TEPA) (50.8g; 0.268mole) and N,N-Bis(2-hydroxyethyl)ethylenediamine (EDA2EOasy) (17.0g; 0.115mole) were mixed together and added over approximately 30 minutes. After the amine addition was complete the mixture was stirred for 3 hours and the, vacuum released. 100SN process oil (200g) was added and after the temperature had been adjusted to 1500C, boric acid (77.4g; 1.25mole) was added. The mixture was stirred for an hour and then maleic anhydride (11.4g; 0.116mole) was added.The mixture was stirred for a further 15 minutes and then the water of reaction was removed by applying a vacuum of 100mm Hg for one hour. The vacuum was then released and a further charge of process oil (155g) made. The product after filtering contained 1.40% Nitrogen and 1.0% Boron.

Example 2 The procedure of Example 1 was repeated except that the charge of TEPA was 65.2g (0.345mole) and the EDA-2EOasy was replaced by diethylene triamine alkoxylated with one mole of ethylene oxide (DETA-EO) (5.6g; 0.038mole). The product after filtering contained 1.70% Nitrogen and 0.86% Boron.

Example 3 Example 2 was repeated except that the charge of TEPA was 58.0g (0.307mole) and the charge of DETA-EO was 11.3g (0.077mole). The product contained 1.54% Nitrogen and 0.91% Boron.

Example 4 Example 2 was repeated except that the charge of TEPA was 50.7g (0.268mole) and the charge of DETA-EO was l6.9g (0.115mole). The product contained 1.48% Nitrogen and 0.87% Boron.

Example 5 Example 1 was repeated except that the EDA-2EOasy was replaced by N-(2-hydroxyethyl)ethylenediamine (EDA-EO) (11.9g; 0.113mole) and the first charge of process oil was increased to 400g. The product contained 1.2% Nitrogen and 0.84% Boron.

Example 6 Example 5 was repeated except that the TEPA charge was 58.lg (0.307mole) and the EDA-EO charge was 7.9g (0.075mole).

The product contained 1.34% Nitrogen and 0.84% Boron.

Example 7 Example 5 was repeated except that the TEPA charge was 65.3g (0.346mole) and the EDA-EO charge was 4.0g (0.038mole).

The product contained 1.41% Nitrogen and 0.80% Boron.

Example 8 Polyisobutylenylsuccinic anhydride (PIBSA) prepared from polyisobutylene with a number average molecular weight of 1300 (300g; 0.207mole) was stirred and heated to 167C and a vacuum applied. Tetraethylene pentamine (TEPA) (15.24g; 0.08lmole) and N,N'-Bis(2-hydroxyethyl)ethylenediamine (EDA2EOsy) (5.10g; 0.034mole) were mixed together and added over 30 minutes. After the amine addition was complete the mixture was stirred for 3 hours and the vacuum released. l00SN process oil (60g) was added and after the temperature had been adjusted to 1500C, boric acid (23.2g; 0.375mole) was added. The mixture was stirred for an hour and then maleic anhydride (3.4g; 0.035mole) was added. The mixture was stirred for a further 15 minutes and then the water of reaction was removed by applying a vacuum of 100mm of Hg for one hour. The vacuum was then released and a further charge of process oil (46.5g) made. The product after filtering contained 1.35% Nitrogen and 0.79% Boron.

Example 9 Example 8 was repeated except that the charge of TEPA was 19.6g (0.104mole) and the charge of EDA-2EOsy was 1.7g (0.012mole). The product contained 1.57% Nitrogen and 0.80% Boron.

Example 10 Polyisobutylenylsuccinic anhydride (PIBSA) prepared from polyisobutylene with a number average molecular weight of 1300 (500g; 0.345mole) was stirred and heated to 16700 and a vacuum applied. Tetraethylene pentamine (TEPA) (25.4g; 0.134mole) was added first followed by N,N-Bis(2hydroxyethyl)ethylenediamine (EDA-2EOasy) (8.5g; 0.057mole) with a total addition time of 30 minutes. After the amine addition was complete the mixture was stirred for 3 hours and the vacuum released. 100SN process oil (bog) was added and after the temperature had been adjusted to 1500C, boric acid (38.7g; 0.626mole) was added. The mixture was stirred for an hour and then maleic anhydride (5.7g; 0.058mole) was added.

The mixture was stirred for a further 15 minutes and then the water of reaction was removed by applying a vacuum of 100mm of Hg for one hour. the vacuum was then released and a further charge of process oil (77.5g) made. The product after filtering contained 1.40% Nitrogen and 0.88% Boron.

Example 11 Example 10 was repeated except that the EDA-2EOasy was added first followed by the TEPA. The product after filtering contained 1.45% Nitrogen and 0.87% Boron.

Example 12 Example 8 was repeated except that the EDA-2EOsym was replaced by diethanolamine (DEA) (3.63g; 0.035mole). The product after filtering contained 1.29% Nitrogen and 0.85% Boron.

Example 13 Example 1 was repeated except that the EDA-2EOasy was replaced by diethanolamine propoxylated on oxygen with 4 moles of propylene oxide (DEA-4PO) (38.8g; 0.115mole). The product after filtering contained 1.31% Nitrogen and 0.92% Boron.

Example 14 Example 8 was repeated except that the EDA-2EOsym was replaced by diethylene triamine alkoxylated with 1.5 moles of ethylene oxide (DETA-1.5EO) (5.82g; 0.034mole). The product after filtering contained 1.40% Nitrogen and 0.96% Boron.

Example 15 Example 8 was repeated except that the EDA-2EOsym was replaced by diethylene triamine alkoxylated with 2.0 moles of ethylene oxide (DETA-2.0EO) (6.58g;0.034mole). The product after filtering contained 1.43% Nitrogen and 0.87% Boron.

Example 16 Example 8 was repeated except that the EDA-2EOsym was replaced by diethylene triamine alkoxylated with 1.2 moles of propylene oxide so that > 97% of the secondary amine is reacted (DETA-1.2PO-S) (5.95g; 0.034mole). The product after filtering contained 1.48% Nitrogen and 0.83% Boron.

Example 17 Polyisobutylenylsuccinic anhydride (PIBSA) prepared from polyisobutylene with a number average molecular weight of 1300 (600g; 0.414mole) was stirred and heated to 167"C and a vacuum applied. Tetraethylene pentamine (TEPA) (36.95g; 0.196mole) and (DETA-1.2PO-S) (5.95g; 0.034mole) were mixed together and added over approximately 30 minutes. After the amine addition was complete the mixture was stirred for 3 hours and the vacuum released. 100SN process oil (120g) was added and after the temperature had been adjusted to 1500C, boric acid (46.4g; 0.75mole) was added. The mixture was stirred for an hour and then maleic anhydride (6.8g; 0.069mole) was added. The mixture was stirred for a further 15 minutes and then the water of reaction was removed by applying a vacuum of 100mm of Hg for one hour.The vacuum was then released and a further charge of process oil (93g) made.

The product after filtering contained 1.58% Nitrogen and 0.89% Boron.

Example 18 Example 8 was repeated except that the EDA-2EOsym was replaced by aminoethylpiperazine alkoxylated with 1.1 moles of ethylene oxide so that the hydroxyethyl group is on the ring nitrogen (AEP-l.lEO) (6.11g; 0.034mole). The product after filtering contained 1.59% Nitrogen and 0.86% Boron.

Example 19 Example 8 was repeated except that the EDA-2EOsym was replaced by triethylene tetramine alkoxylated with 1.0 moles of ethylene oxide (TETA-EO) (6.53g; 0.034mole). The product after filtering contained 1.56% Nitrogen and 0.91% Boron.

Example 20 Example 8 was repeated except that the EDA-2EOsym was replaced by triethylene tetramine alkoxylated with 2.0 moles of ethylene oxide (TETA-2EO) (8.22g; 0.034mole). The product after filtering contained 1.70% Nitrogen and 0.90% Boron.

Example 21 Example 8 was repeated except that the EDA-2EOsym was replaced by 2-hydroxyethylpiperazine (HEP) (4.48g; 0.034mole). The product after filtering contained 1.43% Nitrogen and 0.96% Boron.

In Examples 22-26 the following mole ratios and charges were used. In each case the general procedure of Example 1 was followed.

EXAMPLE 22 23 24 25 26 (1):[(2)+(3)] MALEIC ANHYDRIDE 1.6:1:0.3 1.8:1:0.5 2:1:0.4 2:1:0.4 2:1:0.4 (mole ratio) Moles of BA / Mole [(2)+(3)] 4.0 2.0 2.0 3.0 3.0 PIBSA, g 300 300 300 300 300 TEPA, g 17.14 15.24 13.69 17.60 18.58 EDA-2EOasy, g 5.75 5.10 4.59 1.53 0.77 Process OIL, g 60 60 60 60 60 BORIC ACID, g 32.00 14.20 12.80 19.20 19.20 MALEIC ANHYDRIDE, g 3.80 5.70 4.06 4.06 4.06 P.OIL, g 46.50 46.50 46.50 46.50 46.50 Nitrogen, % 1.43 1.37 1.24 1.39 1.46 Boron, % 1.30 0.54 0.51 0.73 0.70 Example 27 Example 8 was repeated except that the EDA-2EOsym was replaced by morpholine (3.0g; 0.035mole). The product after filtering contained 1.32% Nitrogen and 0.85% Boron.

Example 28 The procedure of Example 1 was repeated except that the charge of TEPA was (58.0g; 0.307mole) and the EDA-2EOasy was replaced by N- (2-(4-Morpholinyl) ethyl) -1,2-ethane diamine (MEED) (14.3g; 0.038mole). The product after filtering contained 1.47% Nitrogen and 0.93% Boron.

Comparative ExamPle 1 Example 5 was repeated except that the EDA-EO was replaced by N,N-dimethyl-1,3-propanediamine (DMAPA) (11.7g).

The product contained 1.2% Nitrogen and 0.82% Boron.

ComParative Example 2 Example 1 was repeated except that the EDA-2EOasy was replaced by ethylenediamine alkoxylated with 3.0 moles of propylene oxide (EDA-3PO) (26.8g; 0.114mole). The product contained 1.4% Nitrogen and 0.91% Boron.

Comparative Example 3 Example 8 was repeated except that the EDA-2EOsym was replaced by hexamethylenediamine alkoxylated with 3.0 moles of propylene oxide (HMDA-3PO) (10.02g; 0.035mole). The product after filtering contained 1.29% Nitrogen and 0.85% Boron.

Comparative Example 4 Polyisobutylenylsuccinic anhydride (PIBSA) prepared from polyisobutylene with a number average molecular weight of 1300 (1000g; 0.69mole) was stirred and heated to 16700 and a vacuum applied. Tetraethylene pentamine (72.4g) was added over approximately 30 minutes. After the amine addition was complete the mixture was stirred for 3 hours and the vacuum released. l00SN Process oil (200g) was added and after the temperature had been adjusted to 1500C, boric acid (77.4.g; 1.25mole) was added. The mixture was stirred for an hour and then maleic anhydride (11.4g; 0.116mole) was added. The mixture was stirred for a further 15 minutes and then the water of reaction was removed by applying a vacuum of l00mm of Hg for one hour.The vacuum was then released and a further charge of process oil (155g) made. The product after filtering contained 1.70% Nitrogen and 0.87% Boron.

The product of each example was blended into a standard 15W-40 engine oil formulation from which the conventional ashless dispersant had been omitted. In all but one case the product was used at a concentration in the finished lubricant of 7 wt% (including the diluent oil associated with the dispersant). The finished lubricant was thus made up by weight of 72.7% mineral oil, 15.6% of an oil solution of an hydrogenated diene viscosity index improver, 0.2% pour point depressant and conventional amounts of zinc dialkyl dithiophosphate, overbased calcium sulfonate, low base calcium sulfonate, calcium sulphurized phenate, phenolic antioxidant, aromatic amine antioxidant, anti-rust agent, antifoam agent, process oil, and the 7% of product under test, the proportions of the additive components being on an as received basis.The product of Example 1 was also blended at a concentration of 8.5wt%. When this was done the amount of mineral oil was reduced to 71.2%.

Each formulated lubricant was subjected to the Volkswagen PV-3344 seal test. A pass in this test corresponds to a minimum elongation (EL) of 160%, a minimum tensile strength (TS) of 8.0 MPa and no seal cracking.

The results obtained are reported in the table below.

ALKOXYLATED TEPA:AA PIBSA: PV3344 AMINE(AA) mole ratio AMINE:MA EL, % TS, MPa Cracking Example 1 EDA-2EOasy 70:30 1.8:1:0.3 193 10.2 NO Example 1(8.5%) EDA-2EOasy 70:30 1.8:1:0.3 232 10.3 NO Example 2 DETA-EO 90:10 1.8:1:0.3 169 8.3 NO Example 3 DETA-EO 80:20 1.8:1:0.3 173 8.4 NO Example 4 DETA-EO 70:30 1.8:1:0.3 180 8.7 NO Example 5 EDA-EO 70:30 1.8:1:0.3 202 10.3 NO Example 6 EDA-EO 80:20 1.8:1::0.3 181 8.9 NO Example 7 EDA-EO 90:10 1.8:1:0.3 174 8.4 NO Example 8 EDA-2EOsym 70:30 1.8:1:0.3 205 9.7 NO Example 9 EDA-2EOsym 90:10 1.8:1:0.3 182 8.8 NO Example 10 EDA-2EOasy 70:30 1.8:1:0.3 232 10.9 NO Example 11 EDA-2EOasy 70:30 1.8:1:0.3 220 10.5 NO Example 12 DEA 70:30 1.8:1:0.3 227 11 NO Example 13 DEA-4PO 70:30 1.8:1:0.3 219 9.9 NO Example 14 DETA-1.5EO 70:30 1.8:1:0.3 212 10.2 NO Example 15 DETA-2EO 70:30 1.8:1::0.3 210 10.3 NO

ALKOXYLATED TEPA:AA PIBSA: PV3344 AMINE(AA) mole ratio AMINE:MA EL, % TS, MPa Cracking Example 16 DETA-1.2PO-S 70:30 1.8:1:0.3 199 9.7 NO Example 17 DETA-1.2PO-S 85:15 1.8:1:0.3 179 9.8 NO Example 18 AEP-1.1EO 70:30 1.8:1:0.3 196 9.4 NO Example 19 TETA-EO 70:30 1.8:1:0.3 190 9 NO Example 20 TETA-2EO 70:30 1.8:1:0.3 180 8.5 NO Example 21 HEP 70:30 1.8:1:0.3 205 10.1 NO Example 22 EDA-2EOasy 70:30 1.6:1::0.3 194 10.4 NO Example 23 EDA-2EOasy 70:30 1.8:1:0.5 193 10.1 NO Example 24 EDA-2EOasy 70:30 2.0:1:0.4 196 10.1 NO Example 25 EDA-2EOasy 90:10 2.0:1:0.4 184 9.8 NO Example 26 EDA-2EOasy 95:5 2.0:1:0.4 175 9.6 NO Example 27 MORPHOLINE 70:30 1.8:1:0.3 237 11 NO Example 28 MEED 80:20 1.8:1:0.3 170 9.7 NO C. Example 1 DMAPA 70:30 1.8:1:0.3 145 8.1 YES C. Example 2 EDA-3PO 70:30 1.8:1:0.3 157 9.2 NO C. Example 3 HMDA-3PO 70:30 1.8:1:0.3 159 8.4 NO C. Example 4 - 100:0 1.8:1:0.3 148 8.3 YES It is particularly significant to note that the formulations of Example 1 (8.5%) gave a pass result where as that of Comparative Example 4 gave a fail result. Both formulations had the same N content of 0.12%.

The dispersants in accordance with the present invention (Examples 1-28) all gave an excellent pass result in the PV3344 test. The Comparative Examples on the other hand each show a fail result in one or more aspects of the test.

The diesel performance of several products of the examples was assessed in the MWM "B" test carried out in accordance with the CEC L-12-A-76 method. In this test a pass result corresponds to a minimum piston merit value of 65.

The soot handling capability of lubricating oils containing the products of Example 6 and Comparative Example 4 was assessed in accordance with the XUD 11 ATE test. The XUD 11 ATE test forms part of the proposed ACEA European oil sequence for service-fill oils for light duty diesel engines.

In the XUD 11 ATE test a pass result corresponds to a minimum piston merit of 43 and a maximum viscosity increase at 1000C for a 3% soot content of 200%. The results obtained are shown in the tables below.

MWM "B" Example 1 79 Example 6 76.2 Example 17 76 Example 27 90 Comparative Example 2 65 Comparative Example 4 74.6

All of the formulations tested gave a pass result, the formulations in accordance with the present invention providing the best results.

XUD 11 ATE Piston Merit Viscosity increase % Example 6 44 191 Comparative Example 4 47 224 Thus, both formulations tested satisfied the piston merit requirement of the XUD 11 ATE test. However, the Comparative Example gave a fail result on the viscosity increase aspect of the test.

Claims (37)

1. An oil-soluble dispersant obtainable by boronating and acylating the product formed by reacting (1) a polyalkenyl succinic acylating agent, (2) a polyamine and (3) a nitrogen-containing compound of formula R1[N(R1)R]q-Y in which: Y is -N(R) 2, piperazinyl optionally N-substituted by a group R1 or a group RltN(Rl)R]q~ or is a 4-morpholinyl group; q is from 0 to 10; R is an alkylene group having from 2 to 6 carbon atoms; and R1 is independently selected from hydrogen and a group of formula (R2O),R3 in which r is O to 6, R2 is an alkylene group having 2 to 6 carbon atoms and R3 is an hydroxyalkyl group having 2 to 6 carbon atoms, provided that when Y is -N(R1)2 or optionally substituted 1-piperazinyl the nitrogen-containing compound has on average from 1 to less than 3 free hydroxyl groups per molecule.

2. A dispersant according to claim 1 in which the polyalkenyl succinic acylating agent is a polyisobutenyl succinic anhydride derived from polyisobutene having a number average molecular weight of about 900 to about 1500.

3. A dispersant according to claim 1 or 2 wherein the polyamine (2) is a polyalkenyl polyamine containing 3 to 6 nitrogen atoms per molecule.

4. A dispersant according to claim 3 wherein the polyamine (2) is tetraethylene pentamine, or a mixture of polyamines which approximates tetraethylene pentamine.

5. A dispersant according to any one of claims 1 to 3 wherein the polyamine (2) is a mixture of hydrocarbyl polyamines containing 10 to 50 weight percent acyclic alkylene polyamines and 90 to 50 weight percent cyclic alkylene polyamines.

6. A dispersant according to any one of claims 1 to 5 wherein in the nitrogen-containing compound (3) Y is -N(R,)2 or optionally substituted l-piperazinyl, q is O to 4, R is ethylene and Rl is hydrogen or a group of formula (R2O),R3 in which r is 0 and R3 is an hydroxyalkyl group having from 2 to 4 carbon atoms.

7. A dispersant according to claim 6 wherein the nitrogen-containing compound (3) is diethanolamine or ethylene diamine, diethylene triamine, triethylene tetramine piperazine or aminoethylpiperazine N-substituted by on average 1 to 2 hydroxyethyl or hydroxypropyl groups per molecule.

8. A dispersant according to any one of claims 1 to 5 wherein in the nitrogen-containing compound (3) Rl is hydrogen or a group of formula (R2O),R3 in which r is 1 to 3, R2 is an alkylene group having 2 or 3 carbon atoms and R3 is an hydroxyalkyl group having 2 or 3 carbon atoms.

9. A dispersant according to claim 8 wherein in the nitrogen-containing compound (3) q is 0 and Y is -N(R,)2.

10. A dispersant according to any one of claims 1 to 5 wherein in the nitrogen-containing compound (3) Y is 4-morpholinyl, q is O to 2 and R is an alkylene group having 2 to 4 carbon atoms.

11. A dispersant according to claim 10 wherein the nitrogen-containing compound (3) is morpholine or N-(2-(4 morpholinyl)ethyl-1,2-ethanediamine.

12. A dispersant according to any one of claims 1 to 11 wherein the mole ratio of polyamine (2) to nitrogencontaining compound (3) used in the reaction is from 95:5 to 1:1.

13. A dispersant according to claim 12 in which the mole ratio of polyamine (2) to nitrogen-containing compound (3) is 9:1 to 2:1.

14. A dispersant according to any one of claims 1 to 13 wherein in the reaction the mole ratio of polyalkenyl succinic acylating agent (1) to total of polyamine (2) and nitrogen-containing compound (3) is from 1.2:1 to 4:1.

15. A dispersant according to claim 14 wherein the mole ratio of polyalkenyl succinic acylating agent (1) to total of polyamine (2) and nitrogen-containing compound (3) is 1.5:1 to 3:1.

16. A dispersant according to any one of claims 1 to 15 wherein boronation is performed using boric acid.

17. A dispersant according to any one of claims 1 to 16 wherein acylation is performed using maleic anhydride.

18. A dispersant according to claim 1 substantially as hereinbefore described.

19. A process for preparing an oil-soluble dispersant which comprises reacting, concurrently or sequentially in any order, a polyalkenyl succinic acylating agent (1), a polyamine (2) and a nitrogen-containing compound (3) of formula R1 [N (R1) R)q? in which R, Rl, q and Y are as defined in claim 1, amd then boronating and acylating, concurrently or in any order, the reaction product obtained.

20. A process according to claim 19 wherein the polyalkenyl succinic acylating agent (1) is as defined in claim 2.

21. A process according to claim 19 or 20 wherein the polyamine (2) is as defined in claim 3, 4 or 5.

22. A process according to any one of claims 19 to 21 wherein the nitrogen-containing compound (3) is as defined in any one of claims 6 to 11.

23. A process according to any one of claims 19 to 22 wherein in the reaction the mole ratio of polyamine (2) to nitrogen-containing compound (3) is as defined in claim 12 or 13.

24. A process according to any one of claims 19 to 23 wherein the mole ratio of polyalkenyl succinic acylating agent (1) to total of polyamine (2) and nitrogen-containing compound (3) is as defined in claim 14 or 15.

25. A process according to any one of claims 19 to 24 wherein boronation is performed using boric acid.

26. A process according to any one of claims 19 to 25 wherein acylation is performed using maleic anhydride.

27. A dispersant when obtained by a process as claimed in any one of claims 19 to 26.

28. A lubricating oil composition comprising an oil of lubricating viscosity and an oil-soluble dispersant as defined in any one of claims 1 to 18 or 27.

29. An additive concentrate comprising an oil-soluble dispersant as defined in any one of claims 1 to 18 or 27.

30. The use of an oil-soluble dispersant as defined in any one of claims 1 to 18 or 27 in a lubricant composition for lubricating an engine or other device.

31. The use according to claim 30 wherein the lubricant composition comes in contact with a fluoroelastomer.

32. A method of improving the soot handling capability of an oil of lubricating viscosity which comprises incorporating therein an oil-soluble dispersant as claimed in any one of claims 1 to 18 or 27.

33. A process according to claim 19 substantially as hereinbefore described in any one of Examples 1 to 28.

34. A composition according to claim 28 substantially as hereinbefore described.

35. A concentrate according to claim 29 substantially as hereinbefore described.

36. Use according to claim 30 substantially as hereinbefore described.

37. A method according to claim 32 substantially as hereinbefore described.