LUBRICANT FOR A TWO-STROKE MARINE ENGINE

Abstract

Relating to the field of lubricant, more particularly relates to lubricant for marine engine, notably for a two-stroke marine engine. More particularly, relates to a lubricant for a marine engine including at least one lubricant base oil and at least one fatty amine.

Claims

1.-15. (canceled)

16. Lubricant composition comprising: at least one lubricant base oil, at least a di-fatty-alkyl(ene) polyalkylamine composition comprising one or more polyalkylamines of formulae (I) or (II): ##STR00005## wherein, each R is, independent of the other R, an alkyl moiety or an alkylene moiety with 8 to 22 carbon atoms, which is linear or branched, n and z are independent of each other either 0, 1, 2, or 3, and when z is superior than 0 then o and p are independent of each other either 0, 1, 2, or 3, or derivatives thereof, whereby said polyalkylamine composition comprises at least 3% by weight of branched compounds of formula (I) or (II), with regards to the total weight of polyalkylamine compounds (I) and (II) in the composition, branched compound signifying that: in formula (I) at least one of n and z are superior or equal to 1, in formula (II) n is superior or equal to 1.

17. Lubricant composition according to claim 16, wherein the polyalkylamine composition comprises at least 4% w/w of branched compounds of formula (I) or (II), with regards to the total weight of polyalkylamine compounds (I) and (II) in the composition, branched compound signifying that: in formula (I) at least one of n or z are superior or equal to 1, in formula (II) n is superior or equal to 1.

18. Lubricant composition according to claim 16, wherein the polyalkylamine composition comprises at least 5% by weight, with regards to the total weight of compounds (I) and (II), of products of formulae (I) and (II) with a linear structure, linear meaning n is 0 in formulae (I) and (II) and z is 0 in formula (I).

19. Lubricant composition according to claim 16, wherein the polyalkylamine composition further comprises derivatives of polyalkylamines of formula (I) or (II), wherein said derivatives are alkoxylates which are optionally methylated.

20. Lubricant composition according to claim 16, wherein the polyalkylamine composition further comprises derivatives of polyalkylamines of formula (I) or (II), wherein said derivatives are methylated.

21. Lubricant composition according to claim 16, wherein the polyalkylamine composition has a BN measured according to standard ASTM D-2896 from 150 to 350 milligrams of potash per gram of amine compound.

22. Lubricant composition according to claim 16, having a BN, measured according to standard ASTM D-2896, greater than or equal to 70 milligrams of potash per gram of the lubricant composition.

23. Lubricant composition according to claim 22, wherein the percentage by mass of di-fatty-alkyl(ene) polyalkylamine mixture with respect to the total weight of the lubricant composition is from 2 to 10%.

24. Lubricant composition according to claim 16, having a BN determined according to the standard ASTM D-2896 of at most 50 milligrams of potassium hydroxide per gram of the lubricant composition.

25. Lubricant composition according to claim 24, wherein the percentage by mass of di-fatty-alkyl(ene) polyalkylamine mixture with respect to the total weight of the lubricant composition is comprised between 0.1 and 15%.

26. Lubricant composition according to claim 16, further comprising additives chosen amongst a neutral detergent, an overbased detergent or mixtures thereof.

27. Lubricant composition according to claim 16, wherein the percentage by mass of di-fatty-alkyl(ene) polyalkylamine mixture with respect to the total weight of lubricant is chosen such that the BN provided by these compounds represents a contribution comprised between 5 and 60 milligrams of potash per gram of lubricant, determined according to the standard ASTM D-2896.

28. Lubricant composition according to claim 27, wherein the percentage by mass of di-fatty-alkyl(ene) polyalkylamine mixture with respect to the total weight of lubricant is chosen such that the BN provided by these compounds represents a contribution comprised between 10 and 30 milligrams of potash per gram of lubricant of the total BN of said cylinder lubricant, determined according to the standard ASTM D-2896.

29. A method for lubricating a marine engine, comprising contacting the engine with a lubricant composition according claim 16 as a cylinder lubricant.

30. The method of claim 29, wherein the engine is a two-stroke marine engine.

31. The method of claim 29, comprising operating the engine with fuels having a content of sulphur inferior than 1% by weight relative to the total weight of fuel.

32. The method of claim 31, comprising operating the engine with fuels having a content of sulphur inferior than 0.5% by weight relative to the total weight of fuel.

33. The method of claim 29, comprising operating the engine with fuels having a content of sulphur from 1 to 3.5% by weight relative to the total weight of fuel.

34. The method of claim 29 for reducing the formation of deposits in the hot section of a marine engine.

Description

EXAMPLE 1: SYNTHESIS OF THE PRODUCT 2HTY OF FORMULA (II) WITH N=1

[0138] Duomeen 2HT is available from AkzoNobel.

[0139] Other chemicals were sourced from SigmaAldrich, unless indicated differently.

[0140] A fully branched product with 4 amine functions was prepared using a 1 L glass reactor with turbine stirrer to which chemicals can be dosed using a Prominent Gamma/L membrane pump and which was thermostatted using a Lauda K6KP heating bath.

Raw Materials

[0141]

TABLE-US-00003 Intake Molw. Intake Chemical Supplier (g) (g/mol) (mol) Duomeen 2HT AkzoNobel 342.0 566 0.604 Hydrochloric acid (36%) JT Baker 3.06 36.5 0.014 Water Tap 1.12 18.0 0.062 Isopropanol JT Baker 34.2 60.1 0.569 Sodium carbonate Acros As needed, see text Acrylonitrile Acros 81.5 53.1 1.299 Raney Cobalt CatAlloy As needed, see text Ammonia Air products As needed, see text

Procedure & Results

[0142] The cyano-ethylation step is performed by charging the reactor with Duomeen 2HT, isopropanol (co-catalyst and solvent for the dicyano-product that is formed), water, and HCl, and subsequent dosing, in approximately three hours, of the acrylonitrile. Reaction pathway:

##STR00003##

wherein HT stands for hydrogenated tallow.

[0143] After a conversion of 80% the reaction rate was so slow that the reaction was stopped. Vacuum was applied to the reactor, the temperature was increased to 110 C. to remove the acrylonitrile, water & IPA. The product was washed and neutralized in two steps with 4% Na.sub.2CO.sub.3 solution to remove all HCl, and subsequently hydrogenated using the same equipment. Reaction pathway:

##STR00004##

[0144] Thereto the stirred reactor containing the dicyano-product was charged with a conventional Raney Cobalt catalyst, such as A-7000 ex Johnson Matthey or Acticat1100 ex CatAlloy, and subsequently heated to 130 C. while sparging with nitrogen, to remove traces of acrylonitrile and water. Then the reactor was charged with ammonia (13-14.10.sup.5 Pa) while kept at a temperature of 105 C. Then the reactor was heated to 150 C., and hydrogen was added to maintain a pressure of 49.10.sup.5 Pa. After completion of the reaction, the temperature was lowered to 80 C. and remaining hydrogen and ammonia were flushed out using nitrogen.

[0145] The resulting composition was analyzed using GC-MS and found to contain>70% of the product 2HTY of formula (II) with n=1, as well as more than 14% w/w of the linear product (HT).sub.2N(CH.sub.2).sub.3NH(CH.sub.2).sub.3NH.sub.2, a little starting product (HT).sub.2N(CH.sub.2).sub.3NH.sub.2, and some unidentified further alkylamines.

EXAMPLE 2A AND 2B: SYNTHESIS OF A MIXTURE OF LINEAR AND BRANCHED PRODUCT (TETRAMEEN 2HTB)

[0146] A mixture of linear and branched product (Tetrameen 2HTb) was prepared by the two cycle procedure wherein the cyano-ethylation and the hydrogenation steps above were repeated. The 0.6 mole of the Duomeen 2HT was combined with 0.65 mole of acrylonitrile and reacted in the first cyano-ethylation step. After hydrogenation, the triamine was combined with another 0.65 mole of acrylonitrile and reacted. At the end of each cyano-ethylation step, NMR was used to analyze the reaction mixture and to determine if one mole of acrylonitrile had reacted per mole of starting material. If the reaction rate was found to be too slow, some additional acrylonitrile was dosed and after 1 hour the analysis was repeated. This cycle was repeated till the desired reaction was obtained. The final product was analyzed using GC-MS applying the following conditions:

TABLE-US-00004 Gas chromatograph TRACE ULTRA GC Interscience MS system ISO GC-MS Column Fused silica WCOT, 20 m 0.32 mm ID stationary phase Sil 5 CB, 100% polydimethyl-siloxane, cross-linked film thickness 0.12 m Carrier gas Helium flow 2 ml/min. Temperatures injector 275 C. column initial: 200 C. during 1 min rate: 20 C./min final: 310 C. during 15 min Injection volume 1 l, approx. 250 mg sample in 10 ml cyclohexane

[0147] In the examples no additional acrylonitrile had to be added after the first cyanoacrylation step which was conducted at a temperature of 85 C. and 75 C., for examples 2a and 2b respectively. In the second cyanoacrylation step the temperature was 85 and 80 C., for examples 2a and 2b respectively. In example 2a an additional amount of 0.025 mole of acrylonitrile was needed to complete the second cyanoacrylation step, while in example 2b an additional amount of 0.12 mole of acrylonitrile was added before the addition of 0.60 mole of acrylonitrile was achieved. The highest amount of branching was observed in the sample that was highest in temperature.

[0148] It was confirmed that the off-white products, which were pasty/viscous liquids at room temperature, contained more than 13.8% w/w of branched product of formula (I) with one or more of n and z 1, and also contained more than 14% w/w of the linear product with n=z=0.

EXAMPLE 3: EVALUATION OF THERMAL RESISTANCE PROPERTIES OF LUBRICANT COMPOSITION ACCORDING TO THE INVENTION

[0149] A lubricant composition C.sub.1, has been prepared with the following compounds: [0150] lubricating base oil 1: Mineral oils Group I or brightstock of density between 895 and 915 kg/m.sup.3, [0151] lubricating base oil 2: Group I mineral oils, in particular called 600R viscosity at 40 C. of 120 cSt measured according to ASTM D7279, [0152] detergent package comprising an anti-foaming agent [0153] Tetrameen 2HTB, prepared by following the protocol of example 2a.

[0154] The composition C.sub.1 is disclosed in Table II. The percentages disclosed in Table II correspond to weight percent.

TABLE-US-00005 TABLE II C.sub.1 Composition (invention) Base oil 1 18.0 Base oil 2 49.6 Detergent package 26.9 Tetrameen 2HTB 5.5 TBN (Total base 100 number in mgKOH/g of composition)

[0155] The thermal behaviour of the composition C.sub.1 was also measured by the continuous ECBT test on aged oil, where the mass of deposits (in mg) generated under determined conditions is measured. The lower this mass, the better the thermal behaviour.

[0156] This test makes it possible to simulate both the thermal stability and the detergency of the marine lubricants when the lubricant composition is injected on the hot section of an engine and notably, on the top of the piston and comprises three distinct phases. The first phase was realized at a temperature of 310 C.

[0157] The test utilizes aluminium beakers which are similar to pistons in shape. These beakers are placed in a glass container, maintained at a controlled temperature of the order of 60 C. The lubricant is placed in these containers, themselves equipped with a metallic brush, partially submerged in the lubricant. This brush is rotated at a speed of 1000 rpm, spraying lubricant over the inner surface of the beaker. The beaker is maintained at a temperature of 310 C. by an electric resistive heater, regulated by a thermocouple.

[0158] This first phase lasted 12 hours and the lubricant projection was continued for the duration of the test.

[0159] The second phase consists of a neutralization of 50 BN points of the lubricant composition with 95% sulfuric acid, in order to simulate the phenomenon of neutralization of the composition to be closer to real conditions of use of the lubricating composition in a marine engine.

[0160] The third phase is identical to the first, except that this phase has been carried out at a temperature of 270 C.

[0161] This procedure allows simulating the formation of deposits in the piston-segment assembly. The result is the weight of deposits measured in mg on the beaker.

[0162] The result is disclosed in Table III.

TABLE-US-00006 TABLE III C.sub.1 Compositions (invention) ECBT on aged oil 75 (mg)

[0163] This result shows that the specific choice of a fatty amine according to the invention significantly reduces the formation of high temperature deposits, and therefore improves the heat resistance lubricating compositions.

EXAMPLE C.SUB.2 .AND COMPARATIVE EXAMPLE A TO F

[0164] To a base oil comprising additives, a fatty acid alkyl polyamine according to the invention or according to the prior art was added and thoroughly blended, followed by neutralization of 50 BN points of the lubricant composition with 95% sulfuric acid, in order to simulate the phenomenon of neutralization of the composition to be closer to real conditions of use of the lubricating composition in a marine engine.

[0165] The structure of the tested alkyl polyamines is detailed in Table IV.

[0166] The composition of the lubricant oil is detailed in Table V.

[0167] Measurements of the viscosity (Pa.Math.s) at 40 C. of the blends of lubricant and alkylpolyamines, as prepared above, were performed by measuring the viscosity at a shear rate of 0.01 s.sup.1. All measurements were performed at 40 C. on an RC301 rheometer from ANTON PAAR. The results are displayed in table V.

TABLE-US-00007 TABLE IV Example Name Nomenclature C.sub.2 Tetrameen 2HTb Mixture of compounds (I) and (II) A Tetrameen T N- Mono tallow alkyl tripropylene tetramine B Duomeen 218 i Di-N-C18alkyl propylene diamine (CH3-branched) C Triameen C N- Mono coco alkyl dipropylene triamine D Triameen 2HT N- Di(hydrogenated tallow alkyl) dipropylene triamine E Tetrameen OV N- Mono-oleyl tripropylene tetra amine F Duomeen 2HT Di-N-hydrogenated tallow propylene diamine

TABLE-US-00008 TABLE V Composition C.sub.2 A B C D E F Tetrameen 2HTb 4.8 Tetrameen T 3.4 Duomeen 218 i 8.8 Triameen C 3.1 Triameen 2HT 6.3 Tetrameen OV 3.4 Duomeen 2HT 8 Detergent package 22.1 22.1 22.1 22.1 22.1 22.1 22.1 Base oil 1 24.6 25.0 21.1 25.3 23.5 27.0 21.5 Base oil 2 48.5 49.5 48 49.5 43.5 47.5 48.4 Vicosity (Pa .Math. s) 0.30 0.75 0.40 6.90 0.58 1.10 0.40

[0168] From these results, it can be concluded that the alkyl polyamines according to the invention are superior to alkyl polyamines according to the prior art with regards to viscosity increase limitation: the viscosity of the finished oil composition comprising alkyl polyamines according to the invention does not increase after preparation as described here above as much as the increase of the viscosity of the finished oil comprising alkyl polyamines according to the prior art after preparation.