COMPOSITIONS COMPRISING AN ALTERNATIVE TO DI-ISOTRIDECYL ADIPATE

Abstract

The present invention concerns compositions, and more specifically lubricating compositions, comprising an alternative to di-iso tridecyl adipate (DITA). The present invention therefore discloses compositions comprising di-(2-hexyldecyl) succinate, advantageously from a renewable source, and the uses thereof as lubricating compositions, in particular as hydraulic oils or engine oils.

Claims

1. A composition comprising: di-(2-hexyldecyl) succinate, and an antioxidant for lubricants and/or an anti-wear agent for lubricants.

2. A process for the preparation of the composition according to claim 1, comprising a step of mixing di-(2-hexyldecyl) succinate with the antioxidant and/or the anti-wear agent.

3. A method of lubricating an engine comprising applying an engine oil comprising the composition according to claim 1 to an engine.

4. Engine oil comprising a composition according to claim 1.

5. Hydraulic oil comprising a composition according to claim 1.

6. Gear oil comprising a composition according to claim 1.

7. Metalworking oil comprising a composition according to claim 1.

8. A process for improving the lubricating power and/or the hydrolytic stability and/or the oxidation stability and/or the compatibility with elastomers and/or the solvent power of a composition, comprising introducing di-(2-hexyldecyl) succinate into the composition.

9. (canceled)

10. A composition consisting of di-(2-hexyldecyl) succinate and a base oil.

11. (canceled)

12. The composition according to claim 1, wherein the di-(2-hexyldecyl) succinate comprises at least 90% carbon of renewable origin.

13. (canceled)

14. (canceled)

15. The engine oil according to claim 4, wherein the di-(2-hexyldecyl) succinate comprises at least 90% carbon of renewable origin.

16. The hydraulic oil according to claim 5, wherein the di-(2-hexyldecyl) succinate comprises at least 90% carbon of renewable origin.

17. The gear oil according to claim 6, wherein the di-(2-hexyldecyl) succinate comprises at least 90% carbon of renewable origin.

18. The metalworking oil according to claim 7, wherein the di-(2-hexyldecyl) succinate comprises at least 90% carbon of renewable origin.

19. The composition according to claim 10, wherein the di-(2-hexyldecyl) succinate comprises at least 90% carbon of renewable origin.

Description

EXAMPLE 1

Preparation of di-(2-hexyldecyl) Succinate

[0217] The di-(2-hexyldecyl) succinate shown in FIG. 1 can be prepared via a conventional esterification process by heating succinic acid with at least a stoichiometric quantity of 2-hexyldecanol.

[0218] Preparation of 2-hexyldecanol

[0219] 30 g of an aqueous solution of KOH and 0.2 g of a Cu/Ni catalyst (in a proportion 80/20) were added to 1020 g of octanol prepared from renewable resources. While bubbling nitrogen through the medium at a flow rate of 30 L/hour, the reaction medium was heated until reaching 220° C. after 2 h30. After 1 hour at this temperature, the medium was cooled down and filtered. The filtrate was distilled under reduced pressure in order to give 2-hexyldecanol.

[0220] Esterification of Succinic Acid

[0221] 2.05 mol of 2-hexyldecanol as prepared above, 1 mol of succinic acid (BioAmber®) and 0.05% of a metallic catalyst were introduced into a reactor equipped with a mechanical stirrer, under a nitrogen atmosphere. The temperature of the reaction medium was taken rapidly to 150° C., then gradually increased (10° C./hour) until reaching 220° C.

[0222] When the acid value had stabilized at a value less than 0.5 mg KOH/g, the reaction medium was neutralized by the addition of a stoichiometric quantity of a 50% soda solution.

[0223] The residue was filtered through a Gauthier filter in the presence of 1% of a silicate type filtration adjuvant.

[0224] In this way, DHDS is obtained, prepared from resources of renewable origin.

EXAMPLE 2

Determination of the Properties of di-(2-hexyldecyl) Succinate and Comparison with di-isotridecyl Adipate

[0225] 1. Materials

[0226] The following three esters were tested: [0227] DHDS was prepared according to the process described in Example 1. [0228] DITA was prepared according to a process similar to that of Example 1, from adipic acid and isotridecanol. [0229] Di-isostearyl succinate (DISu) was prepared according to a process similar to that of Example 1, from succinic acid and isostearyl alcohol.

[0230] 2. Methods

[0231] 2.1 Acid Value

[0232] The acid value was measured according to the standard ASTM D 664.

[0233] 2.2 Hydroxyl Value

[0234] The hydroxyl value was measured according to the standard AOCS Cd 13-60.

[0235] 2.3 Saponification Number

[0236] The saponification number was measured according to the standard AOCS Cd 3-25.

[0237] 2.4 Kinematic Viscosity

[0238] The kinematic viscosities at 40° C. and at 100° C. were measured according to the standard ASTM D 445.

[0239] 2.5 Viscosity Index

[0240] The viscosity index was calculated according to the standard ASTM D 2270.

[0241] 2.6 Flash Point

[0242] The flash point was measured according to the standard ASTM D 92.

[0243] 2.7 Pour Point

[0244] The pour point was measured according to the standard ASTM D 97.

[0245] 2.8 Fire Point

[0246] The fire point was measured according to the standard ASTM D 92.

[0247] 2.9 Hydrolytic Stability

[0248] The hydrolytic stability was measured according to the standard ASTM D 2619 (Beverage bottle method).

[0249] A mixture of 75 g of one of the esters tested and 25 cm.sup.3 of water as well as a copper plate were enclosed in a capped Coca Cola bottle. The whole was placed under slow rotation for 48 h in an oven at 93° C. At the end of the test, the acid value and the kinematic viscosity at 40° C. of the ester, the weight of the copper plate, as well as the acidity of the aqueous phase were measured.

[0250] 2.10 Oxidation Stability

[0251] The oxidation stability was measured according to the standard ASTM D 2272 method A (Rotating Pressure Vessel Oxidation Test (RPVOT)) with 1.5% of Additin RC9321).

[0252] The RPVOT method measures the resistance to oxidation by the air of an oil under specific conditions. It makes it possible to evaluate the service life of an oil by determining the break point or the induction period of a sample of oil in the presence of oxygen, water and a copper-based catalyst. In the present application, DHDS and DITA formulated respectively with 1.5% of Additin RC 9321® (mixture of antioxidant and anti-corrosion agent well known to a person skilled in the art, used as reference, marketed by RheinChemie-Lanxess®) were tested. Each sample was placed in a container under pressure and rotated at an angle of 30° at a speed of 100 rpm in an oil bath heated to a high temperature (150° C.). The number of minutes necessary in order to reach a specific pressure drop represents the oxidation stability of the sample.

[0253] 2.11 Compatibility with Elastomers

[0254] The compatibility with elastomers was measured according to the standard ISO 1817 by heating at 80° C. for 168 hours.

[0255] 2.12 Renewability

[0256] The renewability was measured according to the standard ASTM D 6866.

[0257] 3. Results

[0258] The results are presented in Table 1 below:

TABLE-US-00001 TABLE 1 DITA DHDS DISu Acid value (mg KOH/g) 0.1 0.02 0.09 Hydroxyl value (mg KOH/g) <4 0 13.5 Saponification number (mg KOH/g) 215-225 206 176 Kinematic viscosity at 40° C. 27.3 26.8 44.2 (mm.sup.2/s) Kinematic viscosity at 100° C. 5.37 5.30 8.50 (mm.sup.2/s) Viscosity index 135 142 Flash point (° C.) 236 264 234 Pour point (° C.) −57 −64 −7 Fire point (° C.) 266 286 262 Hydrolytic stability Acid value before test (mg KOH/g) 0.03 0.02 0.09 Acid value after test (mg KOH/g) 0.11 0.08 0.27 Difference in acid value (mg KOH/g) 0.08 0.06 0.18 Acidity of the aqueous phase 0.07 0.07 0.01 (mg KOH/g) Kinematic viscosity at 40° C. 23.7 26.8 44.2 before test (mm.sup.2/s) Kinematic viscosity at 40° C. 23.9 26.7 40.0 after test (mm.sup.2/s) Kinematic viscosity variation at 0.8 −0.4 −10.5 40° C. (%) Appearance of the copper plate 3a* 2c* 3a* Weight of the copper plate before 4.9877 5.2623 5.3640 test (g) Weight of the copper plate after 4.9870 5.2613 5.3637 test (g) Variation in the weight of the 0.05 0.05 0.02 copper plate (mg/cm.sup.2) Oxidation stability (min) 1120 835 Compatibility with elastomers Volume difference of the NBR 1 15 6.8 (%) Volume difference of the HNBR 1 11.2 4.4 (%) Volume difference of the FKM 2 0.5 0 (%) Renewability (% carbon 14) 0 96 *The appearance of the copper was determined according to the colour scale, varying from light orange (1a) to glassy black (4c), given in the standard ASTM D 130.

[0259] It is noted that the DHDS has: [0260] good viscosity and in particular a kinematic viscosity at 40° C. of 27.3 mm.sup.2/s, a kinematic viscosity at 100° C. of 5.37 mm.sup.2/s, measured according to the standard ASTM D 445, [0261] good hydrolytic stability, measured according to the standard ASTM D 2619, by a small difference in acid value (0.06 mg KOH/g), a low kinematic viscosity variation at 40° C. (−0.4%) and a low variation in the weight of the copper plate (0.05 mg/cm.sup.2), [0262] good oxidation stability, [0263] good low-temperature stability, in particular with a pour point equal to −64° C., measured according to the standard ASTM D 97, and [0264] good compatibility with elastomers selected from acrylonitrile butadiene rubber, such as NBR 1, hydrogenated acrylonitrile-butadiene rubber, such as HNBR 1, fluorinated rubber, such as FKM 2.

[0265] The improved hydrolytic stability of the DHDS compared to the DITA can be observed by the difference in acid value and the viscosity variation that are lower for the DHDS than for the DITA.

[0266] The pour point of the DHDS (−64° C.) is lower than that of the DITA (−57° C.), which demonstrates a better low-temperature stability.

[0267] As regards the compatibility with elastomers, the volume difference (or swelling) observed for the DHDS is 6.8% with the NBR 1, whereas it is 15% with the DITA under the same conditions. The volume difference observed for the DHDS is 4.4% with the HNBR 1, whereas it is 11.2% with the DITA under the same conditions. No volume variation was observed for the DHDS with the fluorinated rubber (FKM 2), whereas a volume variation of 0.5% was observed with the DITA under the same conditions. The DHDS thus has a better compatibility with elastomers than the DITA.

[0268] The viscosity index of DHDS (142) is also better than that of DITA (135). DHDS therefore has a viscosity that is more stable under temperature variations than DITA, which makes it possible to reduce the impact of temperature on the performance of the composition constituted by DHDS, in particular a lubricant composition (as the performance of a lubricant composition is very closely linked to the viscosity).

[0269] The flash point of DHDS (264° C.) is higher than that of DITA (236° C.), which makes DHDS usable over a wide range of temperatures, in particular at higher temperatures than DITA.

[0270] DISu does not have good hydrolytic stability. Its kinematic viscosity at 40° C. is higher (44 mm.sup.2/s) than that of DITA and its pour point is too high (−7° C.) with respect to the desired properties. Therefore this diester does not have the necessary properties to be able to substitute for DITA.

EXAMPLE 3

Composition of an Engine Oil Comprising Only Synthetic Oils

[0271] An engine oil based on synthetic oils is prepared by mixing the following compounds (in % by weight of the total weight of the composition): [0272] PAO 40 (polyalphaolefin having a kinematic viscosity at 100° C. comprised between 38 and 42 cSt): 52%, [0273] PAO 6 (polyalphaolefin having a kinematic viscosity at 100° C. comprised between 5.8 and 6.2 cSt): 22%, [0274] DHDS: 15%, [0275] HiTEC® 1255 (additive package comprising dispersants and inhibitors): 10%, [0276] HiTEC® 4702 (antioxidant): 0.5%, [0277] Irganox® L-57 (antioxidant): 0.5%.

[0278] This engine oil has a kinematic viscosity at 100° C. comprised between 16.3 and 21.9 cSt, which makes this an SAE 50 grade oil.

[0279] “cSt” represents centistoke, which is a unit of measurement that is usual in the field of lubricants (1 cSt=1 mm.sup.2/s).

EXAMPLE 4

Composition of an Engine Oil Comprising a Vegetable Oil

[0280] An engine oil based on vegetable oil is prepared by mixing the following compounds (in % by weight of the total weight of the composition): [0281] Vegetable oil esters: 40.4%, [0282] Hydrorefined oils (Group II): 24%, [0283] DHDS: 20%, [0284] Viscosity improvers: 2.5%, [0285] Dispersants: 12%, [0286] Pour point depressant: 0.1%, [0287] Antioxidant: 1%.

EXAMPLE 5

Composition of a Hydraulic Oil

[0288] The hydraulic oil is prepared by mixing the following compounds (in % by weight of the total weight of the composition): [0289] DHDS: 97.75%, [0290] Dioctyldiphenylamine (antioxidant): 1%, [0291] Butylated hydroxytoluene (antioxidant): 1%, [0292] Alkylated benzotriazole (anti-corrosion agent): 0.1%, [0293] Succinic anhydride amine (anti-rust agent): 0.1%, [0294] Silicone polymer (anti-foaming agent): 0.05%.

EXAMPLE 6

Composition of a Gear Oil

[0295] A gear oil was prepared by mixing the following compounds (in % by weight of the total weight of the composition): [0296] PAO 8 (polyalphaolefin having a kinematic viscosity at 100° C. comprised between 7.7 and 8.2 cSt): 50.6%, [0297] DHDS: 15%, [0298] Polyol ester (Radialub® 7257 marketed by Oleon®): 25%, [0299] Viscosity improvers (Viscobase® 11-574, marketed by Evonik®): 6% [0300] Additive package (HiTEC® 307 (comprising antioxidants and anti-corrosion agents, marketed by BASF®): 2.65% [0301] Antioxidant (Irganox® L135, marketed by BASF®): 0.3% [0302] Antioxidant (Irganox® L06, marketed by BASF®): 0.45%.

EXAMPLE 7

Composition of a Metalworking Oil

[0303] A rolling oil was prepared by mixing the following compounds (in % by weight of the total weight of the composition): [0304] DHDS: 56%, [0305] Hydrorefined oil: 20%, [0306] Trimethylolpropane trioleate: 3%, [0307] Additive package comprising an antioxidant, a dispersant and a detergent: 21%.