Use of a biodegradable lubricant base, and method for the preparation thereof
The present invention relates to the use of a fluid lubricant base comprising at least one biosourced and biodegradable compound having formula (I) in order to lubricate devices and/or machines, such as wind turbines, wherein said at least one compound having formula (I) corresponds to formula (I) in which R1, R2 and R3 are, independently, linear or branched saturated hydrocarbon groups comprising at least 16 carbon atoms, at least one group among R1, R2 and R3 comprises, on the hydrocarbon chain thereof, at least one ester group O—CO—R4, where R4 is a linear or branched alkyl radical comprising from 1 to 10 carbon atoms, preferably from 1 to 6 carbon atoms. The lubricant base has an acid number, in mg KOH/g measured according to the standard ISO 6618, which ranges from 0 to 0.5. The present invention further relates to a method for manufacturing the lubricant base as defined above and to the lubricant base thus obtained.
1 . A method for lubricating devices and/or machines, comprising utilizing a fluid lubricating base comprising at least one biosourced and biodegradable compound of the formula (I),
wherein said at least one compound of the formula (I) has the following formula:
wherein R 1 , R 2 and R 3 are independently linear or branched saturated hydrocarbon groups comprising at least 16 carbon atoms, at least one group of R 1 , R 2 and R 3 is branched on its hydrocarbon chain with at least one ester group O—CO—R 4 wherein R 4 is a linear or branched alkyl radical comprising from 1 to 10 carbon atoms,
wherein said lubricating base has an acid number, in mg KOH/g, measured according to standard ISO 6618, which ranges from 0 to 0.5, and
wherein the lubricating base has a resistance to hydrolysis, measured according to DEF STAN 05-50 (part 61) method 6, which ranges from 300 to 3500 hours.
2 . The method according to claim 1 , wherein R 4 is a linear or branched alkyl radical comprising from 1 to 6 carbon atoms.
3 . The method according to claim 1 , the hydrocarbon groups R 1 , R 2 and R 3 comprise from 18 to 24 carbon atoms.
4 . The method according to claim 1 , wherein the group R 4 of the ester group —O—CO—R 4 is selected from a methyl, ethyl, propyl or iso-propyl radical.
5 . The method according to claim 1 , wherein, on said at least one hydrocarbon chain R 1 , R 2 and R 3 branched with the ester group —O—CO—R 4 , the latter is positioned in position 9, 10, 12 or 14.
6 . The method according to claim 1 , wherein at least two hydrocarbon groups among R 1 , R 2 and R 3 are/is branched with the ester group —O—CO—R 4 .
7 . The method according to claim 6 , wherein each hydrocarbon group R 1 , R 2 and R 3 are/is branched with the ester group —O—CO—R 4 .
8 . The method according to claim 1 , wherein the lubricating base also comprises at least one other biodegradable lubricating compound, different from the compound of the formula (I).
9 . The method according to claim 1 , wherein the lubricating base has a demulsification time, measured according to ASTM D 1401, ranging from 0 to 30 minutes.
10 . The method according to claim 9 , wherein the lubricating base has a demulsification time, measured according to ASTM D 1401, ranging from 0 to 15 minutes.
11 . The method according to claim 10 , wherein the lubricating base has a demulsification time, measured according to ASTM D 1401, ranging from 0 to 10 minutes.
12 . The method according to claim 1 , wherein the lubricating base has a resistance to hydrolysis, measured according to DEF STAN 05-50 (part 61) method 6, which ranges from 600 to 3000 hours.
13 . The method according to claim 12 , wherein the lubricating base has a resistance to hydrolysis, measured according to DEF STAN 05-50 (part 61) method 6, which ranges from 750 to 900 hours.
14 . A process for preparing a lubricating base according to claim 1 , comprising a step (i) of preparing said at least one compound of the formula (I), said step (i) including the following successive steps:
(a) providing at least one previously hydrogenated vegetable oil or hydrogenating a vegetable oil, said vegetable oil being comprised of at least one triglyceride comprising at least 50% (relative % determined by GPC) of fatty acids having at least one saturated or unsaturated, linear or branched hydrocarbon chain comprising at least 16 carbon atoms, one of said fatty acids being branched with at least one hydroxyl group —OH;
(b) selectively esterifying, at said at least one hydroxyl group —OH, said at least one fatty acid of said hydrogenated vegetable oil obtained at the end of step (a) with at least one organic acid anhydride;
(c) recovering at least one vegetable oil ester having the formula (I),
so as to obtain a lubricating base comprising an acid number, in mgKOH/g, measured according to standard ISO 6618, ranging from 0 to 0.5, and
having a resistance to hydrolysis, measured according to DEF STAN 05-50 (part 61) method 6, which ranges from 300 to 3500 hours.
15 . The preparation process according to claim 14 , wherein the vegetable oil of step (a) comprises at least one triglyceride of the following formula:
wherein the hydrocarbon groups R 1 , R 2 or R 3 are independently saturated, linear or branched hydrocarbon groups comprising at least 16 carbon atoms, at least one of R 1 , R 2 and R 3 is branched on its hydrocarbon chain with at least one hydroxyl group —OH.
16 . The preparation process according to claim 14 , wherein the vegetable oil is selected from one or more of the following oils: castor oil, lesquerella oil or any other oil comprising at least 50% fatty acids (relative % determined by GPC) selected from: ricinoleic acid (C18:1-OH), densipolic acid (C18:2-OH), lesquerolic acid (C20:1-OH), or auricolic acid (C20:2-OH).
17 . The preparation process according to claim 14 , wherein the process comprises the following intermediate steps between said esterification step (b) and the step (c) of recovering said at least one vegetable oil ester:
(b1) a topping step;
(b2) a cooling step,
(b3) optionally a neutralisation step;
(b4) optionally a fine filtration step.
18 . The preparation process according to claim 14 , wherein the organic acid anhydride has the formula (II) below:
where R and R′ are independently selected from a linear or branched alkyl chain comprising from 1 to 12.
19 . The preparation process according to claim 18 , wherein the organic acid anhydride of formula (II) is selected from the group consisting of acetic anhydride, butyric anhydride or isobutyric anhydride and a mixture thereof.
20 . A lubricating base obtained by the preparation process according to claim 14 , wherein it has an acid number, in mg KOH/g, measured according to standard ISO 6618, ranging from 0 to 0.5 and wherein it has a resistance to hydrolysis, measured according to DEF STAN 05-50 (part 61) method 6, which ranges from 300 to 3500 hours.