Low pour point derivatives of dimer fatty acids

Abstract

The present invention relates to specific derivatives of dimer fatty acids, compositions comprising them and a method to reduce pour points.

Claims

1. Derivatives of dimer fatty acids obtainable by the process comprising the following steps: i) dimerizing a fatty acid mixture feedstock, whose oleic acid content is more than 80 wt % based on weight of fatty acid mixture contained in the feedstock, by heating in the presence of a clay catalyst; ii) separating monomer fatty acids from the dimer fatty acids formed during step i); and iii) derivatizing dimer fatty acids to produce dimer fatty esters, amides, alcohols or alkanes; wherein the derivatization step is an esterification, an amidification, a reduction or a decarboxylation reaction of the carboxylic functions of dimer fatty acids, wherein the fatty acid mixture feedstock are fatty acids from high oleic sunflower oil.

2. The derivatives of dimer fatty acids of claim 1, wherein the temperature of dimerization is between 200 and 250? C.

3. The derivatives of dimer fatty acids of claim 1, wherein the clay catalyst is bentonite.

4. A base oil comprising the derivatives of dimer fatty acids of claim 1.

5. A composition comprising: derivatives of dimer fatty acids of claim 1; and an additive used in the field of lubricants.

6. A lubricant composition comprising the composition of claim 5.

7. The composition of claim 6, wherein the lubricant composition is an engine oil, a hydraulic fluid, a drilling fluid, a gear oil or a compressor oil.

8. A method to reduce the pour point of derivatives of dimer fatty acids by carrying out an esterification, an amidification, a reduction or a decarboxylation reaction of the carboxylic functions of dimer fatty acids obtained by the process comprising the following steps: i) dimerizing fatty acid mixture feedstock, whose oleic acid content is more than 80 wt % based on weight of fatty acid mixture contained in the feedstock, by heating in the presence of a clay catalyst; and ii) separating the monomer fatty acids from the dimer fatty acids formed during step i), wherein the fatty acid mixture feedstock are fatty acids from high oleic sunflower oil.

9. A method to reduce the pour point of a composition comprising adding derivatives of dimer fatty acids produced in the presence of a clay catalyst from dimer fatty acids from fatty acid mixture feedstock, whose oleic acid content is more than 80 wt % based on weight of fatty acid mixture contained in the feedstock, and wherein the fatty acid mixture feedstock are fatty acids from high oleic sunflower oil.

10. The method of claim 9, wherein the quantity of derivatives of dimer fatty acids, added to the composition, is of at least 50 wt % based on the weight of the composition.

Description

EXAMPLE 1

Process For Preparing Dimer Fatty Acids

(1) 1.1 Preparation of dimer fatty acids from fatty acids obtained from high oleic sunflower oil

(2) Dimerization

(3) 1800 g of fatty acids obtained from high oleic sunflower oil (comprising 83.7 wt % of C18:1, 7.3 wt % of C18:2, 3.7 wt of C16:0 and 3 wt % of C18:0) and 90 g of natural bentonite clay catalyst were placed together in an autoclave. Air was flushed out of the autoclave with nitrogen. While stirring, the mixture was heated to 230? C. This reaction temperature was held for 3 hours, the pressure had built up to 4 barg (5.10.sup.5 Pa).

(4) The reaction mixture was then cooled down to 80? C., while removing gaseous components by venting with nitrogen. After adding 27 g of 75 wt % phosphoric acid, temperature was raised again to 130? C. and pressure was lowered to 60 mbar. These conditions were held for one hour until all water was removed from the product.

(5) The clay catalyst was subsequently removed from the reaction product by vacuum filtration.

(6) Recovering of the Dimer Fatty Acids

(7) The dimer fatty acids, amounting to substantially 44 wt %, were separated from the monomer fatty acids by distillation up to 260? C. under 2 mbar.

(8) 1.2 Preparation of Comparative Dimer Fatty Acids from Rapeseed Fatty Acids

(9) Those comparative dimer fatty acids were prepared as described above using fatty acids obtained from rapeseed oil (comprising 61.7 wt % of C18:1, 18.4 wt % of C18:2, 10.1 wt % of C18:3, 4.5 wt of C16:0 and 1.5 wt % of C18:0) instead of fatty acids obtained from high oleic sunflower oil.

EXAMPLE 2

Process For Preparing Esters of Dimer Fatty Acids

(10) 2.1 Preparation of 2-ethylhexyl ester of dimer fatty acids according to the invention

(11) 796 g of dimer fatty acids prepared in Example 1.1 and 554 g of 2-ethylhexanol are loaded in a 2 liter glass reactor equipped with a Dean Stark set up, which allows efficient recycling of distilled and condensed 2-ethylhexanol and removal of the reaction water. The molar ratio 2-ethylhexanol to dimer acid equals 3.1.

(12) The reactor is heated to 210? C. and atmospheric pressure under continuous recycling of the distilled 2-ethylhexanol and removal of the reaction water through the Dean Stark set up. When an acid value of 9 mg KOH/g is reached, the Dean Stark set up is removed and the reaction is continued until the acid value is lower than 3 mg KOH/g. At this moment the reactor is gradually put under vacuum until a pressure of 5 mbar is reached, and the remaining excess of 2-ethylhexanol is distilled at 210? C. Acid values are measured according to standard ISO 660:2009.

(13) 2.2 Preparation of comparative 2-ethylhexyl ester of dimer fatty acids

(14) This comparative dimer fatty esters were prepared as described above using comparative dimer fatty acids prepared in Example 1.2.

(15) 2.3 Preparation of methyl ester of dimer fatty acids according to the invention

(16) The methyl ester was prepared according to method described in Example 2.1 using methanol instead of 2-ethylhexanol.

EXAMPLE 3

Pour Points of Dimer Fatty Acids and Esters Thereof

(17) Pour points were determined according to method described in ASTM D97. Results obtained are gathered in Table 2 below:

(18) TABLE-US-00001 TABLE 2 Pour points of dimer acids and esters thereof according to the invention and of comparative dimer fatty acids and esters thereof Pour point (? C.) Dimer fatty acids ?11 Comparative dimer fatty acids ?12 2-ethylhexyl ester of dimer fatty acids of ?63 the invention Comparative 2-ethylhexyl ester of ?54 dimer fatty acids Methyl ester of dimer fatty acids of the ?48 invention

(19) As can be seen, esters of dimer acids of the invention have a lower pour point. The pour point of 2-ethylhexyl ester of dimer fatty acids is lowered by 16% when prepared from fatty acids obtained from high oleic sunflower oil instead of rapeseed oil.

(20) Methyl ester of dimer fatty acids of the invention has a lower pour point that the pour point (?43? C.) of the methyl ester of dimer fatty acids obtained from a high oleic acid content as fatty acids feedstock, using zeolite as catalyst as described in patent application U.S. 2016/0097014 A1.

(21) For applications such as in lubricant field, the lower the pour point the better. This makes the derivatives of dimer fatty acids disclosed in this invention particularly useful as base oil for lubricant compositions used in cold regions, for automotive or industrial applications.

EXAMPLE 4

Kinematic Viscosities of Dimer Fatty Esters

(22) Kinematic viscosities were determined according to method described in ASTM

(23) D445. Results obtained are gathered in Table 3 below.

(24) TABLE-US-00002 TABLE 3 Kinematic viscosities of dimer fatty esters Kinematic Kinematic viscosity at viscosity at 40? C. (m.sup.2/s) 100? C. (m.sup.2/s) 2-ethylhexyl ester of dimer 89.4 12.9 fatty acids of the invention Comparative 2-ethylhexyl 94 14.0 ester of dimer fatty acids

(25) Kinematic viscosity at 40? C. and 100? C. of 2-ethylhexyl ester of dimer fatty acids prepared from fatty acids obtained from high oleic sunflower oil, are slightly lower than kinematic viscosity 2-ethylhexyl ester of dimer fatty acids prepared from fatty acids obtained from rapeseed oil.