WO2001072691A2

WO2001072691A2 - Low pour point primary amides

Info

Publication number: WO2001072691A2
Application number: PCT/US2001/040381
Authority: WO
Inventors: David Charles Lewis; Jeffrey Jon Vipond
Original assignee: Huntsman Specialty Chemicals Corp; Huntsman Petrochemical LLC
Current assignee: Huntsman Specialty Chemicals Corp; Huntsman Petrochemical LLC
Priority date: 2000-03-29
Filing date: 2001-03-28
Publication date: 2001-10-04
Anticipated expiration: 2002-09-29
Also published as: WO2001072691A3; BR0109899A; MXPA02009493A; CA2404150A1; AU2001255814A1

Abstract

A method of preparing reduced pour point amides. The method involves reacting an etheramine and a fatty acid, or a methyl ester thereof, in a molar ratio from about 0.1:1 to about 10:1. The resulting low pour point primary amides are also disclosed. These low pour point primary amines have a low vapor pressure, and exhibit excellent emulsifying and lubricating properties. A method of lowering the pour point of high pour point amides is also disclosed. This method involves blending the low pour point amides of the present invention with amides having pour points higher than the pour point of the primary amides of the present invention.

Description

LOW POUR POINT PRIMARY AMIDES

Technical Field This invention relates to amides, and, more particularly, to low pour point primary amides that are particularly useful in metalworking applications.

Background of the Invention

Amides of fatty acids are widely used in metalworking applications because of their lubricity and emulsification properties. Unfortunately, these amides also have other properties that tend to make them difficult to use in metalworking applications. For example, amides derived from secondary amines tend to form nitrosamines, which are suspected to be carcinogens. Hence, the use of these amides in metalworking applications is not favored because most metalworking applications involve humans. Alternatively, amides derived from primary amines typically have high pour points, meaning they are solids even at high temperatures. Such high pour points make the use of these amides impractical under standard metalworking conditions. Accordingly, numerous methods have been developed to reduce the pour point of amides derived from primary amines.

One conventional method involves formulating the amide to have a high amine-to- fatty acid ratio, i.e. a 2:1 ratio. While this increased amine content tends to reduce the pour point of the amide, it also causes the pH of the amide to rise beyond what is acceptable for metalworking applications involving aluminum. In particular, excess primary amines tend to elevate the pH of the resulting amide above about 8.8, the pH at which aluminum begins to corrode.

Another conventional method involves mixing the amide with one or more high molecular weight fatty acids. While this method may reduce the pour point of the amide, the excess fatty acid tends to considerably dilute the amide, thereby reducing the lubricity and emulsification properties of the amide.

Therefore, what is needed is a method for reducing the pour point of amides derived from primary amines, wherein the pour point of the amides is reduced without adversely affecting the properties of the amides that make them useful in metalworking applications.

Summary of the Invention In one embodiment, the present invention includes a method of reducing the pour point of amides derived from primary amines. The method involves reacting an etheramine and a fatty acid, or a methyl ester thereof, in a molar ratio from about 0.1:1 to about 10:1. The resulting low pour point amides have the following general structure:

O

R_i-(O-R₂)_x-N-C-R₃ H

where R| is independently a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; R is a straight or branched chain alkyl group with from about six to about fifty-four carbon atoms; and x is an integer from about one to about one hundred.

In another embodiment, the present invention also includes low pour point amides derived from the reaction between an etheramine and a fatty acid, or a methyl ester thereof. These amides have the following general structure:

O

R,-(O-R₂)_χ-N-C-R₃ H

where Ri is independently a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; R₃ is a straight or branched chain alkyl group with from about six to about fifty-four carbon atoms; and x is an integer from about one to about one hundred. In another embodiment, the present invention further includes a method of reducing the pour point of high pour point amides. This method involves blending the low pour point amides of the present invention with amides having pour points higher than the pour point of the primary amides of the present invention.

Detailed Description of the Preferred Embodiment

One embodiment of the present invention involves a method for preparing low pour point primary amides. The method involves reacting an etheramine with a fatty acid, or a methyl ester thereof, in a molar ratio from about 0.1:1 to about 10:1, wherein the low pour point amides have the following general structure: O

R_j-(O-R₂)_χ-N-C-R₃ H

where Rι is independently a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; R₃ is a straight or branched chain alkyl group with from about six to about fifty-four carbon atoms; and x is an integer from about one to about one hundred. Preferably, to prepare the low pour point primary amines, a first reactant, either an etheramine or a fatty acid, or a methyl ester thereof, should be charged to a reactor. An inert gas sparge stream should then be run through the first reactant. Then, the reactant that was not charged to the reactor (i.e. either the fatty acid (or the methyl ester thereof) or the etheramine), should be added to the reactor, and preferably is added to the reactor periodically, and in incremental amounts. The second reactant may be added to the reactor simultaneously, along with the sparge stream, or the sparge stream may be temporarily removed to allow for the addition of the second reactant. During the addition of the second reactant, the temperature of the reaction should be closely monitored to ensure that a proper reaction rate is maintained. Because the reaction between the fatty acid, or the methyl ester thereof, and the etheramine is an exothermic reaction, the temperature within the reactor increases as the reaction proceeds. This increased temperature tends to cause the reaction to proceed more rapidly, which in turn further elevates the temperature within the reactor. In order to maintain a proper reaction rate, the reaction temperature must be controlled. Preferably, the temperature is controlled by controlling the rate at which the second reactant is added to the reactor. Preferably, the second reactant should be added to the reactor so that the temperature within the reactor remains less than about 250°C.

The etheramine used in the present invention may include any number of commercially available etheramines suitable for forming a primary amide, including, but not limited to, etheramines and polyetheramines derived from alcohol alkoxylates and alkyl phenol alkoxylates, and etheramines and polyetheramines derived from cyanoethylated alcohols. Preferably, the etheramine comprises an etheramine having the following general structure:

ι-(0-R₂)_x -NH₂ where Ri is a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; and x is an integer from about one to about one hundred. More preferably, the etheramine comprises an etheramine from the JEFFAMINE® M series, the JEFF AMINES® D series, or JEFFAMINE® C-300 (all commercially available from the Huntsman Corporation, Houston, Texas), and has branching in its structure. JEFFAMINE® C-300 comprises a mixture of amines having the following general structure:

R,-O- (C₃H₆0)₂-NH₂

where R| is independently a straight or branched chain alkyl group with from about twelve to about fourteen carbon atoms.

The fatty acid, or the methyl ester thereof, used in the present invention may comprise any number of commercially available fatty acids, or the methyl esters thereof, that react with an etheramine to form a primary amide. Preferably, the fatty acid, or methyl ester thereof, may include, but is not limited to, fatty acids with from about six to about twenty-four carbon atoms, fatty diacids with from about six to about twenty-four carbon atoms, and fatty dimer trimer acids with from about thirty-six to about fifty-four carbon atoms. More preferably, the fatty acid comprises ACINTOL® FA-2 Tall Oil Fatty Acid ("TOFA") (commercially available from Arizona Chemical, Panama City, Florida), which is a blend of fatty acids having the following general structure:

R₃-COOH

where R₃ is independently a straight or branched chain alkyl group with from about fifteen to about seventeen carbon atoms.

The inert gas sparge stream used in the present invention may comprise any number of inert gases suitable for use as a sparge stream. Preferably, the sparge stream is nitrogen gas. The sparge stream preferably is utilized throughout the entire course of the reaction, and is removed only if it becomes necessary to add reactants to the reactor.

Preferably, the preparation of the low pour point primary amides of the present invention may be represented by the following general equations: O O

(D I CO-ϊy-.-NH_jj + R,-C-OH- → R₃-C-N-₍R -O)_ι-R₁ H

O O

(II) R.-(O-R₂)_χ-NH₂ + R₃-C-O-CH₃ — ^■> R₃-C-N-(R₂-O)_χ-R₁

H

where R| is a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; R is a straight or branched chain alkyl group with from about six to about fifty-four carbon atoms; and x is an integer from about one to about one hundred. Equation (I) represents the reaction when a fatty acid is used, and equation (II) represents the reaction when a methyl ester of a fatty acid is used. Although not represented in the equations, water is formed as a byproduct of both reactions.

In some applications, as is described above, the presence of excess reactants (i.e. etheramines, fatty acids, or the methyl esters thereof) in the resulting product can be undesirable. In these applications, therefore, it is preferable to react the etheramine and the fatty acid, or the methyl ester thereof, in fairly equal stoichiometric amounts. Preferably, for such applications, the etheramine and the fatty acid, or methyl ester thereof, should be reacted in a molar ratio of about 1.1 : 1.

In another embodiment, the present invention also includes reduced pour point primary amides. The reduced pour point amides of the present invention are derived from the reaction between an etheramine and a fatty acid, or a methyl ester thereof. These reduced pour point amides have the following general structure:

O

R.-(0-R₂)_χ-N- C- R₃ H where R] is independently a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; R₃ is a straight or branched chain alkyl group with from about six to about fifty-four carbon atoms; and x is an integer from about one to about one hundred. The low pour point primary amides of the present invention have a low vapor pressure, making these amides safer to use in poorly ventilated metalworking environments. In addition, the amides of the present invention also exhibit excellent emulsifying and lubricating properties. Accordingly, the low pour point primary amides of the present invention may be used for a variety of purposes, including, but not limited to, use as a lubricant or as an additive in metalworking formulations. For these and other applications, the low pour point primary amides of the present invention may be used alone, or in combination with other amides and/or formulation aids. Such formulation aids may include, but are not limited to, polyalkylene glycols, amine fatty acids, and mineral oil. Such amides may include, but are not limited to, tall oil fatty acid amides, decanoic acid amides, and soya fatty acid amides.

Another embodiment of the present invention includes a method of reducing the pour point of high pour point amides. This method involves blending the low pour point amides of the present invention with any number of commercially available amides having pour points higher than the pour point of the primary amides of the present invention. In particular, the low pour point primary amides of the present invention are particularly suited for reducing the pour point of amides formed from alkanolamines, such as diethanolamine or monoethanolamine.

The following examples are illustrative of the present invention, and are not-, intended to limit the scope of the invention in any way.

Preparation of the Primary Amide Example 1 281.62 grams of JEFFAMINE® C-300 were charged to a reactor. The JEFFAMINE® C-300 was then agitated within the reactor by passing a nitrogen sparge stream though the reactor. Then, 218.38 grams of ACINTOL® FA-2 Tall Oil Fatty Acid were slowly added to the reactor, as the temperature was monitored to ensure that the temperature in the reactor did not, exceed 180°C. When the addition of the ACINTOL® FA-2 Tall Oil Fatty Acid was complete, the reactants were allowed to digest at 180°C for about eight hours. Comparison of the Pour Point and Free Amine Content

Example 2

The pour point and free amine content of the JEFFAMINE®/TOFA amide produced in Example I was determined, and then compared with the pour point and free amine content of other amides commonly used in metalworking applications. Table 1 details the results of the comparison.

Table 1

Amide Free Amine Pour Point

Content (%) (°C)

Lauryl Monoethanolamide 1 : 1 7 78-82

Lauryl Diethanolamide 1:1 7 51

I,auryl Diethanolamide 2:1 20-30 <20

Stearamide MEA 1:1 1.5 85-90

Stearamide DEA 1:1 5.0 50-55

Oleamide MEA 2:1 24 -15

JEFFAMINE® TOFA amide prepared in Example 1 3-4 -19

Table 1 shows that the JEFFAMINE®/TOFA amide prepared in Example 1 is the only amide having both a low pour point and a low free amine content.

Lubricity Testing of the Primary Amide Example 3 The JEFFAMINE®/TOFA amide produced in Example 1 was then blended in the following proportions:

Component Amount

Emulsifier¹ 13.5%

Mineral Oil (Shell 100 SUS Napthenic oil) 76.5%

JEFFAMINE®/TOFA amide prepared in Example 1 10.0%

¹ The emulsifier comprises 54% SURFONIC®L24-4, 17%SURFONIC®L24-9, 17% TOFA, and 12% water. A comparative formulation was also blended as follows:

Component Amount

Emulsifier' 15%

Mineral Oil (Shell 100 SUS Napthenic oil) 85%

'The emulsifier comprises 54% SURFONIC®L24-4, 17% SURFONIC®L24-9, 17% TOFA, and 12% water.

Five grams of the blended JEFFAMINE®/TOFA amide formulation were then diluted in ninety-five grams of tap water. Similarly, five grams of the comparative formula were diluted in ninety-five grams of water. The two diluted formulations, as well as a non-diluted JEFFAMINE®/TOFA amide sample, were then subjected to a FALEX® Wear Test. The FALEX® Wear Test is used to measure the wear and frictional characteristics of lubricants under a variety of test conditions. A lubricant is deemed more effective under the FALEX® Wear Test if the metal tested develops fewer "teeth" during the course of the test. Table 2 details the results obtained from the FALEX® Wear Test.

Table 2

Wear on Steel Wear on Aluminum

Formulation (# of teeth) (# of teeth)

Comparative formula (no JEFFAMINE®/TOFA amide) 98 93

With 10% JEFFAMINE®/TOFA amide 48 60

100% JEFFAMINE®/TOFA amide 11 Non-detectable

Table 2 demonstrates that the JEFFAMINE®/TOFA amide prepared in Example 1 exhibits excellent lubricating properties. Table 2 also shows that the JEFFAMINE®/TOFA amide prepared in Example 1 is also an effective additive for improving the lubricating properties of other formulations.

Pour Point Reduction Characteristics of the Primary Amide

Example 4 The JEFFAMINE®/TOFA amide produced in Example 1 was then blended with a soybean oil/DEA amide to determine whether the JEFFAMINE®/TOFA amide can function as a pour point depressant. Table 3 details the results.

Table 3

Formulation Pour Point

Soybean oil/DEA amide (1: 1) 35°C

30% JEFFAMINE®TOFA amide/70% soybean oil/DEA amide -3°C

JEFFAMINE®/TOFA amide -19°C

Table 3 demonstrates that the JEFFAMINE®/TOFA amide prepared in Example 1 is capable of substantially reducing the pour point of a higher pour point amide.

Although illustrative embodiments have been shown and described, a wide range of modification, changes, and substitution is contemplated in the foregoing disclosure. In some instances, some features of the disclosed embodiments may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Claims

Claims What is claimed is:

1. A method for preparing low pour point amides that comprises reacting an etheramine and a fatty acid, or a methyl ester thereof, in a molar ratio from about 0.1 : 1 to about 10:1, wherein the resulting low pour point amides have the following general structure:

R₁- (0-R₂)_χ-N-C-R₃ H

where R- is independently a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; R is a straight or branched chain alkyl group with from about six to about fifty-four carbon atoms; and x is an integer from about one to about one hundred.

2. The method of claim 1, wherein the etheramine is selected from a group consisting of etheramines and polyetheramines derived from cyanoethylated alcohols and etheramines and polyetheramines derived from alcohol alkoxylates and alkyl phenol alkoxylates.

3. The method of claim 1, wherein each Ri is independently a straight or branched chain alkyl group with from about twelve to about fourteen carbon atoms; R₂ is propylene; and x is 2.

4. The method of claim 1, wherein the fatty acid comprises a fatty acid with from about six to about twenty-four carbon atoms.

5. The method of claim 1, wherein the fatty acid comprises a fatty diacid with from about six to about twenty-four carbon atoms.

6. The method of claim 1, wherein the fatty acid comprises a fatty dimmer trimer acid with from about thirty-six to about fifty-four carbon atoms.

7 The method of claim 1, wherein the etheramine and the fatty acid, or the methyl ester thereof, are reacted in a molar ratio of about 1.1:1.

8. The method of claim 1, wherein etheramine and the fatty acid, or the methyl ester thereof, are reacted at a temperature less than about 250°C.

9. A low pour point amide prepared by reacting an etheramine with a fatty acid, or a methyl ester thereof, wherein the low pour point amide has the following general structure:

Rf (o-R₂> - - ?c-R₃

H

where K_\ is independently a straight or branched chain alkyl group with from about one to about eighteen carbon atoms; R₂ is an alkylene group with from about two to about four carbon atoms; R is a straight or branched chain alkyl group with from about six to about fifty-four carbon atoms; and x is an integer from about one to about on hundred.

10. The low pour point amide of claim 9, wherein the etheramine and the fatty acid, or methyl ester thereof, are reacted in a molar ratio from about 0.1:1 to about 10:1.

11. The low pour point amide of claim 9, wherein the etheramine and the fatty acid, or methyl ester thereof, are reacted in a molar ratio of about 1.1:1.

12. The low pour point amide of claim 9, wherein the etheramine is selected from a group consisting of etheramines and polyetheramines derived from cyanoethylated alcohols and etheramines and polyetheramines derived from alcohol alkoxylates and alkyl phenol alkoxylates.

13. The low pour point amide of claim 9, wherein each Ri is independently a straight or branched chain alkyl group with from about fourteen to about sixteen carbon atoms; R₂ is propylene; and x is 2.

14. The low pour point amide of claim 9, wherein the fatty acid comprises a fatty acid with from about six to about twenty-four carbon atoms.

15. The low pour point amide of claim 9, wherein the fatty acid comprises a fatty diacid with from about six to about twenty-four carbon atoms.

16. The low pour point amide of claim 9, wherein the fatty acid comprises a fatty dimer trimer acid with from about thirty-six to about fifty-four carbon atoms.

17. The low pour point amide of claim 9, wherein etheramine and the fatty acid, or the methyl ester thereof, are reacted at a temperature less than about 250°C.

18. A method of reducing the pour point of a high pour point amide, wherein the method comprises blending the high pour point amide with a low pour point amide prepared by reacting an etheramine with a fatty acid, or a methyl ester thereof, wherein the low pour point amide has the following general structure:

O

R₁-(O-R₂)_χ-N-C-R₃ H

19. The method of claim 18, wherein the etheramine and the fatty acid, or methyl ester thereof, are reacted in a molar ratio from about 0.1:1 to about 10:1.

20. The method of claim 18, wherein the etheramine and the fatty acid, or methyl ester thereof, are reacted in a molar ratio of about 1.1 :1.

21. The method of claim 18, wherein the etheramine is selected from a group consisting of etheramines and polyetheramines derived from cyanoethylated alcohols and etheramines and polyetheramines derived from alcohol alkoxylates and alkyl phenol alkoxylates.

22. The method of claim 18, wherein each Ri is independently a straight or branched chain alkyl group with from about fourteen to about sixteen carbon atoms; R₂ is propylene; and x is 2.

23. The method of claim 18, wherein the fatty acid comprises a fatty acid with from about six to about twenty-four carbon atoms.

24. The method of claim 18, wherein the fatty acid comprises a fatty diacid with from about six to about twenty-four carbon atoms.

25. The method of claim 18, wherein the fatty acid comprises a fatty dimer trimer acid with from about thirty-six to about fifty-four carbon atoms.

26. The method of claim 18, wherein etheramine and the fatty acid, or the methyl ester thereof, are reacted at a temperature less than about 250°C