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Publication numberUS2763638 A
Publication typeGrant
Publication dateSep 18, 1956
Filing dateJul 27, 1955
Priority dateJul 27, 1955
Publication numberUS 2763638 A, US 2763638A, US-A-2763638, US2763638 A, US2763638A
InventorsNevin Charles S
Original AssigneeAmerican Cyanamid Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Treatment of tall oil fatty acids
US 2763638 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent TREATMENT OF TALL OIL FATTY ACIDS Charles S. Nevin, Stamford, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application July 27, 1955, Serial No. 524,801

6 Claims. (Cl. 260--97.5)

This invention relates to methods of improving the drying properties of tall oil fatty acid mixtures containing low percentages of rosin acids and more particularly is concerned with methods of improving the drying properties, color and odor of tall oil fatty acid mixtures from which substantially all or at least a major proportion of the rosin acids have been removed.

Tall oil is a mixture consisting primarily of (l) rosin acids related to the abietic acids and (2) fatty acids for the most part oleic and linoleic acids. It is obtained as a by-product in the manufacture of kraft paper by the sulfate process. In this process, chips of pine wood are digested under heat and pressure with a solution of sodium hydroxide and sodium sulfide in order to free the cellulose of other wood constituents. The highly alkaline solution forms soluble sodium soaps of the lignin and rosin and of the fatty acids originally present as esters. These are washed out of the wood pulp as a dark solution, known as black liquor, which is concentrated, cooled and allowed to stand whereby fatty acid and rosin soaps separate out as a dark brown, curdy mass called black liquor soap. This black liquor soap is skimmed off and is boiled with sulfuric acid to convert the sodium soaps into free rosin and fatty acids. The reaction mixture is allowed to settle and the clear, brown, crude tall oil separates out and may be collected.

Crude tall oil comprises a mixture of rosin and fatty acids and is normally clear, dark brown oil containing from about 35 to about 55% by Weight of rosin acids and from about 60 to about 40% by weight of fatty acids, plus from about 5 to about by weight of other constituents, primarily unsaponifiables and materials of unestablished chemical identity.

Crude tall oil is ideal for applications where rosin acids and fatty acids can be used together and are employed in many commercial instances such as in the paint and varnish industries in applications where their dark color or other restrictions do not prohibit their use.

Distilled and fractionated tall oil products with reduced amounts of rosin acids are commercially available. Their composition ranges from about 20 to about 35% by Weight of rosin acids and from about 80 to about 65% by weight of fatty acids, plus from about 1 to about 5.5% by weight of unsaponifiables and other materials. These products are light-colored and are excellent for industrial applications in the paint, enamel and varnish industries, having excellent drying properties, color and odor.

More highly fractionated products from which substantially all or at least a major portion of the rosin acids have been removed are also commercially available. Such products may comprise, for example, from about 1 to about 12% by weight of rosin acids and from about 83 to about 98% by weight of fatty acids, plus from about 1 to about 5% by weight of unsaponifiables and other materials. These products are even lighter colored, have a relatively good odor but, due to their low rosin acid content, do not possess the fast drying properties possessed by the less fractionated mixtures having a higher rosin acid content.

Inasmuch as such more highly fractionated products containing lower percentages of rosin acids are more desirable from a color retention and flexibility standpoint but are less desirable from a drying standpoint, it is a principal purpose of the present invention to improve their drying properties to render them more desirable from both standpoints and consequently of more widespread industrial application.

Attempts have hitherto been made to remove the interfering constituents responsible for the poor drying qualities of such refined tall oil fatty acid. products containing low amounts of rosin acids but such attempts have been either unsuccessful or uneconomical. Such prior attempts have included, for example, fractional distillation, extraction of the soaps with selected solvents, extraction of the free acids with furfural, extraction with propane by the Solexol process and separation by low temperature crystallization.

it has now been found that, if these tall oil fatty acid products containing from about 1 to about 12% by weight of rosin acids and from about 83 to about 98% by weight of fatty acids, plus from about 1 to about 5% by weight of unsaponifiables and other interfering materials, are treated by the combined processes of the present invention, the interfering materials are removed and/or modified and the treated products possess vastly improved drying characteristics.

More specifically, it has now been found that, if these tall oil fatty acid products containing negligible or low amounts of rosin acids are treated with metallic zinc, the zinc apparently reacts with the fatty acids to release hydrogen and thus creates reducing conditions which affeet the nature and properties of the undesirable natural antioxidants or interfering materials (particularly, the boiling points thereof) whereby a simple distillation may be employed to separate them from the desired tall oil fatty acid mixture.

Additionally, it is believed that the zinc or the zinc tallate which is formed acts presumably somewhat as catalyst to promote polymerization or condensation re actions of such interfering materials to change their properties whereby they are rendered non-volatile under conditions of temperature and pressure wherein the tall oil fatty acid mixture is volatile and may be separated by a simple distillation.

Such conditions and reactions, however, do not ap parently affect the tall oil fatty acids to any substantial degree inasmuch as the product coming over during the distillation is similar to the original material existing prior to the zinc treatment, the sole difference being the removal of the interfering anti-drying bodies.

Experimentation proved that simple distillation of the tall oil fatty acids without prior zinc treatment does not alter the composition, the appearance, or the drying properties of the tall oil fatty acids.

While as little zinc as 0.05% by weight of the tall oil fatty acids show some improvement in the drying properties, it is preferable to use from about 0.1% to about 0.5% by weight of the zinc. In general, however, amounts ranging up to about 1 or 2% may be used effectively, with larger amounts up to 5%, for example, presenting no material advantage.

The line is preferably added in a finely divided form such as zinc dust or zinc powder. However, zinc in any other desirable form may also be used as, for example, mossy zinc, zinc turnings or granular zinc.

The temperature used for treatment of acid mixture with metallic zinc 200 to about 235 the tall oil fatty is preferably from about (3., but temperatures ranging from 150-250 C. are effective within the broader aspects of the present inventive concept. The pressure maintained during the treatment of the tall oil fatty acid mixture is preferably normal atmospheric pressure but it is to be appreciated that subatmospheric or superatmospher ic pressures may be used with corresponding changes in temperatures.

The time required for the zinc treatment of the tall oil will vary depending upon the temperature, the quantity of the anti-drying compounds, color bodies and odoriferous material present in the tall oil, the degree of agitation. the rate of bubbling of the inert gas through the liquid if an inert gas is used in conjunction with the heat treatment in the presence of zinc, etc.

The distillation procedures employed in carrying out the principles of the present invention are the simple distillations normally carried out in the industry. Temperatures and pressures are, of course, interdependent and vary within wide related ranges. In the present case, however, it has been found that temperatures of from about 200 to about 240 C. and pressures of from about 3 to about 15 mm. are preferred, although lower and higher values are effective, provided the conditions are such that the tall oil fatty acids are distillable away from the undesirable natural antioxidants and interfering antidrying bodies.

The distillations may also be carried out in the presence of steam or an inert gas such as carbon dioxide, nitrogen, etc., at relatively higher pressures of from about 30 to about 70 mm. or more.

With regard to the interfering materials which prevent the desirable drying properties of the tall oil fatty acid mixtures and which are removed by the combined processes of the present invention, it is presumably believed that they comprise phenolic bodies and other antioxidants and that they are normally present in amounts of from about 0.01% to about 1.0% by weight. Their exact chemical structure and nature, however, has not been established but it has been determined that, once they are removed by the combined processes herein described the treated tall oil fatty acid mixture containing low percentages of rosin acids acquires excellent drying properties.

The invention will be further illustrated in greater detail by the following specific examples and evaluations. It should be understood, however, that although these examples may describe in particular detail some of the more specific features of the present invention, they are given primarily for the purpose of illustration and the invention in its broader aspects is not to be construed as limited thereto.

In these examples, it is to be stated that the term Acintol FA #1" refers to a singly-fractionated tail oil fatty acid mixture approximately comprising 92.5% fatty acids (425% linoleic acid; linoleic acid; 47.2% oleic acid and 2.8% saturated acids), 3.5% rosin acids and 4.0% unsaponifiables and other materials. It is also to be stated that the term Acintol FA #2 refers to a doubly-fractionated tall oil fatty acid mixture approximately comprising 96.8% fatty acids (46.1% linoleic acid; 0% linolenic acid; 48.4% oleic acid and 2.1% saturated acids), 1.0% rosin acids and 2.2% unsaponifiables and other materials. These percentages, as are all other percentages referred to herein, are by weight based on the total weight of the completed acid mixture, unless otherwise indicated.

The Hours to Reach system referred to in the following tests is based on the number of hours required for the film to obtain the described film characteristics. Under test conditions in an air-conditioned room at 77 F. (12 F.) and 50% (i4%) relative humidity, (1) Dust Free indicates that a finger may be drawn lightly over the film without leaving a mark, (2) Set to Handle indicates that finger marks produced by light pressure may be removed by gently polishing, (3) Light Tack indicates a light tacky feeling as obtained by a 50 gram- 4 5 second Tack test results and (4) Tack Free indicates the complete absence of tack as obtained by a 300 gram weight-5 second Tack test result (ASTM-D 15450 T-p. 61).

EXAMPLE 1 A sample of tall oil fatty acids containing 1.2% rosin acids, 2.4% unsaponifiables, 5.0% conjugated linoleic acids, and 42.5% total linoleic acids was heated under an atmosphere of nitrogen to 235 C. To the hot fatty acids, 0.3% of zinc dust based on the weight of the fatty acids present was added and the mixture was stirred for 30 minutes while maintaining the temperature at 235 C. During the reaction some of the zinc dust particles agglomerated. By discontinuing the stirring, this unreacted zinc immediately settled and was readily separated from the fatty acids. The fatty acids were distilled at 220- 235 C. and 10 mm. Hg pressure giving a yield of 97% product and 3% residue. The treated fatty acids product contained 0.9% rosin acids, 2.2% unsaponifiables, 4.5% conjugated linoleic acids, and 40.7% total linoleic acids.

EXAMPLE 2 A sample of Acintol FA #2 tall oil fatty acids was heated under an atmosphere of nitrogen to 235 C. To the hot fatty acids, 0.3% of zinc dust was added and the mixture was stirred for 30 minutes while maintaining the temperature at 235 C. During the reaction some of the zinc dust particles agglomerated. By discontinuing the stirring, this unreacted zinc immediately settled and was readily separated from the fatty acids. The fatty acids were distilled at 220-235 C. and 10 mm. Hg pressure giving a yield of 97.1% product and 2.9% residue. The treated fatty acids product contained 1.0% rosin acids, 2.2% unsaponifiables, 4.5% conjugated linoleic acids, and 46% total linoleic acids. Drying time evaluations for the treated and untreated fatty acids are shown in following examples.

EXAMPLE 3 A sample of Acintol FA #2 tall oil fatty acids was heated under an atmosphere of nitrogen to 215 C. To the hot fatty acids, 0.2% of zinc dust was added and the mixture was stirred for 60 minutes while maintaining the temperature at 215 C. During the reaction some of the zinc dust particles agglomerated. By discontinuing the stirring, this unreacted Zinc immediately settled and was readily separated from the fatty acids. The fatty acids were distilled at 220235 C. and 10 mm. Hg pressure giving a yield of 96.5% product and 3.5% residue. The treated fatty acids product contained 1.0% rosin acids, 2.2% unsaponifiables, 4.8% conjugated linoleic acids, and 45% total linoleic acids.

EXAMPLE 4 were distilled at 220235 C. and 10 mm. Hg pressuregiving a yield of 96.8% product and 3.2% residue. The

treated fatty acids product contained 3.2% rosin acids, I

3.8% unsaponifiables, 4.1% conjugated linoleic acids, and 40.7% total linoleic acids. Drying time evaluations for the treated and untreated fatty acids are shown in following examples.

EXAMPLE 5 To determine the effect of the zinc treatment on the drying properties ofthe tall oil fatty acids, drying rates were" evaluated for white, air-drying enamels made from treated tall oil fatty acids and untreated tall oil fatty acids and a commercially available rapid drying expensive distilled fatty acid mixing having an approximate composition of 54% linoleic acid, 40% oleic, 2% linolenic acid and 4% saturated fatty acids.

Enamel composition Vehicle: Long oil alkyd--23.4% phthalic anhydride, 19.2% pentaerythritol, and 57.4% fatty acids specified. Pigment/binder: 100/ 100 (TiOz pigment) Drier:0.4% lead and 0.04% cobalt Thinner: Varsol #1 to 70 Krebs units Film thickness 0.0015 inch wet films on glass Hours to reach description Acintol Aeintol Commer- Film Description FA 2 FA 2 cial Untreated, Zinc Fatty ours Treated, Acids, ours hours Dust Free- 4 2 1. 5 Set to Handle 6 3 2. 5 Light Tack. 7 3. 5 3 Tack Free 24 6 6 EXAMPLE 6 In this example, drying evaluations for alkyd clears prepared from the specified fatty acids are presented.

Alkyd clear composition 1) 23.4% phthalic anhydride (2) 19.2% pentaerythritol (3) 57.4% fatty acids specified 70% of (1)+(2)+(3) in Varso1#1 Alkyd composition reduced to 50% nnvolatile.

Drier: 0.4% lead; 0.04% cobalt. Film thickness: 0.0015 inch wet films on glass.

Hours to reach description Acintol Acintol Commer- FA 2 FA 2 cial Film Description Untreated, Zinc Fatty ours Treated Acids, hours hours Dust Free 4 2. 2. 5 Set to Handle--. 6 3 3 Light Tack 8 4 3.5 Tack Free 24 8 7 EXAMPLE 7 The procedures of Example 6 were carried out substantially as set forth therein with the sole exception that Acin- 6 tol FA 1 was used instead of Acintol FA 2. The evaluations were as follows:

Although I have described specific examples of my inventive concept and several tests thereof, as well as the chemical and physical characteristics of particular samples thereof, I consider the same not to be limited to the specific substances mentioned therein but to include various other compounds of equivalent constitution as set forth in the claims appended hereto. It is understood, of course, that any suitable changes, modifications and variations may be made without departing from the spirit and scope of the invention.

What I claim is:

l. A method of improving the drying properties of a tall oil fatty acid mixture containing from about 1 to about 12% by weight of rosin acids and from about 0.01 to about 1% by weight of slow-drying interfering materials which comprises heating the mixture with metallic zinc in an amount from about 0.05 to about 2.0% by Weight of said mixture at a temperature of from about to about 250 C. and distilling the resulting mixture to separate and leave behind slow-drying interfering materials to obtain a tall oil fatty acid mixture possessing improved drying properties.

2. A method as defined in claim 1 wherein the metallic zinc is present in an amount from about 0.1 to about 0.5% by weight of the mixture.

3. A method as defined in claim 1 wherein the mixture is heated at a temperature of from about 200 to about 235 C.

4. A method of improving the drying properties of a tall oil fatty acid mixture containing from about 1 to about 12% by weight of rosin acids, from about 83 to about 98% by weight of fatty acids and from about 0.01 to about 1% by weight of slow-drying interfering materials which comprises heating the mixture with metallic zinc in an amount from about 0.1 to about 0.5 by weight of said mixture at a temperature of from about 200 to about 235 C. and distilling the resulting mixture to separate and leave behind the slow-drying interfering materials to obtain a tall oil fatty acid mixture possessing improved drying properties.

5. A method as defined in claim 4 wherein said distillation takes place at a temperature of from about 200 to about 240 C. at a presssure of from about 3 to about 15 mms.

6. A method as defined in claim 4 wherein said distillation is carried out in the presence of a member of the group consisting of steam and inert gas.

No references cited.

Non-Patent Citations
Reference
1 *None
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3257438 *May 18, 1962Jun 21, 1966Tenneco ChemProcess for removing stilbene from tall oil fatty acids
US4222933 *Jul 30, 1979Sep 16, 1980Westvaco CorporationTreatment of rosin
US4957662 *Sep 19, 1979Sep 18, 1990Masao SuzukiMethod for purifying fatty acids
Classifications
U.S. Classification530/209, 554/205, 554/175, 554/177, 554/188
International ClassificationC09F7/00, C11B13/00
Cooperative ClassificationC11B13/005, C09F7/00
European ClassificationC11B13/00B, C09F7/00