US3481977A - Carboxylation - Google Patents

Description

Dem-2,1969 E. J.,M'ILLE R, JR., ET 3,431,977

CARBOXYLATION Original Filed April 26, 1965 EFFECT OF INCREASING AMOUNT OF HF ACID F ORMED I 1 l l I l I I /0 I5 MOLE 6 HF per MOLE UNSATURATED AC/ D INVENTORS Eugene J M/Y/er, Jr Ago Mo/s BY Domingo Soy United States Patent 3,481,977 CARBOXYLATION Eugene J. Miller, Jr., Wheaton, Ago Mais, La Grange Park, and Domingo Say, Chicago, Ill., assignors to Armour and Company, Chicago, Ill., a corporation of Delaware Continuation of application Ser. No. 450,993, Apr. 26, 1965. This application July 10, 1968, Ser. No. 752,432 Int. Cl. C07c 57/04, 57/16, 57/12 U.S. Cl. 260537 6 Claims ABSTRACT OF THE DISCLOSURE Unsaturated fatty acids are carboxylated with carbon monoxide by the use of 15 to 30 moles of HF per mole of acid.

This application is a continuation of application Ser. No. 450,993 filed Apr. 26, 1965, now abandoned.

This invention relates to carboxylation, and more particularly, to the carboxylation of unsaturated fatty acids with carbon monoxide in the presence of hydrogen fluoride to effect extremely high yields of high quality diacids.

Roe and Swern of the U.S. Department of Agriculture in the Journal of the American Oil Chemists Society periodical, volume 37, pages 661 to 668 (1960), report that unsaturated fatty acids may be carboxylated with carbon monoxide using large amounts of H SO Isolation of the product was accomplished, however, by dousing the reaction mixture in water. Economical reclamation of the sulfuric acid catalyst from this aqueous mixture presents difliculties which leave the process far from being a commercial one. This is unfortunate because the product, carboxy-fatty acid, is extremely attractive in various technologies. It not only possesses the desirable physical and chemical properties of a long chain fatty acid, but, in addition, has a second carboxy group which makes it extremely useful as an intermediate for forming bifunctional fatty compounds and as a monomeric material in polyester work. Other uses will become evident as this disclosure proceeds.

It should be evident that if one could accomplish substantially quantitative yields with practically quantitative reclamation of catalyst, an extremely valuable advance would be made.

An object of this invention is to provide an improved carboxylation process for unsaturated fatty acids.

Another object is to provide a carboxylation process of the above character, which utilizes relatively mild reaction conditions.

Still another object is to provide a carboxylation process of the above character which is relatively fast.

A further object is to provide a carboxylation process for unsaturated fatty acids having high yield, in fact, almost quantitative.

A still further object is to provide a carboxylation process of the above character which allows for almost quantitative recovery of the catalyst in usable form.

Other objects of the invention will in part be obvious and will in part appear hereinafter:

It has now been sur isingly found that substantially quantitative yields of dicarboxylic acids may be obtained by the carboxylation of unsaturated fatty acids if 'one utilizes liquid hydrogen fluoride as a catalyst, in the nature of solvent quantities. The molar ratio of unsaturated acid to HF should range from about 1:15 to 1:30 or more, although no improvement in yield is effected by the use of greater than 30 moles of HF per mole of unsaturated acid.

A molar equivalent or slightly in excess of a molar equivalent of water (based on the unsaturated acid) is Patented Dec. 2, 1969 also used with said large amounts of HF. The use of less than equivalent amounts of water would tend to favor formation of by-products, such as ester, while large excesses of water would only serve to dilute the HF unnecessarily, thereby complicating efiicient catalyst recovery.

Carbon monoxide, which serves as the carboxylating agent, should be used at pressures ranging from slightly superatmospheric to 1000 p.s.i.g., the prime essential be ing intimate contact between the gaseous and liquid reaction phases. A preferred range of carbon monoxide pressure is 50 to 500 p.s.i.g.

When such ratios are utilized, over dicarboxylic acid is generally formed. As indicated hereinafter, the sharp breakoff in percent diacid formed depends upon utilization of the concentration ranges and ratios indicated above.

Isolation of the carboxy-fatty acid formed under said concentration ranges and ratios is accomplished by distillation of the HP from the reaction mixture with subsequent recovery. Almost quantitative recovery, generally in the range of 97-99%, of the HF can be eifected in this way. The concentration of recovered HP is usually within the range of -98%, which is suitable for reuse in carboxylation reactions.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following examples which illustrate the invention in detail:

EXAMPLE I A l-liter Monel autoclave is charged with 415 g. (20.75 moles) of liquid hydrogen fluoride and 19.8 g. (1.1 moles) of water. The unit is sealed and the temperautre raised to 30 C. Carbon monoxide gas is introduced to a pressure of 50 p.s.i.g. and 278 g. (1.0 mole) of commercial oleic acid are pumped in over a one hour period at 30 C/50 p.s.i.g. The reaction is allowed to proceed under these conditions for an additional hour. Then at the end of one hour, the stirring is stopped and the hydrogen fluoride distilled off under a 5 p.s.i.g. nitrogen purge at temperatures ranging from 30 C. to a maximum of 150 C.

Total HF recovery (99%) g 410 Total HF concentration percent 95 Crude carboxystearic (302 g.) is obtained in 92% mass yield having the following analysis: Neutralization equivalentl98 (calculated 173.2).

TABLE OF PHYSICAL AND CHEMICAL PROPERTIES [Solubility Data (Weight to Weight Basis) at 25 0.] Solvent:

Isopropanol. 10%

Benzene, 10%

Iso-octane, 10%

Kerosene, 10%

Skelly F, 10%

Mineral Oil, 10%

Water, Insoluble EXAMPLE II The oleic acid used in this carboxylation is commercial grade consisting of about 93% active, the remainder being saturated acids. The mole ratio of oleic acid: HF:H O is 10:20: 1.3.

A 300-ml. Monel autoclave is charged with g. (6.0 moles) of liquid hydrogen fluoride and 7.02 g. (0.39 mole) of water at approximately 0 C. The unit is secured and temperature is taken up to 25 C. Carbon monoxide gas is introduced to a pressure of 500 p.s.i.g. and then 84.15 g. (0.3 mole) of oleic acid is pumped into the reaction mixture over a period of one hour at 25-29 C./ 320-500 p.s.i.g. The reaction is allowed to proceed for an additional 30 minutes at 25-27 C./300500 p.s.i.g. Then the reactive mixture is cooled to about C., and the unit vented and opened. The reaction mixture is transferred to a 500 ml. round-bottom stainless steel flask (equipped with a magnetic stirrer, thermocouple and heating mantle). Hydrogen fluoride is distilled off by heating and stirring over a period of 3 hours at 16160 C. Carboxystearic acid will be obtained as a dark oil in 97.0% mass yield (95.7 g.) having the following analysis:

Neutralization equivalent (calculated 173.2) 186.5 Activity (percent) 92.8 Saponification equivalent 183.5 Iodine value 6.81

EXAMPLE III Netralization equivalent (calculate 115.1) 153.5 Activity (percent) 75.0 Saponification equivalent 134.4 Iodine value 10.6

EXAMPLE IV In like manner, erucic acid is carboxylated using a mole ratio of acid: HF:H O of 1.0:20.0:1.2 at 25-30 C./300450 p.s.i.g. carbon monoxide pressure. The HF is removed by distillation, as in Example II, yielding carboxybenhenic acid in essentially quantitative yield having the following analysis:

Neutralization equivalent (calculated 192.3) 215 Activity (percent) 89.5 Saponification equivalent 206.5 Iodine value 3.6

EXAMPLE V TO X In order to ascertain the effect of varying the concentration of unsaturated acid (specifically oleic acid), HF and water, a series of runs are made using essentially the same method as illustrated in Example II. The results are tabulated as follows:

'4 in accordance with the method of this invention are those falling within the following formula:

x+y+z=5 to 19 a+b=1 to 3, and either may be 0.

Typical of such fatty acids are 10-undecenoic acid, lauroleic acid, myristoleic acid, palmitoleic acid, oleic acid, gadoleic acid, erucic acid, linoleic acid, linolenic acid, eleostearic acid, licanic acid, arachidonic acid and clupanodonic acid. Most of these are found in natural fats and oils such as vegetable, animal and marine fats and oils. If desired, mixtures of unsaturated fatty acids may be carboxylated by the technique of this invention.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in carrying out the above method without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

Now that the invention has been described, what is claimed as new and desired to be secured by Letters Patent is:

What is claimed is:

1. A method for the carboxylation of unsaturated fatty acids falling within the formula:

x+y+z=5 to 19 a+ b=1 to 3, and either may be 0.

to form dicarboxylic acids comprising adding in a one step process at least one unsaturated fatty acid to an autoclave containing carbon monoxide at pressures ranging from slightly superatmospheric to 1000 p.s.i.g. and a mixture of about 15 to 30 moles of hydrogen fluoride per mole of said unsaturated fatty acid and water slightly in excess of a stoichiometric quantity of said unsaturated fatty acid.

1 The neutralization equivalent of pure earboxystearic acid is 164.2. Allowing for the 7% saturated acids present in commercial grade oleic acid, however, raises the neutralization equivalent theoretically obtainable to 173.2.

2 Mass yield was not calculated in this case since no diacid was formed as evidenced by the high neutralization equivalent.

From this table and the graph attached it is evident that the use of at least 15 moles of HP to one mole of unsaturated acid is critical in order to obtain satisfactory conversions to the carboxy-fatty acid. A quantity of HF sufiicient to dissolve the unsaturated acid appears to be the prime requirement. The practical upper limit of moles of HF per mole of unsaturated acid is about 30, although higher quantities may be utilized if desired.

to form dicarboxylic acids comprising the steps of adding The unsaturated fatty acids that may be carboxylated in a one step process at least one unsaturated fatty acid to an autoclave containing carbon monoxide at pressures ranging from slightly superatmospheric to 1000 p.s.i.g. and a mixture of about 15 moles to 30 moles to each mole of said unsaturated fatty acid of hydrogen fluoride as a catalyst-solvent and water slightly in excess of a stoichiometric quantity to said unsaturated fatty acid and subsequently distilling off the hydrogen fluoride to eflfect a high yield of a high quality dicarboxylic acid as well as good recovery of the hydrogen fluoride.

3. The method of claim 2 wherein the unsaturated fatty acid used is oleic acid.

4. The method of l-claim 2 wherein the unsaturated fatty acid used is l0-undecenoic acid.

5. The method of claim 2 wherein the unsaturated fatty acid used is erucic acid.

6. The method of claim 2 wherein the unsaturated fatty acids used consist of a mixture of fatty acids as found in natural fats and oils.

References Cited JAMES A. PATTEN, Primary Examiner V. GARNER, Assistant Examiner

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