US2756242A - Preparation of epoxidized acids - Google Patents

Description

United States Patent PREPARATION OF EPOXIDIZED A'CIDS, ESTERS AND NITRILES Edward F. Riener, Haddonfield, N. J., assignor to Rollin & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Application October 12, 1954, Serial No. 461,915

8 Claims. (Cl. 260348.6)

This invention relates to a process of preparing epoxidized acids, esters and nitriles. It relates to the preparation of epoxy acids containing 16 to 22 carbon atoms and to esters and nitriles of these epoxy acids. It has as its main object the preparation of epoxidized acids, esters and nitriles without the use of peracids, such as performic and peracetic acids, which are usually employed in the preparation of epoxides.

The process of this invention comprises reactingpreferably in the presence of an organic solvent at a relatively low temperaturea strong base, such as an alkali metal hydroxide, with a saturated aliphatic nitrile which contains 16 to 22 carbon atoms and which also contains vicinal halogen and acyloxy groups, or with a saturated aliphatic acid which contains 16 to 22 carbon atoms and which also contains vicinal halogen and acyloxy groups, or with an ester of such an acid.

The acyloxy-halo nitriles, acids and esters, which are thus reacted, are themselves prepared by reacting an olefinically unsaturated acid containing 16 to 22 carbon atoms or an ester or nitrile of such an acid with a tertiaryalkyl hypohalite in the presence of an organic acid, preferably formic or acetic acid, according to the process of U. S. Patent 2,054,814. Such acyloxy-halo compounds are the subject of another of my applications for Letters Patent, Serial No. 423,846, filed April 27, 1954. These compounds all contain 16 to 22 carbons in the acid or nitrile chain and in the acid chain or acid moiety of the ester, and they also contain at least one grouping having the configuration 2 (IJCOR -CHCH in which the portion is a part of the acid chain, and in which X is a chlorine or bromine atom, and in which R represents a hydrogen atom or a lower alkyl group, preferably a methyl group.

The acids, esters and nitriles can contain as many as three such groupings in their acid moieties by virtue of 7 having been made from acids containing as many as three double bonds. The acids and nitriles which give rise to acyloxy-halo compounds and hence to the epoxy acids and nitriles by the process of this invention include oleic, erucic, eleostearic, linoleic, linolenic, clupadonic, palmitoleic and palmitolenic acids and the corresponding nitriles. All of these acids occur in animal or vegetable oils and fats, such as soybean, cottonseed, rapeseed, safllower, linseed, and sardine oils and tallow; and they are readily obtained by saponification of the oils or fats. The instant process is also applicable to the acyloxy-halo esters of (a) the above described acids, and (b) monohydric or polyhydric alcohols. Thus, the esters which are embraced are those of (a) the acyloxy-halo-substituted acids described above, and (b) alcohols which are typified by the following: ethyl, isopropyl, n-butyl,

sec-butyl, tert-butyl, tert-amyl, n-octyl, Z-ethylhexyl, 2- ethyl-butyl, lauryl, octadecyl, cyclohexyl, benzyl and phenethyl alcohols; glycols such as ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, 2-ethylhexandiol-1,3,dodecandiol-1,12; polyalkylene glycos such as diethylene glycol and trithylene glycol; gycerol; pentaerythritol; and the isomers and homologues of the above. This process also applies to the production of epoxidized animal and vegetable oilsparticularly those listed aboveby the conversion of the derivatives of the oils which contain a plurality of acyloxy-halo groupings on the acid moieties of the oils.

In the preferred embodiment of the instant process, an acid or ester or nitrile containing at least one such acyloxy-halo grouping is dissolved in a solventpreferably an alcohol such as methanol, ethanol or butanol and is reacted with a strong base. Strong bases constitute a recognized class of compounds which ionize almost completely in water to provide hydroxyl ions. The most common of the strong bases are the hydroxides of the alkali metals such as sodium hydroxide and potassium hydroxide. Strong organic bases include quaternary ammonium hydroxides such as trirnethylbenzylammonium hydroxide. Strong bases also include anion-exchange resins which contain quaternary ammonium hydroxide groups and which, although they are insoluble, provide hydroxyl groups. Such resins are well known and are available commercially. They are described, for example, in U. S. Patents 2,540,985; 2,591,573; and 2,614,099.

The reaction whereby acyloxy-halo groupings are converted to epoxy groups has been carried out as low as -10 C. and as high as 150 C. A very satisfactory procedure is to hold the reaction mixture including a solvent at its refluxing temperature. Since at high temperatures the esters tend to hydrolyze, it is preferred, in the case of esters, to employ a solvent which boils below about 100 C. and to operate within the range of about 40 C. to about 85 C.

Two hydroxyl groups of the strongly basic compound are required to convert one acyloxy-halo grouping to one epoxide group. Ordinarily, however, an excess of the base over the stoichiometrical amount is used. Since the acyloxy groups and the halogen groups per se are split ofi during the reaction as salts of the strongly basic compound there does not appear to be any point in using any but the cheaper formoxy-chloro or acetoxy-chloro derivatives even though the compounds containing bromine groups and higher acyloxy groups are easily converted to the corresponding epoxy compounds.

The epoxy products of this invention are used in the preparation and modification of a wide variety of resinous materials where advantage is taken of the reactivity of the epoxy groups. The esters and nitriles in particular are employed as plasticizers and stabilizers for those plastics which are degraded by light and heat and which include vinyl halide resins, vinylidene halide resins, chlorinated rubber and the like. Heavy metal salts of the epoxidized acids, particularly the cadmium and lead salts, are also used as stabilizers in vinyl resin compositions.

The following examples serve to further illustrate the process of this invention:

EXAMPLE I A. Preparation of n-hexyl 9,10(10,9)-

formoxychlorosteare A mixture of 183.3 g. (0.5 mole) of n-hexyl oleate, 400 ml. of 98% formic acid, and 1 g. of p-toluenesulfonic acid was stirred and held at 10 to 15 C. while 60 g. (0.55 mole) of t-butylhypochlorite was added over a period of one hour. The mixture was stirred at 10 to 15 for one-half hour longer. The cooling bath was then removed and the white reaction mixture was stirred at room temperature for 18 hours. The reaction mixture was then added to one liter of water. with one liter of benzene. The extract was washed with water until free of acid, and the benzene solution was concentrated on a steam bath under vacuum. The residual clear pale oil weighed 220g. (theory: 223 g.). A small amount of NaCl present in the oil was removed by filtration. The oil was placed under high vacuum (0.3 mm.) for one-half hour, during which time its loss in weight was found to be negligible. It was a mixture of the n-hexyl esters of 9,10- and 10,9-chloroform'oxystearic acid as confirmed by analysis. (Chlorine: theory=7.95 analysis: 8 .2 Acid number: theory=; analysis=0.3).

B. Conversion of n-hexyl 9,10(10,9)-f0rm0xychl0r0- stearate to n-hexyl 9,10-ep0xylstearate A solution of 16.8 g. (0.3 mole) of potassium hydroxide in 600 ml. of anhydrous ethanol was added at room temperature to 44.7 g. (0.1 mole) of the mixture of chloroformoxy esters prepared above. The solution was stirred for four hours. A crystalline solid formed. The reaction mixture was then poured into 500 ml. of water and extracted with 500 ml. of benzene. The oil was washed twice with water and was then dried over anhydrous MgSO4 and was finally filtered. The filtrate was concentrated on a steam bath, under vacuum. The residual pale oil had an oxirane oxygen-content of 3.80%. It was compatible with polyvinyl chloride and not only served as a plasticizer but also as a stabilizer.

EXAMPLE II A solution of 59 grams (0.12 mole) of n-hexyl 13,14- (14,13)-formoxychlorobehenate (prepared from n-hexyl erucate) in 75 grams of ethanol was stirred and cooled by means of an ice-bath to 0 to '5 C. A solution of 19.8 grams (0.35 mole) of potassium hydroxide in 334 grams of ethanol was added over a period of 30 minutes, after which the mixture was stirred at 0 to 5 C. for an additional hour. The reaction mixture was then poured into water, extracted with benzene and the product was isolated by the procedure described in Example I. A yield of 49.5 grams of an oil was obtained. Analysis proved it to be n-hexyl 13,14-epoxybehenate.

EXAMPLE III The general procedure described above was followed in the preparation of 9,10-epoxystearonitrile. Thus, a solution of 46 grams (0.13 mole) of 9,10(10,9)-formoxychlorostearonitrile in 60 grams of ethanol was stirred and cooled to 0 to 5 C. To the stirred solution was added over a period of 50 minutes a solution of 22.4 grams (0.4 mole) of potassium hydroxide in 377.6 grams of ethanol. The reaction mixture was then stirred at 0 to 5 C. for an additional 50 minutes. The product was isolated in the manner described in Example I and a yield of 37 grams of 9,10-epoxystearonitrile was obtained. Its composition was confirmed by analysis.

EXAMPLE IV Epoxidized soybean oil was prepared by the procedure of Example I. Thus a solution of 67 grams (0.25 mole) of formoxychloro-soybean oil in 100 ml. of ethanol was stirred and maintained at 0 to 5 C., by means of an ice-bath, while to the solution was added, over a period of an hour, a solution of 56.1 grams (1.0 mole) of potassium hydroxide in 944 grams of ethanol. The reaction mixture was allowed to warm to room temperature and stirring was continued overnight. The product, epoxidized soybean oil, was isolated in the manner described. It was completely compatible with polyvinyl chloride and exerted a definite plasticizing effect.

EXAMPLE V The conversion of acyloxy-halo compounds to the cor- This was extracted I responding epoxy-derivatives by means of strongly basic, quaternary ammonium, anion-exchange resins is somewhat slower than when. a caustic alkali is employed. However, the use of such resins provides a safe and practical method which can be employed to advantage when large masses of reactants are involved or when an acyloxy-halo compound is particularly reactive.

The rate of conversion of Z-ethylbutyl 9,l0(l0,9)- chloroformoxystearate to 2-ethylbutyl epoxystearate by means of such a strongly basic anion-exchange resin was studied. The progress was followed by measurements of the amount of oxirane oxygen which developed as the formoxy-chloro groupings were converted to epoxide groups. Solutions of the chloroformoxystearate in methanol at a concentration of were treated with a pulverized commercially available, strongly basic anionexchange resin known to have been made by reacting trimethylamine with a chloromethylated copolymer of styrene and divinylbenzene by the process of U. S. Patent No. 2,591,573. The resin was used in the ratio of 250 grams per hundred grams of the ester; and in all cases all of the resin was added at the outset to the methanol solution at room temperature.

It was found that approximately 40% of the chloroforrnoxy ester was converted to the corresponding epoxy ester in one hour at 40. C. or in 15 minutes at the refluxing temperature. In 2 hours at 40 C. the conversion was approximately 50% while in 18 hours at room temperature (20 to 25 C.) the conversion was approximately 65%.

I claim:

1. A process for preparing epoxidized acids, nitriles and esters which comprises reacting a strong base with a member of the class consisting of saturated aliphatic nitriles containing 16 to 22 carbon atoms, saturated aliphatic acids containing 16 to 22 carbon atoms and esters of said acids, said member also containing groupings having the structure in which X is an atom of a halogen from the class consisting of chlorine and bromine, and R is a member of the class consisting of a hydrogen atom and a methyl group.

2. The process of claim 1 in which the'strong base is .an hydroxide of an alkali metal.

7. The process of claim 6 in which the vegetable oil is soybean oil.

8. The process of claim 6 in which the vegetable oil is safilower oil.

References Cited in the file of this patent UNITED STATES PATENTS 2,458,484 Terry Jan. 4, 1949 2,485,160 Niederhauser Oct. 18, 1949 2,556,145 Niederhauser June 5, 1951- 2,569,502 Swern Oct. 2, 1951

Claims (1)

1. A PROCESS FOR PREPARING EPOXIDIZED ACIDS, NITRILES AND ESTERS WHICH COMPRISES REACTING A STRONG BASE WITH A MEMBER OF THE CLASS CONSISTING OF SATURATED ALIPHATIC NITRILES CONTAINING 16 TO 22 CARBON ATOMS, SATURATED ALIPHATIC ACIDS CONTAINING 16 TO 22 CARBON ATOMS AND ESTERS OF SAID ACIDS, SAID MEMBER ALSO CONTAINING GROUPINGS HAVING THE STRUCTURE