Alkali Metal Salts Of Polyacetylenic Polyoic Acids

Abstract

Radiant-energy photosensitive crystalline alkali metal salts of polyacetylenicpolyoic acids and the partial lower alkyl esters of the acids, which acids contain a minimum of two acetylenic linkages as a conjugated system; and a preparing of a clear and transparent body containing polyvinyl alcohol fixedly positioning dispersed radiant-energy photosensitive crystalline alkali metal salts.

Parent Case Text

RELATED APPLICATIONS

This application is a continuation-in-part of my copending application Ser. No. 555,229, filed June 6, 1966, entitled "Image Formation, Materials Therefore and Their Preparation," issuing on Mar. 17, 1970, as U.S. Pat. No. 3,501,297, under the title "Photographic Process Using Polyacetyleneicdioic Acid Crystals."

Description

In general this application relates to photosensitive crystalline polyacetylenic compositions of matter. More particularly it relates to certain photosensitive crystalline alkali metal salts of polyacetylenicpolyoic acids and partial lower alkyl esters of these acids and their preparation, and in particular to alkali metal salts of polyacetylenicdioic acids and the partial lower up-to-C.sub.3 -alkyl esters of these acids and to their preparation and incorporation of these salts in a clear and transparent body.

In my aforementioned copending application, issuing as U.S. Pat. No. 3,501,297, there is taught and claimed a process for photographic formation of a visual positive image through employment of crystals of an alkali metal salt of a polyacetylenicdioic acid having a minimum of two acetylenic linkages as a conjugated system. In other related copending applications, Ser. NOS. 555,238; 555,230; and 562,125 issuing on Mar. 17, 1970, as U.S. Pat. Nos. 3,501,303; 3,501,302; and 3,501,308, respectively, there are taught and claimed photosensitive image-receptive elements, process of formation of a visual print-out image, process for direct photographic formation of a visual print-out image, and radiant-energy sensitive compositions of enhanced photosensitivity and their process of preparation and their employment in a photographic process for direct formation of a visual image.

In general, the present invention's alkali metal salts of polyacetylenicpolyoic acids and the partial lower alkyl esters of these acids are radiant energy photosensitive in their crystalline form and are of utility in the elements, composition, and processes taught in the aforementioned applications. Some of these salts are useful in the particular process claimed in my aforementioned copending application and others are useful in various elements, compositions, and processes of the other aforementioned applications.

In general, the photosensitive crystalline polyacetylenic compositions of matter of the invention are alkali metal salts of polyacetylenicdioic acids, having a minimum of two acetylenic linkages as a conjugated system, and of the partial lower alkyl esters of these acids. They preferably are of the following general structure:

YOOC--(-CH.sub.2 --).sub.ml (-C.tbd.C--).sub.n (-CH.sub.2 --).sub.m2 --COOY

wherein n is an integer of at least 2 and with especial preference for n is 2, i.e., a diacetylenic compound, and ml and m2 each are integers, not necessarily the same, but by especial preference the same, greater than 4 and less than 14, and each Y is an alkali metal atom (i.e., lithium, sodium, potassium, rubidium, or cesium atom) or one Y is an alkali metal atom and the other Y is a lower alkyl radical of up to three carbon atoms and by especial preference is the methyl radical. The preferred alkali metal salts are the lithium, potassium, and sodium salts with lithium salts especially preferred. Included within and illustrative of the photosensitive crystalline alkali metal salts of the invention are:

each of the dilithium, disodium, dipotassium, dirubidium, and dicesium salts of 7,9-hexadecadiynedioic acid, 8,10-octadecadiynedioic acid, 9,11-eicosadecadiynedioic acid, 10,12-docosadiynedioic acid, 11,13-tetracosadiynedioic acid, 12,14-hexacosadiynedioic acid, 13,15 -octacosadiynedioic acid, 14,16-triacontadiynedioic acid, 15,17-dotriacontadiynedioic acid, 15,17-tetratriacontadiynedioic acid, and 16,18-hexatriacontadiynedioic acid; and

each of the monolithium, monosodium, monopotassium, monorubidium, and monocesium salts of each of the monomethyl, monoethyl, and monopropyl esters of 7,9-hexadecadiynedioic acid, 8,10-octadecadiynedioic acid, 9,11-eicosadecadiynedioic acid, 10,12-docasadiynedioic acid, 11,13-tetracosadiynedioic acid, 12,14-hexacosadiynedioic acid, 13,15-octacosadiynedioic acid, 14,16-tricontadiynedioic acid, 15,17-dotriacontadienedioic acid, 15,17-tetratriacontadiynedioic acid, and 16,18-hexatriacontadiynedioic acid.

Most conveniently one prepares the alkali metal salts of the invention from their corresponding polyacetylenicpolyoic acids and the lower alkyl monoesters of those acids. My aforementioned copending application includes citations of patents and journal articles which include exemplary and illustrative teachings of known methods for preparation of polyacetylenicpolyoic acids and their lower alkyl monoesters. For examPle, 9,11-eicosadiynedioic acid and 10,12-docosadiynedioc acid are reported by Black et al, J. Chem. Soc. (1953), 1,787, 1,790, 1,791, as byproducts of coupling reactions; 9,11-eicosadiynedioic also is taught by Seher in Fette u. Seifen, 55 (1953), 95and 10,12-docosadiynedioic acid also is taught by Sher in Fette u. Seifen, 55 (1953) 95, and in Annalen, 589 (1954), 222. A particularly convenient method of preparation is an oxidative coupling or dehydrocondensation reaction of terminal acetylenic compounds whose other terminus is of lower alkyl ester structure, and depending on whether one couples the same or different of such terminal acetylenic compounds there is provided the symmetrical or unsymmetrical lower alkyl polyacetylenicdioate. This coupling reaction will be more readily understood from a typical and illustrative preparation, which follows, of the dimethyl ester of 10,12 -docosadiyne dioic acid. These diesters through known hydrolysis and/or ester interchange methods then are converted to their corresponding diacid and lower alkyl monoester. Conversion of a dimethyl ester of a diynedioic acid to its corresponding monomethyl ester will be more readily understood from a typical and illustrative preparation, which follows, of the monomethyl ester of 10,12-docosadiynedioic acid.

ILLUSTRATIVE PREPARATION OF DIMETHYL ESTER OF 10,12-docosadiynedioic ACID

200 grams of a commercially available 10-undecynoic acid is heated in 600 ml. of boron trichloride-methanol solution (10 percent w/v) to 60.degree.C. 10 minutes after the solution becomes clear it is poured into liter of ice water and extracted with three 400 ml. portions of petroleum ether (b.p. 30.degree.- 60.degree.C.). The combined petroleum ether extracts are washed with two 200 ml. portions of water and dried over magnesium sulfate. Filtration and removal of the petroleum ether under reduced pressure yields 213 grams of the colorless liquid, methyl 10-undecynoate, b.p. 106.degree.-7.degree.C. at 2.5 mm. Hg.

Into a 5 liter, three-neck flask are placed 20 grams of cuprous chloride, 24 grams N,N,N', N'-tetramethylethylenediamine (TMEDA), 2,400 ml. of methanol and the 213 grams of the aforeprepared methyl 10-undecynoate. The reaction mixture is stirred vigorously while oxygen is bubbled therethrough. The temperature of the reaction mixture is maintained below 45.degree.C. by occasional cooling with an ice-bath during the first hour of the reaction. After approximately 12 hours, the stirring and oxygen flow are discontinued and the methanol removed using a rotary evaporator and reduced pressure. The residue is extracted with four 300 ml. portions of petroleum ether (b.r. 30.degree.-60.degree.C.) and the resulting bluish solution washed with five 100 ml. portions of an aqueous 4 percent hydrochloric acid solution and followed by washing with two 200 ml. portions of water. The resulting colorless petroleum ether solution is dried over magnesium sulfate. The magnesium sulfate is removed by filtration and the filtrate concentrated to about 800 ml. and cooled. The resulting white crystalline product is collected by filtration and dried, yielding 185 grams of dimethylester of 10,12-docosadiynedioic acid, m.p. 41.degree.-42.degree.C., ##SPC1##

(in this example and other examples, which follow, the nuclear magnetic resonance (N.M.R.) spectra are obtained on a Varian Associates HR-60 spectrometer in deuteriochloroform solution. Chemical shifts are reported in cycles per second downfield from the internal standard tetramethyl silane at 60 Mc./sec. The number in parenthesis is the relative area of the resonance.)

ILLUSTRATIVE PREPARATION OF MONOMETHYL ESTER OF 10,12-docosadiynedioic ACID

2 liters of methanol are poured into a 5-liter flask followed by 185 grams of the dimethyl ester of 10,12-docosadiynedioic acid. The mixture is stirred until the diester dissolves. To the resulting solution are added 509 ml. of 0.928 N. barium hydroxide-methanol solution. The reaction mixture is stirred at room temperature for 24 hours. The precipitated barium salt is removed by filtration and washed with methanol. The methanol filtrates are concentrated and filtered until no further barium salt can be obtained. The barium salt is triturated under 500 ml. of 1 N. HCl and the resulting mixture extracted with three 300 ml. portions of ether. The combined ether extracts are washed with 200 ml. of water and dried over magnesium sulfate. After removal of the magnesium sulfate by filtration and the ether by reduced pressure distillation, the resulting solid is recrystallized from petroleum ether (b. r. 30.degree.-60.degree.C.). The crystalline product is collected by filtration, washed with cold petroleum ether and dried. A conversion to 118 grams of monomethyl ester of 10,12-docosadiynedioic acid, m.p. 61.degree.-62.degree.C., is obtained. N.M.R. spectrum; ##SPC2##

In addition, 18 grams of unsaponified dimethyl ester and 8 grams of the diacid are isolated and recovered.

The infrared spectra (Perkin-Elmer 521 spectrometer) of the diyne diester and half-ester products of the preceding examples are consistent with the expected absorption bands. All obtained UV spectra (Carey Model 14M) show the uniquely characteristic absorption of the diyne group (--C.tbd.C--C.tbd.C--) with maxima at 215, 225, 240 (.epsilon..apprxeq.380) and 254.mu.(.epsilon..apprxeq.230).

In general, to provide the alkali metal salts of the invention one conveniently converts the corresponding polyacetylenicopolyoic acid or its lower alkyl monoester. In preparation of the preferred alkali meal salts of the invention one appropriately converts a partial lower alkyl ester of the formula

ROOC--(--CH.sub.2 --).sub.m1 (--C.tbd.C--).sub.2 (--CH.sub.2).sub.m2 --COOH

wherein m1 and m2 each are integers, not necessarily the same, but by special preference the same, greater than 4 and less than 14, and R is an alkyl radical selected from the group consisting of methyl, ethyl, and propyl radicals, or one converts its corresponding diacid, or converts a mixture of the partial lower alkyl ester and its corresponding diacid.

In one conversion method, an appropriate amount of an alkali metal hydroxide, oxide, acetate carbonate, or like reactant known for preparation of alkali metal salts of organic acids from the corresponding organic acids, is reacted therewith in a suitable solvent to provide the particularly desired mono- or di-alkali metal salt. Alternatively the lower alkyl di- and mono-esters of the polyacetylenicpolyoic acid are saponified in whole or part, as desired, by the action of the requisite amount of an alkali metal hydroxide or like reactant to provide the particular mono- or di-alkali metal salt as desired. Preparation techniques and methods are well known in the art for such conversions of organic acids and their esters, with it only necessary when applying a particular method to polyacetylenicpolyoic compounds that care be used in its selection and application so as not to be destructive of the polyacetylenic structural portion of the polyoic acid being thus treated.

In utilization of photosensitive crystalline polyacetylenic compounds, including the alkali metal salts of this invention, in the various applications taught in my aforementioned copending applications, there are employed useful photosensitive image-receptive elements comprised of the alkali metal salt and a carrier means which serves to fixedly position the photosensitive crystalline alkali metal salts of the invention. My aforementioned copending application, Ser. No. 555,229, maturing into U.S. Pat. No. 3,501,297, includes considerable teachings and description therein as to nature and identity of the carrier means, preparation of various useful image-receptive element, various image-forming applications, and the like, and by this reference hereto, that description is incorporated in this application to further teach useful embodiments and applications employing the alkali metal salts of the invention.

In some image-forming applications, an image-receptive element, comprised of the alkali metal salts of the invention fixedly positioned by the carrier means, should be clear and transparent. In these applications the unexposed element serves as a camera film or the like and the exposed element serves as a negative for subsequent transmission exposure in reproduction of positive copies of the image thereon. In these embodiments, it is requisite that the element be clear and transparent, and especially in its background areas. With many photosensitive crystals of various photosensitive crystalline polyacetylenic compounds, a requisite and desirable clarity and transparency is not readily obtained. In the present invention, however, it advantageously has been found that the alkali metal salts of the invention can prepared as a suspension of very fine crystals in the order of micron and submicron size suspended in resinous binder solutions and upon removal of the solvent therefrom will provide a clear and transparent body, such as a free-formed film and/or a clear and transparent coating on a clear and transparent suitable substrate to provide useful image-receptive elements.

The description herein of the invention now will be amplified by the following specific examples of various illustrative embodiments of the invention.

EXAMPLE 1

Methyl Potassium 10,11-docosadiynedioate

To monoethyl ester of 10,12-doscadiynedioic acid of an acid number of 150 to 160, which had been prepared from its corresponding diester by a hydrolysis technique, there is added aqueous potassium hydroxide in the amount calculated to neutralize the half-ester constituent. The resulting clean solution is filtered. The filtered solution now containing methyl potassium 10,12-docosadiynedioate, is evaporated to substantial dryness on a paper. Upon drying, crystalline methyl potassium 10,12-docosadiynedioate is precipitated onto the surface of the paper and this crystalline methyl potassium 10,12-docosadiynediote undergoes a visible color change upon exposure to ultraviolet radiation of a wavelength of 2,537 A.

EXAMPLE 2

There is added dropwise about 0.45 gram of aqueous 50 percent potassium hydroxide to a mixture of about 4 grams of water and about 1 gram of monomethyl ester of 10,12-docosadiynedioic acid product of an acid number of about 166. The resulting solution is filtered and 1 gram of the filtered solution added with stirring to 0.86 gram of aqueous 20 percent polyvinylpyrrolidone (such as a medium viscosity grade of commercially available polyvinylpyrrolidone). The resulting solution of about 20 percent solids is applied to coat the surface of glass microscope slides and dried. The resulting elements comprise a glass substrate having adhered thereto a dry solid coating comprised of about 47 percent of polyvinylpyrrolidone binder containing dispersed therein about 53 percent of fine crystalline methyl potassium 10,12-docosadiynedioate.

These elements are useful as image-recording elements in electron microscopy to provide a visible blue-colored image of an electron microscopic specimen.

EXAMPLE 3

Dipotassium 7,9-Hexadecadiynedioate

To an aqueous dispersion of 7,9-hexadecadiynedioic acid there is added aqueous 50 percent potassium hydroxide in an amount sufficient to dissolve the polyyne and to give an aqueous solution of dipotassium 7,9-hexadecadiynedioate. This aqueous solution of the dipotassium salt is mixed with aqueous polyvinyl alcohol and coated onto a glass surface as described in preceding examples. The resulting element comprises a glass surface having adhered thereto a dried film of polyvinyl alcohol containing dispersed crystals of the dipotassium salt.

A screen is laid over the elements coating and exposure made to ultraviolet radiation. No visible image is observed after this exposure. The exposed element then is immersed in concentrated hydrochloric acid for about 10 seconds and dried at about 50.degree.C. A faint image now is observed and upon exposure of this acid-treated element completely overall to ultraviolet radiation there results a blue-colored positive image of the screen.

In place of hydrochloric acid other strong mineral acids, such as sulfuric acid and the like may be used, and in place of immersion an acid vapor treatment is useful.

EXAMPLE 4

A monomethyl ester of 10,12-docosadiynedioic acid product of acid number of about 155-160 (theoretical acid number of this monoester is about 149 with this product being prepared from its diacid so as to contain both monoester and diacid in an amount providing the product with acid number 155-160) is mixed with its corresponding diacid, 10,12-docosadiynedioic acid in an amount to provide a polyyne product mixture of acid number of about 170. To this mixture in water there is added dilute aqueous potassium hydroxide in an amount between 100 to 120 percent of the amount calculates equivalent to neutralize all carboxyl groups present in the diacid and monoester contained in the mixture. This amount of dilute aqueous potassium hydroxide dissolves the major portion of the acetylenic compounds. The resulting neutralized water solution of the potassium salt is filtered and the filtrate is mixed with about 12 percent by weight of an aqueous polyvinyl alcohol that is about 88 to 90 percent hydrolyzed polyvinyl acetate, such as commercially available Elvanol 51-05. It then is applied as a coating to a glass plate and air dried at about 45.degree.C. The dispersed potassium salt in the dried film approximates particles about 0.5 to 1.5 microns in size. The ratio of potassium salt to polyvinyl alcohol in the applied dispersion is such that the dried coating consists essentially of about 60 percent polyyne potassium salt crystals and 40 percent polyvinyl alcohol. A second coating application of the dispersion is applied and air dried. Thereafter, the resulting image-receptive element consists essentially of the glass plate substrate material and adhered thereto dried clear and transparent coatings approximating 0.1 gram per square inch, of polyvinyl alcohol binder containing dispersed therein crystals of methyl potassium 10,12-docosadiynedioate.

In the preceding Example 4, diacid is added to bring the monoester product to an acid number approximating 170 in order to produce a substantially clear and transparent dried coating. At lower acid numbers and those approaching theoretical for the monoester, the photosensitive potassium salt prepared therefrom results in a polyvinyl alcohol coating which is not clear but is translucent. At acid numbers greater than 170 or those wherein the diacid content exceeds about 7-1/2 percent and more of the polyyne mixture, the photosensitive potassium salt in the resulting dried coating is not as photosensitive to electron beam irradiation as that derived from a lower than 170 acid number monoester product.

In the resulting elements of dried photosensitive films on the glass plate, the polyyne potassium salt loadings can range up to about 75 percent by weight. At higher loadings, insufficient polyvinyl alcohol binder is present to firmly adhere all crystalline particles to the glass plate and some crystals brush off relatively easy. In films of less than one-half mil dry thickness, polyyne potassium salt loadings of the dried film lower than about 40 percent by weight are not desirable in that sufficient photosensitive material is not present to produce an image of suitable density upon a short duration exposure to an electron beam.

EXAMPLE 5

Methyl Lithium 10,12-Docosadiynedioate

There slowly is added 0.84 gram of finely ground LiOH.sup.. H.sub.2 O to a stirred filtered solution of 7.8 grams of the monomethyl ester of 10,12-docosadiynedioic acid dissolved in 40 ml. methyl alcohol. A fine white crystalline precipitate of methyl lithium 10,12-dicosadiynedioate appears. The resulting solution with some precipitate formed therein then is cooled by permitting to stand overnight in about 40.degree.F. refrigerator to permit additional crystalline precipitate to form. When the resulting crystalline precipitate is filtered off through collection on a filter paper in a Buchner filter and then air dried, it appears to be fine particle crystals somewhat gelatinous in appearance. Yield is about 6.2 grams. A small sample of this precipitate, now having a slight bluish cast, on a hot-block melting-point bar changes to a pink color at about 96.degree.C., from a pink to an orange color at about 120.degree.C., becomes transparent at about 165.degree.C., and apparently melts within the range of 184.degree.-192.degree.C. In contrast, the monomethyl ester of 10,12-docosadiynedioic acid on the same hot-block melting-point bar melts at about 57.degree.C.

A small portion of the above-prepared methyl lithium 10,12-dicosadiynediote is slurried in distilled water to provide a suspension thereof in water and quickly flowed onto a paper substrate and permitted to air dry thereon. The resulting product is an image-receptive element comprised of a paper support means having fine crystalline photosensitive methyl lithium 10,12-docosadiynedioate relatively fixedly positioned and physical adhered thereto. This element is useful for direct photographic formation of a visual print-out image through exposure to ultraviolet 2,537 A. radiation.

EXAMPLE 6

There is added 0.21 gram of fine LiOH.sup.. H.sub.2 0 to a stirred filtered solution of 1.8 grams of the monomethyl ester of 10,12-docosadiynedioic acid dissolved in 20 ml. of methyl alcohol. A light pasty mass of methyl lithium 10,12-dicosadiynedioate forms quickly, is centrifuged therefrom, and the clear liquid thereover removed. The resulting pasty precipitate is mixed with and dispersed in 20 ml. of acetone, and then in centrifuged therefrom and the acetone thereover removed. This lithium salt, still containing a minute amount of acetone, is washed with water and the water filtered therefrom. Whereupon the lithium salt, still damp from the water, is mixed with and readily dispersed in an aqueous 10 percent by weight polyvinyl alcohol solution and flowed to provide a thin coating thereof on thin film of a polyethylene terephthalate polymer. This coating then is permitted to air dry. The resulting product is an image-receptive element comprised of the polymer film having fine crystalline photosensitive methyl lithium 10,12-docosadiynedioate fixedly positioned and adhered thereto by means of the polyvinyl acetate. This element is useful for direct photographic formation of a visual print-out image through exposure to ultraviolet 2,537 A. radiation.

EXAMPLE 7

Example 6 is repeated except that in place of the aqueous polyvinyl alcohol solution there is employed 15 ml. of a 10 percent by weight N-type ethyl cellulose dissolved in an 80:20 parts by weight toluene:ethanol solvent. There again results a useful image-receptive element of utility for direct photographic formation of a visual print-out image.

Example 8

Example 6 is repeated up to the adding of the lithium salt to the aqueous 10 percent polyvinyl alcohol solution, then it is heated to about 60.degree.C. to provide an apparently clear solution. This clear solution then is permitted to cool to about 25.degree.C. whereat the lithium salt precipitate reappears to provide an overall pasty appearing mass. A portion of this pasty appearing mass is spread as a thin coating on a glass slide and dried in a forced air oven at about 50.degree.C. The resulting element is very sensitive to ultraviolet 2,537 A. radiation and useful for direct photographic formation of a visual print-out image. The image formed upon such radiation is a dark blue. An exposed element, having this dark blue image thereon, then is placed on a hot plate and heated. As the temperature of the element increases the blue color of the image changes to an orange color, apparently at or within a temperature range of about 95.degree.-120.degree.C. Upon removal of the element from the hot plate and cooling of the same, a reverse color change occurs with the orange colored image going back to its original dark blue color. In contrast a similar imaged element containing therein the monomethyl ester of 10,12-docosadiynedioate upon suitable heating irreversibly changes its image color from a dark blue or purple to an orange to red color and upon cooling continues to retain its orange to red coloration.

EXAMPLE 9

Lithium acetate is prepared by suspending 0.42 gram of LiOH.sup.. H.sub.2 O in 5 ml. of methyl alcohol and adding minute drops, dropwise, of glacial acetic acid thereto until a pH of about 6.0 results. This appeared to require about 1 ml. of the glacial acetic acid. The above-prepared lithium acetate in methanol then is added to a 15 ml. methanol solution of 3.8 grams of the monomethyl ester of 10,12-docosadiynedioate. Upon addition a reaction is observed, and within several minutes small crystals form and separate. The crystals are centrifuged therefrom, washed with acetone, reseparated by centrifuging again, and then washed with distilled water. The water then is filtered from the crystals and an aqueous 15 percent polyvinyl alcohol solution added thereto and thoroughly mixed therewith to disperse the fine crystals therein. Coatings of this polyvinyl alcohol solution containing the fine crystals dispersed therein then are placed on thin films of polyethylene terephthalate polymer and are air dried. The resulting element is useful for direct photographic formation of a visual print-out image through exposure to ultraviolet 2,537 A. Radiation.

EXAMPLE 10

Methyl Sodium 10,12-Docosadiynedioate

To an aqueous dispersion of a small amount of the monomethyl ester of 10,12-docosadiynedioic acid in distilled water, there are added, dropwise, drops of an aqueous 10 percent sodium hydroxide solution until a pH of about 9 is reached and a clear solution results. This aqueous solution, now containing methyl sodium 10,12-dicosadiynedioate dissolved therein, is evaporated to substantial dryness on a paper to provide a deposit of crystalline methyl sodium 10,12-dicosadiynedioate within and on the paper. Upon exposure to ultraviolet 2,537 A. radiation, exposed crystals of the sodium salt slowly, and within less than 5 minutes, undergo a color change to a light purple color.

In view of the foregoing description and presented illustrative specific examples of the invention, it will be apparent readily to one skilled in the art that the invention within its true scope includes more than that illustrated by specific examples and that the invention is to be limited only to the extent as set forth in the appended claims which follow.

Claims

What is claimed is:

1. Radiant-energy photosensitive crystalline alkali metal salts of polyacetylenicpolyoic acids and the partial lower alkyl esters of said acids, which salts have the structural formula

YOOC-- (--CH.sub.2 --).sub.m2 (--C.tbd.C--).sub.2 (--CH.sub.2).sub.m2 --COOy

wherein m2 is an integer greater than 4 and less than 14, and each Y is an alkali metal atom or one Y is an alkali metal atom and the other Y is an alkyl radical selected from the group consisting of the methyl, ethyl, and propyl radicals.

2. The alkali metal salt of claim 1 which is methyl potassium 10,12-docosadiynedioate.

3. The alkali metal salt of claim 1 which is dipotassium 7,9-hexadecadiynedioate.

4. The alkali metal salt of claim 1 which is methyl lithium 10,12-docosadiynedioate.

5. The alkali metal salt of claim 1 which is methyl sodium 10,12-docosadiynedioate.