US2893875A - Fatty acid-epichlorohydrin adducts - Google Patents

Description

United States Patent FA'ITY- ACID-EPICHLOROHYDRIN ADDUCTS Ralph J. Chamberlain, Stamford, Conn., assignor to American Cyanamid Company, New York, N.Y., a corporation of Maine- No Drawing. Application April 30, 1958 Serial No. 731,868

6 Claims. c1. 99- 166 'The present invention relates to a new and novel group of reaction products. More specifically the invenlion is concerned with wax-like adducts obtained by combining, in aqueous media, long-chain fatty acids, an alkali metal and epichlorohydrin. The invention also contemplates their method of preparation.

Products of theipresent invention are synthetic, organic, wax-like materials of relatively low melting point. Although apparently they are mixtures, they soften and melt within a surprisingly short temperature range, usually about 4-5 C. Moreover, they appear to correspond approximately to the formula:

wherein R is the residue of the long-chain fatty acid. There appears to be no wholly satisfactory explanation either for their relatively sharp melting point range or for their apparent composition and other behavior, seemingly as" materials of definite structure. they will be generically referred to in this discussion as adducts. v

In general, the adducts of the present invention are solid, wax-like, yellowish-white to white materials, and odorless at ordinary temperatures. They soften and melt completely at relatively low temperatures of some 35'60 (3., usually 4'O-50' C. Resultant oils appear substantially colorless to pale yellow. These oils may be readily applied to a cool surface to obtain effective, but readily removable protective coatings.

Their lack of color and odor make these adduct films suitable for use as food coatings; A protective film applied, for example, by dipping is strong and flexible but easily-peeled. Their low softening point ranges allow their safe application to vegetables, fruits and meats.

In general, the process of the present invention may be simply described. An aqueous soap solution or emulsion is formed by adding a fatty acid to an aqueous solution of an alkali-metal salt or hydroxide. At a moderately elevated temperature, stirring produces a thick white soap. Thereafter, epichlorohydrin is added with continued heating. and stirring until reaction is substantially completed as evidenced by conversion of the soap to an oil. The latter is collected, washed, pur'ifiedand cooled to obtain the wax-like adduct product.

Adducts of soaps and epichlorohydrin have been previously prepared under anhydrous conditions, isolated and treated with glacial acetic acid. Resultant products have been used as protective coatings.- However, they Accordingly I 2 ,893,875 7. Patentedduly 7, 19.59

are not wholly satisfactory in use nor is the necessarily anhydrous process wholly satisfactory for commercial development. Both the process and the products of;the present invention are surprisingly free from such deficiencies.

Within the general process outlined above, the present invention permits considerable latitude in, practice. However, certain precautions should be observed for optimum results. These are separately noted .in the following discussion.

Any ofa large number of available fatty-acids may be employed. For optimum results they should belongchain fatty acids. Since the adduct should be. waterinsoluble and solid at ordinary temperatures, acids con,- taining at least nine carbon atoms should be used, those of about 1222 carbon atoms being preferred. Forexample,. excellent adducts are obtained using lauric, palrnitic and stearic acids. The acids used need not be completely pure and the better commercial grades, which are mixtures of severalsuch acids, may be used. Although acids which are substantially saturated are preferred, in such mixtures inclusion of minor amounts of unsaturated acids such as oleicand the likeis permissible. In general, however, unsaturated acids should be avoided if possible. I

As discussed above, in .thepreferred practice the fatty acid is saponified in situ to obtain a soap solutionor emulsion. To provide the aqueous medium'some two to three parts by weight of water per part by weight of fatty acid (or 275-550 mols H O per mol offa-tty acid) is good practice. This water should be a solutioncontaining available alkali-metalions, usually sodium... They should be present to about -200 mol percentexcess. More can be present but appreciably more is not needed. An appreciably lesser amount does not give adequate results. The alkali metal may be supplied in anydesired form,for example as a soluble. salt such as. the carbonate or as an oxide or hydroxide.

If so desired, the soap may be preformed. In such case, it should'be taken up in an alkaline solution containing' the excess alkali metal. However, when preformed soaps are used, itismuch more difficult to obtain uniform solutions or suspensions and preparation of the soap in situ is preferable.

Although not essential, the aqueous alkaline solution may contain a catalyst for the epichlorohydrin reaction. Although not utilized, during saponification, the catalyst is usually added to the alkali-metal solution for convenience. This should be a soluble quaternary ammonium halide, preferably 'an iodide. Excellent results are ob tained with .tetrame'thylarnmonium iodide. Other analo gous halides may be used. When used, some 0.0 1 to about 0.05 mol parts of halide per mol part of fatty acid is good practice.

After saponification is completed, the epichlorohydrin is added, usually in one batch. At least about three mol parts of'epichlorohydrin per mol part of fatty acid should be used. Although adducts can be formed using lower epichlorohydrinzfatty acid mol ratios,,yields are low, the products are poorly defined and they do not have the desired properties. Some epichlorohydrin excess is desirable to insure complete reaction. How.-

-ever, since any unreacted excess must substantially be removed from the product, an unnecessarily-large excess should be avoided. Use of fatty acidzepichlorohydrin.

molratios of from about 1:3 to about 1:3.3 is good practice.

The reaction may be readily carried out in any vessel equipped for warming and agitation. A reaction temperature above the melting point range of the product adduct is necessary in the second stage and is usually employed in both. Temperatures which produce excessive evaporation or boiling should be avoided as unnecessarily complicating the apparatus requirements. Some 5085 C. is usually good practice. A temperature above the melting point of the product adduct is unnecessary during the first or saponifrcation stage. If both stages are not carried out successively in the same vessel, saponification may be carried out at any desired temperature.

Control of the reaction in both stages is easily maintained because of the visual changes. Each stage should be continued with heating and stirring until reaction appears to be completed. Thereafter, the molten adduct is easily decanted. It may be easily purified in any desired manner. That which is preferred is washing with hot water containing a small amount of some alcoholic solvent such as isopropanol. Thereafter, any residual water and epichlorohydrin is removed by stripping under reduced pressure and the adduct solidified by cooling.

A typical adduct preparation of the present invention is shown in the following example which is intended as illustrative only. Except as otherwise noted all parts are by weight.

EXAMPLE 1 About 475 parts of sodium carbonate is dissolved in about 2000 parts of water and about 850 parts of stearic acid (94% real) is added. Agitation for about one and three quarters hours at an average temperature of about 68 C. produces a'thick white soap. About 875 parts of epichlorohydrin is added and agitation continued at about 80 C. Within about 20 minutes the soap appears completely converted to a pale yellow oil. After a short additional heating period, the oil is allowed to separate and is removed by decantation. It is washed three times with hot water containing about 5-10% isopropanol and then distilled for about thirty minutes at about five mm. Resultant clear oil is allowed to solidify as a substantially colorless to light yellow wax. This product adduct melts completely at from about 40-44 C. Analysis indicates a probable molecular weight of about 403 and the following content.

Carbon Hydrogen Chlorine Percent Percent Percent Theory 64 10. 7. 9 ound 67 ll 7. 7

EXAMPLES 2-5 The procedure of Example 1 is repeated using one mole proportion of stearicacid but varying the mol proportions and conditions. Illustrative results are shown below in Low yields and poor products.

4 EXAMPLES 6-10 The procedure of Example 5 is followed using fattyacidzsodium carbonate and fatty acidzepichlorohydrin ratios of 1:1.1 and 1:3.1 respectively but substituting about one mol proportion of other fatty acids. The stearic acid used is from a different source than that used in Example 1. Typical results are shown in Table II. All adducts are light yellow to light tan in color.

Table 11 Time Temp, Melting Ex. No. Acid (mins), 0., Range,

2nd 2nd -O. Stage Stage 1 Product poorly defined.

EXAMPLE 11 To illustrate the use of the adducts of this invention as protective coating, a product obtained as in Example 5 is melted. Prepared meat products were dipped therein. Uniform coatings were readily obtained. No appreciable loss in weight occurs after refrigerated storage for several weeks. Uncoated samples showed very appreciable loss during the same period. The coatings were easily removed. Pieces of copper and silver metal are coated by dipping. The coating is removed from one surface and the same allowed to stand in the open. The uncoated surfaces discolor badly. When the remaining coating is removed the protected surfaces show substantially no color change. Coated fruits show little change at room conditions after time periods in which untreated samples completely deteriorate.

I claim:

1. A process of preparing a stable, wax-like chemical adduct which comprises, heating at above about 50 C. a mixture containing from about 3.0 to about 3.3 mol parts of epichlorohydrin, and an aqueous mixture comprising about one mol part of an alkali metal soap of a long chain fatty acid, from about 275 to about 550 mol parts of water and at least two mol parts of available alkali metal ions, whereby said soap is converted toa waterimmiscible oil, and collecting and solidifying said oil.

2. A process according to claim 1. in which said aqueous mixture is obtained by dissolving in from about 275 to about 500 mol parts of water at least about three mol parts of an alkali metal as member of the group consisting of alkali-metal salts and hydroxide, adding thereto about one mol part of a long-chain fatty acid containing at least nine carbon atoms.

3. A process according to claim 1 in which said fatty acid comprises stearic acid.

4. A stable wax-like stable chemical adduct obtained by heating at above about 50 C. a mixture containing from about 3.0 to about 3.3 mol parts of epichlorohydrin, and an aqueous mixture comprisingabout one mol part of an alkali metal soap of a long chainfatty acid, from about 275 to about 550 mol parts of water and at least two mol parts of available alkali metal ions, whereby said soap is converted to a water-immiscible oil, and collecting and solidifying said oil.

5. A strong-flexible film comprising a thin layer of a stable wax-like chemical adduct obtained by heating at above about 50 C. a mixture containing from about 3.0 to about 3.3 mol parts of epichlorohydrin, and an aqueous mixture comprising about one mol part of an alkali metal soap of a long chain fatty acid, from about 275 to about 550 mol parts of water and at least two mol parts of available alkali metal ions, whereby said soap. is

5 converted to a water-immiscible oil, and collecting and solidifying said oil.

6. A composition of matter comprising an edible food stufi enclosed in a strong, flexible, easily-peeled protective layer of a chemical adduct obtained by heating at above about 50 C. a mixture containing from about 3.0 to about 3.3 mol parts of epichlorohydrin, and an aqueous mixture comprising about one mol part of an alkali metal soap of a long chain fatty acid, from about 275 to about 550 mol parts of water and at least two mol parts of available alkali metal ions, whereby said soap is converted to a water-immiscible oil, and collecting and solidifying said oil.

No references cited.

Claims (3)

1. 4. A STABLE WAX-LIKE STABLE CHEMICAL ADDUCT OBTAINED BY HEATING AT ABOVE ABOUT 50* C. A MIXTURE CONTAINING FROM ABOUT 3.0 TO ABOUT 3.3 MOL PARTS OF EPICHLOROHYDRIN, AND AN AQUEOUS MIXTURE COMPRISING ABOUT ONE MOL PART OF AN ALKALI METAL SOAP OF A LONG CHAIN FATTY ACID, FROM ABOUT 275 TO ABOUT 550 MOL PARTS OF WATER AND AT LEAST TWO MOL PARTS OF AVAILABLE ALKALI METAL IONS, WHEREBY SAID SOAP IS CONVERTED TO A WATER-IMMISCIBLE OIL, AND COLLECTING AND SOLIDIFYING SAID OIL.
2. 5. A STRONG-FLEXIBLE FILM COMPRISING A THIN LAYER OF A STABLE WAX-LIKE CHEMICAL ADDUCT OBTAINED BY HEATING AT ABOVE ABOUT 50* C. A MIXTUR*E CONTAINING FROM ABOUT 3.0 TO ABOUT 3.3 MOL PARTS OF EPICHLOROHYDRIN, AND AN AQUEOUS MIXTURE COMPRISING ABOUT ONE MOL PART OF AN ALKALI METAL SOAP OF A LONG CHAIN FATTY ACID, FROM ABOUT 275 TO ABOUT 550 MOL PARTS OF WATER AND AT LEAST TWO MOL PARTS OF AVAILABLE ALKALI METAL IONS, WHEREBY SAID SOAP IS CONVERTED TO A WATER-IMMISCIBLE OIL, AND COLLECTING AND SOLIDIFYING SAID OIL.
3. 6. A COMPOSITION OF MATTER COMPRISING AN EDIBLE FOOD STUFF ENCLOSED IN A STRONG, FLEXIBLE, EASILY-PEELED PROTECTIVE LAYER OF A CHEMICAL ADDUCT OBTAINED BY HEATING AT ABOVE ABOUT50* C. A MIXTURE CONTAINING FROM ABOUT 3.0 TO ABOUT 3.3 MOL PARTS OF EPICHLOROHYDRIN, AND AN AQUEOUS MIXTURE COMPRISING ABOUT ONE MOL PART OF AN ALKALI METAL SOAP OF A LONG CHAIN FATY ACID, FROM ABOUT 275 TO ABOUT 550 MOL PARTS OF WATER AND AT LEAST TWO MOL PARTS OF AVAILABLE ALKALI METAL IONS, WHEREBY SAID SOAP IS CONVERTED TO A WATER-IMMISCIBLE OIL, AND COLLECTING AND SOLIDIFYING SAID OIL.