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H. M. TEETER, L. E. GAST, and J. C. C O W A N Northern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture, Peoria, 111.
Promising Materials for Protective Coatings Vinyl Ethers o f Polyunsaturated Fatty Alcohols Polymers of vinyl ethers from linseed and soybean oils dry to films that adhere well to metal and are alkali-resistant. These organic compounds hold promise as coatings for cans and other metallic articles
FOR
P
several years, the U. S. Department of Agriculture has been investigating the properties of vinyl ethers of polyunsaturated fatty alcohols, particularly those derived from linseed and soybean oils. Polymers obtained by cationic polymerization of these vinyl ethers show good drying properties and, when properly formulated, the films have superior adhesion to metals and resistance to alkali. A large number of polymers and copolymers can be prepared from such ethers.
Table I. Conjugation and Geometric Isomerism in Vinylation" of Soybean Alcohols Conjugated Diene Isomers* cis. trans. Temp., trans, trans, Ratio Total, O c. % % t,t/c,t 7% 17jC 180a 225c a
27 12.7 9
10 24.8 20
0.37 37 2.0 37.5 2.2 29 Reaction time 1.5 hr.; 5.0% KOH
catalyst. * By infrared spectrophotometry. Acetylene absent. Acetylene present.
Experimental Polyunsaturated fatty alcohols prepared by sodium reduction of linseed and soybean oils were supplied by the ArcherDaniels-Midland Co. These are mixtures corresponding to the fatty acid composition of the original oils.
The decrease in total conjugation a t the higher temperature is probably caused by polymerization or cyclization. Because drying properties3 of polyunsaturated vegetable oil derivatives are profoundly affected by the presence of conjugation, nonconjugated fatty vinyl ethers were investigated. Excellent
yields of these products were obtained by a modification of Watanabe's procedure (5, 6) for vinyl transetherification: A mixture offatty alcohol (1 mole), ethanolfree ethyl vinyl ether (IO moles), and mercuric acetate (0.031 mole) was allowed to stand a t room temperature for 40 hours (alternatively, the mixture may be refluxed for 20 hours). Analysis after the reaction period showed approximately 88 to 90% conversion of fatty alcohol to vinyl ether. Anhydrous potassium carbonate (0.05 to 0.06 mole) was then added and unreacted ethyl vinyl ether and by-product ethanol were removed by distillation, first a t atmospheric and then a t reduced pressure. T h e residue was decanted from the potassium carbonate, and additional ethyl vinyl ether (40 moles based on fatty alcohol remaining in the crude fatty vinyl ether) and mercuric acetate (0.062 mole per mole of fatty alcohol remaining) were added. The mixture was allowed to
Alcohol; Linseed Soybean Free fatty acids, % Sapon. No. Iodine value Acetyl No. Conjugation, % Diene Triene
0.38 1.3 202.6 186.3
0.25 2.8 137.6 185.3
1.6 0.3
