Corrosivity of non-aqueous solutions of copper ions useful in olefin separation processes is greatly reduced by addition of from about 0.5 to about 15 percent by weight of a metal salt of an ortho-hydroxy aromatic carboxylic acid to such solutions. BACKGROUND OF THE INVENTION It has long been known that olefinically unsaturated hydrocarbons react with aqueous and non-aqueous solutions of cuprous salts to form cuprous-olefin complexes. This general reaction is employed commercially for the separation of more highly unsaturated hydrocarbons from mixtures with less-highly unsaturated hydrocarbons, for example, separating olefins from paraffins. Aqueous media separation processes are of relatively limited efficiency because of the tendency of the aqueous medium to enhance the disproportionation of cuprous ion to non-complexing species, cupric ion and metallic copper, by forming the relatively more stable aquo-cupric complex, e.g., Cu(H.sub.2 O).sub.4.sup..sup.+.sup.+. Non-aqueous media, such as alcohols and amines as proposed by U.S. Pat. No. 2,376,239, issued May 15, 1945 to Evans et al., ethylene glycol-acetonitrile, as proposed by U.S. Pat. No. 2,275,135, issued March 3, 1942 to Fasce, the xylenes, and propionitrile as proposed by U.S. Pat. No. 3,401,112, issued Sept. 10, 1968 to Dunlop et al., while being more efficient for olefin separation, have the disadvantage of being undesirably more corrosive to the metals of which parts of practical scale separation apparatus are constructed, particularly ferrous metals such as iron and carbon steel. Such corrosion is apparently due to the small amounts of cupric ions inherent in cuprous salt olefin separation systems. Corrosion has been found in these systems even when the apparatus used is scrupulously decontaminated prior to use and the solutions are carefully purified.
The present invention relates to a composition that is useful as a penetration and fixture freeing agent. Specifically, the composition aids in the freeing of metal fixtures, such as hardware. In a preferred embodiment, the composition is a combination of a lower alkyl aromatic carboxylic acid ester, a lower alkyl alcohol, and a light petroleum distillate vehicle or carrier. In a highly preferred embodiment, the composition is methyl salicylate, isopropanol, and kerosene.
