US2240806A - Stabilization of metal soap solutions in oil - Google Patents

Description

Patented May 6, 1941 STABILIZATION F METAL soar SOLUTIONS IN OIL Thomas E. Sharp, Chicago, 111., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application June 7,1939,

Serial N0. 277,905

6 Claims.

This invention relates to the stabilization of metal soap solutions with oil andit pertains more particularly to the stabilization of soluble oils containing aluminum oleate.

So-called soluble oils are oils which contain oil-soluble emulsifiers so that when they are added to water with or without a certain amount of stirring they readily emulsify. A very important soluble oil particularly for use in tree sprays is a white oil (or parafiln distillate of high unsulfonatable residue) containing about /2 to 4%, preferably 2 of aluminum oleate, usually with a smaller amount of a hydroxy ester of a high molecular weight organic acid such as glyceryl mono-oleate or glycol mono-oleate. The aluminum soap may be made from a relatively pure oleic acid or it may be made from commercial grades of oleic acids obtained by thesplitting of fats, cottonseed oil, etc. Such a soluble oil may for instance have the following formula:

Per cent White oil 96 Aluminum cottonseed soap (aluminum oleate) 2 /2 Glyceryl mono-oleate 1 /2 When soluble Oils of the above type are stored over-extended periods of time an insoluble resinfact is that outstandingly good antioxidants like alpha naphthol are not nearly as effective as the above compounds for preventing soap separation. Outstanding antioxidants such as ortho-phenylene diamine, salicyl aldehyde amine, etc. areentirely inefiective,soluble oils containing them become very cloudy and are badly precipitated. It appears that the problem of maintaining the soap in solution is a very different problem than that of stabilizing the white oil against oxidation not only because most antioxidants are inoperative, but because the separation problem with which the present invention is concerned leads to the precipitation of a fiocculent material which is entirely different from the product resulting from white oil oxidation.

The invention will be described as applied to soluble oils for use in tree sprays, but it should be understood that the invention is equally apous material separates from the oil. The exact chemical composition of this resinous material has not as yet been determined, but it appears to be a polymerized metallic soap or some compound of a metallic soap formed from a combination with the glyceryl mono-oleate.

These resinous deposits separate out to such an extent that the soluble oil becomes quite opaque with fiocculent precipitates which separate out, thereby rendering the oil commercially unsalable. The object of this invention is to provide a method and means for preventing the separation of these resinous deposits. A further object is to I provide an improved soluble oil containing alumitoxic materials such as derris and rotenone,-the

plicable to soluble oils containing aluminum soaps and used for other industrial purposes. aluminum soap may be prepared from any fat or fatty a'cideither of animal, vegetable or synthetic origin. The aluminum soap may be present in amounts ranging from about /2 to 4% and it may be supplemented by about /2 to 3 or 4% of glyceryl oleate, glyceryl mono-oleate, glycol oleate, diglyool oleate, glycol .mono-oleate, etc. The oil may be an ordinary paramn distillate such as straw oil, diamond paraflin oil, etc., or it may be a more refined technical white oil or a relatively pure grade of white oil. The viscosity of the oils may range from that of Mineral Seal (about 40 to 50 seconds Saybolt at 100 F.) to fairly heavy oils ranging in viscoslties from to 120 seconds Saybolt at F. and for some industrial purposes even more viscous oils may be used.

Although the preferred soaps are aluminum oleates, it should be understood that the invention is also applicable to aluminum stearates, palmitates, naphthenates, etc., particularly when these soaps are employed with glyceryl oleate, glyceryl naphthenate and similar esters.

Of the substituted phenol compounds I have found that beta naphthol is particularly effective. Guaiacol (mono methyl ether of catechol) not only prevents soap separation but maintains an even higher degree of color stability than beta naphthol. Octyl beta naphthol and tertiary butyl catechol have given excellent results both from the standpoint of preventing soap separation and from the standpoint of color stability. It will thus be seen that the phenol maybe substituted by an aryl or cyclic group as exemplified The by beta naphthol. This cyclic group may be entirely independent of the ring structure of the phenol, as illustrated by cyclo hexyl catechol. The substituting radical may be an alkyl radical as illustrated by octyl beta naphthol. The substituting groups on the phenol may comprise both alkyl and hydroxy radicals as exemplified by tertiary butyl catechol. The substituting group may be an ether instead of an alkyl or OH group as illustrated by guaiacol. Broadly speaking, therefore, the invention contemplates the use of substituted phenols although the preferred embodiments of the invention are the specific compounds hereinabove set forth.

The substituted phenols must be used in critically small amounts, preferably ranging from about .05% to .1%, although slightly more or less, i. e. from a trace to about .5% of the substituted phenols may be used for particular purposes without departing from the invention. A preferred example of the invention is a soluble oil with the following formula:

When the above oils were stored at temperatures of 130 F. they stood for months without,

any soap separation and without going off color. However, when the same formulae were stored under these conditions without the substituted phenol the soap separated out in less than two weeks.

The outstanding stabilizer against soap separation is beta naphthol or an alkyl substituted beta naphthol such as octyl beta naphthol or amyl beta naphthol.

The outstanding examples of soaps requiring stabilization are aluminum oleates, stearates, etc. as hereinabove described. It should be understood, however, that the invention may be applied to the stabilization of soluble oils containing other polyvalent metal soaps or heavy'metal soaps such as soaps of zinc, magnesium, iron,

lead, etc. The invention is, of course, only applicable to those soaps which separate out from soluble oil solutions in the form of resinous deposits or flocculent precipitates, a phenomenon which is altogether separate and distinct from the stabilization of solid or semi-solid greases against oil leakage.

While I have described in detail preferred embodiments of my invention it should be understood that the invention is-not limited to the particular compounds listedthe broad classes of compounds has been set forth and the use of other members of these classes will be apparent to those skilled in the art.

I claim:

1. An improved soluble oil of about the following formula:

Percent Oil 95.9 to 95.95 Aluminum soap 2 /2 Glyceryl mono-oleate 1 Beta naphthol .05 to.1

2. The method of stabilizing a tree spray oil of about the following composition:

- Percent White oil 96 Aluminum soap 2 Glyceryl mono-oleate 1% against soap separation on standing, which method comprises adding to said tree spray oil about .05 to .1% of a beta naphthol compound.

3. The method of claim 2 wherein the compound is unsubstituted beta naphthol.

4. The method of claim 2 wherein the compound is an alkyl substituted beta naphthol.

5. The method of preventing soap separation from soluble oils containing an oil soluble polyvalent metal soap and an ester of the class consisting of glycol and glyceryl esters of high molecular weight organic acids said ester containing insufficient amounts of the acid constituent to be completely esterified, which method comprises adding to a solution of said soap and said ester in said oil about .05 to .1% of a substituted phenol of the class consisting of beta naphthol, an alkyl beta naphthol, guaiacol and a lower alkyl catechol.

6. The method of claim 5 wherein the soluble oil contains about to 4% of an aluminum soap and about A; to 4% of the ester.

THOMAS E. SHARP.