US1769795A - Art of treating oils - Google Patents

Description

Patented July l, 1930 UNITED STATES WILLIAM G. LEAMON, OF NEWARK, OHIO ART OF TREATING 'OILS No Drawing.

' This'invention relates to art of treatingoils; and it relates "more particularly to the treatment of mineral oils such as petroleum, petroleum distillates and residua, in the man- .ufa'cture of valuable Commercial products;

and the invention also relates to novel compositions of matter employed in such treatment.

In prior co pending applications Serial Nos. 621,076 and 624,268, this applicant has disclosed and claimed various embodiments of a procedure which may be termed a modify; ing treatment of oils with the aid of a catalytic material functioning as a polymerizing or condensing agent in such manner as to simplify removal of undesirable constituents from a given oil without necessarily effect ing conversion of said oil in the sense of cracking. Among the treating agents disclosed in said prior applications as useful in thus improving mineral oils are solutions ofaluminum chlorid or zinc chlorid in certain solvents E differing from but miscible with the oil to be treated, among such solvents being ethyl ether metal chlorids such as aluminum chlorid, or

zinc ch1orid, or both, for the purpose of polymerizing or condensing resinor gum-forming constituents contained in an oil which it is desired to purify or refine. 1

While the present invention is of broad application in the treatment of oils to improve the same, its greatest present utility is in the treatment of crude motor fuel for the purpose of rendering the same stable, that is, to so treat it that the finished product will not undergo substantial changesin composition resulting in the formation and deposi- Application filed August 26, 1925. Serial No. 52,687.

tion of gummy or resinous polymers. It is a well-known fact that many commercial motor fuels of the gasoline type develop such deposits upon standing for time periods of greater or less length depending upon the particular motor fuel. Furthermore, even where a motor fuel may not show a gummy or resinous deposit upon standing for a long time, such polymers may exist in solution and their presence become manifest when the fuel is used in an engien, either through sticking of the valves or deposition of carbon in the cylinders. It is the elimination of these gumforming constituents from mineral oils, specifically from motor fuel fractions, that forms one of the principal objects of-the present invention.

It has been found that a solution of either zinc chlorid or aluminum chlorid in eth l acetate (acetic ether, CH CO C H can e used as the treating agent in a purifying or improving process of the character above described. Somewhat better results are obtained with zinc chlorid than with aluminum chlorid. The salts need not be strictly anhydrous but should contain only very little water, if any. Assuming the use of zinc chlorid, a saturated solution ismade by adding an excess of commercial granulated or fused zinc chlorid to ethyl acetate. A vigorous reaction takes place between the salt and the ethyl acetate indicating that the result is something more than a mere solution of the zinc chlorid in the solvent. In all probability a complex compound of 'zinc chlorid and ethyl acetate is formed. In treating in accordance with the invention a crude motor fuel fraction derived from the cracking or conversion of a heavy mineral oil, for example, the zinc-chlorid-ethyl-acetate solution prepared as above described may be added to the motor fuel in amount equal in a typical instance to about 0.25% by weight of the motor fuel to be treated. While thisper- .centage may be varied somewhat in practice, it need not ordinarily exceed 0.50% as a rule and practically need never amount to as much as 1%. The solution is readily miscible with the, motor fuel and it diifuses rapidl therethrough even without agitation, a

ing reaction. The treatment may be effected after the addition of the treating solution at ordinary temperatures, but the reaction can be speeded up by moderate heating. A precipitate of gummy polymers forms soon and settles rather rapidly. This precipitate can be separated by decantation or filtration, and in some cases where the motor fuel is thus freed from this precipitate it can be used without further treatment. However, redistillation of the treated motor fuel in an ordinary re-run still is generally advisable, especially where, as is often the case, the action of the treating solution forms polymers which are soluble in the motor fuel and therefore are not precipitated out with or as the gummy deposit or precipitate before mentioned. It is of course also possible to add th treating solution directly to a charge of the crude motor fuel fraction in a re-run still, either with or without the further addition of fullers earth, pumice, a silica-gel, or other granular adsorptive solid material, the addition of adsorptive material being advantageous for various reasons among which may be mentioned the fact that the precipitable gummy polymers and coloring matter are precipitated upon and firmly held by such adsorbent material and are thus prevented from being deposited upon the bottom of the still where they might be subjected to drastic overheatin and decomposition with resultant bad efi ect upon the distillate produced. It has also been found that a solution of aluminum chlorid in normal propyl alcohol can also be used effectively in some cases in this general method of improving mineral oils, particularly motor fuel fractions of the gasoline type. In preparing such a treating solution, aluminum chlorid, for example, is added in excess to normal propyl alcohol and a vigorous reaction ensues with production of a saturated solution. Here again the result is probabl more than a mere solution and involves ormation of an aluminumchlorid-propyl-a'lcohol com lex of some kind. Excellent results can be o tained by using this treating solution in the proportion of about 0.25% by weight of the mineral oil to be treated, this proportion being capable of variation within reasonably wide limits but not more than 0.5% by weight being ordinarily required, and practically never more than 1% as a maximum. Usually the polymers formed when using this solution are not precipitated but remain dissolved in the oil, giving it a red or green color; but separation maybe effected by redistllling. When too large an amount of the treating solution is used, say as much 2-per cent, the color of the distillate is darkened. Best'results are obtained when the quantity of treating solution added to the oil to be treated is so limited that the color of the mixture does not go beyond a red and change to green.

In using ethyl acetate and normal propyl alcohol as solvents as above described, it is not essential that they be anhydrous. A Water content of 0.5% appears to be unobjectionable and in the case of propyl alcohol somewhat better results are sometimes obtained where a slight percentage of water of somewhat better color in the finished motor v fuel or other mineral oil to be treated. This advantageous effect of the presence of a slight amount of water in the solvent has been observed also in preparing a treating solution by dissolving zinc chlorid in ethyl ether.

"In still another embodiment of the broad invention, use may be made under proper conditions of certain solventswhich, although capable of dissolving metal chlorids such as aluminum chlorid and zinc 'hlorid, and also miscible with oils, do not when employed alone yield with such chlorids solutions effective to treat oils in accordance with the principles of the invention. For example, if it be attempted to improve crude motor fuel by treatment with a solution of either aluminum chlorid or zinc chlorid in ethyl alcohol alone, no useful result in obtained. The same is true when methyl alcohol is employed. If, however, an ether be incorporated in such a solvent, it is found that the resultant solution of metal halid is an active improving agent in treating an oil. Thus, if dimethyl oxid (dimethyl ether) prepared in any turn saturated with dimethyl ether to produce the final treating solution, which may then be employed for improving oils in the manner hereinabove described. It is especially advantageous to use methyl alcohol in the form of synthetic methanol in preparing the ether-alcohol solution as described. "It is also possible first to pass the dimethyl ether into the'alcohol and then dissolve the metal chlorid in the composite solvent, but this method of procedure is generally less satisfactory.

Etherizing an ethyl alcohol solution of a catalytic metal salt with dimethyl ether also yields treating solutions useful in practicing the invention.

Methyl alcohol and ethyl alcohol solutions of metal salts may also be treated with ethyl ether to form ether-alcohol solutions of said salts which are active treating solutions withaddition of methyl or ethyl ether to catalytic metal salt solutions which themselves already function as active treating solutions, has the effect of rendering such solutions substantially more active. Thus adding either methyl or ethyl ether to a propyl alcohol solution of aluminum chlorid gives a more active treating solution-than when the salt is dissolved in propyl alcohol only. It is to be understood that in these cases also, the etheralcohol solvent may be made up first and the salt then dissolved therein, but such procedure is less advantageous.

The action of any of the above-described treating solutions prepared by dissolving only zinc chlorid in a solvent can also be accelerated by adding thereto a solution of alu minum chlorid. Aluminum chlorid alone in a treating solution is sometimes rather more active than is convenient or desirable; but by adding a small proportion to a zinc chlorid solution, a distinct promoting or accelerating effect is produced and yet the action of the resultant combined solution is not too rapid or drastic but on the contrary is easily controllable and otherwise advantageous. For example, to a saturated solution of zinc chlorid in ethyl ether may be added a saturated solution of alminum chlorid in ethyl ether or in propylalcohol. The quantity so added may vary widely but in practice such additions of the aluminum chlorid solution may range from 1 to 10 per cent by volume of the zinc chlorid solution, but a range of from 2 or 3 to 5 per cent is usually amply effective.

The addition of a very small amount of an acid, such as sulfuric acid, or acetic acid, for example, to any of the treating solutions hereinabove described also has a promoting or accelerating effect upon its action. Only a trace of such acid in the solution is in most cases sufiicient to produce the desired effect.

It is to be understood that the term ether as used herein includes not only the true ethers, but also the so-called acetic ether.

What I claim is:

1. The process of improving amineral oil containing gum-forming constituents which comprises subjecting the same to the polymerizing action of a solution of a catalytic metal chlorid in ethyl acetate. M

2. The process of improving a mineral oil which comprises subjecting the same to the action of a solution of zinc chlorid in ethyl acetate. r

3. The process of improving a mineral oil containing gum-forming constituents which comprises subjecting the same to the poly merizing action of a solution of catalytic metal halid in ethyl acetate.

4. The process of improving a mineral oil which comprises subjecting the same to the action of a solution of a catalytic metal halid in asolvent that comprises acetic ether and propyl alcohol.

5. The process of improving a mineral oil containing gum-forming constituents which comprises subjecting the same to the poly-v 7. The process of improving a mineral oilcontaining gum-forming constituents which comprises subjecting the same to the polymerizing action of a solution of a catalytic metal halid in an ether-alcohol solvent.

8. The process of improving a mineral oil containing gum-forming constituents which comprises subjecting thesame to the polymerizing action of a solution of a catalytic metal halid in a mixture that comprises an ether and a solvent miscible with the oil to be treated.

9. The process as set forth in claim 7, further characterized by the fact that the catalytic metal halid employed, is zinc chlorid.

10. The process of improving a'mineral oil which comprises subjecting the same to the action of a solution comprising both zinc chlorid and aluminum chlorid in'association with a mixed solvent that dissolves both and is misciblecwith the oil to be treated.

11. The process as set forth in claim 10, further characterized by the fact that the proportion of aluminum chlorid present in the treating solution is relatively small as compared to that of zinc chlorid.

12. The process as set 'forth in claim 10,

further characterized by the fact that the treating solution comprises a mixture of a solution of zinc chlorid in an ether and a solution of aluminum chlorid in propyl alcohol.

13. The process as set forth in claim 7 further characterized by the fact that the treating solution also contains a small proportion signature.

WILLIAM G. LEAMON.