US2039576A - Method of treating hydrocarbon motor fuels and products resulting therefrom - Google Patents

Description

Patented May 5, 1936 UNITED STATES PATENT 0 v 2,039,576 FFICE METHOD OF TREATING HYDROCARBON MOTOR FUELS AND PRODUCTS RESULT- ING THEREFB/OM GeorgeW. Ayers, Jr., Chicago, Ill assignor, by mesne assignments, to Gasoline Antioxidant Company, Wilmington, Del, a

Delaware corporation of No Drawing. Application October 1, 1934;

Serial No. 746,419

4 Claims. (Cl. 44-9) This invention relates to the treatment of hydrocarbon oils, particularly to those oils suitable for use as motor fuels. With reference to its more specific aspects, the invention has to do with the treatment of cracked distillates, parinhibiting agents may be seen in the following table, whichrepresents the action of the factors which contribute to the formation of gum in ticularly those distillates produced by high temperature or vapor phase cracking methods, to

prevent or minimize the formation of gums or gum compounds in distillates of this character. Cracked petroleum products, particularly gaso-= line, upon being exposed for some time to air,

light or heat, form resinous materials which may be dissolved by the petroleum product or which may form an insoluble deposit. These resinous products are formed particularly 'in large amounts when vapor phase gasoline, that is, gasoline which contains a large per cent of unsaturated compounds is stored for several months. If a tank car of gasoline, for example, is exposed for some time to the heat ofthe sun, formation of these undesirable resinous products is accel-- erated.. If these gums are permitted to form and remain in the motor fuel product they are apt to interfere with the proper flow of the motor fuel-through the fuel passages of internal combustion engines by permitting the gum to deposit in such passages to an extent sufficient to clog or obstruct the passages against the free and proper flow of the fuel to the combustio cylinders.

It is, therefore, an outstanding object of .the invention to treat motor fuels containing large quantities of unsaturated constituents with com-- pounds'which for convenience may be termed negative catalysts or inhibitors, which we have discovered will arrest for all practical purposes the formation of the objectionable resinous or gum compounds in the motor fuel product, so

that the latter may be subjected to the conditions prevailing in the storage, transportation and handling of motor fuel products without any appreciable developments of the gum substances in said fuel. 7

We have found that certain substances when added to petroleum products slow down the rate of formation of these resinous products. For

example, when catechol is added to motor fuel oil containing unsaturated compounds, the gum formation is inhibited almost entirely for several months. A large number of aminoand hydroxy compounds of the aromatic series added to gasoline and it was found that tically all of them had some inhibiting upon gum formation. We are of the opinion this inhibition of gum formation is characteristic of these two classes .of compounds, although there is a difference in. effect, depending upon the particular compound employed. dther com-:- pounds also werefound to exert this inhibitive'i eifect. For example, the eifect of some of these gen and heat:

vapor phase cracked gasoline, namely, light, oxy- Gum after 7 days.

The values shown above represent the amount of gum formed on evaporating 20 c. c. of the gasoline in a glass dish ofapproximately 30 c. c.

capacity and of approximately 10 grams weight,

by placing said materials in a steamsbath for three hours, and then drying for 30 a heated oven maintained at C. r We have determined, furthermore, that when cracked petroleum products, notably .gasolines,

minutes in are oxidizedv by heat, the velocity or rate of oxi- I dation increases with the time; that is tosay, the reaction is auto-catalytic. This is apparently due to the catalytic effect of the oxidized bodies. In order to combat this auto-catalysis. we have used ammonia and organic substitution compounds thereof, in other words, compounds which might combine with the aldehydes, ke-

tones or acids formed by oxidation. When heat-i ed in glass dishes on the steam or water bath, according. to the method previously explained, not only was the gum formation inhibited, but

apparently the nature of the residue seemed al.-

tered, being mainly a light-colored oily liquid rather than a deep orange-colored gummy residue. Characteristic results are given below, using untreated, vapor phase cracked gasoline as the medium: 7

7 Table 2 we s Added agent Gum Gminlinn 1m Gasoline and ammonia 1373 Gasoline and diphenylguanidine 1465 In any case the inhibiting materials may be either in solution or suspension in the gasoline. Gasoline or motorfuel oil containing gum producing compounds is produced by the passing of petroleum vapors through a heated reaction zone wherein the vapors for a desired Period of time are brought to a temperature usually in ex- -1000 F in which'reaction' zone the debons are suitablefor use as motor fuel, and upon emerging from the conversional reaction zone the vapors are subjected to fractional condensation to separate the desired low boiling compounds from the higher boiling compounds. The

low boiling vapors are then passed through apolymerizing catalyst, such as fullers earthfor the purpose of removing therefrom a very large percent of the undesirable unsaturated compounds which produce the gummy or resinous substances and which also tend to discolor the oil. In spite of these precautions, however, it

' has been found that the gum compounds accumulate or form in treated motor fuel products,

and we therefore employ the inhibiting compounds of the character above set forth to minimize or prevent the formation of gums in the finished or treated fuel. It is, of course, possible to apply these inhibiting compounds to untreated fuels, that is, to the fuels whichare obtained directly, without condensation, from the conversion zone of the cracking apparatus. This would require the use of a greater amount of the antigum forming compounds than in the case of con trolling the treatment of cracked gasolines which had been contacted in the vapor phase with fullers earth. Amounts as low as 0.001 'to 0.004%

may be used satisfactorily.

The apparent effect of various substances on the rate of gum formation in the light and in oxygen has been observed. For example, a sample of refined vapor phase gasoline was used with about .002 g. of gum per 20 c. 0.; four oz. sample bottles were filled with the gasoline and small amounts of the anti-gum forming agents were added, after which oxygen was placed in theair space at the top of the bottle and tests were made over periods of 7, 8, 24 and 35 days to determine the rate and quantity of gum formation or inhibition.

The hydrom-compounds of benzene have been found to possess qualities which render them adaptable as negative catalysts or inhibitors,

- catalytic action.

quinone allowed a small amount of gum to formin addition to that already present in the gasoline as'did resorcinol. Phenol when used disclosed quite satisfactory inhibiting effects.

On the other hand, the alcohols were substantially without effect in attaining the ends of the invention, except in the case of methyl alcohol, which was found to possess a very mild negative Ethyl alcohol, 'butyl alcohol and iso-amyl alcohol had practically no effect whatsoever.

Next to thehydroxy-compounds of the benzene series, the amino-compounds were considered to be the best inhibitors of gum formation. Aniline served as an extremely good negative catalyst, with diphenylamine next in order. The substituted ani1inesdimethyl-aniline and diethyl-aniline-had the same effect and are considered to be good anti-catalysts. Hexamethylene-tetrarnine showed a negative catalytic effect,

but drops of gum were deposited on the bottom of the test bottle. In this regard the following were found to be accelerators of gum formation in the order of their effect: Aluminum oleate,

carbon tetrachloride, calcium chloride, manganese borate, tannic acid, pepsin, benzaldehyde and benzoyl peroxide; Nitrobenzene is considered a fair anti-catalyst, as is also acetone.

The following tables disclose results of gum tests on vapor phase gasoline to which the various anti-gum compounds have been added.

Table 3 originalgum Gum after (lamdlagsr Glsmdaflyigbf 8 days 'Strongvarnishodorinmmplsbottlesftsrrunainingincentsd withCu.

In view of the foregoing it will be seen that the present invention provides a method of treating cracked petroleum distillates having large quantities of highly reactive or unsatm'sted compounds therein with other compounds having the Y properties of inhibitors or anti-catalysts by which the further-formation of gum compounds in the cracked distillate is substantially prevented or minimised. This method of treating has-the desirable effect of permitting treated or untreated vaporphasedistillatestobehandledinamanner customary to the'storage and shipment of motor fuels without further development of the highly objectionable andimdesirable gums and resinous compounds. The anti-catalytic substances do not impairinanywaythevalueof the cracked distillate so treated in' any respect since the amount of the anti-catalysts employed in accomplishing the purpose of the invention is relatively small and further, the anti-gum forming materials themselves are of such character which may be added to cracked petroleum dfstilany particular distillate to obtain the data necessary in each particular case. Usually, however, the amount of the inhibitor will constitute but a fraction of one per cent. of the total volume of the distillate so treated. The concentration may vary from 0.001 to 0.006% and with some inhibitors concentrations up to 0.009% may be used. Expressed in other terms, the inhibitor may be added in proportions 'of ten pounds per one thousand barrels to the cracked distillate to prevent gum formation during ordinary handling, storage and transportation of the fuel.

This application is a continuation in part of my oopending application Serial No. 309,685,1iled October 1, 1928.

I claim: 1. The process of producing stabilized gasoline "from distillate resulting' from vapor phase cracking of hydrocarbon oil which comprises contacting said distillate with an adsorptive polymerizing catalyst at a temperature at which a substantial portion of the distillate is in the vapor phaseand thereafter adding to said distillate a small proportion of an amino benzene in sumcient amount to inhibit formation of gum.

2. A process in accordance with claim 1 in which the inhibitor is diethylaniline- .GEORGE W. AYERS, JR.