US1906724A - Motor fuel - Google Patents

Description

pression ratio is much lower than the desired Patented May 2, 1933 UNITED STATES PATENT OFFICE LUDWIG ROSENSTEIN AND WALTER J". HUND, OF SAN FRANCISCO, CALIFORNIA MOTOR FUEL No Drawing.

This invention relates to motor fuels, and deals particularly with the use of substances which, when added to gasoline or other fuel, will effect diminution of elimination or 5 knocking, together with an increase in the efficiency of the motor fuel.

Most of the fuels now produced for automobile consumption have a low compression ratio: that is to say, their highest useful comratio for ordinary operating conditions. Under conditions metwith in theoperation of automobiles, where low compression motor fuels are used, knocking or detonation of the fuel very frequently occurs. This causes a decrease in-the motor efficiency and gives rise to the disagreeable impression that the various motor parts are loose. It has been customary to add to low compression fuels various substances which tend to raise the maximum compression ratio of the fuel, with a diminishing ofthe fuel knock, and with the effecting of a more satisfactory engine operation. Many of these substances are undesirable for the reason that they are comparative- 1y expensive, and their incorporation into commercial gasolines is impractical for this reason. Other compounds which eliminate knocking are unsatisfactory because of the fact that by-products of combustion, caused by interaction with the compounds added, leave deposits in the engine, which interfere considerably with its proper running.

5 It is an object of our invention. in general,

to increase the efliciency of motor fuels by the addition of selenium compounds. It is a further object of our invention to utilize selenium -compounds of the form of diselenides. in

5 It is a further object of our invention to make use of the distinct characteristic color of diselenides for tinting gasoline. Fuels containing diselenides, even in the smallest concentrations, possess a distinctive yellow color which is useful for distinguishing fuels in Application filed August 27, 1930. Serial No. 478,305.

which compounds of this type are incorporated.

It has generally been suggested in the art that certain types of selenium compounds might be made use of to prevent detonation of motor fuels. These compounds, suggested by the prior art, are monoselenide compounds. They are impractical for use as anti-knock agents for the reason that, although the monoselenide compounds ing the highest useful compression of the fuel very considerably, the anti-knock effect of the diselenide compounds being very much in excess of that possessed by any of the selenides heretofore known to be useful.

.The diselenides possess properties which are quite distinct from those of other selenium compounds. They are for the most part solid, crystalline bodies, imparting to gasoline solutions a distinctive yellow color, in even the smallest concentrations; they are, furthermore, relatively non-volatile substances, whereas the selenium compounds heretofore known to the art are highly volatile. In stating that the diselenides are non-volatile, it is meant that their degree of volatility is markedly less than that of the least volatile hydrocarbon constituents of the fuel. This chromophoric effect is very useful in imparting to gasolines an identifying color characteristic, dispensing with the use of added dyestuffs for this purpose.

. The diselenidecompounds utilized accordmg to our invention have the additional advantage that they are non-reactive with respect to the hydrocarbon mixture into which they are introduced. This insures a functionheretofore described in the art have some anti-knock value,

ing of the anti-knock compound which is inde pendent of the type of gasoline used. Many substances used as anti-knocks in the prior art are unsatisfactory because their effect varies considerably with the type of gasoline into which they are introduced. Furthermore, they are oftentimes highly reactive substances and for this reason are unstable. It is of great advantage to prepare anti-knock fuels in which a standard amount of nondetonating compound may be introduced into any type of gasoline to give a standard effect.

A further advantage accompanying the use of dise'enide compounds, which is true of selenium compounds in general, resides in the fact that no residues are formed during combustion which will interfere with the proper-functioning of the engine. One of the biggest disadvantages of certain antiknock compounds known to the art lies in the fact that many insoluble solid compounds are formed during combustion which deposit in the engine, greatly reducing its efficiency and which are extremely difficult to remove. The diselenide compounds, when used as antidetonation agents, form no such injurious deposits. Their use may be continued for an extended period'of time without interfering in any way with the proper engine operation.

The general classof compounds embraced for-use in our invention may be illustrated by the following typical formula:

R and R in this formula may represent either organic or inorganic residues. The organic residues which may be attached to the selenium atoms may be either aromatic or aliphatic. In other words, where the charac teristic diselenide grouping is present in the compound, the nature of the substituent groups which are attached to the selenide atoms is practically immaterial.

As an example if diselenides which may contain inorganic residues directly attached to the selenium atoms, we have used NC-SeSeSe-CN and NC-Se-Se-CN, both of which possess a very high anti-knock value. They are likewise soluble in gasoline to the extent necessary for imparting to the fuel the desired high compression capacity. Other diselenides having inorganic radicals incorporated in the complex have been found to be satisfactory in every respect for the purposes of our invention. 'We have found, ho w ever, that of this particu'ar class of diselenides, the seleno cyanates have proven to be more satisfactory than most of the other compounds within the class. Wherever the term cyanates is used, it is meant to include the isocyanates as well. Likewise, wherever the term nitrile is used. the term will he meant to include isonitrile. Similarly the groups CN and NC are used, these groups are used to illustrate both nitrile and isonitrile groups. This interpretation of these various terms will be adhered to throughout the specification and claims.

Diselenidecompounds having organic substituents within the molecules have been found to be very satisfactory. The aryl substituted compounds, we have found, have decided anti-knock properties. Within this class is or diphenyl diselenide. Obviously, other aryl residues may be substituted in place of the phenyl group. Furthermore, the aromatic nuclei may contain additional substituent groups, for example, amino, nitrile, isonitrile, alky, and in general, the usual substituents which may be included in an aromatic nucleus. \Ve have found amino diphenyl diselenide,

or dianilino diselenide, to possess highly satisfactory anti-detonating properties.

The diarnino substitutes of diphenyl diselenides may take the form of secondary or tertiary amines. Compounds of this type are exemplified in I 1 I H {H and CH3 CH3 flQ O K CH3 CH3 which are alkylated forms of the diamino diphenyl diselenides. Other substituent radlcals than methyl may displace the hydrogen atoms of'the amine groups.

Derivatives of the diselenides formed by attaching aliphatic radicals to the Se atoms,

possess very high anti-detonating effect. As i typical of these substances, I have found 0 21 15 Se- Se (3 H tics.

V the Our invention also contemplates 1n WhlCh use of selenium compounds the groups attached to the different selenium atoms are not. identical. For example, upon one selenium atom may be an organic group, and upon the other'selenium atom may be an inorganic group. Where both selenium atoms have attached thereto organic groupings, one of the substituents may be an aliphatic radical and the other may be an aromatic radical. Furthermore, where the substituents attached to the selenium atoms are either bothv aliphatic or both aromatic, the substituted groups may diiier; for example, where alkyl groups areattached to both solenium atoms, one such group may be a methyl radical, and the other group may be an ethyl radical. -Where both substituents are aromatic, one may be a substituted aromatic group and the other may be an unsubstituted aromatic group one of thegroups may be polycyclic and one of the groups monocyclic, and widely varying changes may be made similarly without departing from the spirit of our invention.

. Mention has already been made of the fact I that the diselenide group is chromophoric and imparts a distinctive golden yellow tint to gasoline. This color intensity is enormously increased by the attachment to the diselenide group of amine groups, particular I In the following table are illustrated the effects of various concentrations of diphenyl diselenide upon the compression value of a Los Angeles straight run gasoline, taken upon the basis of benzol equivalent, benzol.

being taken as the standard of comparison due to its well known anti-knock qualities:

Diphen l Highest diseleni e t g g useful com m 1 M01 pressjon 55 litre ratio A study of the above table showsthat without the addition of the diphenyl diselenide, the highest useful compression for the gasoline taken for the purposes of comparison was 5.43. In order to bring up the compress ar yto add only 5 grams of diphenyl diselenide per litre of fuel. This was found to be equivalent to a benzol content of 31%, necessary to produce an equivalent result in the gasoline used. The effectiveness of the diphenyl diselenide as an anti-knock agent, is therefore obvious.

, It has been suggested in the art that diphenyl selenide has some utility as an antimock agent. The following table illustrates a comparison between diphenyl selenide and diphenyl diselenide, showing the anti-detonating effect of the .diselenide to'be far in excess of that of the monoselenide:

Diphenyl Di henyl Highest useful com- Benzol equivadiselenide se enide pression ratio lent percent Gram Gram Di- Di- Di- Diatoms selatoms selphenyl phenyl phony] phenyl enid per enid per diselemonoseldisele-. monosellitre litre nide enide mde enlde Percent Percent 032 0214 6. 0 5. 57 31 10 .016 0107 5. 68 5. 50 16 6 008 00535 5. 53 5. 45 8 2 004 00267 5. 49 5. 44 5 1 The effectiveness of the diselenide compounds is many times that of the monoselenide per gram atom of selenium in the compound.

The above tables have taken diphenyl diselenide as the basis. This is merely by way of illustration. The other diselenides are known to work in substantially the same way as diphenyl diselenide. For example, d1- ethyl diselenide,

' in the concentration of 5 g. per liter of gasoline, has been found to be the equivalent of 40% benzol, and is therefore 80 times as effective as benzol.

Symmetrical-para-dimethyl-anilino-dlselenide:

in the concentration of 2.5 grams per liter is equivalent to 22% benzol. Therefore it is 88 times as effective as benzol.

Symmetrical-para-dimethyl-anlllno-dlselenide:

alent to 35% benzol. Therefore, it is 70 times as effective as benzoLl Many changes may be made in the structural complex of the .diselenide compounds. I Any such changes are considered to be with- 2. A high compression motor fuel containing an amino diphenyl diselenide.

3. A high compression motor fuel containing a dianilino diselenide.

5 4. A high compression motor fuel containing symmetrical para dimethyl-anilino-diselenide.

5. A high compression motor fuel containing an amino derivative of a diselenide. 6. A high compression motor fuel containing an amino substituted aromatic derivative of a diselenide.

7. A high compression motor fuel containing an amino substituted aliphatic derivative of a'diselenide. J

8. A high compression motor fuel containing an amino substituted diaryl derivative of a diselenide. 9. A high compression motor fuel containing an amino substituted dialkyl derivative of a diselenide.

10. A high compression motor fuel containing an asymmetrical diselenide.

In testimony whereof, we afiix our signatures. g x j LUDWIG'ROSENSTE I N