2,901,336 United States Patent 0 Nice Patented Aug. 25, 1959‘ 2 extremely high octane quality gasolines containing a highly effective additive complement. A particular ob ject of .this invention is to provide novel gasoline com 2,901,336 positions containing, inter alia, a minute concentration ANTIKNOCK COMPOSITIONS of iron pentacarbonyl which cooperates with the remainder of my novel additive complement and with the base fuel Jerome E. Brown, Detroit, Mich., assignor to Ethyl Cor to provide especially high octane qualities. Other im poration, New York, N .Y., a corporation of Delaware portant objects of this invention will be apparent from No Drawing. Application May 15, 1957 the ensuing description. Serial No. 659,222 10 The above and other objects of this invention are ac complished by providing gasoline having .a motor octane 6 Claims. (Cl. 44-—69) number when clear (unleaded) of at least about 76 con taining an organolead antiknock agent, preferably a tetra alkylleatl compound containing from 1 to about 8 car This invention relates to a fundamental advance in the 15 bon atoms in each alkyl group, from about 0.4 to about antiknock art. More particularly, this invention relates 0.6 theory based on the lead of bromine as a brominea to gasoline compositions having markedly improved per containing scavenger, from about 0.8 to about 1.2 theory formance characteristics, notably very high octane qual based on the lead of chlorine as a chlorine-containing ity and reduced engine wear tendencies. scavenger, and iron pentacarbonyl, there being present in It has long been known that lead alkyls have the 20 the gasoline an amount of said agent equivalent to from highly important property of raising the octane quality about 1.58 to about 3.17 grams of elemental lead per of gasoline. For over 30 years, tetraethyllead has been gallon and an amount of iron pentacarbonyl equivalent used as the commercial antiknock agent. Over the years, to from about 0.005 to 0.2 and preferably from about improvements in re?nery technology have also contributed 0.02 to 0.1 gram of iron per gallon. These extremely in large measure to continuous increases in gasoline 25 small concentrations of iron pentacarbonyl-insu?icient quality. In fact, the conjoint use of tetraethyllead with in themselves to materially raise the octane number of progressively higher octane base stocks resulting from the unleaded base gasoline~bring about tremendous these re?nery improvements has raised the average re improvements in the antiknock effectiveness of the lead search octane number of all premium motor fuels mar~ alkyl antiknock agent contained in the fuels of this in keted in the United States from 86 in 1946 to 96 in 1956. 30 vention. In other words, the speci?ed amount of lead By the same token, the average research octane number alkyl is caused by these minute concentrations of iron of all non-premium motor fuel sold in the United States pentacarbonyl to exert the antiknock effectiveness that went from 80 to 89 in this same period. The provision would ordinarily be exerted only by a much larger amount of these higher octane gasolines has, in turn, enabled the of lead alkyl in the absence of iron pentacarbonyl. In progressive development of more e?icient engines. For 35 short, these concentrations of iron pentacarbonyl render‘ example, the average compression ratio of passenger car a given quantity of lead alkyl much more effective as an engines made in this country was 50 percent higher in antiknock than it otherwise would be. Hence, in the 1946 than it was in 1925, whereas by 1956 it was 93 compositions of this invention, the iron pentacarbonyl percent higher than in 1925. This upward trend in engine acts as a promoter of the antiknock effectiveness of the compression ratios continues. However, a new problem 40. lead alkyl. has arisen in attempting to provide still higher octane Iron pentacarbonyl when used pursuant to this inven quality fuels to satisfy the forthcoming higher compres tion is also an effective. inhibitor of engine Wear. sion engines. As an example of the astonishing behavior of the com To gain additional octane numbers by relying on re positions of this invention, a paraf?nic fuel having a motor ?ning methods alone has become increasingly expensive 45: octane number according to ASTM Test Procedure D~357 since these octane numbers are being superimposed upon when clear of 80 containing 3 milliliters of tetraethyllead fuels which already are at very high octane levels. In per gallon (3.17 grams of lead per gallon), 0.5 theory other words, it costs much more to re?ne into a fuel an of bromine as ethylene dibromide, 1.0 theory of chlorine incremental gain of an octane number starting with a as ethylene dichloride and only ‘0.05 gram of iron per 96 octane fuel than it does with an 86 octane fuel. Thus, 50. gallon as iron pentacarbonyl possessed a motor per the use of higher concentrations of tetraethyllead has formance number of 102.1 (a motor octane number of become an economic necessity. Accordingly, the aver 100.7). The corresponding fuel in the absence of iron age tetraethyllead content of premium motor fuels sold pentacarbonyl had a motor performance number of 93.3 in the United States has gone up from 1.5 cc. per gallon (a motor octane number of 98.0). Thus, this minute in 1946 to 2.5 cc. per gallon in 1954. In the same time 55 amount of iron pentacarbonyl (0.12 cc. per gallon) in a. period, the average tetraethyllead content of non-pre fuel of this invention promoted the antiknock effective mium motor fuels sold in the United States has risen from ness of the tetraethyllead to such an extent that an im 1.1 to 2.2 cc. per gallon. It is evident, therefore, that provement of over 8.5 performance numbers (2.7 motor the petroleum industry is rapidly approaching the maxi octane numbers) was realized. To achieve this same mum permissible tetraethyllead concentration—3 cc. per 60 gain in this fuel by the use of tetraethyllead in the absence gallon of motor fuel. Consequently the need exists for of iron pentacarbonyl, it is necessary to use 4.6 milli a new way of still further increasing fuel octane quality liters of tetraethyllead per gallon. Therefore, this ex in an economical manner. tremely small concentration of iron pentacarbonyl in a An object of this invention is to ful?ll the foregoing fuel of this invention made 3.0 milliliters per gallon of need. Another object of this invention is to provide 65. tetraethyllead act as if 4.6 milliliters per gallon were 2,901,336 3 4 present. Moreover, this enormous improvement in oc each of these leaded fuels were further treated with small tane quality was achieved in a leaded gasoline composi concentrations of iron pentacarbonyl. The various fuels tion which, in the absence of this small concentration of were then subjected to the ASTM Research Octane iron pentacarbonyl, already had a particularly high oc Number Test-—ASTM Test Procedure D~908. The re tane quality-a performance number of over 93 (a motor 5 sults are shown in Table I. TABLE I.—EFFECT OF FUEL ADDITIVES ON FUEL AN TIKNOCK QUALITY USING DIFFERENT OCTANE NUMBER BASE FUELS Octane Quality Using 60 Octane Octane Quality Using 80 Octane Cone. of Fe(O0)5, Base Fuel ~ Base Fuel g. Fe/gal. LPN1 APN ? ON 3 AON 4 PNI APN 5 ON 3 AON 4 63. 9 84. 2 - 85.9 ...... __ 95. 4 ____ __ 63. 4 -—0. 5 83.8 — . 4 87. 5 +1. 6 96.0 +0 6 62. 8 -1. 1 8.3,. 4 —-0. 8 88.9 +3. 0 06. 5 +1‘ 1 62.8 —1. 1 83. 4 —0. 8 89. 5 +3. 6 96. 7 +1‘ 3 1 Performance number. 2 Change in performance number. 3 Octane number. 4 Change in octane number. octane number of 98.0). The attainment of such an 25 Referring to the above data, the very small quantities improvement in this high octane region by re?nery of iron pentacarbonyl in the leaded fuel made from the methods is extremely difficult and costly. It will also 60 octane number base stock poisoned the tetraethyllead be seen that the attainment of this octane improvement effectiveness so that in all cases a reduction in octane could not have been accomplished in commercial practice quality resulted. This directly corroborates the ?ndings by the sole use of additional tetraethyllead since the maxi 30 described in US. Patent 2,398,282. However, with the mum tetraethyllead concentration currently considered fuels of this invention—-made from the 80 octane num permissible would have to have been exceeded by a sub ber base fuel——diametrically opposite results were stantial margin. achieved. Thus, very large increases in antiknock quality Such results are totally unexpected. It had been were effected in these fuels via the promoter effect of the established heretofore that mixtures of tetraethyllead and small amounts of iron pentacarbonyl on the tetraethyl iron pentacarbonyl were in most proportions mutually lead antilmock mixture. antagonistic to each other. Many mixtures of tetra Another striking feature of this invention is that in ethyllead and iron pentacarbonyl actually gave a lower the concentrations used to give the promoter effect, iron octane number than the corresponding amount of tetra pentacarbonyl is an effective inhibitor of engine wear, ethyllead alone. Thus, in US. Patent 2,398,282, it was 40 particularly when the engines are operated under very shown that in a motor fuel containing 1.32 grams of lead severe conditions.