Fuels and Society B: 1. Charles Kettering, Thomas Midgley and Tetraethyllead
|2. Alcohol Fuel as a Replacement
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The second door -- thelow percentage class of solution -- was originally represented by iodine. It was far too expensive to be practical, but it led to experiments in 1920 and 1921 that would change the automotive world.
The experiments were guided by a peg board with a portion of the periodic table of elements pasted on it. The board helped the researchers compare their tests of already known knock suppressors (such as bromine, iodine, tellurium, tin and selenium) and new fuel additives (such as arsenic and sulfur). Historians have seen it as a beautiful piece of pure research.
But Midgley and Ketterings interest in ethyl alcohol fuel did not fade once tetraethyl lead was discovered as an antiknock in December, 1921. In fact, not only was ethyl alcohol a source of continued interest as an antiknock agent, but more significantly, it was still considered to be the fuel that would eventually replace petroleum. A May, 1922 memo from Midgley to Kettering was a response to a report on alcohol production from the Mexican "century" plant, a desert plant that contains fermentable sugars. Midgley said he was "not impressed" with the process as a way to make motor fuel:
Unquestionably alcohol is the fuel of the future and is playing its part in tropical countries situated similar [sic] to Mexico. Alcohol can be produced in those countries for approximately 7 - 1/2 cents per gallon from many other sources than the century plant, and the quantities which are suggested as possibilities in this report are insignificantly small compared to motor fuel requirements. However, as a distillery for beverage purposes, these gentlemen may have a money making proposition.[i]
Even as chemists tinkered with various processes to produce tetraethyl lead in a nearby lab, Midgley and Boyd continued working on alcohol for fuel. In a June 1922 Society of Automotive Engineers paper, they said:
That the addition of benzene and other aromatic hydrocarbons to paraffin base gasoline greatly reduces the tendency of these fuels to detonate [knock] ... has been known for some time. Also, it is well known that alcohol ... improves the combustion characteristics of the fuel ...The scarcity and high cost of gasoline in countries where sugar is produced and the abundance of raw materials for making alcohol there has resulted in a rather extensive use of alcohol for motor fuel. As the reserves of petroleum in this country become more and more depleted, the use of benzene and particularly of alcohol in commercial motor fuels will probably become greatly extended. [ii] (Italics indicate section omitted from printed version).
In September, 1922, Midgley and Boyd wrote that vegetation offers a source of tremendous quantities of liquid fuel. Cellulose from vegetation would be the primary resource because not enough agricultural grains and other foods were available for conversion into fuel. Some means must be provided to bridge the threatened gap between petroleum and the commercial production of large quantities of liquid fuels from other sources. The best way to accomplish this is to increase the efficiency with which the energy of gasoline is used and thereby obtain more automotive miles per gallon of fuel.[iii] At the time the paper was written, in late spring or early summer 1922, tetraethyl lead was still a secret within the company, but it was about to be announced to fellow scientists and test marketed. The reference to a means to "bridge the threatened gap" and increase in the efficiency of gasoline clearly implies the use of tetraethyl lead or some other additive to pave the way to new fuel sources.
This inference is consistent with an important statement in an unpublished 1936 legal history of Ethyl Gasoline for the du Pont corporation:
It is also of interest to recall that an important special motive for this [tetraethyl lead] research was General Motors desire to fortify itself against the exhaustion or prohibitive cost of the gasoline supply, which was then believed to be impending in about twenty-five years; the thought being that the high compression motors which should be that time have been brought into general use if knocking could be overcome could more advantageously be switched to [ethyl] alcohol. [iv]
Thus, during the time Kettering and Midgley researched anti-knock fuels (1916 to 1925), and especially after tetraethyl lead was discovered in December of 1921, there were two ethyls on the horizon for General Motors: Ethyl leaded gasoline, which would serve as a transitional efficiency booster for gasoline, and ethyl alcohol, the "fuel of the future" that would keep Americas cars on the roads no matter what happened to domestic or world oil supply. Thus, Kettering's strategy in the post World War I years was to prepare cars for high-octane alternative fuels if needed.
[i] Midgley to Kettering, May 23, 1922, Factory Correspondence, Midgley unprocessed files, GMI.
[ii] Thomas A. Midgley and T.A. Boyd, Detonation Characteristics of Some Blended Motor Fuels, SAE Journal, June 1922, page 451. Note: italics indicate a section used at the oral presentation at a June 1922 SAE meeting but not published in the SAE paper; oral presentation from Midgley unprocessed files, GMI.
[iii] Thomas Midgley and Thomas Boyd, The Application of Chemistry to the Conservation of Motor Fuels, Industrial and Engineering Chemistry, Sept. 1922, p. 850.
[iv] N. P. Wescott, Origins and Early History of the Tetraethyl Lead Business, June 9, 1936, Du Pont Corp. Report No. D-1013, Longwood ms group 10, Series A, 418-426, GM Anti-Trust Suit, Hagley Museum & Library, Wilmington, Del., p. 4.
|Copyright 2001, Laurence
I. Peterson and Matthew E.
College of Science and Mathematics
Kennesaw State University
1000 Chastain Rd.
Kennesaw, GA 30114