T H E JO URATAL OF I N D U S T R I A L A N D ENGIXEERING CHEMISTRY
July, 1922
alkali after titrating the liberated iodine. The amount of alkali found was practically equal to the amount of alkali originally present in the potassium iodide. Even if air be passed through a solution of hypochlorous acid, made by distilling a chlorinated soda-ash solution, the amount of alkali found is not increased appreciably above the blank. The authors conclude that hypochlorous acid cannot be washed over as such. However, if the potassium iodide is alkaline the figure obtained for free chlorine will be low, clue
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to the formation of hypochlorite or hypoiodite. Therefore the solution of potassium iodide employed for chlorine absorption was made neutral or acid with sulfuric acid when used. ACKNOWLEDGMENT The authors wish to acknowledge the helpful suggestions received during the course of this work from hfr. R. E. Gegenheimer, Chief Chemist.
Benzene as a Motor Fuel’ By J. J. Lawton SYRACUSE, N E W YORK
HE demand for motor fuel is rapidly increasing from year
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to year, not only are the world petroleum fields becoming gradually exhausted, but we also have, in the opinion of eminent geologists, to look forward to the time when naturally occurring motor spirit will either be nonexistent or, at best, SO expensive in production as to prohibit its practical use. I n the year of 1919 the world’s consumption of crude petroleum equaled 558,692,519 bbls., of which the United States consumed 377,719,000 bbls. It has been proved beyond the slightest doubt that benzene is an excellent fuel for the internal combustion motor. AS long ago as 1907 attention was called by the Motor Union to the use of benzene as a motor fuel. Those were the days when petrol was a vastly superior fuel to that a t present obtainable, which is a much heavier spirit owing to the inchision in it of a larger proportion of the higher boiling fractions of the crude petroleum. “On the other hand, cars and engines have greatly improved in design since 1907. Many of these improvements, and particularly the almost universal substitution of the spray carburetor for that of the evaporative type, facilitate the use of a much more varying class of fuel in the same engine, with little or no adjustment.” I n fact it may truly be said that any modern and efficient petrol engine will consume benzene quite as efficiently, the change being made practically without trouble or expense. Sir Dugald Clark, an authority on this subject, gives the requirements of a suitable motor fuel as follows:
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EASY STARTING FROM com-The ease of starting depends on the volatility and vapor pressure of the fuel, and it may be stated here that although benzene is far less volatile than gasoline of six to eight years ago, the advantage which gasoline had over benzene is questionable to-day. ABSENCE OF OBJECTIONABLE ODOR, both in the fuel itself and in the exhaust products. The odor of motor benzene is certainly no more unpleasant that that of petrol or gasoline. The prevention of an offensive exhaust depends on the completeness of combustion, and the sulfur content of the fuel. NO LIABILITY TO FORM DEPOSITS in the cylinders and valve passages. The author’s experience tested a so-called good gasoline for residue and found 0.075 per cent compared to 0.027 per cent for motor benzene. ECOKOMICAL CONSUMPTION-i?tere is the point of most importance t o the average motorist. All the above qualities r u s t be met by any manufacturer or distributor in the form of good will or reputation, but the big question-How much will it save the public? How much will it save me? Benzene here has a decided advantage, as one would expect from a consideration of the relative calorific values: C A L O R I F I C VAIXE O F
FUEL Gasoline (Pre-war) Benzene ( 90’s )
MOTORFUELS (BRAME)
Sp. Gr. 15 5‘ C. 0.680-0.76 0.883
*Received March 6, 1922.
--CAL(,R:FIC
VALUE-B. t.u.per 1.b. 13. t.u.per Gal. 18,450 132,500 17,100 150,000
“The motorist thinks of fuel in terms of gallons, not of pounds, and from his point of view the calorific value of benzene is approximately 13 per cent higher than that of petrol or gasoline. When benzene is used in an engine not only is more power available, but the thermal efficiency of the engine is usually found to have increased.” The practical standard is mileage per gallon, and, given a suitable mixture, benzene is far superior to petrol in this respect. The high mileage figures obtained by the Automobile Association and the Royal Automobile Club are evidence of this, and may be supplemented by a number of authoritative trials, the results of which have been published during the past ten years. The average of such tests made by different observers on different types of cars, gives a n increase of 22.7 per cent in miles per gallon. These tests were all taken without alteration to the compression ratio of the engine; but owing to the temperature of spontaneous ignition of benzene being higher than that of petrol, the compression, which is usually 70 to 75 lbs. per sq. in. in a petrol engine, may safely be increased to I50 lbs. in the case of benzene-with obvious further economy. “The rate of propagation of the flame when using benzene is less than that in a petrol-air mixture. There is, in consequence, a marked reduction of any tendency to ‘knock’ under heavy loads, and ignition may be advanced t o a greater extent with a view to eliminating this knock and its serious effects on the engine.” The reason why more mileage can be obtained from a gallon of motor benzene than from straight gasoline is that benzene permits the use of a leaner mixture. All aromatic compounds contain a higher percentage of carbon than the corresponding saturated hydrocarbon so that more air can and should be used in burning them. I n some cars carbon forms more readily; therefore, more heat is produced. If proper care is exercised to make sure the fuel has sufficient air to burn it, very little carbon will form. This is true of all motor fuels, particularly motor benzene. Remember your engines are not supposed to run perpetually without going over them. See if your carburetor is adjusted properly before you condemn a fuel. Benzene has not only been proved to be the best fuel fos an internal combustion engine by all scientific men of the world, but it actually demonstrates the fact.
A Request for Journals The “American Medical Aid for Russia,” with headquarters a t 103 Park Ave., New York City, desires to secure three copies of important scientific publications issued in this country since 1914. They are intended for use a t the University of Petrograd, University of Moscow, and Moscow Academy of Sciences. Anyone who is willing to contribute copies of the SOCIETY’S journals from 1914 to the present date should communicate with the organization a t the above address.
