I N D VSTRIAL d,VD ENGZNEERING CHEMISTRY
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1701.
18, No. 10
NOTES AND CORRESPONDENCE Fire-Point Carbon Test Editor of Industrial and Engineering Chemistry: The writers have read the paper by Byrd and Vilbrandt [THIS JOURNAL, 18, 699 (1926)] describing a proposed new test for the carbon-depositing tendencies of motor oils when used in internal combustion engines. The authors of this paper deplore the lack of real information afforded by laboratory tests directed to the estimation of the carbon-depositing tendencies of a motor oil, and offer a new test which they believe “will more closely approximate the relative tendency of various oils t o produce ‘carbon’ in the internal combustion engine.” The proposing of new tests is a laudable activity, but it is generally recognized t h a t a proposed test should agree in theory with the service intended and, if possible, should give results approximating a constant relation t o those resulting from the service intended. The writers are not convinced that the slow heating of a volume of SO cc. of lubricating oil, in a layer over 2 cm. thick, to its fire temperature, bears any close resemblance to the “broiling” of a film of oil in a cylinder head or piston during engine operation. Failing a close resemblance between test conditions and service conditions, the second feature might be hoped for; that a close relation could be established between test results and service results. Byrd and Vilbrandt have not given any data on this point. I n the absence of such data, we believe that the proposed test can have little value. The Conradson carbon-residue test and its merits as an indicator of carbon-depositing tendency have been the subject of controversy for several years. Experimental worG with motors by different investigators has gradually built up support for the belief that there is a general parallelism between the Conradson value of a motor oil and the amount of “carbon” i t will deposit. This belief has been confirmed in recent papers by the writers of this 1etter.l Careful experimental work under duplicatable conditions showed that, over the range of oils studied, an approximately straight-line relation existed between the Conradson value and the amount of deposit (corrected for oil and ash) found in the engine. The Conradson test thus meets one, and the more important one, of the two requirements for a satisfactory test. Byrd and Vilbrandt have emphasized the fact that their proposed test comes nearer t o service conditions of a motor oil than does the Conradson test, chiefly because their test is an “oxidizing” one. The writers are unable to agree that very much oxidation occurs during the heating, to its fire point, of the body of oil in a n open-cup apparatus. Only a small surface is exposed to the air and this is probably soon blanketed with rising oil vapors. It seems more probable t h a t the principal reaction in this case is a cracking, though it is undoubtedly much less extended than in the Conradson test. As indicated above, the writers believe that the cracking of lubricating oil in the combustion chamber is more responsibfe for carbon deposits than is oxidation, though oxidation undoubtedly occurs. The writers have plotted the data of Byrd and Vilbrandt for Conradson residue against those for “fire-point carbon” in the hope of observing a relationship, but find the points too scattered for use. The writers are unable to agree with many of the statements made by Byrd and Vilbrandt. To mention only a few points, the writers do not believe t h a t “most oils on the market are claimed to be blends of naphthene and paraffin-base oils.” Furthermore, contrary to Byrd and Vilbrandt, the class differenI
Tars
(1926).
JOURNAL,
18, 502 (1926);
J. SOC.A d o r n o f i v e Eng.,
18, 607
tiation or identification of oils by properties dependent upon their sources is generally held to be of considerable value. The identification of a Gulf Coast or a Pennsylvania lubricating oil by an inspection of properties is a common procedure. Furthermore, it should be said t h a t the source of a n oil is not a matter of indifference, since with source will vary-not necessarily, but almost certainly-those properties of an oil which de. termine its performance in service. Finally, the data of Byrd and Vilbrandt concerning the physical properties of the oils used in their work have been examined. With the possible exception of oil No. 1, i t does not appear probable that the properties given for these oils can be matched by any commercial motor oil of American origin and manufacture. Granting the correctness of the viscosities a t 100’ F., the viscosities a t 210’ F. Are considerably too high and those at 180’ F. far too high for oils of the character indicated by the flash point, Conradson residue, and free acidity given. I n most of the cases the viscosity a t 180” F. as given is far too high for the viscosity a t 210” F., irrespective of the character of the oil. SAMUEL P. MARLEY MELLONINSTITUTE OF INDUSTRIAL RESEARCH UNIVERSITY OF PITTSBURGH, P I T T S B U R G H , PA
c’J‘ LIVINGSToliE
W. A. GRUSE
July 27, 1926
Fire-Point Carbon Test Editor of Industrial and Engineering Chemislry: In the July, 1926, issue of THISJOURNAL, R. M. Byrd and F. C. Vilbrandt describe a new test which they state “should be used as the oxidation test for automobile lubricating oils.” This conclusion is arrived a t after their study of a table of tests of twelve automobile oils given in the article. A careful analysis of this. table leads me to believe that this conclusion is hardly justifiable. In the upper part of the accompanying chart are Saybolt viscosity curves of three naphthene-base oils, -4, B, and C, and two paraffin-base oils, D and E . Slopes of all the curves are quite similar. Those of the naphthene-base oils are a little steeper than the paraffin-base curves. Oil E , naphthene-base, and C, paraffin-base, are close together a t 104” F. but 25 seconds. apart at 210” F. Oil D, naphthene-base, and A , paraffin-base, are 75 seconds apart at 104” F. and together a t 210” F. This difference in the viscosity curve of these two types of oil is normal and quite well known. I n the lower part of the chart are shown curves of five oils from the data in Table I of the article, Numbers 1 and 2 , from their specific gravity and flash test, are of naphthene-base origin or consist largely of that grade. Their viscosities are close together a t the lower temperature and farther apart at the higher temperature, which is manifestly incorrect for two oils of the same grade. In numbers 6 and 12 the curve is upward. Number 6 is all or nearly all paraffin-base, and number 12 largely naphthene-base-from their other tests. Those two curves are very apparently incorrect, as viscosity curves on this kind of paper never curve upward in this manner. Other similar inconsistencies appear in the viscosity figures of the other samples. The statement t h a t flash and fire points were determined b y Method 110.31 of Bureau of Mines Technical Paper 323A is hardly consistent with figures reported in other than 5’ I?. units. Number 1, a medium oil, largely of naphthene-base origin, and number 3, a heavy oil and manifestly a paraffin-base blend, have nearly the same Conradson carbon residue. The figure for number 3 may be correct, but 1.1 per cent is certainly much
I S D C S T R I B I ; d S D E S (7 I S E E R I X G C H E X I S T R Y
October, 1926
too high for number 1 unless it is a black oil, hardly possible in an automotive cylinder lubricant. Other inconsistencies in the carbon residue figures would be more apparent if the colors had been stated. But in checking. back these figures given against the other physical tests, inconsistencies nearly as great as the one given are apparent. I
I
1
1
I
1
I
1
I I
/
I I
1
1
I
1 l
1 i
1 1
1 1
I
I
l l O l
I
1
700
z
b
e
I
I
I00
~
140
-
I
/80
Temberature O F -1. B , C-naphthene-base oils; D , E ,F-paraffin-base oils. 1 . 2 , 4 , 12-naphthene- or paraffin-base oils; 6, 9, 11-paraffin-base oils
The material insoluble in petroleum ether after the fire test of an oil is determined is called the “fire-point carbon.” The authors divide their samples into three groups: heavy oils, 0.010-0.011, as evidenced by numbers 1, 3, and 4; heavy medium, 0.0064009, their numbers 2, 5 , and 11; and medium and light oils, 0.004-0.005, numbers 6, 7, 8, 9, and 12. Comparison of the Conradson carbon residue of automotive lubricants is generally admitted a fair gage of their relative carbonforming propensity under similar engine conditions. If these two columns in the table of fire-point carbon and Conradson carbon are compared, there seems very little connection between the two. Taking these latter comparisons and the criticism of their other data above, I do not believe, as stated, t h a t the authors are in any way justified in the last clause of their paper that this test “should be used as the oxidation test for automobile lubricating oils.” R O C H E S T EN. R, Y . I,. R . ADKIXS -4ugust 20, 1926
“Experts” Editor of Industrial and Engineering Chemistry: A41waysa careful reader of your journal, I am moved t o comment on an editorial controversy for the first time, by the open letter of Ford LV. Harris, printed in your July issue on page 764. I do not care where Jlr. Harris is a n engineer or a lawyer; he is wrong in many of his views if I read his fairly clear statements correctly. I t is amazing to learn that there is a man, much associated with legal life, who wishes t o challenge the generality that chemical, technical, or even ordinary civil clisputes as a rule result in the wealth of the attorneys and the poverty of the contestants. He knows of an exception or two; but the wide and unnumbered mass of cases where the truth of this fact is without a question should govern the policies of men t o harmonize rather than fight. It is an economic fact that there is nothing productive, constructive, or profitable in fighting, and your editorial was very well taken. I honestly do not think that professional men despise the arer#
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age lawyer because he does not understand Einstein-most of us do not and admit it-but rather, as in my own case, despise the average lawyer because of his lack of principles, ethics, and honesty, Perhaps this is a natural result of daily contact with a lawyer’s duties as described by Mr. Harris, who justifies misrepresentation, distortion, and suppression of the truth because the lawyer is not under oath, and further is paid to advance the interests of his client. It would appear, if this is a true measure of legal duties, that any scorn of an honest man toward a legal light is well placed. I have never known that a man must be honest, true, and sincere only when he is a technical expert or under oath. I believe Mr. Harris will have some trouble in trying to justify several degrees of honesty. I want t o feel, and believe, that this admirable quality in men has but one analysisone brand of honesty only. Honesty applies in every way and the same way to the attorney in his deliberate acts not under oath as i t does to the “expert” under oath. There certainly is a persistent undertone of bitterness in Mr. Harris’ recital against technical men (which I hope will not creep in here) leading him into very rash statements. If he means that he can select three “experts” who are truly professional men-men who have no doubt that they are chemists, surveyors, or biologists, as the case may be, that can defend either side equal chance of success, I of a technical-or any case-with believe he ought to be better known t o both our technical societies and the Bar Association. If such a statement is ever true, it is far more applicable to a purely nontechnical case where the excessive verbiage-the bottomless pile of precedent and the utter lack of any exactness to the “law”-have full influence. The statement of Mr. Harris about three crooked experts doing some high and fancy perjury to each crooked lawyer is unfortunate and silly. I n practically admitting that lawyers do seduce the honesty of fellow men, hlr. Harris seems to imply that he condemns those so seduced only because they received a small sum for their honor, but a large sum perhaps would justify everything? Is this the opinion of a legal mind, or is Mr. Harris just spitting on technical men in another way? In the last paragraph Harris has covered such a mass of misguided criticism, all toward technical societies and scientists, that I do not ask the space to straighten him out. He should travel. While so grandly putting the whole system of expert testimony in the waste basket, where perhaps it belongs as it is mostly a legal development, he should also study the whole system of legal testimony, and machinery, comparing it with that in England, where many of the ills we have in this country, born of the efforts of our thousands of useless rascally lawyers, are totally lacking. Lawyers, like experts, should sit in a semijudicial capacity-honestly advising a man if he is right or wrong and if he ought to go into court or go away and be ashamed of his intentions. I do not see any point to, or benefit from, his proposals t o correct the situation. Our national technical societies are already well organized and there is no law preventing a judge from retaining a competent chemist or other scientist to aid him if he desires and the chemist would welcome the work. The technical societies are ready to name competent men, always, for specialized work. CHAS.0. BROWX 331 M A D ~ OAve. N , N. Y . August 17, 1926
S E W YORX,
Estimation of the Unsaturated Content of Petroleum Products In the article under this title, THISJOURNAL, 18, 821 (1926). in the formula and definition of bromine number, N (page 822) change 0.08 to 8 and grams to centigrams per gram of sample. In Table I under “Bromine No.” and in the legend a t the right of the figure the numbers should be multiplied by 100.
9. W. FRAXCIS
