NOTES AND CORRESPONDENCE: Influence of Some Chlorinated

NOTES AND CORRESPONDENCE: Influence of Some Chlorinated Hydrocarbons on the Limits of Inflammability of Methane-Air Mixtures. W. Jorissen, H...
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a co-worker of Mr. Niese in the old Matthiessen and Weichers refinery. An important event in which Mr. Niese takes just pride was his participation in the important meeting of April 6, 1876, a t the old building of Kew Pork University in Washington Square, CHEMICAL which resulted in the organization of the AMERICAX SOCIETY. Of the original organizers he and W. H. Nichols are now the only survivors who have maintained a constant membership in the S O C ~ E Tsince P the time of its establishment over fifty years ago. He was one of the charter members in whose honor the banquet was held at the Semicentennial Anniversary of the SOCIETY in Philadelphia last September. For many years Mr. Niese has sought diversion for his leisure moments in his one great hobby, farming. The cattle and horses on his farm in Morristown, New Jersey, have carried off blue rib-

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bons on several occasions, while the products of his fields and dairy have always maintained a n enviable reputation. Few men have enjoyed a wider popularity among their business associates and friends than has Mr. Niese. This is due not so much to his accomplishments and success in business as to his kindly disposition, genial philosophy, and serenity of temperament, which remain unruffled even under the most trying situations. He has held steadfastly to the principle that a moderate rational course is always the smoothest and shortest road to success. I n the ultimate analysis the characters of men are of more value than their accomplishments; but when character and accomplishment are blended together the result is the “four-square man,” of which Henry E. S e s e is a splendid example.

C . A . BROWNE

NOTES AND CORRESPONDENCE Influence of Some Chlorinated Hydrocarbons on the Limits of Inflammability of Methane-Air Mixtures Editor of Industrial and Engineering Chemistry: In your September number’ H. F. Coward and G. W. Jones have published their experiments on the “Extinction of MethaneAir Flames by Some Chlorinated Hydrocarbons.” I noticed with pleasure that the explosion regions CH4-air-CCI4, CH4air-CzHCla, and CH4-air-C~H2Clz are examples of the three principal types of reaction regions (explosion regions) recently described by me.2 With carbon monoxide and hydrogen as inflammable gases 1 had previously studied explosion regions using the same chloro derivative^:^ The explosion region COair-CCla is very small,4 t h a t of CO-air-CzHZClzresembles that of CHI-air-CzHSClz; t h a t of HZ-air-CzHCla resembles t h a t of CH4-air-C~HCls. The same three types found by Coward and Jones we have observed with CO-air-CHCla, CO-air-CH2C12, and CO-air-CHaC1 mixtures5 and also with mixtures of solid substances.6 Using methane as inflammable gas we had only made some preliminary experiments with the chloro derivatives also used by Coward and Jones. No explosion regions were determined. The experiments of VeliSek’ were made with impure methane* (methane 88.7, heavy hydrocarbons 3.8, carbon monoxide 3.7, hydrogen 1.9, oxygen 0.3, nitrogen 1.6 per cent). Therefore, they may not be compared with the experiments of Coward and Jones. There is no difficulty in explaining the differences between their other experiments and ours (with Meuwissen). First of all, the experimental procedure was quite different. Coward and Jones used a glass tube 5 feet long, 2 inches internal diameter, ignition being effected by drawing the flame of a small spirit lamp across the open end of the tube. We used tubes of about 1.5 cm. internal diameter, in which the mixture was fired by one small spark near the top of the tube. Only in some experiments with tetrachloroethylene they used a tube which 1

THISJOURNAL,18, 970 (1926).

Chem. Weekblad, 23, 79 (1926); Chem. News, 132, 150 (1926). Jorissen, Langen van der Valk, and Ongkiehong, Rec. trav. chim., 44, 810, 814 (1925). 4 Jorissen and Langen van der Valk, Chem. News, 132, 151 (1926). 6 Jorissen and Langen van der Valk, Chem. TVeekblod, 23. 80 (1926); Chem. News, 132, 1.51 (1926), see Fig. IX. 8 Jorissen and Ongkiehong, Rec. trav. chim., 45, 540 (1926). 7 Jorissen, Velfgek and Meuwissen, Chem. Weekblad, 18, 636 (1921); Rec. trav. chim., 43, 80, 591 (1924); 44, 132 (1925). 8 Rec. frao. chim., 48, 593 (1924). 2

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somewhat resembled ours, but their spark was much stronger (gap 5 mm.) and they do not say whether or not they passed only one spark, as we do, using a method analogous to that of Slumberger and P i o t r o w ~ k i . ~As to the influence of the intensity of the spark, I can refer to the experiments of Emich‘o and Bone.” Then the great influence of the mode of propagation must be mentioned. The curves representing White’s results on the explosion limits of hydrogen-ammonia-air mixtures have shown12 t h a t the explosion region for upward propagation extends itself to the ammonia axis, b u t not t h a t for doynward propagation. In our experiments downward propagation always took place, in those of Coward and Jones always upward propagation. In the latter case the explosion regions will be larger and the effect of CCL, etc., will be found t o be smaller. Finally, the chloroderivatives used had partly a different degree of purity, as shown by the following table of boiling points:

Pentachloroethane s-Tetrachloroethane Perchloroethylene Trichloroethylene s-Dichloroethylene

COWARD AND JOKES 0 c . 143 to 161 (tech.) 144 to 146 119 to 121 8 5 . 8 to 87 56 to 60

JORISSEN A N D O

159.6 to 142.8 to 120.5 to 86.3 to 53.5 to

MEUWISSEN

c.

160.4 143.4 120.8 86.5 54.5

(770 mm.) (769.5 mm.) (770 mm.) (763.1 mm.) (770 mm.)

Mentioning the different results which we observed using different burets, Coward and Jones say: This inconsistency proves that Jorissen was not observing whether or not his mixtures were capable of propagating flame per se. His apparatus is not satisfactory t o insure certain ignition and also t o give the resultant flame a long enough “run” t o enable observers t o judge whether it is self-propagating when it has lost the initial impulse due to the source of ignition. I n all our experiments we have determined the limit between reaction (some propagation) and no reaction (no propagation a t all). When we investigated a certain reaction region we always took care to do so under the same conditions (same tube, spark, substances, etc.). Thus, the reaction regions CO-CHC13-air, CO-CHnClz-air, and CO-CH3C1-air, mentioned above, which we compared with each other, have been determined under the same circumstances. J. Gasbet., 43, 941 (1914). Site. A k a d . Wiss. Wien, 16, 10 (1897). 11 Bone and Weston, Proc. Roy. SOC.(London), llOA, 615 (1926).

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Jorissen, Rec.

chim., 44, 1048 (1925).

~ ~ Q Z J .

INDUSTRIAL A N D ENGINEERING CHEMISTRY

March, 1927

New Words and Old

Finally Coward and Jones say: Jorissen’s failure to appreciate the experimental requisites in this type of work is further illustrated by the following quotation from his first paper: From Bunsen’s observations on the explosibility of hydrogen-oxygen mixtures a lower explosion limit of about 6.1 vol. per cent may be calculated. When we compare this limit with that for hydrogen-air mixtures as determined by J. Roszkowski, viz.: 9 . 5 vol. per cent, we note the considerable influence of nitrogen. For the proportion between the concentrations of hydrogen and oxygen has been increased from 6 1/93.9 t o 9.50/19.

The comparison between Bunsen’s observations on hydrogenoxygen mixtures with Roszkowski’s on hydrogen-air mixtures involves other variables, the explosion vessel and the means of ignition. It is unnecessary so to complicate matters, for Roszkowski himself made a direct comparison between the lower limit of hydrogen in air and in oxygen, finding them t o be 9.5 and 9.7 per cent, respectively.* * * Hence in comparable experiments the influence of nitrogen in this example is inconsiderable.

1 suppose t h a t Coward and Jones did not see t h a t I was comparing proportions. M y reasoning remains the same, whether I compare t h e proportions 6.1/93.9 and 9.5/19 or 9.7/90.3 and 9.5/19. In both cases the increase is considerable. I n addition to those already cited, I should like to refer those who are interested in this question t o my other papers on reaction regions.1s I* Rcc. trau. chim., 45, 162, 224,400, 633,849 (1926); Chem. N e w s , 133, 290 (1926); Trans. Furuday Soc., 22. 291 (1926).

THE UNIVERSITY LEIDEN,HOLLAND October 29, 1926

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W. P.

JORISSEN

. . . .........

Editor of Industrial and Engineering Chemistry: Mr. Jorissen’s commentary on our paper includes no denial of our conclusion t h a t he “has much overestimated the effect of small amounts of chlorinated hydrocarbons on the limits of inflammability of methane in air.” We agree with his explanations as to why our results differ so much from his. We pointed out in our paper wherein we find his experimental procedure inadequate to decide whether or not a given gaseous mixture will propagate flame-that is, inadequate t o determine limits of inflammability which, according to the titles of the papers criticized, was his object. There are wide ranges of noisily explosive mixtures which Jorissen has declared to be outside the limits of inflammability, because he did not succeed in inflaming them. H a d he used a sufficiently narrow tube, he would have found t h a t no gaseous mixture a t all was inflammable! As for the last point raised by Mr. Jorissen, surely his original statement (quoted and requoted) meant t h a t the great difference between the lower limit of hydrogen in air and in oxygen was due t o the great difference between the proportions of hydrogen and oxygen in the two cases. We showed that there was, in fact, very little difference between the limits. What interest remains, therefore, in the proportions of hydrogen and oxygen? PITTSBURGH EXPERIMENT STATION H. F. COWARD u. s. BUREAUO F MINES G. W. JONES PITTSBURGH, PA. December 29, 1926

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Editor of Industrial and Engineering Chemistry: I n the January number of INDUSTRIAL AND ENGINEERING CHEMISTRY,I have read with interest your derivation of certain new words which you propose as differentiating between the upper and lower strata of “substitutes.” Praiseworthy as is your effort in this connection, I cannot refrain from drawing your attention, first to the rairon d’ttre of such formations, and second t o the etymological processes here concerned. Thus, t3 be specific, the word “substitute” does not carry with it the idea of inferiority. I n fact, there are many cases where superiority is connoted by the term “substitute.” One purchases synthetic oil of wintergreen perfectly well aware t h a t he is obtaining a pure methyl salicylate, whereas he knows full well t h a t when he purchases natural oil of wintergreen he is obtaining a product of nature consisting for the most part of methyl salicylate but always carrying slight impurities. Many such examples may be cited, all of which are clearly indicative that the word “substitute” is not subject to as much criticism as your article would infer. Furthermore, from the standpoint of etymology we are not accustomed t o coining new words, of close significance t o >words already in use, by reverting to the elemental roots of these latter and hand-picking them, a s i t were, in order that, by addition of prefixes and suffixes to these roots, we may derive a new formation carrying a slightly differentiated meaning from the original compounded word. For example, the word “surgeon” is derived from x&p. hand, and ;pyov, work. Therefore, a surgeon is one who works with his hands and the term as such is used only in the medical profession. If now we might wish t o describe a particularly adroit surgeon who can work with his feet, we cannot call him a “pedurgeon” and expect to get away with it. For thus we would lose the significance of the compounded word already in use. We must therefore build up the new word from the compounded word already in use by adding proper prefixes or suffixes. Thus a surgeon adept with his feet should be called a “pedosurgeon.” I maintain, therefore, that the word “substitute” must remain exactly a s i t is. If you want t o devise a word that will carry with i t the idea of distinct superiority you can introduce the word “supersubstitute.” I n this connection I must say t h a t “equistitute” is foreign to the chemist’s mind. There is nothing that is exactly the same as anything else. Chemically, therefore, we cannot have “equistitutes.” Now t h a t you have introduced the subject of fine distinctions, may I ask you, through the pages of your highly valued journal, to emphasize the difference between “component ”and “constituent.” So many of our chemists never seem t o realize t h a t we are using a language replete with words and words with many fine shades of meaning. The word “component” refers only t o the parts of a whole which have been merely placed together. Thus, we have the “components” of petroleum: the various hydrocarbons, and nitrogen and sulfur compounds; but there are no such things as “constituents” of petroleum, There are, of course, “constituents” of hydrocarbons in petroleum: hydrogen and carbon; just as we may say t h a t hydrogen and oxygen are “constituents” of water. The roots of the word “constituent” mean “stand together” or “built in together” and, therefore, are characteristic of the elements as combined in the compound. When I hear anyone speaking of the “constituents” of coal and the “constituents” of steel I do not know what the man is talking about, and i t is my regular practice in all such cases, no matter how learned he may be, t o ask him just what he has in mind and, as a rule, I find t h a t he is very poorly informed on the etymology of chemical terms. Chemically, the word “constituent” refers to the