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passages. It is difficult t o see what bearing this experiment can have on t h e use of ozone in ventilation. T h e ozone which was forced into t h e lungs m u s t have been several hundred times as concentrated as i t is ever used i n ventilation. It would have been q u i t e as logical t o place animals in pure oxygen or even in a n atmosphere of jo per cent oxygen a n d also force these gases directly i n t o t h e lungs. When t h e animals died a n d t h e lungs were found. t o be inflamed, t h e conclusion might be drawn b y highly academic experimenters t h a t i t is dangerous t o breathe air containing 2 0 per cent oxygen. Jordan a n d Carlson carried out experiments with w h a t might be called low concentrations of ozone. T h e y subjected 4 cats, 4 rabbits, 6 guinea pigs a n d 1 2 r a t s t o ozone of I p a r t per million nine hours daily during t w o weeks s o t h a t irritation of t h e eyes a n d nose was produced. Body weight, appetite a n d general condition were noted. N o ill effects on appetite a n d body weight or general condition could be observed. T h e conclusion could, therefore, be drawn t h a t ozone in moderate concentrations is harmless b u t Jordan a n d Carlson warn us t h a t this conclusion is not justified. T h e y s a y : “ W e desire t o state, however, t h a t this test does n o t warrant t h e conclusion t h a t t h e ozone in concentrations t h a t m a y be used in practical ventilation is harmless t o man. T w o weeks is a short t i m e in t h e life of a m a n . If ozone i n ventilation should come into general use, i t would mean in t h e case of office a n d shop workers exposure t o ozone from six t o t e n hours a d a y , six d a y s of t h e week, from nine t o twelve months of t h e year for from t w e n t y t o fifty years. And even if this prolonged exposure t o ozone should prove harmless t o t h e robust person, what a b o u t t h e unfortunate person whose lungs have only slight power of resistance?” Jordan a n d Carlson seem t o have fallen into t h e error of assuming t h a t because t h e y have not tried t o , a n d therefore have n o t demonstrated actually, benefit from t h e use of ozone, this is equivalent t o having demonstrated t h e reverse, i. e . , t h e harmfulness of ozone If t h e facts presented in this paper are properly interpreted t h e y will be found t o be i n accordance with t h e view t h a t ozone is a powerful disinfectant a n d deodorizing substance, which, i n suitable concentration, is without a n y injurious effects whatever. T h e elimination of odor is b y n o means t h e least imp o r t a n t function of ozone a n d there is n o other agency available except dilution with fresh air. I n m a n y cases it is impossible t o introduce enough air for t h i s purpose without producing annoying a n d dangerous drafts of air not t o mention expense of blower installation a n d operation as well as heating t h e air. As a m a t t e r of fact, before ozone was available, disagreeable odors have often been considered unavoidable nuisances which could n o t be eliminated o r overcome. With reference t o t h e alleged harmful effects of ozone, n o single instance of h a r m t o a person from t h e proper use of ozone i n ventilation h a s been published b u t all adverse opinions h a v e been deduced, b y inference, as i n t h e paper b y Jordan a n d Carlson, from
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experiments performed with very high concentrations while all efforts t o produce h a r m experimentally with weak ozone have failed. Jordan a n d Carlson report t h a t twenty-six animals, exposed for fourteen days, during nine hours each d a y , t o concentrations high enough t o cause irritation of t h e eyes a n d nose, suffered no ill effect whatever. Hill cites t h e cases of t h e numerous workers in t h e London underground tubes who have shown no ill effect in three years. Gminder cites t h e unharmed workers in t h e spinning mills a t Reutlingen. a n d numerous similar instances of prolonged proper use of ozone without a single complaint are t o d a y in existence. T h e Jordan a n d Carlson report is t h e most elaborate a n d convincing laboratory test t h a t has been published. POLYTECHNIC INSTITUTE, BROOKLYN
THE FLUORESCENCE OF PETROLEUM DISTILLATES B y BENJAMIN
T. BROOKSA N D RAYMOND F. BACON
Fluorescence is one of t h e most striking characteristics of petroleum distillates b u t its cause is not known, at least some of our best authorities a t t r i b u t e i t t o causes which have nothing t o d o with t h e phenomenon. T h e heavier distillates from Pennsylvania a n d certain other crude petroleums have a marked greenish fluorescence, a n d t h e t r a d e has come t o associate this prope r t y with Pennsylvania oils. For some i s e s i t is common practice t o “debloom” t h e oils by sun-bleaching or b y t h e addition of certain “deblooming” substances. T h e subject therefore has some practical as well as theoretical interest.2 Engler considers t h a t t h e fluorescence of mineral oils is d u e t o their colloidal character. Crude oils a n d t h e heavier distillates are optically nonhomogeneous a n d show a marked Tyndall effect, b u t thisprope r t y cannot be considered as indicating colloidal properties since m a n y organic compounds having large molecular weights show t h e Tyndall effect when i n t r u e solution. Schneider a n d Just3 claim t o have observed ultramicroscopic particles in a “yellow mineral oil” a n d a sample of “paraffin oil.” Holde14 studying t h e physical condition of lime soaps in grease, s t a t e d t h a t colloidal particles are n o t discernible a s such under t h e microscope. I t is probable, however, from t h e researches of Holde t h a t such greases, as well a s oils containing asphaltic or resinous m a t t e r , are t o be regarded as colloidal, not true solutions. Schulz5 claimed t h a t t h e effect of adding “deblooming” substances, such as nitrobenzol a n d nitronaphthol, was merely t h a t of adding something having a high refractive index, t h u s making t h e oil optically homogeneous. This theory of t h e fluorescence of mineral oils seemed very plausible. However, since m a n y examples of nonfluorescent oleo-resinous solutions a n d mixtures 1 Presented at the 49th Meeting of the American Chemical Society, Cincinnati, April 6-10, 1914. 9 Cf. “Relations between physical Properties and Constitution,” Kayser, “ Handbuch d. Spectroscopie,” Vol. IV, p. 839; Kauffmann. ‘‘ Beziehungen zw. Fluoreszenz u. Chem. Konstitution,” Snmml. Chem. U. Chem.-techn. F’orfrllge, 11, 1906. a 2. f. wisiensch. Mikroscopie, 1906, p . 489. 4 Z . f. angew. Chem., 31 (1908). 2138; Koll. Zfschr., 3 (1908), 270. 5 Petrol. Bert., 6 , 2 0 5 .
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are known a n d since t h e fluorescence of mineral oils persists after repeated distillation a n d is quite marked in distillates boiling a s low as 2 0 0 ’ C., we believed t h a t resinous or asphaltic m a t t e r could not be a contributing factor. Our experiments have shown t h a t , in general, oxidizing agents partially or wholly destroyed t h e fluorescence. Certain facts suggested t o us t h a t sulfur or carbon in colloidal suspension might be t h e cause of t h e phenomenon. Stable colloidal suspensions of carbon, in water a n d various organic liquids, have been prepared’ a n d described as nonfluorescent a n d brown t o black in color. Sulfur, on t h e other hand, often shows bluish colors when in colloidal degree of dispersion a n d t h e blue color of ultramarine .blue is undoubtedly caused b y so-called colloidal sulfur.* We have succeeded in proving t h a t colloidal USpensions have nothing t o do with t h e fluorescence of mineral oils. Working on t h e theory t h a t ultramicroscopic particles were present, I O O cc. of a highly fluorescent lubricating oil were diluted with kerosene t o about 500 cc. in order t o decrease t h e viscosity. The solution was placed in a suitable cell containing two round copper plates spaced 2 cm. a p a r t . T h e oil between t h e plates was subjected t o a unit direction field of 30,000 volts. potential difference for t h i r t y minutes without a n y visible change in t h e fluorescence or flocking out of a n y kind of substance. A sample of t h e same solution, carefully dried by calcium chloride, was filtered through t h e finest filter paper a n d examined under a n ultramicroscope of t h e Zsigmondy-Siedentopf t y p e b u t no particles whatever were visible. It was found t h a t unless t h e oil was carefully dried a n d filtered, particles were visible in t h e light cone. These may have been minute drops of water or dust. T h e fact t h a t t h e ultraviolet light cone is made visible t o t h e eye with bright fluorescence has n o significance so far a s t h e colloid theory is concerned since as a general rule t h e wave length of t h e emitted fluorescent light is always greater t h a n t h e incident ray, in this case from ultraviolet t o visible blue. F u r thermore, t h e ultraviolet cone contains a certain amount of t h e visible rays. N o more rigid proof of t h e nonexistence of substances in colloidal suspension in carefully purified fluorescent mineral oil, could be desired. I n order, further, t o test t h e arrangement a n d efficiency of our instrument, a colloidal gold “solution” was made b y t h e formaldehyde reduction method, one of platinum b y t h e Bredig method, and one of palladium by reducing with hydrogen according t o Paal, a n d t h e beautiful results characteristic of this instrument were obtained . Percolation through Fuller’s earth is a n excellent a n d well known method for clarifying a n d bleaching oils. A sample of a highly fluorescent lubricating oil was allowed t o r u n through a five foot t u b e packed with fine Fuller’s e a r t h . T h e resulting oil was very light in color b u t highly fluorescent a n d when a little t a r r y m a t t e r , which gave brown nonfluorescent solutions in Thomae, KolZ. Ztschr., 11 (1912), 268; Vanzetti, Koil. Z f s c h r . . 13 (1913), 6. Liesegang. KoZl. Ztsckr., 7 (1910). 307; Hoffmann, Chem. Zlg.. 1910, p . 10i9.
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kerosene, was added t o t h e oil until t h e color matched t h e original oil, t h e t w o could not be distinguished. T h e fluorescent material is therefore only slightly absorbed by Fuller’s earth a n d is probably not of very great molecular complexity. While working on t h e colloidal suspension theory, t h e marked solubility of sulfur in mineral oils was noted. A 2 0 0 cc. sample of a light machine oil was heated t o 100’ C. with an excess of flowers of sulfur, filtered hot, a n d on cooling about 0.5 gram of sulfur crystallized o u t . Guiselin’ states t h a t benzine dissolves 0.5 per cent sulfur a t z o o C. It is extremely improbable t h a t a stable colloidal suspension could exist in which t h e solubility of one phase in t h e other is a s great a s in t h e case of sulfur a n d petroleum oils. Carbon disulfide added t o a fluorescent lubricating oil weakens t h e fluorescence almost t o t h e point Of extinction; what remains is dark greenish. Before making t h e experiments with t h e ultramicroscope, this was thought t o favor t h e sulfur suspension theory, Or t h e theory of Schulz based on optical homogeneity.’ Further experiments with other solvents showed t h a t t h e character of t h e fluorescence was affected by t h e various common solvents in t h e same way as in t h e case of t h e diamino derivatives of terephthalic acid methyl esters, studied b y K a ~ f f m a n n . ~T h e effect of t h e various solvents was even more marked with solutions of t h e purified fluorescent material described below. The fluorescence colors observed were as falloffs: Amyl Aniline, Benzo
.
, ,
.. Bluish green, passing into green on concentrating
Chlorofor
Pyridine.
. . . . . . ~. . . . . . .
Greenish blue Bluish green
I n most cases t h e addition of small amounts of solvents having high refractive indices has practically no effect on t h e fluorescence. The effect of adding nitro compounds therefore must have a n explanation different from t h a t offered b y Schulz. T h e introduction of a nitro group i n t o t h e molecule of a fluorescent benzol derivative, such as t h e terephthalic esters, completely destroys its fluorescence. It appears t h a t a nitro group in t h e solvent has t h e same effect as a nitro group in t h e molecule of t h e active compound itself. This is not surprising in view of t h e marked effect of other solvents. We believed t h a t possibly t h e fluorescent substance in mineral oil owed this property chiefly t o the presence of one or more amino groups as auxochromes b u t , a s will be shown below, this cannot be t h e case. Although we have f o u n d t h a t oxidizing agents destroy t h e fluorescence, i t is probable t h a t t h e action of nitro compounds is purely physical since we have added N204, nitrated kerosene or nitrobenzol t o fluorescent lubricating oils chilled t o -10’ C. a n d destroyed. t h e fluorescence. It is highly improbable t h a t oxidation of a n y hydrocarbons could t a k e place under these conditions since 1 2
Pelroleurn, 1913, p. 1309. T h e refractive index of carbon bisulfide is ND-ZOO -1.6276. Ann. d . Chem. (Liebig), 393 (1912). 1.
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T H E J O U R N A L O F I N D U S T R I A L A N D E-VGINEERING C H E M I S T R Y
a t o o C., N204 merely adds on t o ethylene bonds without oxidation.’ There is also t h e possibility t h a t such compounds a s picric acid a n d nitrobenzol form nonfluorescent addition products, or double compounds, such as is t h e case with pyrene a n d chrysene. However. t h e simple nitro paraffines are not known t o form such double compounds a n d “nitro kerosene” is fully as efficacious as nitrobenzol for neutralizingfluorescence. The following experiment is interesting in this connection: A sample of a highly fluorescent lubricating oil was “debloomed” b y t h e addition of nitrobenzol. This oil was t h e n shaken out six times with one-half i t s volume of 96 per cent alcohol, after which t r e a t m e n t t h e blue fluorescence h a d reappeared a n d exactly matched a sample of t h e same oil n o t treated with nitrobenzol, b u t shaken o u t with alcohol in t h e same way as t h e first sample. Refining such a “debloomed” oil with sulfuric acid yields a fluorescent oil identical in this respect with t h a t obtained by refining t h e original oil. T h e action of nitro compounds in neutralizing fluorescence must therefore be purely physical in character. T h e fact t h a t exposure t o t h e atmosphere for some time partially destroys a n d changes t h e character of t h e fluorescence suggeSted t h a t what took place during this process was slom autoxidation. S i t r o u s acid readily neutralized t h e fluorescence of lubricating oils, b u t t h e oils gradually became dark colored a n d resinous. Distillation of t h e latter d a r k colored oil in v a c u o or with superheated steam yielded oil having a bluish fluorescence. Repeated washing with alkali removes only a small p a r t of t h e coloring matter. Shaking a p a r t of a sample df pale engine oil with nitrous acid for three minutes, followed b y washing with water a n d filtering through Fuller’s earth, gave a less resinous, light colored oil, very similar t o t h a t obtained b y sun-bleaching. Oxides of nitrogen, generated b y t h e action of dilute nitric acid on a metal, were t h e n tried a n d i t was found t h a t t h e sun-bleached oil could be matched, with respect t o color a n d fluorescence. provided t h e temperature of t h e oil was not permitted t o rise above 10’C , before washing with dilute alkali. A t low temperatures addition of oxides of nitrogen t o unsaturated compounds probably results as shown b y Jegorow. Unless t h e oil is chilled before passing in t h e oxides of nitrogen, oxidation appears t o result, accompanied by rise in t e m perature, darkening in color a n d formation of resinous material. S o method of removing t h e resinous coloring m a t t e r without at least partially restoring t h e bluish fluorescence was found. T h e effect, on t h e color of t h e oil, of nitric acid in sulfuric acid when used for refining is well known a n d constitutes one of t h e advantages of acid made b y t h e contact process over t h a t made b y t h e chamber method. VC’e t h e n made a series of experime&s t o determine t h e chemical properties of t h e fluorescent substance. T h e efficiency of sulfuric acid, particularly fuming It acid, in removing fluorescence is well known. was found t h a t t h e wash water from freshly prepared acid sludge t a r , made b y refining lubricating stock, was highly fluorescent. This suggested t h a t t h e Jegorow, J prahl. C h e m , 86 (1912), 512.
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fluorescent material formed water-soluble sulfonic acids, or t h a t t h e fluorescent substance was a base a n d removed a s a soluble sulfate. The latter hypothesis can hardly be t r u e since dilute acids do not extract t h e fluorescent material f r o m t h e oil. A quantity of such fluorescent aqueous solution was made alkaline a n d extracted with ether b u t no fluorescent material was obtained indicating t h a t t h e substance in question is not a base. A dilute acid solution of t h e fluorescent substance was nearly neutralized with lime t o remove t h e excess of sulfuric acid. T h e filtered aqueous solution was evaporated nearly t o dryness a n d t h e crystalline residue, containing sulfate of lime, extracted with alcohol. Twelve liters of lubricating distillate yielded, in this way, a b o u t I gram of a n impure crystalline residue which was intensely fluorescent when dissolved in t h e different solvents named above. The a m o u n t obtained was t o o small to be thoroughly investigated, b u t we hope t h a t we shall have a n opport u n i t y in t h e near future t o prepare a quantity of this highly interesting material sufficient for further work. The above results were enough t o show t h e general character of t h e substance. T h e crude fluorescent substance probably contains one or more compounds of t h e benzene series resembling or perhaps identical with chrysene, fluorene o r pyrene. Such compounds a r e known t o be formed b y t h e pyrogenic decomposition of many organic substames. Klaudy a n d Fink, in 1900. isolated a yellow crystalline substance, giving highly fluorescent solutions from t h e residuum of a cracking still. T h e y give i t t h e formula C2iH18. A large proportion of t h e fluorescent substance or substances is formed during t h e distillation of t h e crude. This was shown b y distilling a sample of Oklahoma crude a t atmospheric pressure a n d under a pressure of 5 mm. of mercury. The distillates in t h e first series were very much more fluorescent t h a n t h e latter. This is also t r u e of t h e distillates from coal when distilled a t atmospheric pressure a n d under a pressure of 5 m m . Parallel with this difference i t should be noted t h a t substances of t h e benzol series form a much greater proportion of t h e coal t a r obtained a t ordinary pressures, paraffines a n d olefines constituting over 8 0 per cent of t h e coal t a r obtained by distilling in vacu0.I It is also well known t h a t no fluorescent substances are known belonging t o t h e paraffin series. Halogenation destroys t h e fluorescence. as is t o be expected. Hydrogenation also destroys i t . MELLON INSTITUTE UNIVERSITY O F PITTSBURGH
PITTSBURGH
THE MANUFACTURE OF ETHYL ALCOHOL FROM WOOD WASTE-PRELIMINARY EXPERIMENTS ON THE HYDROLYSIS OF WHITE SPRUCE2 By F W. KRESSMAKN T H E P R E S E N T V A L U E O F W O O D WASTE
T h e value for most of t h e wood waste produced t o d a y is limited t o its fuel value for t h e production of power a t t h e mill. I n some cases, methods of closer utilization have been worked out. b u t compared with t h e 1 Jones and Wheeler, J . Chem SOC. (London), 1914, 140. 2 Presented a t the 49th Meeting of the American Chemical Society, Cincinnati, April 6-10, 1914.
