Aug., 191j
THE JO
R -V.-I L 0F I
D 1-S T RI d L A -VD E -VGI S E E RI S G C H E V I S T R Y
11-The laboratory distillations gave 4 0 per 'cent more acetate of lime t h a n commercial yields, b u t t h e acetic acid was not greatly influenced b y variations in t h e method of distilling. 111-The application of t h e laboratory methods t o a commercial retort holding 4','2 cords of wood indicated possible yields of alcohol 3 0 per cent higher t h a n b y t h e usual methods of firing a n d a n increase of I j per cent in yields of acetate of lime. IY-The best results were obtained b y slow distillation during t h e critical stage rather t h a n b y lowering t h e temperature at which t h e reaction took place. This was accomplished b y rapidly removing t h e moisture content of t h e wood in t h e first stages, a n d t h e n anticipating t h e period when destructive distillation or critical stage began. At this point t h e temperature of t h e fire was decreased. \.'--This method of temperature control gave promise of being entirely applicable in t h e commercial plant. T h e fuel requirements were only slightly higher t h a n t h e usual methods of firing a n d t h e cycle of operation was not changed. . VI-The studies of temperature control have shown t h a t wood alcohol either eshibits sufficient stability in t h e retort or its formation is of a simple enough character t o allow it t o be easily effected a n d t h e a m o u n t recovered greatly increased. Acetic acid, however, is apparently much more subject t o variations in t h e original n-ood decomposition a n d methods of preventing t h e m a n y interreactions going on in t h e complex vapors of a large retort will be required t o secure yields of this product t h a t will more nearly approach t h e theoretically possible yields. FIJREST PRODUCTS IABORATORY, MADISOS, W~scows~s
THE DETERMINATION OF BENZOL IN GAS MIXTURES B y G. A . BURRELLA N D I. 1%'. ROBERTSON Received April 29. 1915
With t h e present great demand for benzol a n d t h e installation of plants a t different places for obtaining t h i s constituent. there has arisen a demand for a rapid method of determining the benzol content of gas mixtures. Hence a scheme follows which t h e authors have used in determining i t in t h e carbureted mixed coal a n d n-ater gas of Pittsburgh. Fig. I illustrates t h e apparatus. T h e bulb contains phosphorus pentoside for removing water vapor. T o s t a r t a determination t h e apparatus is connected t o a vacuum p u m p a n d exhausted of its air: a Gerky pumli will do. The gas mixture is then introduced a t atmospheric. pressure. t h e barometer read. a n d t h e t w o bulbs immersed in a mixture? of solid carbon dioxide a n d acetone or alcohol. After waiting about I O .minutes. as much gas as possible is withdrawn from t h e bulbs b y means of t h e vacuum p u m p . T h e gases removed will be those of high vapor pressure a t -:So C. In t h e case of t h e mixed coal a n d water gas t h e authors worked with. t h e y are C o n , 02,CO, HS, CH4, Nn. CzH,. CzH6, C3H8, C3Hs a n d C4Hs; in fact, Published with the permission of the Director of the Bureau of Mines. This mixture gives a temperature of about - i s 0 C . The solid carbon dioxide. obtained b y releasing the gas from a commercial cylinder, through a cloth towel, is mixed with acetone or alcohol to the consistency of slush.
669
practically all t h e gases except t h e benzol. S e x t t h e stopcock on t h e apparatus is closed, t h e cooling mixt u r e removed. a n d t h e benzol allowed t o vaporize at room temperature. I t s pressure is t h e n read on TABLEI-BENZOL DETERMINATION I N P I T T S B U R G H GAS 7 SAMPLE No. 1 i 4 4 mm. i 4 4 mm. Original pressure of g a s . . . , , . , . , , , 10 mm. 9 mm. Partial pressure oi benzol v a p o r . . . . , loo - 1.34 q X "0 = 1.31 __ P E R C E S T A G E OF B E N Z O L . . . . . . . , . , . . 744 744
t h e side-arm mercury manometer attached t o t h e apparatus. This pressure compared with t h e atmospheric pressure gives t h e percentage of benzol in t h e gas mixture. T h e results of t w o determinations are shown in Table I . T o obtain other d a t a on this method of separation, the distillate from t h e above freezing process was next passed into fuming sulfuric acid. I n t h e case of Sample No. I there was obtained 7 . 3 2 per cent of illuminants, a n d in t h e case of Sample No. 2 . j.39 per cent. T h e total illuminants in t h e Pittsburgh gas. as found by absorption in fuming sulfuric acid. is 8 . 6 7 per cent. In other words, t h e benzol percentages as found when added t o 7 . 3 2 a n d 7.39! respectively, equal 8 . 6 6 a n d 8,.j o per cent, or almost identicaily t h e same quantities as t h e total illuminants in t h e coal gas. Benzene reacts with oxygen as follo\Ts: CeHs 7 . j0, = 6COz 3Hz0. The contraction is 2 . j volumes a n d t h e carbon dioside is 6 volumes. Table I1 shows t h e results of analysis of t h e residual vapor t h a t was held in t h e liquefaction bulb (Fig. I ) when t h e coal gas was cooled a t a temperature of -78' C. Before analysis t h e benzol was diluted with air.
+
+
TABLEII--AKALYSIS
OF B E N Z O L
VAPOR CC
volume taken for analysis.. . , , , . . . , . , , , , , Oxygen added . .. .. .. . .. . .. Total v o l u m e . . . . . . . . . . . . . . , . . . . . . . . , . . l'olume after burning . . . . . . . . . . . . . . . . . . . , . Contraction due to burning . . . . . . . . . . . . . . Volume after KOH absorption., , , . . . . . , , . , , , Carbon dioxide produced b y burning.. , . . . , , . . , ,
.. ,
.. . , . .,
28.29 51 Y I
E?
?i 47
i.>,
4.i6 64.2.5 1 I .47
I t will be observed t h a t t h e ratio of t h e carbon dioxide t o t h e contraction is almost esactly 6 : 2 . j , showing t h a t t h e vapor obtained in t h e benzol deTraces of other termination was principally benzol. easily condensible \-apors m a y have been present b u t apparently in such small quantities as to be negligible. The authors n-ere unable t o find, in t h e literature, t h e vapor pressure of benzol a t -78" C., b u t apparently it is x-ery small. Benzol boils a t 8 0 . I Z O C.: at --zoo t h e vapor pressure is j . 76 m m . ' The a u t h o r s prepared saturated x-apors of benzol b y shaking t h e pure liquid with air. It was a simple matter t o pre1
Landolt and Bornstein Tables, 1906, p. 143; according t o Regnault.
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T H E J O C R X A L OF I,VDCSTRIAL A N D EiVGINEERING C H E M I S T R Y
pare unsaturated vapor b y merely diluting t h e saturat e d vapor with air. The percentage of benzol was checked b y combustion analysis. It was found t h a t all of t h e benzol could be separated a t -78' C. T h e above tests show t h a t as far as t h e Pittsburgh gas is concerned t h e method is satisfactory. I n extracting benzol from coke-gven gases (largescale operations for this purpose are in progress), t h e gas is washed with a petroleum distillate, in which t h e benzol is dissolved, also toluol a n d other products. As a check on t h e efficiency of t h e scrubbing apparatus there is needed a rapid test for t h e benzol, etc. I n this casc, toluol or other easily condensible hydrocarbons would interfere with t h e test, as t h e vapor pressure of toluol is only o . o o j 8 mm. a t -78' C.' T h e best one could d o would be t o estim a t e t h e m together, along with a n y other vapors t h a t might also be retained, so t h a t t h e test would give t h e efficiency of absorption of all t h e easily condensible vapors in t h e scrubbing oil. T h e authors have made no experiments with coke-oven gas. Acknowledgment is made t o Dr. G. A. Hulett, cbnsulting chemist t o t h e Bureau of Mines. for suggesting this scheme of analysis. LABORATORY O F GAS IKVESTIGATIONS BCREAUOF MINES, PITTSBURGH
THE POTASH SITUATION? By
EDWARD HART
T h e files of t h e P a t e n t Office show t h a t t h e question of supplying our own potash has greatly exercised t h e brains of inventors. Among t h e sources of supply so f a r proposed two have seemed t o me of special interest. With t h e termination of t h e present highly artificial situation, German competition of t h e old-fashioned S t a n d a r d Oil brand must again be encountered. I t seems highly improbable t h a t most of t h e processes which must depend for revenue upon t h e price of potash alone can be successful because t h e nature of t h e German source of supply is such as t o give t h e m a n immense initial advantage. A considerable amount of potash must in t h e near f u t u r e come from cement fume. This appears t o exist chiefly as sulfate. A sample, which I obtained from this source, contained 94 per cent sulfate and 5 per c e n t carbonate. T h e sulfur probably comes from t h e coal. T h e total amount obtainable from this source is problematical, of course, a n d it is questionable whether all t h e potash can be extracted, b u t if we place t h e a m o u n t recoverable as - 0 . 4 per cent sulfate. t h e t o t a l amount obtainable would be in t h e neighborhood of 60,000 tons annually. This cement dust has caused much annoyance a n d e v e n serious loss in Northampton C o . ; P a . , a n d t h e a d j a c e n t districts a n d cement manufacturers recognize t h a t condensation of this fume is one of t h e problems t h a t must soon be solved. T h e y also seem t o be of t h e opinion t h a t so far no practical solution has been offered. T h a t this fume must be condensed is quite independent of any revenue t o be derived from t h e Landolt a n d Barnstein Tables, 1912, p . 394; according t o Barker. Presented a t t h e 50th Meeting of the American Chemical Society. N e w Orleans, March 31 t o April 3, 1915. 1
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Vol. 7 , NO.8
materia! recovered. T h e dust recovered, only partly converted into cement, is worth, as cement material, b u t 7 j cents per ton. Another source t h a t has attracted much attention is t h e potash of feldspar. Arthur S.W a t t s has enumerated t h e feldspar supplies of t h e Eastern United States.' H e has, however, omitted t o mention t h e fact t h a t a considerable amount of very fine potash feldspar is imported from Canada n-here it occurs in a great lens deposit, unlike any other deposit I have seen, about t h i r t y miles north of Kingston. This deposit is not a pegmatite in t h e ordinary sense of t h a t term. T h e spar occurs as a mass of uniform composition in a deposit which has been mined as a n open cut, 4 0 feet in a-idth, together with lump quartz of apparently good quality in a deposit of less width alongside of a n d partly surrounded b y t h e spar. This deposit contains no mica. T h e mining cost of this material is very low, as very little cobbing is needed, b u t t h e cost of transportation t o our markets is very high. A s t u d y of t h e analyses quoted b y W a t t s shows t h a t very few orthoclase deposits r u n above 1 2 per cent K 2 0 , a n d as a ' m a t t e r of fact, I think 1 1 per cent is a much safer basis for such calculations. This corresponds to 2 2 0 pounds K20, 350 pounds KC1 or 4 2 2 pounds K2S04 per short t o n of spar. L u m p spar of this quality cannot be obtained a t t h e mine at less t h a n $3.00 t o $3.50 per ton, f . 0. b. car. M a n y of t h e processes proposed contemplate t h e extraction as chloride b y some modification of t h e J . Lawrence Smith method, using calcium chloride a s t h e material for supplying chlorine. If we allow two cents per pound as t h e value of potassium chloride, a figure above t h e t r u t h for normal conditions, a n d z * / ~ cents for potassium sulfate (which m a y be produced in m y own process) this would yield: 350 lbs. KC1 a t 2 c e n t s . , , . , . . . . . . , , . , . . . . . . . . . 422 lbs. K2SOn a t Z1/* c e n t s . . . . . , . . . . . . . . . . .
. . .
$7.00 9.49
I t is a t once evident t h a t t h e probability of profit from any process which contemplates only t h e extraction of potash from this material is very small. I n mining feldspar in most localities, only a small proportion of t h e material taken out can be classed as N o . I spar, and very large refuse heaps accumulate which may contain as much as 9 per cent potash a n d I j per cent alumina. I n addition t o this, not a few of t h e openings yield quantities of material so mixed with mica a n d still high in potash, as to be available for potash extraction, while quite useless as feldspar. I t is from these materials, quite low in first cost, t h a t our potash must be derived. Such material exists in quantity in t h e district near Erwin, Tenn., on t h e Carolina, Clinchfield a n d Ohio Railroad, where a plant is t o be erected by t h e Clinchfield Products Company in t h e near future. This location has t h e advantage of proximity t o supplies of cheap coal a n d barytes, both of which are needed in t h e exploitation of t h e process t o be used. Briefly, t h e process consists in heating a mixture of feldspar refuse a n d barytes in proper proportion in a 1
Trans. A m Ceramic Soc., 16 (1914), 80.
