Effects of Indene on Naphthalene Determinations by Picric Acid'"

an aqueous picric acid solution, form insoluble picrates. Evidence is presented and literature cited showing definitely thd presence of indene and cou...
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September, 1924

INDUSTRIAL A N D ENGINEERING CHEMISTRY

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Effects of Indene on Naphthalene Determinations by Picric Acid'" By R. L. Brown and H. G. Berger PITTSBURGH EXPERIMENT STATION, BUREAUOF MINES,PITTSBURGH, PA.

HE determination of naphthalene is em-

T

drocarbons was treated hot with solid picric acid and the solution then allowed to cool. Indene brought into contact with an aqueous solution of picric acid gives an insoluble picrate. T h e properties are such as to permit this picrate, when it is present, to be carried along with naphthalene picrate, and to be reported as naphthalene in a determination of the latter by the prevailing methods. The evidence for these statements follows. INDENE PICRATE The indene used boiled a t 179" to 180" C. at 760 mm. pressure, and showed a specific gravity of 0.9893 a t 20" and an index of refraction n"," 1.5600. It yielded the characteristic dibromide (2,3-dibromoindan) and oxybromide (2-bromo-3-hydroxyindan), the latter melting a t 129" t o 130" C. When a stream of nitrogen was led through a sample of the indene a t room temperature and then through a saturated or nearly saturated aqueous solution of picric acid, an immediate precipitation in that solution occurred. This precipitate was indene picrate melting a t 98" C., which, on being decomposed with alkali, yielded indene, which was again characterized by its conversion into the oxybromide (melting point 130" C.). Like naphthalene picrate, the picrate of indene may be crystallized from a hot solution by allowing it to cool. It is soluble in benzene and is left behind by the evaporation of the benzene. It dissolves in alcohol, from which it is precipitated by the addition of water. It showsapproximately the same thermal stability as naphthalene picrate. Liquid indene in contact with an aqueous picric acid solution gives a ready precipitation of indene picrate crystals. Coumarone also forms a picrate when brought into contact with an aqueous solution (approximately saturated) of picric acid. Precipitation of a picrate results whether the coumarone is in the liquid state or entrained as a vapor in a gas stream. The picrate showed properties similar to those enumerated for indene picrate.

Indene and coumarone, when entrained in a gas and passed through an aqueous picric acid solution, form insoluble picrates. Evidence is presented and literature cited showing definitely thd presence of indene and coumarone in coal gas and indene in carbureted wafer gas. Quantitative figuresfor indene in coal gas are giuen. The conclusion is drawn that the picrate method for the determination of naphthalene in gas is much in error unless the indene picrate present be determined and a correction applied. I n sixteen instances picrates obtained from coal gas and carbureted water gas have been found to be mixtures of from 50 to 75 per cent naphthalene picrate and 25 to 50 per cent indene picrate. The presence of indene picrate in naphthalene picrates obtained from these industrial gases is a logical explanation of many determinations which give results higher than theory permits. The significance of the true character of the precipitate obtained in naphthalene determinations in the gas industry is pointed out, both in the sale and distribution of manufactured gas, and as a guide to operation of the carbureting units in water-gas plants.

ployed in the control of the naphthalene contents of combustible gases for domestic consumption. Such control is sought in order to prevent condensation in and stoppage of the smaller distributing pipes. I n the case of carbureted water gas, which constitutes about 60 per cent of the manufactured gas used, the picric acid method of determining naphthalene is also employed a t producing plants to a greater or lesser degree as a nuide in the oDeration of t h i carbureting ;nits. The prevailing methods'** of determining naphthalene in gas and in by-product oils, either from carbureted water-gas plants or from coal-gas or coke-oven plants, are based on the formation of an insoluble picrate of naphthalene in aqueous picric acid solution. The details of the methods are too well known and generally accessible to require description, except to say that they depend upon the determination of the amount of picric acid that combines with naphthalene to form naphthalene picrate, This is determined in one of two ways-namely, (1) from the amount of the naphthalene picrate formed, or (2) from the change in concentration of picric acid in the solution in which the naphthalene picrate has formed and from which it has been removed. This change is determined from the difference in titrations against a standard alkaline solution, or by the change in the electrical conductivity of the solution. As the method is a t present employed, it is evident that the presence of appreciable amounts of any hydrocarbons or other compounds which give an insoluble precipitate with picric acid in its aqueous solution would destroy the accuracy of the method. Little regard has been given to this possibility, although Kuster' warns against the presence of acenaphthene, chrysene, and both naphthols, but says that phenanthrene does not interfere. Hofsass, Hermann, and Mezger' state that chrysene, acenaphthene, and phenanthrene all form picrates and, if present, interfere with accurate naphthalene determinations. I n 1916 an investigation of INDENE IN COALGAS the literature on solvent naphtha resins revealed to the writers the strong probability of the presence of other interWith these facts established, the question arose as to what fering compounds in most gases. Experience in investigating extent indene was present in coal gas, and more particularly the gummy meter problem2 convinced the writers early in in carbureted water gas. 1922 that the method must be a t fault. Kramer and Spilker3 I n a search of the literature the writers have found, with the in 1890 reported that indene and coumarone formed picrates when the solvent naphtha fraction containing the two hy- exception of benzene, toluene, and xylenes, and the assertions in patent claims for solvent naphtha resins, little information 1 Received April 7, 1924. Presented before the Section of Gas and Fuel as to the actual molecular composition of the light oils in coal Chemistry e t the 67th Meeting of the American Chemical Society, Washgases produced in the United States and in modern installaington, D. C!., April 21 to 26, 1924. tions. The presence of indene in coal gas and its light oil 9 Published by permission of the Director, U. S. Bureau of Mines. was shown by Kramer and Spilker3 about thirty years ago, * Numbers in text refer to bibliography at end of article.

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and by other workers in Germany, mostly during the ten years that followed. Several samples of coke-oven light oil were examined, with the results given in Table I. (Coke-oven data have been used

As a test on actuai coke-oven gas, exactly 85 cubic feet of coke-oven gas, taken after the final cooler and before the lightoil scrubbers, were passed a t an average rate of 1.2 cubic feetper hour through a train of three bottles containing saturated

TABLE I-LIGHT OIL ANALYSES DISTILLATION ___ First drop At 100" C. At 200' C. Per cent Per cent 72 55 SO 75 78 94 90 2 5 25 5 (140O C.) 10 150OC.) loo 92 190OC.)

7 -

Sample 1 2 3 4

MATERIAL Crude benzene Primary light oil Secondary light oil Commercial secondary solvent naphtha

30 per cent of light oil up to 200' C.

One ton of coking coal yields 10,000 cubic feet of gas, which contains on the average 3 gallons of light oil4and its content may be taken a t 0.3 gallon per 1000 cubic feet. Taking its approximate specific gravity a t 0.880, the light oil content is therefore (8.33 pounds X 0.88 X 7000 X 0.3) 15,390 grains per 1000 cubic feet, or 1540 grains per 100 cubic feet. Since the indene content alone is 2.25 per cent of the total light oil, it follows that there are 34+ grains of indene per 100 cubic feet, which may give picrates when the gas is passed through a picric acid solution.

Since gas at 20" C. and saturated with naphthalene5 carries approximately 15 grains per 100 cubic feet, the potential error due to indene is enormous. I n those light-oil fractions boiling from 160" to 174' C., a large part of this bromine-absorbing material was found to be indene. The chemical literature lists coumarone as the only other unsaturated compound to be expected in appreciable quantities in solvent naphtha boiling between 160" and 190" C. As previously stated, coumarone gives a picrate under favorable conditions. I n fact, the picrate-forming content of the total light oil, fxclusive of naphthalene, totals 3.0 per cent. This is equivalent to about 45 grains per 100 cubic feet of possible picrateforming material. The correctness of this figure is attested by the fact that the sum of the indene and coumarone present in solvent naphthas, as determined by complete polymerization by the acid method, averages 35 to 40 per cent. A typical example from dozens of such determinations is as follows: First drop, 149' C.; 5 per cent up t o 165' C.; 40 per cent a t 175' C.; 90 per cent a t 187" C , 97.5 per cent a t 200° C. Resin content, 39 per cent.

The composition of light oil has been variously reported in the literature.6 An average and approximate composition of cokeoven light oil, exclusive of naphthalene and wash oil, may be considered as benzene, 6.5 per cent; toluene, 14 per cent; xylenes and other hydrocarbons boiling up to 150", 8 per cent; secondary solvent naphtha boiling between 150" and 200' C., 8 per cent; forerunnings and residuals, 5 per cent. On the basis of 8 per cent for the secondary solvent and an approximate figure of 39.0 per cent for the picrate-forming constituents of that fraction, the total content of indene and coumarone in coke-oven light oil is thus seen to be approximately 3 per cent.

INDENE PICRATE FROM COALGAS The degree to which this potential source of error is real In the laboratory the average of many tests showed that from 45 to 50 per cent of the indene carried by nitrogen a t 20" C. was removed as picrate by a saturated picric acid solution. has been fixed.

--

--FRACTION175" to 190' C.Volume Unsaturation Per cent Per cent total total light oil Per cent light oil 60 1 8 3 70 1.75 2.5 60 18.0 7"

..

I

in considering the case of coal gas, because the writers are more familiar with data from that source.) It can therefore be definitely asserted that indene is a proved constituent of present-day coke-oven gas. On the basis of Sample 1, in which indene constitutes at least 2.25 per cent of that portion boiling below 210' C. (1.8 per cent being in the fraction boiling between 175" and 190" C. and 0.45 per cent in the fractions collected below 175" and above 190" C.), calculation shows the possible error due to the presence of indene in a naphthalene determination by the picric acid method to be 34 grains per 100 cubic feet.

Vol. 16, No. 9

90

30

--

..

Melting point oxybromide O

c.

130.5 t o 131 130 t o 131 129 t o 130 130

t o 131

picric acid solution. The resulting picrates were decomposed with alkali, and the hydrocarbons thereby released were titrated for unsaturation. This unsaturation, calculated as indene, amounted to 0.82f gram or 12.7 grains per 100 cubic feet of gas. From the material titrated, the oxybromide of indene was recovered and its identity established in the manner previously described. Similar tests on the picrates obtained from the gas from several separate plants gave strictly analogous results. It was thus found that indene existed as a contaminating picrate in naphthalene-in-gas determinations, and apparently to a serious extent. The extent of the contamination was studied in a number of plants by the aid of methods described in the appendix to this paper. The results are given in Table 11. TABLE11-PICRATE ANALYSES-COAL GAS

Plant

OF OIL SOURCE

A

Coke oven

B

Coke oven Vertical retort

Cb D E

Horizontal Vertical

F1

Coke oven

Fz

Coke oven

G

Coke oven Lean coke oven Estimated average accuracy

H

Total picrates CioHs Samole Grains 15 4.62 1.64 2 2.23 3 1.91 4 1 30.00 7.18 1 3.48 2 3.09 1 3.69 2 3.00 1 6.31 2 5.96 1 2 6.58 3 3.12 1 5.89 2 4.12 1 5.53 2 3.63 3.85 1 0.01

INDENE---------^ ClOHB

Grains 1.40 0.68 0.82 0.75 12.7 2.33 1.06 0.96 1.26 0.92 1.85 1.37 1.23 0.68 1.27 1.03 1.57 1.09 0.79==0.03

equivalents Grains 1.56 0.64 0.90 0.83 14.0 2.57 1.17 1.05 1.39 1.0 2.0 1.51 1.35 0.75 1.4 1.13 1.73 1.20 0.87-

Per cent of total Dicratev 34 39 40 43

0.04

Within 2

47

36 34 34 38 34 32 25 20 24 24 27 31 33 22.6

+

__

to .5

This sample was not dried as were the other three. b Plants C and E are the same, samples were secured 1 month apart.

a

INDENE IN CARBURETED WATERGAS In 1893 Dennstedt and Ahrens' reported the presence of traces of indene in condensate from the illuminating gas of Hamburg. The presence of indene in considerable quantities in the natural condensate of carbureted water gas in the United States was pointed out by Brown in 1922.* An examination of eight samples of natural condensate collected during that year from six different plants has given the results in Table 111. TABLE111-INDENE Samule 86

118 121 99 100 102 104 105

NAPHTHALENE IN CARBURETED WATER-GAS CONDENSATE -INDENE ISOLAT&D-As indene As resin Size of sample Naphthalene cc. Per cent Per cent Per cent 2000 7.6 20.1 6.3 2000 1.5 15.9 8.0 2500 7.0 14.8 7.5 4.0 850 50.0 16.4 2.3 25.4 1.500 30.0 25.3 30.0 1000 i:5 11.2 1500 13.0 1000 8.0 28.5 4.8 AND

The presence of this amount of indene in the natural condensate indicates a relatively high partial pressure of

September, 1924

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ticularly true where penalties for overrunning the specified maximum are involved. It is therefore conceivable that indene picrate, being mistaken for naphthalene picrate, may cause the payment of indemnities or penalties, or the running of a naphthalene scrubbing system without sufficient grounds. I n view of the evidence presented in this paper, reported tests on naphthalene scrubbing plants,l*g as well as all investigntions involving measurements of naphthalene in coal gas and carbureted water gas in which the formation of picrates has been used as a bssis of determination, must be subjected to re-interpretation, and certainly in proportion to the degree to which they are based on quantitative measurement. CARBURETED WATERGAS-Carbureted water gas is composed by volume of about 80 per cent water gas and 20 per cent oil gas. To its heating value the water gas contributes about 230 B. t. u. of the normal 530 to 565 B. t . u. per cubic foot of finished gas, and the remaining3OOi?o 335B. t.u. aresupplied by the oil gas. It is the aim of the operator, therefore, to secure the maximum cracking efficiency-that is, to produce the maximum heating value per cubic foot of finished gas per gallon of oil used-in the carbureting units of carbureted water-gas plants. I n the practical attainment of TABLE IV-PICRATE ANALYSES-CARBURETED WATERGAS Per cent Total --INDENE-this aim, the chief factor considered is that of temperature, As CtoH~a of total picrates although contact and time are directly involved. It has Grains grains picrates REMARKS Plant Sample Grains 5.74 1.30 1.43 25 been well establisbed'l and widely recognized that, other con5.44 1.27 1.40 26 . 26 1.22 1.47 ditions being constant, cracking efficiency in a given installa5.58 1.06 25 4.18 0.96 tion increases with rise of operating temperature and reaches a 0.90 3.70 0.82 24 9.56 4.24 4.66 49 maximum at a temperature 100' to 200" F. above the usual 4.78 45 10.63 4.34 temperature (1350" to 1400" F.) employed today. The de2.86 44 2.60 6.46 1.17 3.74 1 06 31 gree of cracking efficiency attainable in practice is limited by 0.98 37 2.62 0 89 Same plant as C 1.62 54 3.04 1.47 the necessity of keeping the production of naphthalene low Samples secured 1 4.3 53 8.12 3.9 month later enough to escape stoppages in the distributing system, and Same plant as D 4.66 2.33 50 2.12 to escape carbon deposits in the machines such as would Samples secured 4.4 60 4.04 7.40 3.50 separately; sam3.18 5.83 60 seriously interfere with the production of gas. Consequently ple dirty; indene figures in 2 in the control of the cracking process and its temperature, it has been considered desirable to follow the production of naphthalene. I n the past, the precipitation of picrates has been considered After titration with bromine each of the samples mentioned an indication of naphthalene in the gas, and the amount, a in Tables I1 and I V was steam-distilled and the residue treated measurement. I n view of the evidence in this paper the for the recovery of the bromohydroxyindanlo produced from picrate method in that usage has been untruthful and misthe indene originally present. It was present in every case. leading. I n fact, instead of indicating excessive heats, as The combined crystals obtained from all coal-gas samples heretofore supposed, picrates, by reason of their high indene after being washed with alcohol melted a t 129.8" C., and that picrate content, are equally indicative of the presence of from carbureted water gas melted a t 129.4' C. These two products of incomplete cracking in the gas. According to materials, mixed with an equal part of 2-bromo-3-hydroxy- Egloff and Towmey,12when oils are cracked a t 1300' F. or indan, melting point 130.5" C., melted a t 130.4' and 130.1 C., above, the condensable cracked oils are aromatic and contain respectively. no aliphatic hydrocarbons, and naphthalene production beIt is therefore definite that the picric acid method for the gins at 1380" F. The work just cited, as well as that of others,I3 determination of naphthalene in either coal or carbureted has shown that under cracking conditions the order of thermal water gas is unreliable. It is equally apparent that many stability in the aromatic series is as follows: Higher homomethods based on picrate formation for the determination logs, xylene, toluene, benzene, naphthalene, anthracene, of coal gas and carbureted water-gas by-products, such as carbon plus hydrogen. Theoretical reasons previously deoils, tars, etc., must be quite inaccurate. veloped and experimental evidence presented by the writer in an earlier paperl4 show that indene must be placed in this SIGNIFICANCE OF ACCURACY IN THE DETERMIKATION OF sequence as a higher homolog of bendene. Its presence in NAPHTHALENE excessive quantities in the gas and in picrates therefrom is The dotermination of naphthalene in industrial gases is of indicative, therefore, either of low cracking temperatures or of considerable commercia1 significance. The deposition of cracking that is incomplete or not uniform, which cannot be solid naphthalene in pipes in distributing systems, which for a priori reasons, and is not the most efficient. It follows results in stoppages, entails economic loss and annoyance to that, to the extent that the picrate test and its supposed determination of naphthalene have caused the lowering of both producer and consumer. COALGAS-The preceding statements hold whether the cracking temperatures below that which (with the other factors gas is distributed directly or is a by-product coke-oven gas involved) would give the maximum cracking results or effisold to a distributing company. I n the latter case, where ciency, just t o that extent has the picrate test been an expenthe transfer may involve many million cubic feet daily, and sive one to the industry. This is true for two reasons. where the naphthalene content must conform to limits speci- First, the lessened cracking efficiency requires a proportionfied by contract, its determination is essential. This is par- ally greater oil input.

indene. The vapor pressure of indene being about ten times that of naphthalene between 20" to 30" C., it follows that in the gas in the outer parts of the distributing systems the indene must be relatively much greater in amount than the naphthalene. Therefore the possibility of error in naphthalene determinations a t holder or distributing stations is large. This is demonstrated by the fact that when natural gas containing drip-oil vapor was passed through a picric acid solution, picrates containing a considerable amount of indene picrate were obtained. This test was applied to three samples of drip oil, each of which was taken from a different system in various parts of the United States. All were strongly positive. Indene is, of course, present in carbureted water gas a t the plant,O and therefore constitutes a continued potential source of error there, where the majority of naphthalene tests, both qualitative and quantitative, are made. Qualitative tests in ten carbureted water-gas plants indicated this potential error to be an actual one, and quantitative measurements showed the error to be considerable. The extent of this error and the composition of the picrates obtained. from carbureted water gas from six other plants are given in Table IV.

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Por 1 per cent loss in cracking efficiency an increase in oil input o r 1 per cent must be made if the heating value of the gas is to be maintained. On the basis of 3 gallons of oil per 1000 cubic feet of gas produced, for each cent in price of the oil used, the cost is about 0.03 cent for each per cent decrease in cracking efficiency. Differences of 10 units in cracking efficiencies in quite similar plants are often encountered, while 5-point differences are everyday affairs. With gas oil a t 4 cents a gallon, a 5-point drop in cracking efficiency entails a cost increase of about 0.6 cent per 1000 cubic feet. For a plant with a daily output of only 5,000,000 cubic feet, this means $10,940 a year.

Second, poor cracking ultimately gives rise to gummy deposits in meters, unless offset through compression and cooling, exceptional condensation, mixture with coal gas, or other means. The relationships between oil cracking, light-oil composition, and gummy deposits in meters have been presented in other papers.14 The production of gummy deposits and the troubles they entail are decidedly costly.16 The facts presented in this paper offer an entirely logical explanation for the fact that naphthalene determinations on gases often give values approximating or greater than the theoretical ones for naphthalene in a dry gas.16 Such values are greater than can exist for a gas that is in contact and in approximate equilibrium with gas condensate (drip oil) in which naphthalene is so extremely soluble. It is unfortunate that, although the general picrate-forming properties of indene and its presence in coal gas have been known for thirty years, the picrate method for naphthalene has been adopted by the gas industry, and adapted by many experimenters up to the present time without sufficient question as to whether its basic reaction was specific. ACKNOWLEDGMENTS The writers are indebted for samples and valuable cooperation to the following officials of corporations of the gas and fuel industry: J. A. GONDER, chief chemist, Chicago By-product Coke Co., Chicago, Ill. B. L. PEABLES, chemist, Haverhill Gas Light Co., Haverhill, Mass. ’ I ’ A. .MIGHILL, research chemist, Stone & Webster, Inc., Pawtucket, R. I . E. F. POHLMANN, chemist, People’s Gas Light & Coke Co., Chicago, Ill. E. H. EARNSHAW, assistant general manager, Public Service Gas Co., Newark, N. J. J. F.WING,Boston Consolidated Cas Co , Boston, Mass. A. A. KOHR,chief chemist, Seaboard By-product Coke Corp., Jersey City, N. I. R. W. CAMPBELL, chief chemist, coke plant, Jones & LaughIin Steel Corp., Pittsburgh, Pa. W. A. WAGNER, chemist, coke plant, Jones & Laughlin Steel Corp., Pittsburgh, Pa. H. M. WAXMAN,chief chemist, coke department, Wheeling Steel Corp., Wheeling, W. Va. CALEBDAVIES.superintendent, Republic Iron & Steel Co., Youngstown Ohio. B. M. LIVEZEY,chief chemist, coke plant, Carnegie Steel Co.,Clairton, Pa.

APPENDIXON METHODS BASISOF THE METHOD In the following description of the technic employed in the examination of mixtures of indene and naphthalene picrates, enough typical experimental data bearing on the basic steps of the method are given to indicate its accuracy and limitations. The method is not presented as a best or as a practical method, but rather as one which was considered sufficiently accurate to achieve the purpose of the writers. Since the object of the analyses was to determine the relative proportions of indene and naphthalene picrates constituting the mixture, efforts were directed towards obtaining a method for the quantitative estimation of small amounts of indene. With that and the easily and accurately obtainable value for the picric acid of the total picrate mixture the amount of naphthalene could be calculated. Following preliminary experiments on end points and other details in titrations of indene with a standard bromine solution, the accuracy and applicability of the method were tested through the various steps involved. The results are illustrated by the following representative data:

Vol. 16, No. 9

1-TITRATION O F INDENE ( A ) Sample Measured by volume and calculated Found Grams Grains Grains 0.10 1.54 1.50

3.08 3.15 0.20 6.16 5.95 0.40 (B)Constancy of titration of samples of a standard solution Cc. of bromine solution Average Solution I 0.86 0.86 0.85 0.85 0.86 0.85 0.86 0.856 SolutionIIa 0.86 0.87 0.88 0.89 0.88 0.87 0.88 0.87 0.875 a The last four titrations were made by a second operator. 11-RECOVERYAND TITRATION OF INDENE ( A ) From i t s picrate Indene in picIndene inVolume picric Picrate rate as detroduced acid solution used formed termined Grains cc. Grains Grains

1.5 3.0 3.0 6.0

200 200 400 500 ( B ) From a mixlure of

Indene introduced Grains

Volume picric acid solution used cc. 400 400

3.0 3.0 3.0

400

1.42 1.45 2.86 2.55 2.29 2.30 4.58 4.50 indene and naphlhalene Picralcs Picrate formed Grains

Difference Grains

1.0.03 -0.31

...

-0.08

Indene in filtrate Total acas determined counted for Grains Grains

2.55 2.50 2.50

0.35 0.60 0.50

2.90 3.10 3.00

The picrates in the samples used under I1 were prepared by vigorously shaking the indicated volume of nearly saturated picric acid solution with the requisite amount of indene to give the weights indicated. Since the extremely small volumes of indene were measured as such, and in view of the agreement under 1-23,the procedures were judged to be sufficiently accurate for the purpose of the paper.

PROCEDURE The picrates, obtained a t the various plants by the passage of the gas through bottles containing a saturated solution of picric acid,18 were separated by filtration, pressed as dry as possible on filter paper, and divided into samples for analysis. Each sample was dissolved in 15 cc. of C. P. benzene in a glass-stoppered flask. About 5 cc. of water were added, and the picric acid in the solution was titrated with 0.1 N sodium hydroxide, sodium alizarin sulfonate being used as the indicator. The end point was approached slowly, much shaking being necessary near the close to complete the titration. The benzene, which contained the indene and naphthalene set free, “58 carefully separated and poured into a 1-ounce “French square, glass-stoppered bottle. A second extraction with 10 cc. of benzene was made and the solution added to the first portion, the whole being dried with a few granules of calcium chloride. The benzene used for this purpose showed a sulfuric acid color test of less than 1 and no immediate absorption of bromine. The determination of the indene was based on the fact that 1molecule of indene adds 1 molecule of bromine a t room temperatures, and the titrations were made with a solution containing bromine (0.3 gram per cc.) dissolved in carbon tetrachloride. Since very small volumes were involved, a buret constructed from a Haldane gas pipet and graduated to 0.01 cc. was used. It yielded drops 0.01 cc. in volume. The bromine solution was added a few drops a t a time until a definite bromine color began to persist. I n fixing the end point use was made of certain of the color standards used.in the sulfuric acid color test for benzene.18 The end point was considered reached when first the solution being titrated, having been brought to a color equivalent of No. 8 of the standards, had not faded in color below that of standard No. 6 a t the close of 3 minutes. Additions of 0.02 and 0.03 cc. were involved a t the end. A determined blank of 0.03 cc. was subtracted from the observed volume of solution used, this representing the solution necessary to produce a color equal to standard No. 6 in the 25 cc., used in the extraction and titration. From the bromine added in the titration the indene present was calculated in grams, then in grains, and converted into naphthalene equivalents in grains, as expressed in the tables. For good results, samples OF picrates free from tarry matter, C. P. reagents, and thoroughly experienced technic were found essential.

BIBLIOGRAPHY I-(Q) (b) (c)

(d)

(e)

“Gas Chemists’ Handbook,” 1922, pp. 267 and 346. Fulweiler, U. S.Patent 1,443,330(1923). White, “Technical Gas and Fuel Analysis,” 1913, p. 164. Sperr, Mer. Chem. Eng., 17, 646 (1917). From Lunge, “Coal-Tar Ammonia,” Vol. 11, 1916, p. 842;

INDUSTRIAL A N D ENGINEERING CHEYI

September, 1924

Ruster, Ber., 27, 1101 (1894); Fronsac, Rev. chim. bura applicada, 17, 4; &Thomas, Gas World, 63, 644 (1915), J. Gas Lighting, 182, 701 White and Ball, J. Gas Laghting, 88, 262, 323 (1905); Jorissen and Rutten, (1915). J . SOC.Chem. I n d . , 28, 1179 (1909); Wien, J. Gasbel., 64,891 (1911); Albrecht 6-Sperr, Trans. Am.+nst. Chewz. Eng., 9, 274 (1916); Blauvelt, Trans. and Muller, Ibrd., 64, 592 (1911); Rutten, Ibgd., 6% 694 (1909); Bunte, A m . Inst. Min. Eng., 61, 452 (1918-19), Haddock, Am. GUS Eng. J., 108, Ibid., 66, 1260 (1912); Helpert, 2. angew. Chem., 29, 58 (1916). 173 (1918); Willien, A m . Gas Inst. News, December, 1917; Marquard, v) From Chemical Absfracfs (additional to those above): F a b E , Blast Furnace Steel Plant, 7,256 (1919); Brown, A m . Gas Assoc. Monthly, 6 , Rev. cham. ind., No. 210, 146 (1907); Gair. J. Gas Lighfang, 100,771 (1908); 309 (1923). Jorissen and Rutten, Chem. Weekblad. 6 , 261 (1909); J . Gasbel., 63,269 (1910); 7-Dennstedt and Ahrens, "Jahrbuch der Hamburgeschen wissenSchlumherger, Ibad., 66, 1257 (19121, Eyndhoven, Ibid., 69, 107 (1916); scha~tlen ~ ~ ~ iSg8, ~ ~ p. 132. l ~ ~ ~ , , t Runblauch, Gas J.. 137, 64 (1917); Anon., Cos Age, 41, 28 (1918); Kun8-Brown, Proc. Tech. Section, A m . Gas Assoc., 4, 280 (1922). blauch, J. Gasbel., 61, 134 (1918); J. SOC.Chem. Ind., 87, 458A (1918); Col9-Brown and Howard, I n d . Eng. Chem., 16, 1147 (1923). man. Gas .J., 144, 231 (1919); Pastre, Chem. Met. E w . , 23, 286 (1920); 10-Berger and Brown, A m . Gas Assoc. Monthly, 6, 123 (1924). Fabre, Rev c h i n . ind., 28, 214 (1919): M e w s , Gas u. Wasserfach, 64, 413 Il-Downing and pohlman, proc, A m . Gas Inst., 11, 588 (1916); A m . (1921); Coffman, A m . Gas. Assoc. Monthly, 8, 691 (1921); Ht\fsass, HerGas La& J . , 105, 318 (1916), Whitaker and Leslie, J . I d . E n g . C h e w 8, mann, and Gas u. Wasserfach, 64, 722 (1921); Colman and Smith, 593' 684 (1916)' J . SOC.Chem. I n d . , 19, 128 (1900); Gair, Ibid.. 24, 1279 (1905); 26, 1263 12-Egloff and Towmey, J. Phys. Chem., 20, 121 (1916). (1907); Mrade, "Modern Gasworks Practice," 1921, p. 475 (gives Colman 13-Rittman, Byron, and Egloff, J . I n d . Eng. Chem., 7, 1019 (1915); and Smith method); Haddock,Am. Gas. Eng. J.,108,173 (1918); Fulweiler Ibid., 9, A ~ cas , J , 118, 364 (1923); offee, G ~ u ,~ ~ . ~ ~65, 773 ~ (1922); ~ ~ Egloff f and ~ Moore, ~ h , 40 (1917); Rittman and TowmeY, Ibkd.8 8, 20 (1916); see also Dean and Jacobs, Bibliography in Bur. Mines, Tech. Paper Werner, I b i d , 66, 257 (1923). (1922)' (g) Offee, Ibid., 66, 414 (1923); Bunte, Ibid., 66, 490 (1923): 14-Brown. Pohlman, and Berger, Bur. Mines. Rebts of Investigations, Richardson, Gas J., 164, 515 (1923); Pike and West, I n d . Eng. Chem., 16, 2637 (1923); Gas Age Record, 62,645 (1923). 253 (1924). I b B r o w n , Gas Age Record, 60, 571 (1922). 2-Brown, Proc. A m . Gas Assoc., 4, 280 (1922). I G T h o m a s , J SOC. Chem. I n d . , 86, 506 (1916). 3-Kramer and Spilker, Ber., 28, 3276 (1890); 38,2261 (1900). 17-"Gas Chemists' Handbook," 1923, pp. 267 and 346. 4-Gas Age, 46, 173 (1920); A m . Gas Eng. J.,113,83 (1920), Gas Age, 48, 12, 15 (1919); Ibid., 46, 461 (1920); Blast Furnace Steel Plant, 7, lS-Sperr, Met. Chem. Eng., 17, 642 (1917); Weiss, J. I n d . Eng. Chem., 10, 1008 (1918). 256 (1919); Bull. A m . Inst. Min. Eng., 1918, 597, 1677, 1770; Trans. A m . Inst. M i n . Bng., 61,452 (1918-19); Gas Age, 46, 3 (1920).

Effect of Ammonium Chloride upon the Growth of Yeast and the Hydration of Gluten in Beer Wort' By E. I. Fulmer, F. F. Sherwood, and V. E. Nelson DEPARTMENT OR CHEMISTRY, IOWA STATECOLLEGE,AMES,IOWA

I

T HAS been shown2 that in a synthetic medium the concentration of ammonium chloride optimum for the growth of yeast is identical with the concentration of the salt in which a protein, wheat gluten, is least swollen. The experiments here described were undertaken to determine whether this relationship applies to a complex medium containing various sources of nitrogen. TABLE I Normality of NHICI 0.00 0.0118 0.0236 0.0294 0.0341 0.0353 0.0365 0.0382 0.0412 0.0418 0.0424 0.0430 0.0435 0.0470 0.0588 0.0700 0,0820 0.0940 0.106 0.118

0. i29

30' C. synthetic medium -WOR"count" Count (48 hrs.) (22 hrs.) 53 230 194 270 256 352" 295 232 356 389" 242 270 220 213

.. .. ..

Gluten (3.5 hrs.) 58 62 76" 71

..

60

.. .. ..

.. ..

.. .. ..

196 173

245 244

74 88

24s

100

.. .. ..

251 281" 235 233

....

.. .. ..

102.

si ..

42' C. synthetic medium "count" (20 hrs.) 18 35 47

..

si 77 99 139 156' i45 139 123 98

~ W O R Gluten Count (3.5 hrs.) 29 65 63 94 89 157O 93"

..

83

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

86

83 84 77 72

81

.. .. .. *.

..

142"

.. .. 74 .. .. .. .. .. .. .. 64 ..

78

.. ..

91 1080

.. 111 0.140 95 84 .. 0.153 " Indicates maximum effect. "Count" refers to yeast crop. "Gluten" expresses grams loss in weight per 1000 grams of gluten.

..

Beer wort was prepared by mashing at 55" C. 360 grams of malt with 1150 cc. of distilled water. The mash was filtered through toweling, then through filter paper, and heated for 30 I

Received December 22. 1923. :Fulmer, Nelson, and Sherwood, J. A m . Chem. Soc., 48, 191 (1921).

minutes under 15 pounds pressure in an autoclave. After standing for 3 days to permit coagulated matters to settle, the liquid was filtered and was ready for use after sterilization in live steam. The yeast used (Saccharornycea cerevisiae) had been growing continuously in a synthetic medium for 4 years. The methods of estimation of yeast crop and of the hydration of gluten as affected by varying concentrations of ammonium chloride are as described in the previous communication.2 Typical results are given in Table I.

CONCLUSIONS 1-Less ammonium chloride is required for the maximum growth of yeast and minimum hydration of gluten in wort than in a synthetic medium, showing that there is present in wort something which plays a similar role to that of ammonium ion. This conclusion is strengthened by the fact that there is greater relative effect a t higher temperatures. 2-Extracts containing bios or ammonium chloride are mutually beneficial in a medium. The main role of bios in yeast growth cannot be the same as that of ammonium chloride-i. e., the maintenance of the proper state of hydration of protein. 3-Systems of wort and ammonium chloride producing greatest yeast growth are identical with those in which wheat gluten is the least swollen. This is true of both maxima at the temperatures tested. The generalization seems to be indicated that if the addition of ammonium salt to a medium increases its ability to dehydrate gluten, the addition will likewise improve the medium for the growth of yeast, the effect being maximum in any combination in which the gluten is least swollen.