T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
992
fuming sulfuric acid is not proportional t o t h e time of contact. This is t o be expected when one considers the relatively small amount of gasoline vapors ordinarily present in samples of natural gas. I n t h e case of t h e natural gas from which t h e d a t a for t h e preceding curve were obtained, t h e change in composition obtained by 30 passages represents more t h a n two-thirds t h a t produced by 9 0 passages, and while this particular natural gas IS not especially productive of gasoline, undoubtedly 30 passages of any sample of natural gas into fuming sulfuric acid would be sufficient t o give d a t a for t h e amount of gasoline vapor it carries. COMPARISON
HzSz07
O F R E S I D U E S AFTER
TREATMENT
IVITH
AND AFTER REMOVAL O F GASOLINE O K A C O Y -
order t o determine t h e usefulness
MERCIAL SCALE-In
Vol. 6, No.
12
SUMMARY
I-Fuming sulfuric acid exerts a n appreciable absorbing action on certain samples of natural gas, t h e absorption increasing with t h e amount of gasoline vapors which the natural gas carries. n-The average number of carbon a n d hydrogen atoms per molecule of hydrocarbon absorbed b y fuming sulfuric acid (and t h u s t h e average molecular weight of t h e hydrocarbons) may be computed from t h e composition of t h e gas before a n d after absorption a n d from t h e decrease in volume t h a t is obtained. 3-Application of this reagent t o t h e s t u d y of natural gases for t h e production of gasoline may be made b y determining t h e absorption under certain uniform conditions. It is desirable, however, t o determine also t h e composition of t h e portion t h a t is absorbed as a check upon t h e indications obtained b y the decrease in volume. CORNELL UNIVERSITY, ITRACA,N . Y.
THE DETERMINATION OF HYDROGEN IN GAS MIXTURES BY MEANS OF COLLOIDAL PALLADIUM B y G. A. BURRELL A N D G . G. OBBRRELL
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Received September 21, 1914
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of t h e treatment of a sample of natural gas with fuming sulfuric acid as regards i t s availability for t h e production of gasoline, samples of natural gas were obtained from ’before a n d after t h e compressor at points where gasoline is being extracted from natural gas. These samples were analyzed a n d a portion of t h e sample from which t h e gasoline vapor h a d not been removed was treated with fuming sulfuric acid for 30 passages in t h e manner previously described, a n d t h e n analyzed. The results t h a t were obtained a r e shown in t h e following table: TABLE I1 Natural gas I
.
Natural gas I1 - , Per cent CHa CzHa 0%Nz CzHs C3H8ClHla 0% N a Before compressor.. . . . . . 5 8 . 9 4 0 . 0 0 . 0 1 . 1 . 4 1 . 5 2 1 . 8 7 . 6 29.1 After compressor.. . . . . . . 7 1 . 3 2 7 . 2 0 . 0 1 . 5 2 7 . 7 2 9 . 1 . . .. 43.2 (air) After treatment with HISZOI 7 8 . 0 18.3 0 . 9 2 . 8 2 5 . 4 2 3 . 4 . . 11.0 4 0 . 2
.
.
.
................
T h i r t y passages through fuming sulfuric acid caused a decrease i n volume of 9.8 per cent i n natural gas I, a n d 30.0 per cent in natural gas 11;t h e yield of gasoline was about I gallon goo B. per 1000 cu. f t . from natural gas I, a n d about 5 gallons 9 7 O B . per 1000 cu. f t . from natural gas 11. I n spite of t h e pronounced dissimilarity of t h e two samples, there seems t o be a r a t h e r close agreement in t h e composition of t h e residues obtained b y t h e commercial treatment of natural gas for t h e production of gasoline a n d b y treatment of t h e natural gas with fuming sulfuric acid for t h i r t y passages.
I n this paper are reported results obtained by t h e authors, having t o do with t h e use of a solution of sodium picrate and colloidal palladium for determining hydrogen in gas mixtures. Paal a n d Hartman’ originated t h e method. Brunck2 made a n examination of i t a n d recommended it. I n some of t h e authors’ experiments t h e solution was prepared according t o t h e direction of Paal and Hartman, as follows: 2 g. of sodium picrate a n d 2 g. of colloidal palladium were dissolved in I O O cc. of water. I n other experiments t h e solution was prepared according t o Brunck. He first makes a normal solution of sodium carbonate a n d neutralizes 5 g. of picric acid with 2 2 cc. of t h e solution, thereby producing about 5.6 g. of sodium picrate. He then dilutes t h e solution t o IOO cc. with water a n d adds 2 g. of colloidal palladium. The life of t h e solution depends upon t h e presence of t h e unchanged reducible substance, t h e sodium picrate; hence by Brunck’s method there is obtained a solution containing more sodium picrate a n d therefore of longer life. Colloidal palladium itself absorbs large volumes of hydrogen, b u t if used in t h e concentrated form it is costly. I n t h e presence of a n easily reducible substance, like sodium picrate, i t acts only as a catalyst. T h e solution is regenerated, after i t has lost its absorbing power, as follows: The reagent is transferred from t h e gas pipette t o a flask and much diluted sulfuric acid is added drop b y drop t o t h e solution so long as a precipitate results. A large excess of sulfuric acid is avoided because it might cause t h e colloidal palladium t o change t o t h e sulfate through t h e action of atmospheric oxygen. T h e precipitate is washed with water, which, although i t m a y dissolve in some of t h e acid, carries no palladium into solution. The precipitate is t h e n suspended i n a small quantity of water a n d i s 1 Paal, C.,and Hartman. W., “Gas Volumetric Determination of Hydrogen by Catalytic Absorption,” Ber. dcursch. chem. Gcsell., 43 (1910). 243. 2 Brunck, 0.. “Estimation of Hydrogen in Gas Mixtures,” Chem. Z&.. 1910, No. 34, pp. 1313-1314. 1331-1332.
Dec., 1914
T H E J O U R N A L OF I N D l r S T R I A L A N D E N G I N E E R I N G C E E M I S T R Y
dissolved by adding sodium hydroxide drop b y drop. Fresh sodium picrate is t h e n added a n d t h e solution diluted with water t o i t s original volume of about I O O cc. It is t h e n again ready for use. F o r use t h e authors place t h e reagent in a n ordinary Orsat pipette filled with glass tubes a n d bring t h e gas mixture in contact with i t b y passing it back a n d forth between t h e pipette a n d gas burette until absorption is complete. T h e following table shows t h e results obtained when prepared mixtures of hydrogen a n d air were analyzed for their hydrogen content b y means of t h e palladium solution: RESULTSO F ANALYSESOF HYDROGEN-AIR MIXTURES PER CEKT HYDROGEN BY Sample No. 1 2 3 4
Combustion in oxygen 0.8 0.8 3.8 3.9 28.2 28.2 28.5 28.6
Absorption in Pd solution 0.8 0.8 0.8 3.9 3.9 28.3 28.3 28.2 28.2 28.6 28.6
T h e following analyses show t h e results obtained in analyzing t h e coal gas in Pittsburgh: By one method t h e carbon dioxide, illuminants, oxygen a n d carbon monoxide were removed b y means of t h e usual absorbe n t s , a n d t h e methane a n d hydrogen burned with osygen in t h e slow-combustion' pipette. By another method t h e carbon dioxide, illuminants, oxygen, a n d carbon monoxide were removed a n d t h e n t h e hydrogen absorbed by t h e colloidal-palladium solution; t h e residual gas, methane a n d ethane were next burned in t h e slow-combustion pipette. I n both cases nitrogen was estimated b y difference. T h e second column shows t h e results obtained by t h e first method; t h e third column shows t h e results obtained b y t h e second method; a n d t h e fourth column shows t h e results of t h e second column recalculated so as t o make allon-ance for t h e ethane as determined b y t h e second method. T h e third a n d fourth columns should correspond.
ANALYSESOF GAS MIXTURESBY Two DIFFERENTMETHODS Method COz Ill. 0 2 CO H2 C H I CzHa 0.3 3.4 5.6 3.0 1.4 0.0 a 10.3 5118 0.2 3.5 5.6 3.0 1.5 0.0 b 10.6 0.1 7.4 a 5.2 2.9 1.2 0.0 7.5 5093 5.6 3.0 1.1 0.0 0.3 7.7 b 7.4 9.7 5.3 2.3 0.5 1. o 0.0 a 9.6 5052 1.1 9.5 5.6 2.4 0.6 0.0 b 9.6 6.4 0.0 5.1 2.2 0.2 1.2 a 4862 9.0 6.6 0.0 5.2 2.4 1.3 0.2 b 9.0 6.6 0.0 5.2 3.0 1.0 a 0.6 8.2 4837 0.6 6.4 5.4 3.3 1.2 0.0 b 8.1 12.1 a 0.0 1.5 0.8 0.0 3.6 4725 5.3 0.0 1.7 0.7 0.0 12.0 3.3 b 5.5
No.
993 NI
The above samples were collected i n t h e experimental mine of t h e Bureau a t Bruceton, Pa. T h e y were automatically trapped in a special sampling device a s t h e flame of a n explosion traversed t h e entries of t h e mine. T h e following sample was taken from t h e exhaust of a gasoline mine locomotive: A large number of these samples were gathered t o s t u d y t h e composition of t h e exhaust gases under different conditions of usage of t h e motor. It should be added t h a t this sample was collected under particularly bad conditions of motor usage. T h e analysis marked a nTas made b y absorbing t h e carbon dioxide in caustic-potash solution, t h e illumin a n t s in bromine water, t h e oxygen in alkaline pyrogallate solution, a n d t h e carbon monoxide in ammoniacal cuprous-chloride solution; t h e methane a n d hydrogen were then determined b y burning in oxygen a n d t h e nitrogen estimated b y difference. T h e analysis marked b was made in t h e same manner except t h a t after t h e other absorbable gases h a d been removed t h e hydrogen was absorbed by colloidal palladium a n d t h e methane burned in oxygen. ANALYSESO F No. Method 4280 a b
EXHAUST GASES O F COZ 5.9 5.9
Ill. 0.3 0.2
0 2
1.0 0.8
A
GASOLIXEMINE LOCOMOTIVE CO Hz CHI CzHs 1\12 13.38.7 0.8 0.070.0 0.8 0.070.6 13.1 8 . 6
I n t h e analysis of complex mixtures Paal and H a r t man recommend t h a t carbon dioxide, unsaturated hydrocarbons, oxygen a n d carbon monoxide be first removed before absorbing t h e hydrogen by t h e palladium solution. T h e y state t h a t carbon monoxide seems t o retard t h e catalytic effect in t h a t i t slows the reaction. T h e y say t h a t oxygen must be removed because oxygen and hydrogen combine in t h e presence of ANALYSESOF THE COAL GAS O F PITTSBURGH(a) Without With Recalculated from t h e palladium a n d t h e y found t h a t ethylene a n d hydrohydrogen hydrogen Column 1 t o gen form ethane in t h e presence of t h e palladium soluCONSTITUENTS absorption absorption include the ethane coz . . . . . . . . . . . . . . . . . . 2 . 4 2.3 2.4 tion, a n d t h a t even if unsaturated hydrocarbons be Illuminants.. . . . . . . . . . 8.7 8.7 8.7 0 2................... 0.5 0.5 0.5 absent, or present only in negligible quantities, t h e gas co . . . . . . . . . . . . . . . . . . . 1 1 . 8 11.4 11.8 CH4. 37.5 35.0 35.3 mixture must be treated with bromine water, as such 1.1 1.1 CzHs treatment frees t h e mixture of possible traces of sulfur, Hz . . . . . . . . . . . . . . . . . . . 3 5 : 3 35.8 36.4 Nz... . . . . . . . . . . . . . . . . 3 . 8 5.2 3.8 phosphorus a n d arsenic compounds, which, even in , . . 100.0 100.0 100.0 Total traces, retard t h e catalytic effect. (a) T h e analysis mas made over one year ago a n d is slightly different A solution which t h e authors of this paper f r o m some analyses of t h e Pittsburg gas made recently. prepared removed 11.3 cc. of hydrogen per cc. Although t h e hydrogen results should correspond of solution before i t became t o o sluggish t o use. in Columns z a n d 3, t h e agreement is only fair. Theoretically, I cc. of t h e solution should absorb There are given below other analyses made by t h e a b o u t 40 cc. of hydrogen. Long before this theoretical Bureau of Mines. I n one column are shown analyses quantity is obtained, however, t h e solution becomes in which t h e hydrogen a n d methane were determined sluggish in its action. I n analyzing mixtures of hydrotogether b y burning t h e m with oxygen (indicated b y a ) . gen a n d air prepared in t h e laboratory i t was found I n another column are shown t h e results obtained b y t h a t from 6 t o z j minutes were required t o remove t h e absorbing t h e hydrogen with colloidal-palladium solu- hydrogen from mixtures containing from 0.8 t o 30 tion a n d t h e n burning t h e methane1in oxygen (indicated per cent. T o remove t h e hydrogen from coal gas, exhaust gases from gasoline locomotives, a n d from by b). ~
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T H E J O U R N A L OF I h T D U S T R I A L A N D ENGINEERIA’G C H E M I S T R Y
994
Vol. 6, K O . 1 2
gases collected during explosions in mines, a maximum Hanus’ method t h a t i t was considered desirable t o of 30 minutes was required. All determinations were learn t h e values afforded b y this method. Preliminary made by simply passing t h e gas mixture back a n d forth work showed t h a t small variations in t h e method eminto a n Orsat pipette containing t h e solution a n d pro- ployed produced varying results. It has been well vided with glass tubes. T h e removal of t h e hydrogen established t h a t iodine absorption includes not only probably should be performed faster if t h e latter were t h e halogen t a k e n up b y unsaturated compounds, b u t shaken with t h e reagent as in a Hempel pipette. T h e t h a t t h e substitution of halogen for hydrogen with t h e colloidal palladium was obtained by t h e Bureau .from formation of halogen acid occurs simultaneously. Kalle & Company, Germany: 6 g. cost $I j.84. Various methods for determining t h e amount of subI n t h e authors’ opinion t h e advantage of t h e method stitution have been suggested, with t h e view of obtaino v e r t h e use of palladium asbestos or palladium sponge ing a corrected value which would represent t h e addition i s in t h e fact t h a t i t never fails in t h e authors’ ex- only, b u t very little use has been made of them. I t has perience t o work satisfactorily-something t h a t , i n t h e been generally recognized t h a t a n excess of iodine is .authors’ experience, cannot be said regarding t h e use necessary, a n d it has been assumed t h a t all oils are of t h e former substances.’ I n addition, i t can be alike in the amount of excess required. The appended placed in a n ordinary pipette of a gas-analysis ap- results obtained b y us show t h a t this is far from being paratus a n d does not have t o be heated in order t o true. Various quantities of iodine have been suggested excite i t t o action. I t s disadvantage lies in its slow- as t h e proper excess which should be present, b u t pracness of action a n d t h e somewhat troublesome method of tically all of these are given in connection with discussions of t h e Hitbl method, a n d m a y not hold t r u e for regeneration of t h e used material. Hempel2 states t h a t t h e solution slowly loses its t h e Hanus method. Furthermore, there has been a absorbing power even in t h e dark. H e recommends lack of uniformity in t h e use of t h e t e r m “excess of t h a t for each analysis small quantities of t h e freshly iodine.” I n t h e following tables this expression is prepared liquid be used over mercury. T h e authors, used t o mean t h a t percentage of t h e total amount however, have in satisfactofy use a t t h e present time added which remains unchanged a t t h e expiration of one solution t h a t was prepared in January of this year. t h e time allowed for absorption. T h e pipette has been surrounded with black paper. PROCEDURE CHEMIC.4L LABORATORY, BUREAUOF M I N E S , PITTSBURGH, PA.
The method employegl was essentially t h e modification of t h e H a n u s method suggested by Hunt.2 Thirteen a n d two-tenths grams of iodine were dissolved IODINE NUMBER OF LINSEED AND PETROLEUM OILS in I liter of glacial acetic acid (99.9 per cent), a n d 3 cc. By W. H. SMITH A N D J. B. TUTTLE of bromine added. This solution was always allowed Received July 6, 1914 T h e linseed oil used in t h e manufacture of printing t o s t a n d for some days before being used. T h e thioi n k is of t h e so-called “ b u r n t ” type. There are t w o sulfate solution employed was approximately t e n t h general processes for its manufacture-one in which t h e normal, a n d was standardized b y means of potassium oil is heated until t h e vapors t a k e fire a n d continue t o bichromate. Standardization was repeated at frequent burn, t h e oil being allowed t o burn until i t attains t h e intervals. A freshly prepared starch solution was used ; desired viscosity; a n d a second in which t h e oil is heated also a I O per cent solution of potassium iodide, prepared in small amounts a n d kept in a brown bottle. T h e without permitting it t o t a k e fire. B u r n t oil is prepared in several grades, all differing temperature of t h e room was maintained a t 2 5 ’ C. from t h e raw oil i n a n increase of viscosity, specific t o prevent variations caused by change of temperature. gravity, a n d acid number, a n d a decrease in t h e iodine T h e reagents were of standard quality a n d errors number. T h e longer t h e oil is heated t h e greater these caused b y impurities were eliminated b y running blanks with each series of determinations. When i t differences become. I n t h e determination of t h e iodine value of some was desired t o use like amounts of a n oil in a series of b u r n t linseed oils difficulty was experienced i n obtain- tests, 4 g. of t h e oil were dissolved in chloroform ing concordant results. Leeds4 has published some in a 2 0 0 cc. graduated flask a n d t h e solution allowed t o figures for iodine absorption of lithographic oils. K i t t 5 reach room temperature. Ten cc. portions of this has also published a series of results which show de- solution, representing 0 . 2 g. of oil, were measured crease in iodine absorption with increasing viscosity, from a burette. T h e general procedure was as follows: b u t the figures do not agree with those given b y Leeds; T h e exact weight of oil was transferred t o z j o t o their determinations were made according t o t h e Hub1 300 cc. glass-stoppered Jena bottles; t h e required amount method.6 I n recent years this method has been so of Hanus solution was added from a burette. T h e generally replaced b y t h e rapid a n d more convenient mixture was allowed t o s t a n d for exactly 30 minutes in a dark closet; 2 5 cc. of t h e I O per cent potassium iodide 1 G . B. Taylor states, however, t h a t the colloidal palladurn solution does not work satisfactorily on gases obtained by distilling coal a t low temsolution a n d I O O cc. of water3 were added,4 a n d t h e Oct., 1914, p. 845. peratures. See THISJOURNAL, excess of iodine was immediately titrated with thio2 Hempel, Walther, “Contribution t o the Determination of Hydrogen sulfate. a n d Methane in Gas Mixtures,” 2. angew. Chem., 26 (1912), 1841. 3 4 6
Published b y permission of the Director of the Bureau of Standards. J . SOC.Chem. I n d . , 13 (1894). 203. Chem. Rev. Felt. u. Harz I n d . , 8 (1901). 40; J . SOC.Chem. Ind.. 10
