880
I,VDUSTRIAL AND EiVGINEERlNG CHEMISTRY
were tried. A 45 per cent solution of sugar in glycerol was prepared by heating glycerol and sucrose to 130" C. with 0.10 per cent of tartaric acid, and this was tried as the dispersion medium. The refractive index of this solution was 1.4960 a t 25"C., but its viscosity was so high that it stopped the homogenizer when an attempt was made to prepare a wintergreen emulsion. Since no satisfactory dispersion medium of high refractive index was obtained, it was decided to attempt to lower the refractive index of the oil phase by the addition of sufficient quantity of the ethyl esters of coconut oil, prepared by alcoholysis of coconut oil with ethyl alcohol. The essential oils and these esters are mutually soluble. By using a solution of 1 part of oil and 2 parts of ester it was possible to reduce the refractive indices of wintergreen, anise, and cinnamon oils low enough to permit the use of aqueous sugar solution of sufficiently low concentration t o pass through the homogenizer without difficulty. The results of this work have demonstrated that coconut oil ester is a satisfactory material for reducing the refractive index of any essential oil to a value low enough to permit the
5'01. 21, No. 9
use of concentrated aqueous sugar solution as the dispersion medium. Emulsions so prepared were satisfactory from the viewpoint of transparency and stability, but developed a pronounced coconut taste on standing. It is hoped that some other esters more permanent in character than those of coconut oil may serve the same purpose and not develop the objectionable taste on standing. Recommendations
It is recommended to employ 0.25 per cent of gelatin as the peptizing agent for emulsions up to 5 per cent by volume, in order to insure a long period of stability. For higher concentrations of oil, the amounts of gelatin specified in this paper for concentrated orange oil emulsions should be used. Preparation of terpeneless instead of straight oil emulsions is recommended in the case of oils of the terpene variety, such as orange, lemon, and lime. Terpeneless emulsions retain their flavor quality almost indefinitely owing to the removal of the terpenes, which oxidize and produce objectionable taste and odor.
Action of Iron Catalysts on Mixtures of Carbon Monoxide and Hydrogen' Abstract E t i e n n e Audibert a n d Andre Raineau Soc16T6 NaTIoNALE DE RECHERCHES SUR LE TRAITEMENT DES COMBUSTIBLES, VILLERS-SAINT-PAUL (OISE), FRANCE
ABATIER (3) and, more recently, Franz Fischer (2) have studied the catalytic action of the metals of the iron group on mixtures of carbon monoxide and hydrogen. The program of work of the SocibtB Nationale de Recherches has included a study of this catalysis, particularly with a view t o the possibility of its being used for the production of liquid organic products. The present paper is a report of preliminary experiments which, while not presenting a final solution of the problem, do show that this process holds considerable promise. There will be described: (1) The experiments which have led to a selection of the most promising catalysts, (2) the essential properties of these catalysts, (3) an attempt to analyze the mechanism of the catalysis and to discover its defects, (4) the results obtained by the two methods which have been thought most workable.
S
Properties of Metallic Iron
In a previous report (1) it was stated that hydrogen a t 150 atmospheres pressure does not rapidly reduce the hydrate or oxide of iron to the metal when the temperature is below about 450" C. If an iron catalyst, whose reduction from the oxide has accordingly been carried out slowly, is used with a mixture of carbon monoxide and hydrogen a t a total pressure of 150 atmospheres, it is found that a reaction starts a t 250" C. with freshly prepared metal and a t 275-300" C. with metal that has been previously used. This reaction is strongly exothermic and the temperature in the catalyst chamber tends to rise rapidly. The following products are formed: (!)
Methane, carbon dioxide, and water according to the reactions: Abstracted from A n n . ofice natl. combuslibles 1 Received May 6, 1929. liquides, 1988, No. 3, by Daviq F. Smith, Pittsburgh Experiment Station, U. S. Bureau of Mines, Pittsburgh, Pa.
++
++
CO 3H2 CHI H?O (1) 2CO 2H2 CHa COz (2) I n the resulting gas the ratio of carbon dioxide to water varies with the composition of the initial gas, the time of contact, and the temperature of the catalyst. (2) Organic acids, principally or exclusively formic acid, in small quantities not exceeding 0.5 per cent of the weight of the water. The formic acid is quite possibly formed by a secondary reaction between water and carbon monoxide. (3) Carbon, according to the reaction 2 c o +c COL (3) Other things being equal, the speed of this reaction varies with the partial pressure of carbon monoxide and with the catalyst temperature.
+
It is thus concluded that iron prepared by reduction from the oxide does not induce the formation of liquid organic products in a mixture of carbon monoxide and hydrogen a t 150 atmospheres pressure. Properties of Ferric Oxide
When ferric oxide is used in place of metallic iron, a reaction is again noticed in a mixture of carbon monoxide and hydrogen when the temperature reaches 250" C. However, if the catalyst is well cooled to avoid overheating, a t low space velocities not only methane, carbon dioxide, and water, but also liquid organic products are formed. The yield of these liquid organic products, however, rapidly decreases to zero as the oxide is reduced and only methane, carbon dioxide, water, and eventually carbon are formed. Properties of Iron-Alkali Catalysts
Following the work of Fischer, the effect of alkalizing the iron catalyst was determined. To precipitated iron hydroxide were added 2 parts of potassium carbonate to 98 parts of anhydrous ferric oxide. The resulting mixture
I S D U S T R I A L ) .4ND EATGI;VEERISG CHE-WISTRY
September, 1929
881
mas completely reduced by hydrogen a t 150 atmospheres and a t 45&500" C. This catalyst behaved exactly as did reduced iron containing 110 alkali.
96:4, and 946. Based on the ratio of oil to water formed, the mixture with 2 per cent carbonate mas the best, giving a maximum ratio of 0.35.
Properties of Ferric Oxide-Alkali Catalysts
Effect of Addition of Copper
The above iron oxide-alkali catalyst, unreduced t o metal, showed the same behavior as did the unreduced ferric oxide catalyst without alkali. However, the production of liquid organic products contiiiued for a much longer time-several times 10 hours. The catalyst is not permanent and, upon long use, progressive change in the nature of the products and a diminution in the quantity of organic liquids formed per unit time are observed. In the end only reactions 1, 2 , and 3 take place. The rate of this deterioration of the catalyst depends upon the experimental conditions, chiefly the temperature and composition of the gas mixture. The richer the mixture is in hydrogen the longer the organic liquids are formed. The products collect in an oily and an aqueous layer. With n mixture of CO 5H2a t 150 atmospheres, a space velocity jf 3000, and a temperature of 280" C., the following products mere obtained in one experiment: (1) an oil of density 0.7863 produced a t the rate of about 20 cc. per cubic meter of gas; ( 2 ) an aqueous solution of density 1.0028, containing 0.229 equivalents of acid per liter and produced a t the rate of about 85 cc. per cubic meter of gas.
Shortly after the preceding experiments were made (in the early part of 1926), Fischer published a notice of his work on the transformation of carbon monoxide and hydrogen a t atmospheric pressure and stated that the addition of copper to the iron was beneficial. Accordingly, after having shown in the above experiments that the optimum ratio of potassium carboiiate t o ferric oxide is 0.02, the effect of adding copper t o this mixture was determined. The ternary catalyst was prepared by precipitating with alkali a boiling solution of copper and ferric nitrates and adding to the precipitate an amount of potassium carbonate to give a ratio potassium carbonate t o ferric oxide of 0.02. After drying, the mixture was reduced by hydrogen a t atmospheric pressure for about 4 hours a t 200" C. and then for 14 hours a t 300" C. to reduce the copper oxide and not the ferric oxide. It was established, as Fischer indicated, that the copper markedly increases the activity of the catalyst. The improvement is greatest when equal weights of copper and ferric oxide are present. The optimum proportion of carbonate to add to a mixture of equal weights of copper and ferric oxide was now determined. A boiling solution containing the proper proportion of cupric and ferric nitrates was precipitated with sodium carbonate. To the precipitate mas added- varying proportions of potassium carbonate. The mixtures so obtained were reduced as above. The tests were made a t 150 atmospheres and a space velocity of 5000, with a CO 5H2 mixture previously heated to the necessary temperature. The results are presented in Table 11.
+
Properties of Nickel, Cobalt, and Manganese Catalysts
Mixtures of nickel, cobalt, or manganese oxides with 2 per cent of potassium carbonate gave, under the same experimental conditions, no organic liquids. It was therefore concluded that the iron catalysts were the only ones of interest. Promoters for Ferric Oxide
Since only the iron oxide catalysts appeared to be suitable and since some promoting material appeared t o be necessary in order t o prolong their life, mixtures were prepared of ferric hydrate containing for each 98 parts of Fe2O3,2 parts of the following materials: Li2G03,CaC03, SrC03, BaC03, ?IfgcO~,ZnCOa, >InCO3, CuC03, Ag2C03, Crz03, AIt03, No203,WOz, and SiO,. Of these fifteen mixtures only those containing sodium, potassium, or lithium carbonate produced, during the course of the experiment, organic liquids from a mixture of CO 5H2a t 150 atmospheres and a space velocity of 3000. The others gave only reactions 1, 2, 2nd 3. Sodium and potassium carbonate appeared about equally effective; lithium carbonate seemed clearly less effective. With the latter only 10 cc. of organic liquids were produced per cubic meter of gas as against 20 cc. for sodium or potassium carbonate. It was thought that interesting results might be obtained by using ferric hydrate with other salts of sodium or potassium. Accordingly 5 mixtures were prepared containing 98 parts of Fez03 with 2 parts of the compounds KzS04, KQHPO~, KB02, KKO?, and K2S. The last-named catalyst yielded no oil. With the others the results in Table I were obtained under the above experimental conditions.
+
Table I-)
ields w i t h Ferric Oxide Catalysts C o n t a i n i n g Various P o t a s s i u m Salts OIL PER CUBIC COXPOUND METEROF GAS
cc. Sulfate
Phosphate
Borate
Nitrate
11 9 13 19
Since the carbonate seemed to be better than any other alkali salt, the best proportions t o use of this were determined. Mixtures of ferric oxide and potassium carbonate were prepared in the following proportions: 99:1, 98:2,
+
A m o u n t of P o t a s s i u m Carbonate OIL PER CUBIC POlASSIUhf CARBONATE METEROF Gas Per cent Grams 42 1.5 75 1.25 60 0.7,5 20 0.50
Table 11-Optimum
Thus the maximum yield is obtained when 1 per cent of the total mass is potassium carbonate. The catalyst that a p pears to be best has the following composition after reduction a t 300" C.: ferric oxide, 49.5 per cent; copper, 49.5 per cent; potassium carbonate, 1 per cent. The addition of copper, however, does not increase the stability of the catalyst, and in this respect the ternary mixture has the same properties as does the binary mixture. Behavior of Ferric Oxide-Copper-Alkali Catalyst
The catalyst just described was tested with gas mixtures of various compositions, all a t a uniform total pressure of 150 atmospheres and a space velocity of 5000. The results depended to a large extent upon the gas composition. The catalyst tube was 20 mm. in internal diameter and was fitted with a thermocouple well 11 mm. in diameter, leaving an effective cross section of 2 sq. cm. The external surface of the catalyst tube carried 16 longitudinal fins 10 X 95 mm. Since the tube contained catalyst along 7 5 mm. of its length, the cooling surface was 15 sq. cm. per cc. of catalyst. EXPERIMEKTS WITH MIXTURECO 5Hz-The only mixtures with which has been observed neither the formation of carbon nor the presence of carbon dioxide in the products are the GO 5H2mixture and mixtures richer in hydrogen. These mixtures gave more uniform action of the catalyst so that the nature of the products did not appreciably change during an experiment lasting 20 hours. The ap-
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ILIrDVSTRIAL A S D EiYGI-Vh'ERING CHEMISTRY
882
paratus consisted of a catalyst tube, a condenser, and a tube of active charcoal. This arrangement permitted separation of the products into the following fractions: (1) liquid products separated by the condenser, (2) gas and vapors collected by the charcoal, (3) gas in solution in the liquid, which is set free upon release of the pressure, and (4) residual gas which has not been absorbed. The residual gas and the gas from (2) and (3) consist solely of carbon dioxide, hydrogen, and saturated hydrocarbons. The liquid (1) consists of an aqueous and an oily layer. The vapors (2) form a light oil. The combined products in these four groups, from several experiments, gave 100 grams of oil, 7.4 grams of gasoline, and 27.8 grams of aqueous liquid. The gasoline could not be examined exhaustively because of its small amount. However, its density was 0.6765 a t 20" C. A fractional distillation gave 4.2 per cent below 60" C., 21 per cent below 70" C., 42.6 per cent below 80" C., 63.6 per cent below 90" C., 78.0 per cent below 100" C. and 91.5 per cent below 110" C. It seems, therefore, to be a product resembling light gasoline from natural petroleum. The iodine number of the oil indicated 2 per cent unsaturated material. Only slight amounts of aldehydes, ketones, and esters were present. The mixture can thus be considered to consist of saturated hydrocarbons and alcohols. Table I11 gives the results of fractionation of this mixture. Table 111-Fractionation WEIGHT
FRACTIONP E R 40-55' C. 55-750 c. 75-120' C. 120-1800 c. 180-250O C. 250-350" C. Paraffin
Pitch and loss Crude oil
CENT
0.9 8.3 14 3 22.5 22.2 16.1 11.3 4.4 100.0
of Oil Obtained w i t h Ferric Oxide-CopperAlkali Catalyst DENSITY
AT20'C.
....
0.6985
0.7615 0.7800 0.7914 0.805
m. p. 440
....
0.785
ULTIMATE
c
H
COMPOSITE ANALYSIS FORMULA
7 0 %
0
5 0 : 94 66.25 78.33 81.37 84.20
13:22 3i.84 12.71 21.03 14.30 7 37 13.78 4 . 8 5 1 4 , 6 8 1 12
79:26
14:30
...
, . .
OFFRAClION
%
..
6:44
. . . .. . .
CH2.2 00.12
In certain fractions the alcohols were separated from the hydrocarbons. In the 120-180" C. fraction the alcohols represented 50.6 per cent of the total weight. The hydrocarbon residue from this fraction contained 83.83 per cent carbon and 15.83 per cent hydrogen. The mixture of alcohols from the fraction 0-330" C. was separated by distillation into two fractions, 95-160" C. and 16Ck270". From the saponification values the average molecular weight of the alcohols in the first fraction was 100, which corresponds t o CsHI30H; from the second fraction the average molecular weight was 200, which is intermediate between C14H290H and C15H110H. The paraffin fraction separated into a wax melting a t 52-53' C. and containing 85.31 per cent carbon and 14.67 per cent hydrogen; and into a mixture of alcohols melting a t 32-38' C. and having an average molecular weight of about 357. Table IV-Summary
of Liquid Products Obtained w i t h Ternary Catalyst Per cent
Light hydrocarbons: Fraction 55-180' C . From active charcoal Alcohol in solution Fuel oil 180-250' C. Heavy Ail, 250-330' C. Paraffin Pitch Acids
Total organic liquids Water
28 5 29 14 10 7 2 3
8 0
0 0 0 1
7 4
100.0 143.0
The aqueous liquid had a density of 0.97 a t 20" C. and contained 7.14 per cent carbon, 11.27 per cent hydrogen, and 81.59 per cent oxygen. It contained about 2 per cent of acid distilling between 110" and 140" C., which was apparently a mixture of acetic, propionic, and butyric acids.
Vol. 21, No. 9
16.6 per cent of the aqueous liquid consisted of alcohols distilling between 72" and 90" C. Of the latter, 31 per cent boiled between 72.5" and 74.5"C.; 22 per cent to 76" C.; 17.5 per cent to 78.5" C.; 9.5 per cent to 80" C.; and 20 per cent to 90" C. Table IT' gives a summary of the liquid products obtained. A complete materials balance was attempted. From an experiment a t 144 atmospheres pressure, a temperature of 380-360" C., and a space velocity of 4700, the following products were obtained per cubic meter of initial gas: (1) 646.6 liters of gas consisting of hydrocarbons and unreacted gas, (2) 110.5 grams of aqueous liquid, (3) 27.2 grams of oil. The hourly production per liter of catalyst was 3050.5 liters of gas, 520 grams of aqueous liquid, and 107 grams of oil. In 2 hours the carbon, hydrogen, and oxygen in the reacting gas had been converted into (1) gaseous hydrocarbons containing 3.225 gram atoms of carbon and 9.15 gram atoms of hydrogen; (2) water containing 10.1 gram atoms of hydrogen and 5.05 gram atoms of oxygen; and (3) organic liquids containing 2.54 gram atoms of carbon, 6.35 gram atoms of hydrogen, and 0.715 gram atoms of oxygen. The reaction may be represented by 100 CO
+ 222 Hz +56 CH2.84 + 44 CHz.,Oa.,a + 87.5 He0
(4)
If it is imagined that a space velocity is used such that all the carbon monoxide is converted (conversions up to 80 per cent have been obtained) and that the unused hydrogen is recovered, the apparatus would need to be supplied with a 2.22 H1. The transformation of a cubic mixture CO meter of this mixture will furnish (1) 115 grams of the mixture of methane, ethane, and propane having an average composition corresponding to ethane and a heating value of around 10,000 calories per cubic meter; (2) 116 grams of a mixture of saturated liquid hydrocarbons and alcohols; and (3) 219 grams of water. EXPERIJIEI~TS WITH A hlIXTURE CONTAINIKG LESS T H A S 83 PER CENTHYDROGEK-ivith gas mixtures less rich in 5H2 the results are as follows: hydrogen than CO
+
+
The yield of organic liquids drops off rapidly in proporthe increase in the ratio CO:Hz, and finally drops to zero. The formation of carbonaceous deposits on the catalyst increases as the ratio CO:H2 increases. (3) Carbon dioxide appears in the residual gas. (4) The character of the gasoline, aqueous liquid, and oil is substantially unchanged ; the only difference is an increased yield, which may be divided into a slight decrease in the proportion of the lighter products and an increase in the average molecular weight of the heavier products. ( 5 ) When the gas mixture becomes richer in carbon monoxide HZ, the following are the principal reactions: than 2CO 211 CO (n l ) H z -+ C,H,, n Cod (5) (an - 1)CO (n 1)Hz C,Hz,+iOH (n - 1)COr (6) (6) ,Owing to the irregular action of the catalyst no general conclusions can be drawn from the materials balance.
+
+ +
+ +
+ +
Mechanism of Process
Ferric oxide appears to be the active constituent of the catalyst which produces organic liquids-not metallic iron or ferrous oxide. A catalyst that has deteriorated in use, owing t o reduction of the ferric oxide, may, upon using a gas rich in hydrogen, be rejuvenated to a slight extentprobably owing to oxidation of the reduced material by the excess of water vapor which occurs under these conditions. The interesting results obtained by adding a large excess of water vapor t o the gas to keep the ferric oxide from reducing will be presented in another report. Addition of alkali carbonate lengthens the life of the catalyst either by slowing down the reduction of the ferric oxide or, more probably, by facilitating reoxidation of the reduced catalyst.
September, 1929
IiVD GSTRIA Li A N D ENGINEERING CHEMISTRY
I n order to determine whether organic liquids are formed by the action of hydrogen on carbides formed by the action of carbon monoxide on the iron, as suggested by Fischer, hydrogen was passed over the carbonaceous material formed by passing carbon monoxide through the catalyst. The experiment was tried in two cases in which the mass of carbonaceous material ("carbide" of iron) had the composition given in Table L7. of Carbonaceous Material Whose C a t a l y t i c Action Was Tested A B Per cent Per cent . . m 66.2 Iron l'.,, 1 92 Potassium carbonate 0 37 11.25 Carbon 82.19 0 29 Hydrogen 0 9s5 20 38 Oxygen 3 685
Table V-Composition
0
S o organic liquids were obtained in either case. Operation of Ternary Catalyst a t Low T e m p e r a t u r e a n d Pressure
By operating a t low temperature and low pressure it was thought that reduction of the ferric oxide might bt: prevented. Certain Nernst approximation formula calculations indicate that the higher hydrocarbons are still thermodynamically capable of forming a t atmospheric pressure and 250" C. It is thought that alcohols are not thermodynamically capable of forming under these conditions. The formation of liquid hydrocarbons a t atmospheric pressure and low temperatures, as reported by Fischer and Tropsch in 1926, using a catalyst similar to the ternary catalyst described above, had been undertaken by the present authors before Fischer's report was published Using a space velocity of 40 to 50 and a temperature usually slightly below 250" C., gaseous and liquid hydrocarbons, water, and carboq dioxide were formed. The highest yield of liquid hydrocarbons ever obtained was 10 grams per cubic Hz. No carbon formation was observed. meter of CO The ferric oxide is slowly reduced by the HP CO even a t atmospheric pressure and 240" C. Considering the low yields, the difficulty of temperature control, and the possible clogging of the catalyst by heavy products a t these low temperatures, it is thought that the low-pressure process is not so advantageous as the high pressure process.
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S t u d y of Catalysts i n Which I r o n Is in F o r m of a Salt
It appeared possible to improve the catalyst by using the iron in the form of a non-reducible salt in order to avoid the deterioration caused by the gradual reduction of the ferric oxide. However, it was thought of interest first to try replacing the iron by a metal whose oxide would not reduce and which would promote any catalytic action that the copper might have. Accordingly, a catalyst of the following atomic proportions was prepared: Cu, 1; Mn, 1; Fe, 0.02; K, 0.02. A boiling solution of the nitrates of copper, manganese, and iron was precipitated by potassium carbonate. The proper amount of potassium carbonate was then added to this precipitate. The mixture was reduced for 3 hours a t 200" C. and then for 14 hours a t 300' C. A gas mixture, CO H?, was passed over this catalyst a t 150 atmospheres. The products obtained-gaseous saturated hydrocarbons, aqueous liquid, and oil-were of the same character as those obtained with the ternary catalyst described above. The hourly production per liter of catalyst with space velocities from 4000 to 10,000 was, respectively, 200 to 300 grams water and 200 to 600 grams oil. Carbonaceous material was formed on the catalyst with a gas rich in carbon monoxide, as before. Thus the action of the quaternary catalyst in which manganese replaces most of the iron is identical with that of the ternary catalyst.
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883
PREPA4R.4TIoN O F CATALYSTS I N W H I C H THE IRON W A S IN FORM OF A SALT-The exact amount of acid to use could
not be decided in advance because (1) it was not known whether a normal or basic salt should be used, (2) it was desired not to use any more of the acid than absolutely necessary, since it acts as a diluent of the active material in the catalyst, and (3) it was not known how the acid would distribute itself among the various metals present. The following three methods were used in preparing the silicate, phosphate, or borate catalysts: (1) A boiling mixture of the nitrates of copper, manganese, and iron was precipitated by a mixture of soda and sodium silicate, sodium phosphate, or sodium borate. (2) Ferric hydrate was mixed with the acid. The product so obtained was placed in suspension in the soda solution used to precipitate the solution containing the nitrates of copper and manganese. (3) Ferric hydrate and acid were mixed as in (2). This was mixed with the solution of the nitrates of copper and manganese, and the whole was precipitated a t the boiling temperature by soda. In all cases the proper amount of potassium carbonate was added to the resulting paste.
Table VI shows the atomic proportions and method of preparation of the catalysts which were tested: Table VI-Proportions of C o n s t i t u e n t s a n d M e t h o d of P r e p a r a t i o n of Catalysts i n Which I r o n I s i n F o r m of a Salt SILICON, METHOD MANPHOSPHORUS, O F P R E P A COPPER GANESI? IRON POTASSIUMO R BORON RATION Atoms Aloms Atoms Atoms Aloms 0.02 0.03 0.10 0.02 0.025 0.30 0.02 0.03 1.00 0.02 0.02 0.02 0.02 0.02 0.01 0,025 0.30 0.02 0.02 0.02 0.02 0 02 0.02 0.10 0.02 0.025 0.30
QUALITATIVE TEsTs-The twenty-seven catalysts described Hz a t 150 atmosabove were tested using a mixture CO pheres and a space velocity of 10,000. The tests usually lasted 3 or 4 days. The yield was determined a t '/?-hour intervals. After the test the catalyst was carefully examined and weighed in order to determine whether carbonaceous deposits had formed. Carbonaceous material was deposited on the catalyst in the following cases: (1) with all silicate catalysts; (2) with phosphate and borate catalysts prepared by method (1); (3) with borate catalysts prepared by method ( 2 ) or (3) and containing only 1 B to 1 Fe; (4) with borate catalysts prepared by method (3) containing 5 or 15 B to 1 Fe when the temperature exceeded 450" C. Xot a trace of carbonaceous deposit on the catalyst was observed, even after long operation, in the following cases: (1) with phosphate catalysts prepared by methods (2) or (3); (2) with borate catalysts containing 5 or 15 B to 1 Fe when prepared by method ( 2 ) or (3) when the temperature did not exceed 450" C. In the case of the last two catalysts, the yield of organic liquids dropped off no more rapidly than could be accounted for solely by the effect of the heating-an effect such as is noticed in the case of the methanol catalysts which contain copper. Thus it appears that these catalysts solve the problem of the formation of carbonaceous material on the catalyst and a t the same time possess satisfactory catalytic properties for the formation of organic liquids. The phosphate catalysts containing 15 P t o 1 Fe do not appear to be as active as those containing 10 or 5 P t o 1 Fe. With the borate catalysts, however, the catalyst containing 15 B to 1 Fe seems to be as active as that containing 5 B to 1 Fe. PRODUCTS FORMED I N CoNT.4CT WITH IRON PHOSPHATE
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I X D C S T R I A L AiYD ENGIhTEERISG CHEMISTRY
884
AND BORATE CATALYSTS-Tests have been made using the gas mixture CO -I- 1.25 HZa t a pressure of 150 atmospheres and a space velocity of about 10,000. The products obtained with the two catalysts and a t temperatures from 380" to 450" C. did not seem appreciably different, so they were combined. Examination of these products yielded the following results:
(1) Gas. A mixture of carbon dioxide and saturated hydrocarbons, the composition of the latter being about CHS.z; ( 2 ) Liquids. Aqueous and oily layers. ( a ) The aqueous liquid is formed in the proportion of 60 or 70 grams to 100 grams of oil. Its composition is the same as that obtained with the ternary catalyst described above and contains, in addition to very small quantities of acids and other products, 40 per cent of aliphatic alcohols distilling below 180' C. and having an average molecular weight close to that of ethyl alcohol. ( b ) The oil and gasoline were mixed. The mixture is a dark green, fluorescent, slightly viscous liquid similar to crude petroleum. Its density is 0.805 a t 15" C. It was distilled a t atmospheric pressure up to 330" C. and then in a vacuum. The results are given in Table VII. T a b l e VII-Fractionation
of Oil Obtained w i t h Iron P h o s p h a t e a n d Borate Catalysts TEMPERATURE OF WEIGHT VOLUME APPEARANCE OF DISTILLATIONPER CENT PER CENT DENSITY PRODUCT o
The mean molecular weight of the first alcohol fraction is 87 and of the last fraction, 357 (Table IX). YIELDS WITH I R O N PHOSPHATE .4ND BORATEc.4Ta4LYSTSThe quantitative data for four tests using two different catalyst samples are recorded in Table X. The materials balance for two typical experiments, made under practically identical conditions, are given in Table XI. Table XI-Materials
B a l a n c e for T w o Typical Experiments MATERIAL I N 1 CUBICMETEROF ENTERING GAS I N EACHEXPERIMENT Carbon Hydrogen Oxygen G r a m a l o n s G r a m atoms G r a m atoms
As 0 2 As co As H2
Total
(1) In gas: As CO? As 0 3 As co AS
59.0
61.5
0.773
180-200 2 50- 350
16.3 18.5
16.0 18.0
0.624 0.827
3.1 2.9
3.0 1.0
Paraffin Tar and losses
Clear yellow product, very mobile Pale yellow liquid Dark yellow liquid, slightly fluorescent Yellow solid
Taking into account the formation of 25 grams of alcohol with 100 grams of oil, about two-thirds of the organic liquids distilled below 180' C. The results of ultimate analysis of the above fractions are given in Table VIII. T a b l e VIII-U1timate FRACTION 30-180' C. 180-2500 c. 250-350O C. Paraffin Raw product
Analyses of Fractions Indicated i n Table VI1 HYDROGEN CARBON OXYGEN Per cent Per cent P e r cenl 12.87 75.60 11.53 1 2 . 7 0 7.70 79.60 13.25 3.85 82.90 12.90 0.90 86.20 13.70 9.00 77.30
The elementary composition of the raw organic liquid w. With this gas, which corresponds to the formula CH2.1300 contains a small proportion of hydrogen, more unsaturated material was formed. For example, the 30-180" C. fraction is soluble in concentrated sulfuric acid to the extent of 25 per cent and adds 87 per cent of its weight of iodine. There is every indication that the greater part of the products was aliphatic and only a negligible part naphthenic. The alcohols were separated from the hydrocarbons in the gasoline, kerosene, and paraffin fractions. The results are given in Table IX. of Alcohols a n d Hydrocarbons i n Fractions Indicated i n Table V I 1 GASOLINE KEROSENE PARAFFIN (30° to 180O C ) (180O to 250' C )
T a b l e IX-Separation FRACTION
HYDROCARBOhS
Weight, per cent Density at 15' C.
61 5 0 741
Weight, per cent Density at 15' C.
36.5 0.807
70 0 0 807
80 0 (m p. 52 53' C )
ALCOHOLS
Table X-Quantitative
YIELD
20.0 (m. p. 34.35' C.)
D a t a for Four T e s t s on I r o n P h o s p h a t e a n d Borate Catalysts
Pressure, kg. per sq. cm. Space velocity Temperature. O C. Oil and gasoline, grams Aqueous liquid, grams Gas, liters YIELD PER Oil and gasoline, grams Aqueous liquid, grams Gas, liters
30.0 0,823
160 8100 380
PER
157 8460 425
152 11350 450
153 10200 390
CUBIC METER OF GAS
48 40.7 620
53 30
711
66 25 624
HOUR PER LITER OF CATALYST
380 332 5024
270 210 4916
750 290 6963
50.5 31.5 651 512 320 6621
-
-
-
19.28
49.0
19.93
XIATERIAL RECOVERED PER CUBIC METEROF ENTERING GASI N TWO EXPERIMEFTS, a AND b a b a b a b 5.10
4.67
6.05
8.05
3.14 3.30 0.65
2.61 3.36 0.55
...
...
H2
As hydrocarbons (2) In oil (3) In aaueous liquid
Total Error, per cent
...
...
...
...
.. .
, , ,
3 0 ' 4 6 30150 10 00 9.51 6 25 6.60 4 73 3.75
---__-__ 18.24 -5.3
r
30-180
Vol. 21, No. 9
19.44 51.44 +0.9 +5.0
50.36 +2.0
10.20 6.05
9.34 0.42 8.05
0.21 1.72
0.22 1.33
0.86
... ...
...
...
18.74 19.36 -5,s -1.7
Data from the experiments recorded in Tables X and X I give the results recorded in Table XI1 for the distribution of the carbon and hydrogen in the products of reaction. of Carbon a n d Hydrogen in T o t a l Products CARBON HYDROGEN P e r cent P e r cenf As carbon dioxide or water vapor 42 5 * 1 0 190 * 4 0 As gaseous hydrocarbons 270 * 2 0 470 * 4 0 As organic liquids 3 1 0 * 2 0 350 * 4 0 Table XII-Distribution
Since the average composition of the gaseous hydrocarbons is CH,., and that of the mixture of liquid hydrocarbons and alcohols is CHZ.ZOO.~~, the complete reaction may be represented by 100 CO 175.85 Hz -30.75 CHz ZOO12
+
+ 26.78 CHI. + 42 5 COz f
11.3 Hz0
(7)
Thus, the conversion of 1 cubic meter of gas mixture of the composition CO 0.879 H P , weighing 707 grams and having a higher heating value of 3680 calories, gives the quantities of materials recorded in Table XIII.
+
Table XIII-Summary
of Q u a n t i t i e s of Material f r o m 1 Cubic Meter of G a s Grams
Organic liquids Gaseous hydrocarbons Carbon dioxide Water vapor
11s 97 444 4s
The higher heating value of the organic liquids is of the order of 9000 calories per kilogram; and of the gaseous hydrocarbons, 12,000 calories per kilogram. The heating value of the gas converted is, then, distributed in the products in the manner recorded in Table XIV. Table XIV-Distribution
of H e a t i n g Value of G a s Converted Per cent
Organic liquids Gaseous hydrocarbons Sensible heat liberated
28.8 31.6 39.6
Thus, it has been shown that the production of organic liquids can be carried on effectively and continuously in contact with the catalysts just described. These last catalysts permit a conversion of 15 to 17 weight per cent of the gas to a combustible liquid. Twenty-five to 30 per cent of the heating value of the gas appears in the liquid products and about an equal quantity appears in a gas having a heating value of the order of 10,000 calories per cubic meter.
September, 1929
I N D U S T R I A L AiYD E S G I S E E R I S G CHEMISTRY
S u m m a r y a n d Conclusions
1-In contact with catalysts containing ferric oxide, the gas CO 4 H2 a t 150 atmospheres pressure is converted into (1) liquid and gaseous hydrocarbons, saturated and unsaturated; (2) aliphatic alcohols. 2-Industrial application of this process may be possible if it can be operated under conditions such that the ferric oxide is not reduced during use. Temperature control does not suffice to prevent this reduction, but by combining the iron with phosphoric or boric acids it appears that the reduction is prevented. The best catalysts are complex mixtures which have been arrived a t by trial. Although very interesting results have been obtained with them, it is practically certain that the best combination of the constituents has not yet been realized. 3-The organic liquid obtained has a heating value of about 9000 calories per kilogram, and two-thirds of it dis-
885
tils below 180” C. It appears that suitable treatment of this liquid would yield valuable products. 4-Although the yield of organic liquid so far obtained is only about 15 to 17 per cent in weight and 25 to 30 per cent in heating value, nothing indicates that the yields could not be improved. As a matter of fact, the catalyst composition is so arbitrary and so little is known about the catalytic effect of the various constituents of the catalyst, that it seems probable that further work may lead to very important results. Literature Cited (1) Audibert and Raineau, A n n . o 3 c e natl. cornbusiibles l i q u i d e s , 1927, No. 4; Rev, i n d . mint?i.de, January 15, 1928; IND. ENG.CHEX, 20, 1105
(1928).
(2) Fischer, Series of papers in B r e n n r l o . f - C h e n i e and elsewhere. ( 3 ) Sabatier, “Catalysis in Organic Chemistry.” D. Van h’ostrand Xew York, 1922.
Co.,
AMERICAN CONTEMPORARIES Richard Newman Brackett
T
0 E N JOY so large a measure of the esteem and confidence In connection with the performance of the duties of these posiof one’s colleagues and co-workers as to be called on times tions he has carried out much important investigational work and has published a number of interesting bulletins and papers, without number t o discharge tasks and assignments that much of this work having been done in demand thoroughness and efficiency should collaboration with J. H. Mitchell, t o whom occasion a feeling of satisfaction and pride the writer is greatly indebted for material in the man whose friends so regard him. furnished for use in this sketch. Such a man is Richard h’ewman Brackett, A notable contribution to the program of director of the Department of Chemistry the Section of History of Chemistry of the of Clemson College, S. C., and chief chemAmerican Chemical Society a t its meeting ist in charge of state fertilizer control, whose capacity and ability to perform well the in Richmond in April, 1927, was his paper on “Thomas Green Clemson, The Chemvarious commissions delegated to him have ist,’’ giving some very interesting side lights led his fellow members of the Association on the character and achievements of this of Official Agricultural Chemists to draft distinguished South Carolinian, the son-inhim time after time for service in various law of John C. Calhoun, who donated the outstanding phases of the work of the association. old Calhoun estate to the State of South The subject of this sketch was born near Carolina as a site for the land grant college Columbia in Richland County, S. C , Sepwhich bears his name. tember 14, 1863. His early education was As a member of the Association of Official obtained in private schools of Charleston, Agricultural Chemists, Doctor Brackett has while his collegiate training was received been a constant attendant upon its meeta t Davidson College, N. C., from which ings for two decades and has contributed institution he graduated with the degree of much to the success and interest of its proA.B. i n 1 8 8 3 . His graduate work was grams, having served as referee in several pursued a t Johns Hopkins U n i v e r s i t y , divisions of the association work, including where he received the Ph.D. degree in 1887. the position of general referee on fertilizers From 1887 to 1891 he was chief chemR i c h a r d h-ewman Brackett which he filled most capably for a number ist of the Arkansas Geological S u r v e y , of years, while his reviews of the work of and in connection with the performance of the duties of that the association along several lines of investigation have proved position he accomplished some important work in the identimost helpful and interesting to its members. He served as presification of minerals. In collaboration with J. Francis Williams, dent of the association in 1916 and has continued to be active in two new minerals of the kaolinite group, Newtonite and Rec- the furtherance of the objects and purposes for which that body torite, were discovered. In 1891 he came to Clemson College was formed. as associate professor of chemistry and assistant chemist of In addition to his membership in the A. 0.A . C., he has been a the South Carolina Experiment Station, serving in the latter member of the AMERICAN CHEMICAL SOCIETYsince 1887, is a capacity until 1907, at which time the work of the Department fellow of the Association for the Advancement of Science, and a of Chemistry and of the Experiment Station was separated. In member of the South Carolina Academy of Science. 1911 he became director of the Department of Chemistry and As the head of his department and as an instructor he has chief chemist in charge of fertilizer control, and in 1920 he was rendered notable service to his institution and to the students who made chief chemist of the South Carolina Experiment Station. have sat under his teaching. To the latter he has proved, not
