Catalysts for Hydrocarbon Synthesis - American Chemical Society

1 Present address, Tidewater Associated Oil Company, Bayonne, N. J. synthesis. As the hydrogenating component of the catalyst, cobalt, nickel, or iron...
0 downloads 0 Views 620KB Size
Catalysts for Hvdrocarbon Synthesis J

J

J

c, H. RIESZ AND FRED LISTER1, Institute of Gas Technology, Chicago, I l l . L. G. S3’IITH AND V. I. KOMAREWSKY, Illinois Institute of Technology, Chicago, I l l . Hydrocarbon synthesis catalysts are regarded as “cornplex-action” catalysts combining the two functions of hydrogenation and polymerization. Although complicated by carrier and promoter effects, the above was substantiated by the preparation of two-component catalysts containing niclcel, Or iron for the hydrogenating action; thoria, silica, a l ~ m i n a or , zinc oxide proved suitable as Polymerizing ComPonents. Cobalt-thoria, cobaltsilica, and cobalt-alumina were particularly active as catalysts, optimum liquid formation occurring when t h e ‘Ontent Of the was 75 weight %. catalysts produced excessive amounts of gaseous hydrocarbons but iron catalysts, i n t h e absence of elevated Pressure, were relatively inactive.

synthesis. As the hydrogenating component of the catalyst, cobalt, nickel, or iron was employed and thoria, silica, alumina, or zinc oxide served as polymerizing agents. PREPARATION OF CATALYSTS

-411 catalysts used in this investigation were prepared by COprecipitation. Calculated amounts of acid or base were added to the reacting solution to give neutral products. T o assure the formation of a thoroughly uniform product, the operation waa carried out under continuous and vigorous stirring. Care waa also taken t o maintain a temperature of precipitation between 00 and 1 5 O c. The products were thoroughly washed and redispersed in water under vigorous stirring until the test for anions was negative. ALumxa CATALYSTS.Alumina catalysts were prepared by formation of sodium aluminate from aluminum nitrate and hydroxide, which in turn was used to precipitate the metal hydroxide. Depending on the composition desired, nitric acid was added t o the metal nitrate or sodium hydroxide t o the aluminate t o obtain neutralization and complete precipitation.

T



HE production of liquid hydrocarbons from carbon monoxide and hydrogen has assumed industrial significance in this country because gas suitable for synthesis can now be manufactured from natural gas a t low costs ( 3 ) . That the 0 v e r - d synthesis of gasoline from natural gas may prove competitive t o gasoline produced from crude oil in the near future is evidenced by the erection of plants a t Brownsville, Tex., and Hugoton, Kan. A study of the various factors in the synthesis of higher hydrocarbons (9) discloses that one of the most important is the catalyst for the conversion of carbon monoxide-hydrogen mixtures into liquid hydrocarbons. The subject of these catalysts has been studied intensively for over 20 years and a review of the literature reveals t h a t over 100 different catalyst combinations have been reported (IO). Almost all of these catalysts contained three or more ingredients; however, for use at atmospheric pressure, selected combinations of cobalt, thoria, and kieselguhr have been generally accepted as the most active and useful (4). Later work has shown t h a t a portion of the thoria could be replaced by magnesia t o effect a harder form of catalyst for industrial use (1, 7 ) . The role of the catalyst components has been only vaguely understood. Analyzing the possible role of constituents of the mixed catalysts, one might consider that metals such as nickel, cobalt, and iron perform the function of hydrogenating carbon monoxide t o methylene, and oxides such as thoria, silica, magnesia, and alumina act as polymerizing agents in combining methylene into hydrocarbon groupings. In short, hydrocarbon synthesis catalysts might be regarded as “COmPleX-aCtion” catalysts (11), combining the two functions of hydrogenation and polymerization. On the other hand, the polymerizing oxides can also serve as carriers for the hydrogenating metal and in such capacity act to stabilize the catalyst Surface or as Promoters t o enhance the catalyst activity. I n view of these considerations it becomes evident t h a t for each combination of hydrogenating metal and polymerizing oxide there must exist an optimum ratio of metal t o oxide which will produce a maximum conversion to liquid hydrocarbons. The present work demonstrates t h a t the above principles can be applied to Catalysts fo hydrocarbon 1

2NaA102

+ hf(ITO&

4

M2O3

+ AI0 + 2ITaN03

(1)

Catalysts prepared by this procedure had the compositions shown in I. CATALYSTS. Sodium hydroxide was added slowly t o a dilute solution containing cobalt and thorium nitrates. The compositions Of the finished were: Metal Cobalt

Oxide Thoria

Wt Ratio of Metal t o Oxide

Active Metal in Finished Catalysts Weight Yo

100 : 54

65 75 85 95

100 33 100 18 100:s

ZIXC OXIDE CATALYST.Use was made of the solubility of zinc oxide in sodium hydroxide and, as in the case of the alumina catalysts, the precipitation was effected by the reaction of sodium zincate with metal nitrate. NazZnOs

+ M(NO&

--t

ZnO

+ MO + 2Nan’03

(2)

The catalyst prepared bJ, this method had a 100 t o 33 weight ratio of metal t o oxide and the active metal content of finished catalyst was 75 weight %. s I L I c A CATALY~T. For the coprecipitation of silica with a metal hydroxide, a commercially available water glass was used, containing 62.1% tvater, 29.0% silica, and 8.9% sodium oxide. I n the preparation of this cstalyst more sodium hydroxide waa required for the neutralization of the nitrate than was available in the calculated amounts of water glass. Therefore, additional base was included with the water glass. The weight ratio of cobalt to oxide was 100 t o 33, and the active metal content of finished catalyst was 75 weight %. sTaNDARD cATALYST. cobalt-thoria-kieselguhr (100 to 18 to 100) was prepared according t o the method of the Fuel Research Board (6, 6 ) . The kieselguhr used was Johns-Manville Ceiite catalyst carrier, Type I11 (Snow Floss). The weight ratio of

Present address, Tidewater Associated Oil Company, Bayonne, N. J.

718

April 1948

INDUSTRIAL AND ENGINEERING CHEMISTRY

719

systems. The gas was metered with a wet-test meter and after drying with OPPER TURNINGS silica gel-Drierite the synt h e s i s g a s e n t e r e d the reactor. Heavy hydrocarbons and most of the water formed in the reaction over the catalyst were condensed in a water-cooled condenser. To remove the last traces of water a Drierite tube was employed after the condenser. Light hydrocarbons were then condensed in a trap, maintained at about -80" C. with a dry ice-acetone mixture. Condensable gases (C, and C4 hydrocarbons) were vaporized from the trap and collected. Provisions were made to take samples of the residual gas after the dry ice trap. The residual gases were metered through the outlet wet-test meter. About 80 t o 90 cc. of c a t a 1y s t w e r e usually charged into a reaction tube and while the unit was brought up to temperature (165' to 175' C.), nitrogen was flushed through the system. The nitrogen flow was checked with the inlet and outlet gas meters and in this manner leaks could Figure 1. Apparatus for Hydrocarbon Synthesis be detected. As soon as the unit was found to be tight, hydrogen was passed through i t and the temperature raised stepwise t o 375' or 400' c. cobalt to thoria-kieselguhr was 100 to 18 t o 100 and the active and kept a t this temperature for at least 16 hours. The total metal content of finished catalyst was 46 weight %. time allowed for the reduction was about 72 hours and between 100 and 200 volumes of hydrogen $e. volume of catalyst per hour were passed over the catalyst. DESCRIPTION AND OPERATION OF EXPERIMENTAL UNIT Each experimental period lasted for about 24 hours and at the end of each period the water-condensable materials were weighed, The reactor consisted of a salt bath containing the reaction the amount of condensable gases was determined, and a gas tubes. The salt bath was a n open steel vessel, 20 cm. in inside sample was taken. Then the temperature was raised 10" C. diameter by 70 cm. long, charged with Du Pont heat treating Each catalyst was tested a t a variety of reaction temperatures, salts NO. 2. Steel tubes 81 cm. long and 16 om. i n inner &amranging from 150'to 300 C. eter passed through i t and served as reaction chambers. At the end of the experiment the unit was allowed to cool The salt bath was heated electrically and its temperature conwhile the catalyst was maintained under nitrogen. The catalyst trolled by means of a Wheelco Capacitrol. The reactor was inwas then discharged, weighed, and extracted with benzene in a sulated with a 8-cm. layer of refractory insulation encased in a Soxhlet apparatus to remove any collected waxes. Transite tube of 40-cm. diameter; for the support of the catalyst a stainless steel funnel was used. The flow sheet (Figure 1) shows the complete arrangement of AS it was found possible t o duplicate results within 5%, ail the experimental unit. Carbon monoxide-hydrogen mixture data are believed sufficiently accurate to make comparisons t o from a cylinder was purified from iron carbonyls by means of an evaluate catalytic phenomena. A number of tests were run in activated silica trap and from sulfur by passage over copper at 400' C. An Ascarite trap was installed to remove acidic gases. each case t o obtain optimum yields of liquid hydrocarbons. The trap was followed by two bubblers, pressura regulator, and flowmeter. From there the line was connected t o a manifold GAS* Synthesis gas was Obtained in two ways. through which the purified gas passed t o one or more reactor It was purchased from the Matheson Co., Rahway, N. J., the ratio of hydrogen t o carbon monoxide being approximately 2. A representative gas analyzed: 32% carbon monoxide, 65.6% hydrogen, 1.6% nitrogen. If desired, mixtures in varying proportions were made by blending carbon monoxide (Matheson TABLE I. ALUMINACATALYSTS Co.) with hydrogen (Air Reduction Co., Chicago, Ill.). Wt. Ratio Active Metal in O

Metal Nickel

Oxide Alumina

Cobalt

Alumina

Iron

Alumina

of Metal to

Oxide

100:1330 100:566 100:300 100: 100 100:33

Finished Catalyst, Weight %

7 15 25 50 75 25

75 50 100:300 100: 100

25 50

ANALYTICAL METHODS

The analyses of the synthesis gas and the effluent gases were carried out in a Gockel gas analysis apparatus (IS). This procedure tests for the various constituents by absorption-combustion procedures. For the paraffins, a "parsffin index" is obtained which is the value of n in the general formula, C,H2,+ ?. The Cs-Cd fractions were analyzed in a Bodbielniak HydRobot low temperature, fractional distillation apparatus.

720

INDUSTRIAL AND ENGINEERING CHEMISTRY 5

I

I

5

I

I

Vol. 40, No. 4

I

$ $

60

Pa

3

0

a n 40 > I 0 3

5

20

k a

w2 >

o

METAL

0

20

40

60

80

100% BY WT.

ALIOS

100

80

60

40

20

0% BY WT.

Figure 2.

Effect of Metal Content of Catalyst upon Liquid Hydrocarbon Yield

0 METAL AL,Oa

0

eo

40

100

80

60

6o 40

BO

100% BY WT.

20

0 % BY WT.

I

Figure 3. Effect of &letalContent of Catalyst upon Total Hydrocarbon Yield

DISCUSSION OF RESULTS

It was demonstrated in the work that two-component catalysts comprising a hydrogenating meta,l and a polymerizing oxide can be prepared which are as active in producing liquid hydrocarbons as the standard multicomponent catalyst (Table 11). The best, catalyst combinations were found t o be cobalt-thoria, cobalt-silica, and cobalt-alumina. In Table I1 it can be observed that cobalt-thoria gave both the highest liquid yield and the lowest gas yield, thus demonstrating the unique effectiveness of this particular combination for liquid hydrocarbon synthesis. Silica, alumina, and zinc oxide gave, respectively, lower yields of liquids and increased formation of gaseous hydrocarbons. [ I n the case of zinc oxide, a t a space velocity of 229 the liquid yield was increased t o 33 grams per cubic meter; simultaneously, the yield of gases increased to 183 grams per cubic meter which was predominantly methane (9570). I t is believed that the high methane formation in this init'ance can be attributed t o local overheating obtained with this catalyst of low bulk density.] Xckel in combination with alumina produced an active synthesis catalyst, although the strong hydrogenating influence of the nickel in promoting gas formation (mainly methane) is evident. Iron catalysts were found t o be relatively inact,ive and it. is probable that pressure is required t o bring about increased activity. A11 the catalysts studied showed an optimum ratio of metal i l C T I V I T Y AND C A T A L Y S T C O M P O S I T I O S .

t o oxide for maximum production of liquid hydrocarbons, Data for cobalt, nickel, and iron are presented in Table 111: the corresponding curves on alumina shown in Figure 2 relate metal content viith liquid hydrocarbon yield expressed in grams per cubic meter. I t is apparent that cobalt provides the highest yield of liquid hydrocarbons, optimum yield occurring a t about 75 weight yo metal content. Sickel produces a maximum yield a t a lower metal concentration, 50% b j ~IT?-eightof the catalyst giving the highest yield of liquid. Iron catalysts gave much loxver yields, but it appears that an optiniuni ratio of metal to oxide exists which will produce maximum liquid hydrocarbons. SELECTIVITY AND CATALYST COMPOSITIOS.As the hydrogenation metal content of two-component catalysts was increased, the yield of total hydrocarbons also increased (Figure 3). I n the case of nickel and iron, the yield rose rapidly a t first and then increased more slowly. With cobalt the total hydrocarbons increased with higher met,al concentration until a maximum was reached a t 75 weight %. The lower yield of hydrocarbons with a pure cobalt catalyst' may be attributed t o sintering of the catalyst surface either during reduction or under the synthesis conditions. An aceompan\-ing reaction in liquid hydrocarbon synthesis was the formation of gaseous hydrocarbons. The data plotted in

METAL ALIOa

100

Figure 4.

80

60

40

20

0 % BY WT.

Effect of Metal Content of Catalyst upon Gaseous Hydrocarbon Formation

AL,Oa

I

I

I

0

eo

40

I 60

BO

100% BY WT.

100

80

60

40

eo

0 % BY WT.

Figure 5 ,

1

Effect of hletal Content of Catalyst upon Methane Formation

April 1948

INDUSTRIAL AND ENGINEERING CHEMISTRY

721

Figure 4 show that a miniTABLE 11. SYNTHESIS OF HYDROCARBONS WITH TWO-COMPONENT CATALYSTS mum conversion t o C1 and Bulk Bpace Cz gases occurred when the Denaity, Velocity Hydrocarbon metal content of any of the PqlymerComposiReduced Vol./Vol. bf Hydrogenating tion Catalyst, Catalyst/ Temp., Yield, G./Cu. M. three catalysts was 50 weight G./MI. Hour Metal % $:e Weighd % OC. Liquid Gaseous %. As the metal content 114 180 112 28 co ThOn 76:25 0.65 107 180 98 39 75:25 1.32 Si02 was increased above 50 weight 113 200 70 74 1.25 Ah08 75:25 %, the hydrogenating in137 200 15 27 Zn0 75:25 0.23 1.04 103 200 47 82 Ni Ale08 50:50 fluence of the metal became 60:50 1.32 100 250 11 26 Fe AlnOt 0.46 137 190 94 21 predominant and methane Standard catalyst formation was the main reComposition: Co-ThOz-kieselguhr (100 to 18 to 100). action. Nickel, being a strong hydrogenation catalyst, produced only gaseous hydrocarbons with a 75 weight yo catalyst. Pure nickel was found by Sabatier (12) to effect a complete conversion to methane. Use of a pure iron catalyst resulted in nearly complete gas formation, while a pure cobalt catalyst still produced a 'substantial amount of liquid hydrocarbons. Cobalt in these experiments produced the least proportion of gaseous hydrocarbons regardless of the metal concentration, thus demonstrating a hydrogenating action which is particularly suited t o the production of liquid hydrocarbons. Because of the strong hydrogenating ability of nickel, formaMethane formation is a direct indication of the selectivity of any catalyst composition, a low or negligible value being desirtion of higher hydrocarbons was observed with a nickel-alumina able. Figure 5 relates metal content to the percentage of total catalyst containing as little as 7 weight % of metal. Another hydrocarbon yield recovered as methane. Nickel, cobalt, and observation made with the low-nickel catalysts was the relatively iron each had a metal concentration that produced a minimum high proportion of ethane produced (Figure 6). This undoubtconversion t o methane. As the metal concentration was increased edly results from the combination of strong hydrogenating cataabove this value, the hydrogenating influence of the metal conlytic effect with a high concentration of polymerizing comstituent became greater and more methane resulted. As the ponent and was not observed with either cobalt or iron catahydrogenation metal concentration became more dilute, individual lysts. methylene groups attached t o the catalyst surface were too far removed from adjacent methylene groups t o permit extensive polymerization t o higher hydrocarbons. With increasing dilution Go-ThOe of the metal component, the synthesis of all hydrocarbons decreased. Whatever methylene was produced was subjected to synthesis gas containing relatively higher hydrogen concentra100 i tion, thus forming methane as the main reaction. 5

...

(I

Q

1

0, (3

v; z

80

8 K a 0 K

60

n 60

>

r Pa

a . l 40

40

I.

0

a

-I

F

20

0 METAL ALIO1

0

20

40

60

80

100% BY WT.

100

80

60

40

20

0% BY WT.

Figure 6.

Effect of lMetal Content of Catalyst upon Ethane Formation

20

0 COBALT 0

20

40

60

80

100% BY W T

OXIDE

80

60

40

20

0% BY WT

100

, Figure 7. Effect of Cobalt Content of Catalyst upon Liquid Hydrocarbon Yield

INDUSTRIAL AND ENGINEERING CHEMISTRY

722

TABLE IV. ANALYSIS OF CONDENSABLE GASFROM . VARIOUSCATALYSTS Catalyst,s

Co-AlzOa

Standard

AlzOa i p catalyst, wt. % Analysis, mole % CaHs CaHs Iso-Ca% n-CdHa Iso-CaHio n-CaHio

Ki-AlzOs

...

25

50

12.2 33.0 1.8 20.7 0.0 32.3

9.9 37.0 6.2 20.9 0.0 27.0

0.3 58.0 0.5 0.5 9.8 30.9

100.0

100.0

100.0

O F TEMPER.4TURE TABLE V. EFFECT

UPON YIELDS 50:50 NICKEL-ALUMINA CATALYST

Temperature. 'C. Space velocity, cc./cc./hour Volume contraction.. % ._ Yields, g./cu. m. Gas CI a n d Cz Conhensable gas Light hydrocarbons Heavy hydrocarbons T o t i l l i q u i d hydrocarbons Total hydrocarbons Water Gas, Ci and Cz, % of total hydrocarbons Exit-gas analysis, mole %

vu*

Olefins

176 178 16

190 178 32

201 177 44

210 173 49

225 180 57

250

..

45 2 11 6 17 64 63

48 4 22 7 29 81 104

64

79 4 21 2 23 106 137

143 1

..

. 2. 2

,,

15

co

62

1

..

1 145 124

'

..

70

59

66

75

99

0.8

1.0

0.8

1.6

9.4

,.

1.0 0.4 24.3 64.9 3.8 4.8 2.08

1.0 0.4 25.6 60.9 6.2 4.9 1.76

1.0 0.6 22.6 59.4 11.7 3.9 1.42

0.2 1.2 20.5 45.4 19.3 11.8 1.36

_. , .

H1 Paraffins Nitrogen .Paraffin index

4

22 7 28 97 118

180

.. ,.

0 2

OVER A

,.

.,

.,

0.4 0.4' 2.5 27.7 48.8 10.8 1.08

UPOX YIELDS AT 200 C . TABLE VI. EFFECTOF SPACEVELOCITY O

Ni-AlzOa (50350) 177 103 44 66

Catalyst Composition, wt. 70 Space velocity, cc./cc./hour Volume oontraction, % Yields, g./cu. m. Gas, CI a n d Cz Condensable gas Light hydrocarbons Heavy hydrocarbons Total liquid hydrocarbons Total hydrocarbons Water

48 4 22 7 29 81 104

72 10 32 15 47 129 148

61 11 36 11 47 119

Gas, Ci a n d Cz, % of total hydrocarbons

59

56

1.0

2.0 0.2 0.8 15.6 47.6 22.4 11.4 1.35

Exit gas analysis, mole

co2

Olefins Oa

co HZ

Paraffins Nitrogen Paraffin index

Yo

57 79

Co-.4lz08 (75:26) 158 113 56 66

101 63

58 9 41 20

61 128 146

63 11 46 25 70 144 167

76 17 42 27 69 161 172

51

45

44

47

4.0 0.2 0.4 10.1 43.1 29.2 13.0 1.43

2.0 1.o 0.2 35.2 47.3 9.5 4.8 1.75

5.7 016 0.3 34.7 30.4 23.7 4.6 1.06

7.9 1.0 0.0 32.2 25.3 25.1 5,5 1. 0 8

Vol. 40, No. 4

necessary for optimum liquid formation. Zinc oxide appears t o be less suitable as a polymerizing agent than either thoria or alumina (Table 11). However, the recovery of only 10% of the total hydrocarbon yield as methane is still distinctly better than the value observed with pure cobalt. Craxford (2) has investigated the effect of thoria and kieselguhr on the reduction of cobalt carbide and concludes t h a t these act as specific promoters for the two reactions. Application of the hydrogenating-polymerizing concept t o synthesis catalysts does not preclude the possibility of carbide formation as a n initial step, because the reduction of carbide t o methylene and subsequent polymerization can still apply. COA-DEXSABLE GASES. The main gaseous product was methane from all catalysts. However, several catalysts, notably those containing alumina, produced appreciable yields of condensable (Ca-C,) gases. Analyses of gas from three catalysts show that alumina catalysts formed an appreciable quantity of isocompounds (Table 111). The gas from a standard catalyst did not contain substantial quantities of isoproducts. REACTIONTEMPERATURE. The optimum Geld of liquid hydrocarbons occurs usually a t 180" t o 200" C. Gas production increases as the temperature is raised. These observations are demonstrated in the synthesis of hydrocarbons over a nickelalumina catalyst a t constant space velocity (Table V). I n this instance, a n optimum production of heavy hydrocarbons occurred at 190" C. ; as the temperature is raised a higher proportion of lighter hydrocarbons is formed. However, gas is also produced in a n increasing proportion, so t h a t a t 250" C. methane is almost the only product. SPACEVELOCITY. With all catalysts investigated, product compositions were affected considerably by variations in space velocity. At 200" C. with a nickel-alumina catalyst, the highest yield of heavy hydrocarbons occurred a t a space velocity of about 100 (Table VI). At 177 space velocity, the yield of hydrocarbon products was decreased. At 57 space velocity, the yield of lighter hydrocarbons was increased. Methane formation was least a t 100 space velocity as shown by the paraffin index obtained under this condition. Similar remarks apply t o a cobalt-alumina catalyst. LITERATURE CITED

1.0 0.4 25.6 60.9 6.2 4.9 1.76

(1) (2) (3)

Cotton, Ernest, Natl. Petroleum News, 38, R425-34 (1946). Craxford, S. R., Trans. Faraday Soc., 42, 580-5 (1946). Downs, C. R., and Rushton, J. H., Chem. Eng. Progress, 1, 12-20

(4)

Fischer, Franz, and Koch, Herbert, Brennstof-Chem., 13, 61-8

(1947). (1932).

(5) Fuel Research Board, Great Britain, Report for 1937, pp. 13646.

(6) Ibid,1939, pp, 164-7. (7) Hall. C. C, and Smith, S. L., J . SOC.Chem. I d , 65, 128-36 (1946).

Increased pressure will alter the hydrogenating-polymerizing balsnce which causes liquid hydrocarbon production. Thus, at a n operating pressure of 135 pounds per square inch gage a pure iron catalyst was found to produce 70 grams of liquid hydrocarbons per meter of synthesis gas (8). This is in distinction with low yields found at atmospheric pressure with iron catalysts. Figure 7 presents results obtained with a cobalt-thoria series of catalysts and indicates that optimum metal concentra. tion for liquid production is about 75Yo/,. This is in agreement with results obtained with cobalt catalysts containing alumina as the polymerizing oxide (lower curve, Figure 7 ) . A high yield of liquid hydrocarbons obtained with a cobalt-silica catalyst (Table 11) is also evidence that 7 6 7 , metal concentration is

(8) Hofer, L. J. E., Peebles, W. C., and Dieter, W. E., J . Am. Chem. SOC.,68, 1953-6 (1946). (9)' Komarewskv, V. I.. and Riesz, C. H., Natl. Petroleum S e w s , 37, No. 6, R97-8, 100-2, 104 (1945). (10) Xomarewsky, 1 ' . I., Riesz, C. H., and Estes, Frances,' "Fischer-

Tropsch Process," New York, American Gas Association, 1945.

(11)

Xomarewsky, 1'. I., Riesz, C. H., and Thodos, George, J . Am.

(12)

Sabatier, Paul, "Catalysis in Organic Chemistry," p. 144, tr. by E. E. Reid, New York, D. Van Nostrand Co., 1923. "U.O.P. Laboratory Test Methods for Petroleum and Its Products," Method G84-40, Chicago, Ill., Universal Oil Products Co., 1940, Chicago, Ill.

Chem. SOC.,61, 2525-7 (1939). (13)

RECEIVEDM a y 12, 1947. Presented before the Division of Gas and Fuel Chemistry a t the 111th Meeting of the AMERICANCHEXICALSOCIETY, Atlantic City, K.J.