1538
INDUSTRIAL AND ENGINEERING CHEMISTRY
dustry groups, government agencies, and government-industry committees engaged in the cooperative research and development program on xylidines manufacture and utilization. LITERATURE CITED
(1) Am. Soc. Testing Materials, Designation D381-42, Standard
Method of Test for Existent Gum in Gasoline, Air-Jet Evaporation Method. (2) Am. Soc. Testing Materials, Designation D014-44T, Tentative Method of Test for Knock Characteristics of Aviation Fuels. (3) Army-Xavy Aeronautical Specification AN-F-lS, Jan. 25, 1940. (4) Army Service Forces, Office of Chief of Ordnance, Office of Field Director of Ammunition Plants, “Instructions for Packaging, Shipping and Handling of NS and CS Samples,” Inform. Circ., March 25, 1944. ( 5 ) Army Service Forces, Office of Chief of Ordnance, Safety and Security Branch, “Control of Health Hazards Associated with Manufacture of CS (Xylidine), S S (Nitroxylene) and Rlending of CS with Gasoline (AN-F-27 Aviation Fuel) ,” Industrial Hygiene Inform. Circ., Special Series, Aug. 17, 1943. (0) Brown, C. L., Smith, W. M., and Scliarmann, TT’. G., I s n . ESG. CHEM., 40, 1538 (1948). I
Vol. 40, No. 8
(7) Coordinating Research Council, Inc., 30 Rockefeller Plaza. Sew York, N. Y . ,Gasoline Additives Group, Rept., June 23, 1945;
Supp. to Rept., July 1946. (8) Coordinating Research Council, Inc., Gasoline Additives Group, CS Panel, Progress Rept., Dec. 1, 1943. (9) Federal Specification VV-L-791-b, Feb. 19, 1942. (10) Kerley, R. V., Power Plant Laboratory, Wright Field, Ohio, private communication, June 1943. (11) National Advisory Committee for Aeronautics, Wartime Iiepts. E-148 through 152, E-159, E-165, and E-180. (12) Olsen, W. T., Natl. Advisory Comm. Aeronautics, Wartime Rept. E-153,MR June 1943. (13) Petroleum Administration for War, Aviation Gasoline Advisory Committee, Rept. 5 , June 1, 1944. (14) Standard Oil Development Coiiipariy Procedure, Bur. Mines, R e p t . Investigation 3152, November 1931. (15) Standard Oil Development Company, unpublished data. (16) Tischler, A. O., Slabey, V. A , and Olson, W. J., ISatl. Advisory Comm. Aeronautics, Wartime Regt. E-154, MR, .’une 1943. R E C E I V E August D 14, 1947. Presented before t h e Division of Petroleum CHEMICAL Soi.rirr~ Cheiriistrs n t the 112th Meeting of the AIERICAX New York, N. Y.
Production of Xylidines by High Pressure Hydrogenation PROCESS DEVELOPMENT C. L. BROW3
W7.\I. SAIITH
Standard Oil Decelopment C o m p a n y , Elizabeth, il‘. J.
&so Standard Oil C o . (Louisiana Division), Baton Rouge, La.
W. G. SCHARMA4NS Standard Oil Decelopment C o m p a n y , Elizabeth,
Aromatic amines may be Iisccl a s blending agents in aviation gasolines to extend supplies o r to provide increased power output under conditions of rich mixturo operation i n aircraft engines. During World War I1 xylidines were produced for a liinited period at the Louisiana Division of the Esso Standard Oil Co. by a new process which involved the high pressure hydrogenation of nitroxylenes. The nitroxylenes w-ere produced at rarious ordnance works in the United States by the mononitration of xylenes obtained mainly as a by-product in the production of synthetic toluene from petroleum by the hydroforming process. Over-all yields of finished specification xylidines of 85 to 90% of the theoretical w-ere obtained.
T
HE antiknock properties of aromatic amines, notably aniline, when used as blending agents in internal combustion engine fuels have been we11 known for over 20 ycars ( 2 ) . These materials, however, never attained wide usage, and demand was practically eliminated with the development of the more effective tetraethyllead which has been us d in ever increasing amounts throughout the past 24 years (4). During World V a r 11, the aromatic aniincs again received consideration for use as blending agents in aviation gasolines in order to extend the supplies of 100/130 grade aviation gasoline, and to provide improved performance in supercharged engines under conditions of high power output encountered in take-off and rapid climb. At the request of the U. 9. \Tar Department, the Esso Standard Oil Company (Louisiana Division), together with
N. J .
other petroleum and chemical organizations, undertook cornmercial scale production of the isomeric xylidines from the corresponding mixed nitroxylenes. These nitro compounds were to be made a t various Ordnance works (operated primarily for T N T manufacture) in the United States by the mononitration of xylenes, a by-product in the production of synthetic toluene from petroleum by the hydroforming process. This paper relates the work necessary to the development of a high pressure hydrogcnation process for conversion of nitroxylenes to xylidines and the application of this process to the existing laige scale hydrogenation plant a t Baton Rouge. A companion paper (6) presents the results of studies conducted to evaluate the quality and performance characteristics of the xylidines produced by this proccss. At the Louisiana Division of the Fsso Standard Oil Companv in Baton Rouge, La., initial work by the Esso Laboratories on the hydrogenation of nitrobenzene (nitroxylenes were not available at first) in batch autoclaves of 1-liter capacity culminated in less than 10 months in the commercial hydrogenation of nitroxylenes to produce the equivalent of 150,000 pounds per day of specification xylidines. This rapid development proceeded through laboratory and semicommercial pilot plant development in continuous units of three different sizes producing approximately 3, 30, and 8000 pounds of xylidines per day (8). NITROXYLENE QUALITY
The nitroxylenes used in the production of mixed xylidines were produced by E. I. du Pont de Kernours & Company for the U. S. Army Ordnance Department at the Alabama, Oklahoma,
August 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
ll
c
!!
b:
1539
effective nitroxylene-spent acid separation, thorough sodium carbonate washing, thorough water washing, and effective drying by air blowing. The gradual improvement in nitroxylene quality is shown by the typical nitroxylene inspection data presented in Table I. The continued improvements ultimately resulted in the commercial production of nitroxylcnes meeting specifications that were based on laboratory evaluations of quality characteristics and experimental treating studies. During this development work, extensive laboratory treating studies on nitroxylene quality improvement were carried out to evaluate other possible treating methods. Vacuum distillation prior to hydrogenation would be expected to provide the ultimate in nitroxylene quality and tend to remove a majority of the dinitroxylenes always present. On hydrogenation, dinitroxylenes form aromatic diamines which tend to contribute to color instability of the final amine product (6). Because of limited stability data on nitroxylenes and particularly dinitroxylenes, vacuum distillation was considered as potentially hazardous and therefore was investigated in only a preliminary manner. Other methods investigated for improving nitroxylene quality were centrifuging, clay contacting, water washing and settling, air drying and settling, plate and frame filtration, continuous precoat filtration, and chemical pretreatment. Chemical pretreatment comprising alkaline solution washing of the nitroxylenes was found the most satisfactory. As exemplified by the data presented in Table 11, specification nitroxylenes commercially produced by sodium carbonate washing may be further improved by additional carbonate treatment to yield a product equivalent in ash content and acidity t o products from vacuum distillation. Comparable color improvcment was not obtained by the washing procedure, and of course no reduction in dinitroxylene content would be expected, as would be the case with vacuum distillation. NITROXYLENE STABILlTY
and Kankakee Ordnance Works. Initial production, although low in dinitroxylene content, was of unsatisfactory quality; it was characterized by poor color, high solids content (principally iron salts), corrosive nature, and tendency toward further degradation in storage. Subsequent laboratory work a t Baton Rouge, a t the ordnance plants, and at laboratories of other companies cooperating in the project indicated means for improving the quality of the nitroxylenes. The chemical treatment finally developed for use at the various ordnance plants consisted of
A study of the possible hazards encountered in handling nitroxylenes indicated that neither the mono- nor the dinitroxylene would thermally decompose below temperatures of approximately 500" to 600" F. Decomposition in this temperature range was mild, and not accompanied by detonation. Acidic materials removed from crude nitroxylenes were found to have decomposition temperatures of about 440' F., whereas the sodium salts of these acidic materials decompose at about 250" F. This illustrates the importance of thorough alkali (sodium carbonate) washing to remove acidic impurities followed by thorough water washing to remove traces of sodium salts. Studies of the vacuum distillation of sodium carbonate-treated nitroxylenes indicated that this process could be safely carried out if the maximum temperature was not allowcd to exceed 350" F . and if precautions were taken to prevent the accumulation of the alkali salt of any organic acid impurities. Burning nitroxylenes were found to be readily controlled by the usual petroleum refinery fire protection equipment. I n open vessels, either Foamite or water alone (because of its lower specific gravity) wa8 suitable. I n open unconfined fires, liquid carbon dioxide was ineffective, while Foamite allowed ready control.
INDUSTRIAL AND ENGINEERING CHEMISTRY
'1540
solid material on the catalyst. The minimum catalyst temperature a t which appreciable reaction would occur with the sulfur-resistant catalyst contemplated, was found to be about 300" F. with new
TABLE I. TYPICAL NITROXYLENE INSPECTION DATA Acidity "OS, Org; -vt.%, me. Max. Max.
Ash, P.P.M., Max.
Nitroxylene, Na P.P.M., Max.
Color, A.S.T.M., Mar.
Hz0, Vol.5'6, Max.
Specifications 1.0 10 4 0.2 20 0.01 Esso S.O. Co., proposed 1.0 ... 0.2 20 0.01 Ordnance 1-1-44 Reason for specifications Corrosion X X X Reactor plugging X X X X Explosive hazardb X Catalyst life Initial Product ordnance quality" product >50 0.08 >5 7 8 0.6 lmproved ordnance product, 40 0.03 4.0 .. 41/, 0.02 NaHCOs washed Improved ordnance product, NazCOa washed a t Alabama O.W. 26 0 1.6 8 41/2 0.06 0.02 Oklahoma 0.W. 16 0 1.7 5 0.01 Kankakee O.W. 23 0 1.0 6 351/a S/r a Milliequivalents of KOH per 100 grams of nitroxylenes for 10.0 PH. b Applicable t o cases where nitroxylene is preheated or distilled: neither type of processing Standard process. 0 Aromatic diamines less color stable than aromatic monoamines.
..
NITROXY LENE HYDROGEKATION
The usual industrial procedure for the reduction of aromatic nitrocompounds to the corresponding aromatic amines, as typified by the production of aniline, has consisted of the liquidphase reduction of the nitro aromatic (nitrobenzene) in stirred batch autoclaves at low pressures, using iron and hydrochloric acid as the reducing medium. The reaction proceeds exothermally as shown by the following equation:
H
0
. \'o
+ 6 [HI Fe ++ HCl O
N
~
'
+2H20+
\
"
238,000 I3.t.u. per pound mole a t 20' C. and 1 atmosphere The adaptation of this reaction to a continuous process utilizing a fixed bed of solid catalyst involved the consideration of a number of interdependent factors. Basically, reactions of this type
wt.
Mono-, Min.
88 85
Vol. 40, No. 8
70
DiMa;.
3 3
catalyst, thereby defining the rather narrow temperature range of 300" to 450" F. in 92.0 2X . 7 which t o maintain satisfactory 05.5 1.5 reaction conditions. In addit,ion to this narrow range of operat,ing tem93.0 2.4 93.0 1.7 peratures, the heat of hydro92.6 1.8 genation of nitro-aromatic comis employed in pounds to aromatic amines is approximately five times as great, on a volumetric basis, as the heat of hydrogenation of the most highly exothermic reaction on which past experience had been obtained (hydrogenation of iso-octenes t o iso-octanes). The combination of these td7o heat factors (high heat of hydrogenation and relatively low maximum operating temperatures) made temperature control of the reaction by the usual practice of injecting cold recycle gas impractical because of the large quantities of gas required. Obviously the high heat of reaction could be brought into line with past operations by employing a diluent, say to the point where only 20oj, nitroxylene would be present. After preliminary laboratory studies, it was found that by recycling water or water together with crude amine product a satisfactory diluent was available which also had the desirable feature of providing additional high heat removal capacity. Control of the heat of reaction over the narrow temperature range was made possible with reasonable amounts of cooling gas because of the relatively large heat effect brought about in the vaporization of the water diluent. The laboratory pilot plant and commercial equipment used for X
proceed more readily than the hydrocarbon hydrogenation reactions (such as the destructive hydrogenation of gas oils and the hydrogenation of olefins to the corresponding paraffins) with which past experience had been mainly concerned. Low hydrogen pressures and mild temperatures are sufficient to reduce satisfactorily aromatic nitro compounds such as nitroxylenes to the corresponding aromatic amines in either the liquid or vapor phase. Because, however, the hydrogenation equipment available at the Louisiana Division of the Esso Standard Oil Company could be satisfactorily operated only at high pressures (3000 pounds per square inch gage) owing to pressure drop, etc., suitable operating conditio.ns and requirements had to be developed to fit the limitations of the equipment on hand and the characteristics of the feed stock to be processed. Preliminary laboratory thermal stability experiments with nitroxylenes indicated that decomposition with the formation of a carbonaceous residue occurred at temperatures above 500' F. This factor imposed a maximum catalyst temperature of about 450" F. to assure continuous operation with a minimum deposition of
TABLE 11. COMPARISON OF CARBONATE WASHING WITH VACUUM
BISTILLATXON FOR NITROXYLESE Q U A L I ~IMPROVEMENT Y Ash,
P.P.hI.
Organic Acidity, M0.a
Color A.S.T.M.
Ordnance nitroxylene 1.7 41/a Treated with 15% NazCOa soln. l8 0.4 4 41/r 1 Vacuum distilled, 0-80% overhead 4 0.4 Milliequivalents of XOH per 100 grams of nitroxylenes for 10.0 pH.
5
10
15
20
25
H 2 S SOLUBILITY A T 8 0 ° F . , VOLS. AT O 0 c . & 7 6 0 UM./VOL. L I Q U I D
Figure 2. Solubility of Hydrogen Sulfide in Nitroxylenes and Xylidines
30
August 1948
I N D U S T R I A L A N D E N G IN E E.R I N G C H E M I S T R Y
high pressure hydrogenation have been described (8, 6, 7). Figure 1 shows in simple diagrammatic form the flow plan finally developed for both the semicommercial and the commgrcial hydrogenation of nitroxylene. I n order t o minimize any tendency of the nitroxylene toward thermal decomposition under nonhydrogenating conditions, provision was made for injecting it into the inlet stream to the reactor. Preheated recycle water or recycle water plus crude amine product was used together with recpled gas to supply the temperature necessary for initiating the hydrogenation reaction. The use of water as a temperature control medium in the reactor necessitated the development of a catalyst base which would be resistant to the disintegrating action of liquid water in the temperature range of 300" t o 450" F. Laboratory work finally resulted in the adaptation of activated charcoal as a satisfactory catalyst support. Molybdenum sulfide was found t o be suitable as the active ingredient of the catalyst, provided sufficient hydrogen sulfide was present in the reactor to maintain catalyst activity. The required concentration was maintained by absorption of hydrogen sulfide under pressure in the oitroxylene feed. Data on the solubility of hydrogen sulfide in nitroxylenes and xylidines, determined by a volumetric method proposed by Bancroft ( I ) , at various temperatures and pressures are tabulated in Table 111. Data obtained a t 80' F. are presented graphically in Figure 2. Typical operating data for the high pressure hydrogenation of nitroxylenes to- xylidines, with or without xylidine recycle, are tabulated in Table IV. Crude xylidine recycle in admixture with the recycle water (up t o a ratio of 1 part of xylidine to 1 part of nitroxylene) appeared to result in somewhat better maintenance of catalyst activity than did the use of water recycle alone. Crude xylidine recycle in admixture with the nitroxylenes was impractical, owing t o extremely rapid corrosion of feed drums and high pressure pump values. This was not experienced with either nitroxylenes or xylidines alone. The hydrogen consumed in the high pressure hydrogenation of nitroxylenes to xylidines was approximately that stoichiometrically required for reduction of the nitro group to the amino group. I n addition, some hydrogen was always lost through solubility a t high pressures in the liquid product and through purging of gas from the high pressure system in order to control the build up of inerts and thereby maintain the hydrogen content of the recycle gas above a minimum of 80%. Product yields from the hydrogenation step were essentially quantitative when catalyst temperatures were maintained in the operating range of 300" to 450" F. At temperatures above this range, in addition to deposition on the catalyst of carbonaceous matter arising from thermal decomposition of the nitroxylenes, xylidines are reacted to some extent. This resulted in decreased xylidine yield. The effect of high operating temperatures on
Figure 3.
Crude Xylidines Distillation Unit
1341
TABLE 111. SOLUBILITY OF HYDROGBN SULFIDEIN NITROXYLENES A N D XYLIDINES Compound Nitroxylenes
Temperature,
F.
80
100
Pressure, Atm. 1 2 1 2
134 Xylidines
Solubility, Vols. HeS a t 0' C . and 760 Mm./Vol. Liquid
1 2 1 2 1 2 1 2
80 100 134
9.3 18.3 7.5 15.0 5.3 10.5 13.8
27.8
10.8 21.6 7.3 15.6
TABLE IV. TYPICAL DATAON HIGHPRESSURE HYDROGEXATIOW OF
NITROXYLENES Without With Xylidine Recycle Xylidine Recycle Molybdenum sulfide on activated charcoal 0.44 0.44 0 0.4
Catalyst
Nitroxylene, vols./vol. catalyst/hr. Crude xylidine recycle, vols./vol. catalvst / h r . Rec& water vols./vol. catalyst/hr. 1.6 System pressuke, lb./s 3000 Reactor inlet temp., 330 Reactor maximum temp., F. 455 8000 Recycle 3- cooling gas, cu. feet/bbl. total feeda Recycle cooling gas vol. % HZ 80 Recycle cooling vol. % HsS 0.6 Nitroxylene conversion, yo 99.4 Nitroxylene Xylidine Nitroxylene Feed Product Feed Inspection data 1,116 0.974 1.112 Specific gravity at 60' F./60" F. Color (Robinson) 5'/1 51/a 2 Xylidines, wt. % 0 85.6 0 (diazotization) Nitroxylenes, wt.% (polarograph method) Mono93 4 94 6 Di1:s 0.6 116 Water, wt.% Trace 2 0.2
++
cas:
1
a
1.2 3000 335 435 8000 85 0.6 99.9 Xylidine Produot 0.971 8
88.2
}
Water plus nitroxylenes plus recycle xylidines.
xylidines under hydrogenating conditions is given in Table V. At temperatures above 550' F. reaction of xylidine becomes appreciable. Reaction apparently proceeds by deamination and hydrogenation of the aromatic hydrocarbon produced, with little or no hydrogenation of the xylidines themselves t o dimethylcyclohexyl amines, under the conditions of hydrogenation used. CRUDE XYLIDINE DISTILLATION
Specification xylidines were recovered from the crude hydrogenated product by distillation in a manner shown diagrammatically in Figure 3. I n the finishing operation approximately 10 volume yo of a high boiling cracked gas oil flux was added to the crude xylidines, and the resulting blend was topped to remove unnitrated hydrocarbons originally present in the nitroxylenes and rerun to produce an overhead xylidine fraction. Initially, both towers were operated a t essentially atmospheric pressure, but the xylidine product contained so much hydrogen sulfide that it failed to pass specifications. I n the hydrogenation step complex organic sulfur compounds are formed that crack to hydrogen sulfide and organic materials in the high temperature reboiler circuits of the towers. Under the initial conditions of operation, the maximum temperature was reached in the rerun tower reboiler, thereby releasing the hydrogen sulfide which threw the xylidines off specifications.
INDUSTRIAL AND.ENGINEERING CHEMISTRY
1542
TABLE T'. HIGHPRFSSURE IIYDROGEXATION O F X Y I . I D I S E s HIGHTIGMPERATURES Catalyst F e-e- d - qtork - --
Xylidines, vol./vol. catalystihr. System pressure, Ib./sq. inch Reactor maximum temp., 17. Reactor average temp., C a s rate, cu. feet/bbl. xylidines Feed stock Acid insoluble, 7.01, % Hydro product Acid insoluble, 1.01. % .4cid insoluble, wt.% aromatic Acid soluble, wt. yo aromatic
I..,
AT
hIo!yhden.um sulfide on activated cliarcoal Distilled xylidines 7 10 7 3000 500 550 600 050 700 760 480 535 575 63a 675 71.5 7 12,00007 .-
7
2.2
., .,
2.6
6.5
, , , ,
100
F
16.5 31.5
18
,
.
. ,
.. , .
51.0 14
100
Vol. 40, No. 8
countered. I t mas believed that this corrosion, similar to the corrosion experienced in the hydrogenation section when nitroxylenes and xylidines weie niived together, was a result of chemical reduction of unconverted nitroxylenes in the crude xylidine product by means of the iron in the system. No nitroxylenes v,vere found in the finished xylidines or rerun tower bottoms, even though approximately 1 weight yo of nitroxylenes was present a t tirnes in the crude qlidines fed to the distillation system. It is reasonable t o suppose that this corrosion would have been p e vented by opeiation of the hydrogenation section for essentially 1007, conversion of the nitroxylene. CONCLUSION
Khen the topping tov-er pressure was increased so that the maximum temperature reached in the distillation unit was in the topping tower reboiler circuit, no appreciable quantity of hydrogrn sulfide was produced i n the rerun ton-cr. With this method of operation, spccification lylidines m r e produced. Tabulated in Table VI are a few properties tyrical of the finished xylidines, iZdditiona1 propcrtics and further studies on xylidine quality are described in a companion paper ( 5 ) . It is concluded there that well-distilled xylidines produced from nitroxylenes by the high pressure hydrogenation process describecl in this paper compare favorably in physical properties and octane blending value with xylidines preparcd from nitrovylencs by other methods of reduction.
Specific gravity a t 60' F./6Oo F. Color (Saybolt) Xylidines, wt. % (diazorization) Solubility in 3 S HCl, 7% Sulfur, wt. 7, Water, wt. V0 Kitroxj-lenea, wt.' % Distillation, O F. Initial Q6% Final Rich-mixture rating, 4 nil, TELIgal., blending 1-alue b
+90910..918 1 99.9 0.02 0.0 0.0
410 418 425 1480
Specificat ions, AN-X-1 A h . 0.970 8 (Robinson) .. 97 ..
Max. 0.990
..
..
o .'i
..
0.3 2
.. ..
.. ..
1440
a B.jC/, minimum boiling betxeen 410O and 429.8O F. b 1 vol. lo in grade 130 aviation gasoline expressed as indicated mean effective pressure determined on CRF-supercharged aviatiori engine.
Xylidines may be prepared by the high pressure catalytic hydrogenation of nitroxylenes using a fixed-bed solid catalyst. Water in admixture n-ith the nitroxglene feed stock was used to control catalyst temperatures within the desired range by removal of the substantial hcat of reaction both as sensible and as latent heat,. The use of water necessitated the development of a sulfur-resistant catalyst of satisfactory act,ivity supported on a base resistant tBothe disintegrating action of liquid r?-atcr at, temperatures of 300 O to 450' F. Under suitable operating conditions, essentially complete conversion of nit'roxylene with quant'itative xylidine yields vias obtained in the hydrogenation step with hydrogen consumptions equivalent t o that stoichiometrically required for reduction of the nitro group to the amino group plus that, lost as solubility in the liquid product and that' lost in purging of gas from the high pressure recycle gas system in order to control the buildup of inerts. The use of temperatures higher than opt,imum resulted in deposition on the catalyst of carbonaceous matter from the thermal decomposition of some of the nitroxylenes and deamination of a portion of t'he xylidines produced to give ammonia and a hydrocarbon essent'ially non iromatic in nature. Topping of the crude xylidines t,o remove unnitrated hydrocarbons, followed by rerunning t,oremove a higher boiling bott,oms fraction containing aromatic diamines deleterious to the color stabilit,y of t,he xylidines, produced specification cylidines wit'h yields of 85 to go(", of the theoretical. These xylidines were indicated to be equivalent in quality to xylidines produced from nitroxylenes by other methods of reduction. LITERATURE CITED
Bancroft, W. D., and Belden, B. C., J . Phus. Chem., 34, 2123 (1930).
Finished xylidine yields of 85 to goy0 of the theoretical were obtained in the distillation step. Some xylidines (approximately 10 to 15% of the theoretical) were lwt in the rerun tower bottoms which also contained the added flux oil plus diamino compounds that were produced by reduction of the dinitroxylenes originally present as impurities in the nitroxylene feed stock to the hydrogenation process. Complete separation of the aromatic diamines from the desired xylidine product by fractionation in the rerun toner was found desirable because of the deleterious effect of the diamines on the color stability of the xylidines. During the distillation of the crude xylidine product, extensive corrosion of both the topping and rerunning towers was en-
Boyd, T. A , , IND. ETG.CHEM.,16, 893-5 (1924). Brow-n, C. L., Voorhies, A . , Jr., and Smith, W. M., B i d . ,38, 13640 (1946).
Ethyl Gasoline Corp., "Story of Production of Ethyl Fluid in
Baton Rouge," Oct. 3, 1944. Kunc, 3 . F., Jr., Howell, W.C., Jr., and Starr, C. E., Jr.. IND. Eso. CHEM.,40, 1530 (1948).
Murphree, E. Y., Brown, C. L., and Gohr, E. J., Ibid., 32, 120312 (1940).
Murphree, E. V., Gohr, E. J., and Brown, C. L., I b i d . , 31, 10839 (1939).
Voorhies, A , , Jr., Smith, W. M., and Mason. R . B., I b i t l . , 40, 1543 (1948).
RECEIVED JUIS 21,
1947. Presented before the Division of Petrolenin Chemistry a t the 112th Meeting of the AMEP.IC.AX CIIEMIC.AL SOCIETY New York, N. Y
