April 1951
INDUSTRIAL AND ENGINEERING CHEMISTRY
be made unstable by addition of small amounts of pyrrole. Thus a virgin stock which had only a small amount of insoluble gum after 6 months’ storage at 100” F. (0.15 mg. per 100 ml.) gave large amounts of precipitate in 4 wpeks when 0 01% of 2,sdimethylpyrrole was added. One method of improving unstable fuel oils involreq acid t rc=it,ing and, frequently, rerunning. Acid leads to extensive, pol\ merization of pyrroles t o high boiling products which remaiii 111 the acid phase or do not come overhead in the rerunning operation. llcid treatment of a sample of fuel oil originally containing a large quantity of pyrroles removed the greater part of the pyrroles and gave a more stable oil, especially with respect to color degradation. Pyrrole was readily removed from oils t o which synthetic pyrroles were added, by acid treatment and rerunning. T h e removal of pyrroles is undoubtedly one of the reasons why acid treating improves the quality of unstable oils, but i t is not necessarily the only reason. The removal of the substituted pyridine type of compound is easy, because they are relatively strong bases and are readily removed \\it11 even dilute mineral acids. I n the treatment of any distillate, in order to produce a stable product, there should he considered, among other things, the
939
nitro~c’i:(wrn[)oundst h a t may t,c present. If these cumpounde are ~ ~ ~ ~ ~ l ~pyridines i i ~ i their ~ ~ ~ removal : ~ ~ may i t ~not y bc necessary, t,ut i i i : i n > . ~ \ . o i i t will be ettsily arhieved. If the nitrogen compounc!. roiit:iiii appreciable amounts of pyrroles, it will lie necess:iry to I’PnlOVe at, least the more active portion of tlieni. Reinov:ti of thrse compounds will probably rrquire s o i n r drast io treatment such :is Ptrong .Gulfuric ncitl. LI’I‘EKATURE CITED
(1) Ani. For. Testing lfaterials, Philadelphia, “A.$.T.II. Standards on I’c\ti.oleum Prodiicts and Lubricants.” p. 615. October
1947 (2) Bailey, J. K., ~t ( I ! . , J . A m . (’hem. 17.5 -. - llU37). ,.... ,. (3) Ball, J. S., private communication.
SOC., 55, 4136
(19:33): 59.
(4) Fischer-Orth, “Die Chemie des Pyrroles,” pp. 20, 32, Leipzig. Akademische VerlagsgeSellschaft, 1934. (5) ,Mapstone, G. E., Petroleum Refiner, 28, 111 (Octoher 1949). (6):Poth et al., J. Am. Chem. Soc.. 52, 1239 (1930). (7) Thompson, R. B., Druge, L. W.. a n d Chenicek. .I. .t. I X D . ENG.CHEM.,41, 2715 (1949). (8) Treibs, A., Ann., 510, 42 (1934); 517, 172 (1935). RECEIVED August 4, 19.50. Presented beiore t h e Division of Patroleiim s SncimY, Chemistry at tho 1 1 8 t h l l e e t i n g oi t h e . - \ n ~ ~ r c aCHrirrcar. Chicago, Ill.
Chromatographic Investigations of Smokeless Powder DERIVATIVES OF ACARDITE, CARBAZOLE, AND TRIPHENYLAMINE FORNED IN DOUBLE-BASE POWDER DURING ACCELERATED AGING IT‘. A. SCHROEDER, BERTR.k\I KEILIN‘,
IND
K1C:HkRD \I. LE3\11110S2
California Institute of Terhnolopy, Pasadena 1. Calif. Thebe chromatographic-spectrophotometric studies of the reactions of acardite (1,l-diphenylurea), carbazole, and triphenylamine in smokeless powder during accelerated aging were made as a continuation of similar studies of diphenylamine ( 2 4 ) and centralite (25). Of the three compounds, acardite shows the most coniplex reactions, for i t is degraded, with the result that on11 derivatives of diphenylamine can he isolated. 0 1 1 the other hand, carbazole forms derivatives which would he predicted from its similarity in structure to diphenylamine, and triphenylamine in the main yields only simple
nitro compounds. The reactions of these st;tt)ilixers were followed quantitatively. In contrast to the complex and competing reactions of diphenylamine and centralite, the reactions of carhazole and triphenylamine seem to occur in stages such that compounds of the same degree of nitration do not react appreciahly until their precursors are depleted. The relative simplicity of the reactions may he of assistance in further study of reactions in smokeless powder. The chromatographic methods devised permit the separation of structurally related compounds.
M”“”
powder produced the grratest loss of nitrogen whereas diplii?iiyIamine caused the grrstest denitration of nitrocellulose i m t i nit roglycerin and the greatest lowering of viscosity. Carhzole, according to 1Iarqueyrol ( 1 7 ) , is better than diphenylamine as a stabilizer but does not form a very intimate mixture in the powder, as Dalbert ( l a ) also noted. Triphenylamine behaves much like diphenylamine if t,he quantity of either stabilizer is only 2% of the powder, but if it is 5%, triphenj-lamine produces less denitration and loss in weight ( I 1 ). The first product of reaction of triphenylamine is a niononitro compound and not a nitroso derivative as iF found in thc c:iw of diphenylamine (11 j. The present study of the derivatives formed from acarclite, carbazole, and triphenylamine was begun aft,er unpu1)lisheti experiments in these laboratories Kith various stability and surveillance tests showed t h a t these compounds might have merit aa stabilizers for smokeless powder, and after it was found t h x t
study has bern given to the reactions and use of diphenylamine and centralite as stabilizers in sniokeless powder, but little information has been published about powders which are stabilized wit.h acardite (1,l-diphenylurea), carhazole, or t,riphenylamine. Hecker and Hunold ( 1 ) described methods for thi, deterniination of acardite alone or in the presence of diphenylamine or centralite in single- or double-base pon-der. Tonegutti (26, 2 7 ) considers acardite t o he a more satisfactory stabilizer for nitrocrllulose than are diphenylamine or centralite, but reports th:it the latt,rr two are Letter and about equivalent for powdei.:: I J ~lo\\nitroglycerin content. Dalbert ( 1 2 ) found t h a t powders in which some ceiitralitr \\-as replaced by diphenylamine or carbazole did not behave as wrll in a n y respect as when centralite alone mi: present; carbazole in the 1
Present address, r n i r e r s i t y of Southern California, Los ;\ngeles, Calif. P r e w n t address. University of California, Berkeley, Calif.
940
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Vol. 43, No. 4
t - o n i n i u i i stabilizers with that of acardite, carbazole, and triphen>~l:~iiiiiir (Figuiyz 1'1. T h e methods of determination are detailed i n Liter sections. T h r point of depletion of carbazole and centralitr JP RPL is riot wrll tli~terminedhy t,he availa1)le saniples, b u t a niaximnm ('-473 204 142 C-420 C-390 tinit, ir; givrri t)y ssinplcs which were heated for 90 and 84 days. 51.60 .59 00 ;11 5 0 59.0 S9.0 rvqwrtively, and \v(Jrr found to be free of the respective stabilizer. (13.2) '13.22) (13.24) (l2.6i) 1.12 671 Nitroglycerin 43.00 40.00 43.00 40.0 40 0 i )f these compouiitir, diphenylamiiie reacts most rapidly c ~ e n 3.25 1)iuthyl phthalate 3.25 .. 0.75 tlrougli t,he powder \vas hcated a t a lower temperature. Tri~ilcen~-i:~niine is estiausteti niore slowly than diphenylamine but tii(:re rapidly than :icsrtiite. carbazole, or centralite. The tli~ihrnylaniinein locally prepared powders is known t o be deplrtetl :iliout ttvicr as rapidly as i n commercial powders, whereas centralite behaves similarly i n hoth types. If tripheriylamine tiehaves like diphenylamine i i i this rrspect, it may be that its normal deplet i c ) i i actually is siini1:ir to that of acardite, cartmzole, antl rriitralitr. .Although the stabilizer i i i powders which contain acarditcl, r:irI ~ : i z o l e ,and ceiitr:rlite is cdiausted at ahout t h e same time. thr. vourse of thc cleplctions is rather different. T h e equation for :, many German powders of Il-oi~lti ll.:cr I1 contained ; w : i i . t l i : c ~ . l~i.*t-or(lt~r r r x t i o n drscrilles the depletion of acardite very we~l!. An a11 of a tjpical German powder has been given (2.9'). I * : i t tlic r~sliaustionof carbazule and centralite does not ~ e i tnn T h e powders used in t h e present investigation were specially II~IIOIY miy simple-order rquation. made in these laboratories and were aged a t an accelerated rat(' ponclrrs diffrr clirmically in respects other thaii by storage a t 7 5 " C. After extraction and other preliminuy zor-namrly, in tlie presrnce or absence of neuoperations, t'he derivatives were isolated and studied kJ)t i x l sli1t.q or of diethyl phthalate-there i3 no evidence to indicatt. chromatographic-spectrophotoniet~ric methods such as those used th:it t h e rates of depletion of the stabilizer :ire greatly influrncwi for the i n v e d g a t i o n of diphenylamine ( 2 4 ) and centr:ilitr ( I d j. 1,). such additives or by the differences in physical shape. l h e information now availshle concerning t h e lic~havior of I t 11:is t ) t x c s n Imintrtl out (2.5) t h a t it is inadvisable to u w tlij~lir'riyl:rniirie, crnt,r:ilite, aicmiite, cni,l)azolc. arid triplirnyl(~inipirisonsof the rate of dq)letion of different stabilizers t o amine permits >I comparisou of the rates at, n-hivh t h q - are judge the cffectiveness of R coinpound :is a stabilizrr, since it is not tlrpleted during accelerated :iging and of the types of derivatives kiion-n ir-hcthcr. for csamplr. r:ipid dr1)letion means that thi. formed. qtatiilizrr is w r y rffectivc i n rrnioving deleterious producats 0 1 (1tm)inporition or whether it is attacking the powder. ;2crortI(:OIII'OSITION OF P o w n E n s ANI) OBVIOUS EFFE(:I'S OF HEATING itigl).. ronipitrisons such as t,hose made in Figure 1 give an indication oi' the, normal hehavior of a compound in a powder relativr to T:tl)lr 1 preecnts the ( ~ ) n i ~ i ( i s i t i oofn porvtlcrs C'--t20, ( ' :{. provers. The others wei'e parts of co111111~ ..\I1 saniples were stored in v r n t e d metal can.< i i i t ~ l t ~ t r i ( * a l i y tirated ovens at, 75' =,I 2" C. I'owder C--420 coiit :lining ararilitcs ~ ' : i horiginally colorlcss, b u t upon heating became yellow, then red, anti finally red-tiro\vi>. Carbazole powder C-390 was color1es.q at the t~eginniiiy and during hpating became more and more yellow and then sonic,n-hnt bron-nish, Six months after this po\vder had t)rrii j)rrp:iml, tlic surface of unheated samples \vas cowred with cr>.PtiilsLvhicli had a purplish color in reflected liglit. l'robahly the c,ry.-tals \\-rw
wrhazole, hecmse nitroglycerin anti nitrocellulosr w r e its onlv other constituents. This effect apl)arcntlq- is anothrr manifestation of the observation made 1,y 1I:irqueyrol 127) and Dallwrt ( 1 4 ) t.hat carbazole does not iiicrirporatr well in smokelrss powtlrr. During the preparation of C-590 incorporatioii of cnrliazolrx ~ Y R Sdifficult because of its insoluhility. All heated samples of the initially faintly yellon. poivdvr (:--I73 rontairiing triphenylamine wrre green, although a yrlloivieh r w t was apparent as the time of hratirig increased. After samples which had been heated for T and 12 days had aged for a time at rnoni temperature, the surface was covered with colorlcss rrJ-stalS n.liicli probably were triphenylaminc. DEPLETION RATES OF S l A B I L I Z E H S
Previous work (24,26)showed t h a t the depletion of diphenylamine at 71" C. is much more rapid than t h a t of centralite at 75" C. It is therefore of interest t o compare the depletion of these
CHEMICAL CH 4 S G E S OF AC.&RI)ITE
ric:irditc is related structurally both to centralite and to tliiihrnylnniine-to centra1it.e because both are substituted ureas :md t o diphenylamine as an S-substituted diphenylamine. .4crordingly, in acting as a stabilizer, the reactions of acardite may take scvcral paths: (1) formation of nitroacardites, ( 2 ) formation of nitroacardites and derivatives of diphenylamine i n a mannw arialogous to t,he formation of nitrocentralites and derivatives of .V-ethylnniline from centralite, and ( 3 ) formation of derivatives of dipheny1:~nineonly. The nitro and nitroso derivative9 of diphenylaniin(~ are n-ell known, liut information about nitrn:icarditrs seems t o he limited t o the rather ill-defined products of nitrxtion which were isolated by Reudler ( 2 1 ) and Ryan antl O'Toolr ( 22 ). Chromatographic experience suggests t h a t nitrox a r d i t e s should be at least as strongly as or more strongly adsorbed than acardite itself. On the other hand, nitro- and nitrcsodiplirri~~lai~iines are less strongly adsorbed than acardite. Iluring the study of the depletion of acarditc, all colored zoncs on the chromatogram with one exception were washed into the filtrate by the development which was used for the isolation of acardite. Further preliminary st,ridy indicated t h a t only derivativrs of diphenylamine were formed. except for a strongly adsortied compound which was present only in minor amount and could not be identified. On the basis of this information, samples of acardite-stabilized poFder (3-420, which had been heated at 7 5 " C. for 10, 40, and 80 days, were analyzed to determine t h e identity of the derivatives, h u t the change in the quantities of t h r derivatives as a function of the time of heating was not followed.
METHODS.The derivat,ives of diphenylamine formed from acardite were isolated, identified, and determined by the same
INDUSTRIAL AND ENGINEERING CHEMISTRY
April 1951
94 1
T h e coluniii w i s first developed \\ itli I' mi.o t lie i z o ~ i i ' :vliic.li w.usheci iiitroglyceriii ntid soiiie y ~ l l o w c o n i ~ ~ u i i ditit~i s I tie filtrate, next x i t h 2 I- nil. of ether \vhich witsheti from tlie colutnn all ot,her yellow compouiids escept a small zone a t the very t,op of the colurnit, and fiii:il!y 1iosta:idied with I- nil. of ligroin (30" to BO" C,). Tlic zone o f iic>:irdite Xvliich is coI01~1ess:ind :tpprnximrtt~ely i n the middle thirii of the colutnti \v:is located tiy the ceric sulfate reagent (2.5) ivith which it gives :i t)luc~-green color; the acartiit,e was then eluted with 100 ml. o f 1 t i ) 9 ethyl alcohol-ether. S o other colorlc uld he detected o n t,he colunm. T h e quatit,itv nf :t determined si,ect,rophotonietrically. Tal)le 11 g i w .pe.ctropli[itoinctric.
d :\t :t.
BAZOLE ( C - 3 9 0 )
I{RSI.I,TS,
Otie grain of' powi(*t,C'--120,which h:td l i e c i i i lir~:itct! ;.io ('. c,ontairird 0.:30 trig. ui' .V-nitrosorli~~lic~r~~~l:itnitit,, 0.09 iiig. of 2-tiitrudi~~l1c~ti~~l:t1iiine, 0.15 rng. O i biiitrotlipheiiylaniine. :tiid lc~ssthan 0.0 I ing. of tii]iht~ri~l:tmiiie.l'lie Iirwrtiw of .\~-riitroso--i-riitrotli~~hrtiylatiii~ie w:iq in!licutrd by irs
NTRALITE ( R P L 142)
:it
IO
20
30
40
50
60
70
streak rr,:ic)tioti :md pwition on t,ht, column. Iii :iddition, wvc>r:il r ~ t l i c ~ycllow r cwiipouiitis, p r o h l i l y iiiiiitro ntid +ri!iit~oilc,ri\-;itivw, rwre present t i l i t n.erc2 not iiivctstigateti. Thrx most conipletr stiiciy of the deriv:it,ivcs formctl frotii :trartIite \vas inatlc oii llic' wniplv of p o n t l ~ rivhic.h hac1 l ) e t . i i lirattcl for 10 days at, '75" C'. (T~+lilc 111). T h P niononitrr)ili~ilir~iiyI:iniitirs \v(~i'i, riot pwwtit. : i i i d no attempt ~ ' 3 . ' i i i : d c ~ t o ciotcv.t .V-tiiti~n~odiplirn~l~t~ninc..
e0
T I M E OF HEATING, DAYS
Figure 1. Ikerease in Stabilizer Content of I'owders during Storage at 75" C. 1)iphrnylamine p o w d e r stored at 71' C.
nirthods as those u m l i i i thc ptudy ~f di~~heii~-lntiiiiit-staliizc:tl I)owders (24). Acardite was determitied kil- the follo~viiig procedure. Ag paratus, methods, and materials have already been described (24, 2.5). h column (19 X 150 miii.) o f new 2 to 1 siliric arid('elite \\-as prewashed with T' nil. of ether :ind 21' nil. of ligroin ''1. i d . " is defined its the volume of solverit required to \\-et cumpletely it cc~luniuof adsorl~eiit. A sample of po\vder was estracted for 1 hours Lvith niethyleiie ctiloride iri n Soxhlet estractor, and a portion of the estract in methvlene chloride and c:oritaiiiing 1 to 2 m g . of :ic:tidite was then placed on the culuniti.
C'arbazulc 9-Nitrosirx-arbazole I-h itrocarhazole 3-Sitrocarbazole 9-Nitroso-3-nitrucarbazole 3,fi-Dinitrocarbazole
zene fY) Iialilbauni recrystd. twice from benzene 16, IO) IS) 1'9, 1 9 )
' 1 0 , 13. 19. 2 c , ( 9 , 1.7)
(1.9)
L-nknown I1 (proh- Isolated froiii heated uou-der ably 1,fi-dinitrocarbazole) Tri~ihenylaniine Eastinan \ T h i t ~ Label recrystd. froin e t h y l alcohol ( 2 ) 4-nitrotriphenyl( 1 4 , PO! amine -I,?'-Diiiitrotril,henI w l a t e d froin heated w w d p r (4,1 4 ) ylaniine
2.78-247 81 5-82 0 184-188 205-216.5 102-166.5 Ai)iirox. 360
..
125-127
O.XY4
1 87
24t2 2 4 7
226
81 0-81 5
280 300 5 30.5-307 :30&3K?
2 47
1 43 I 46 0 98
281-283
1 26
2 04
Til6-31i
1 91
I 3.1
29i
I 01
2 :3ci
188-189
2 1 3 .E-215 l i 0 (deroltlpvsed) 300 (sulj)linie~ll .100-560 !chars) 1 L ' i - 128
139-140
139-138 i
195-20i
I!l,?
1H3 i
50
I 90 I 48 1 45
i 03
,394 ,'
1 56
I 86
404-405
I 58
2 43
First literature citation under each compound I S f o r nlrthod of i i r e i m r a t l o n ; nieiting j m n t s a r e a1.0 ~ I Y 111 V other references. J l e l t i n g pointe within these extremes are s t a t e d in literature: t h r i r value3 are n o t iis,iaily tl1o-e u i an>- gl,-en prpiraration, Calibrated thermometers were used and stem correction\ u-erp applied. O t h e r niaxiina are iisiiallv t o he observed in t h e spectrnnl, b u t t h a t given is convenient f o r rpectronhotonietric determiination. Methods ar; given in citation ( 2 4 ) . C = concentration, rng. per 100 ml.: D = log 1 1 0 . I).where D = ojiticul deriaity. 1, = intensity of incident light, a n d I = intensity o i t r a n s m i t t e d light. I .\loleciilar extinction coefficient: ET&, = log (Io,I ) . I C , where I = lenqrh of sol\itictn traversed and c = concentration, moles per liter, g Slit w-idth of s p e c t r o ~ j h o t o m e t t rwas 0.9-1.0 n11n.
*
~
The sample wtiic~h h t l I W I * I I 11rated a t 7 5 O c. fur 80 (l:lyh c,o~itainrd0.30 mg. of 2,2',4,4'tc.truriitrodipheriyl~~~iiti~~ pc'r gram of powder atid considerable quantities of the, trinitrotlipheriyliiniines, as u-c,ll it- sonif8 ~,~'-dinitrotliphenylatriitit~, S o n e of these sani1)les contained the blue pigniriit \\-hic.h was very evident iii \ [ E T H O U ~ . The geiieral chroinatographic and spectrophotometric methods, materials, anti apparatus described in previous articles (24, 25) a e r e used in the present study unless specificilly stated otherxise. Tahle I1 shows the methods of preparation, melting points, uud pertinent spectrophotometric data of the conipouritis Ivhich mere prepared to aid in the identification of substances isolated from povi-der. T h e propert,ies of unknown I1 (probably 1,Gdiiiitrocart)azole) which was isolated iii sufficient qu:itit,ity f O l reasonable characterization are also included. Table IT-presents the specific methods for the chromatographic separation not only of the derivatives which had been synthesized and for which a method of separation had been devised, but' also for the isolation of the unknown substances which becwne a p parrnt, during the courpe of the analyses. Quantitative studies of the recovery o f kiioxn amounts of compounds xhich had been
20
40
60
80
100
120
TIME OF HEATING AT 7 S ' C ,
140
160
180
DAY5
Figure 3. Formation and Depletion of Carbazole and Derivatives in Powder C-390 Heated at 75" C.
April 1951 subnutted to the entire isolative procedure were made only for carbazole a n d the two nitroso derivatives. Oarbazole can be determined n-ith the usual accuracy and precision (100 * 3%) and %nitrosocarbazole also if elution is made with ethyl alcohol; recovery of 9-nitroso-3-nitrocarbazole is only about 90%. Because the other derivatives are not labile, there is no reason to expect any difficulty in their recovery.
INDUSTRIAL AND ENGINEERING CHEMISTRY
943
TABLEIV. PROCEDURES FOR ISOLATIOX OF DERIVATIVES OF CARBAZOLE FROM DOUBLE-BASE SMOKELBSS POWDER"
Operation
3. 4.
9-Nitroso-3nitro-CBZ 1-Xtro- and 3-nitroCBZ
Material to B~ Chromatographed* Use ext. (1-2 mg. CBZ) Use ext. Use ext. A.
Use ext.
Sample Solvent Developere,li Vol., Vol., Compn. ml. Compn. V ml. 2-3 1 : 3 h l C - L 5-10 1 : 4 B-L
Color Reactionsa "01, green
1 : 3 MC-L
5
0 . 5 % E.4in L
2
" 0 2 ,
1:3 h i C - L
5
1%EAinL
2
5
1:4B-L
4
Ceric sulfate, green
1 : 3 MC-L
green
...
Remarks Zone a b o u t in t h i r d fourth of oo!umn Zone in third f o u r t h of column; elute with ethyl alcohol Zone of column i n t h i r d fourth Isolate these c d s 3 6 dinitro 8 B Z ' a h d S G from eon6 a t t o p of column Collect 1-nitro-CHZ In filtrate during E-L development; B washes N G froin column a n d 3-nitroCBZ into center of column: 3,6dinitro-CBZ a t t o Insoly. requires h I 8 as sample solvent a n d separate chromatogram Well defined zone in middle of column; h-G a n d I-nitroC B Z in filtrate; others strongly a d sorbed Zone in lower half of column below 3nitro-CBZ a n d 3,6dinitro-CBZ; NG and I-nitro-CBZ in filtrate .4t top of column above 3.6-dinitroCBZ Adsorbed helow 3 , 6 dinitro-CBZ
-
-
RESULTS. 9-Sitroso-3-nitrol:9E-L 2 . 5 a-Nitro-CBZ, B . hlixt. 1 : 3 MC-I> 5 orange with B 0.8 from 4A carbazole was not detected in XaOH any sample of heated powder, but all other derivatives whose properties were known were present in a t least three sam5. 3,6-DinitroUse ext. hI c 20 B 1 . 5 S a O H , orange CBZ 1:4E-L 3 ples. In addition, four unknown substances were isolated 6. Unknown I Use ext. of 3 %IC 10 1:lB-L 4 ... from powder which had been g . powder heated for 90 dags or longer. Of the unknowns, I 1 is quantitatively the most impor7. Unknown I 1 Use ext. 1 : 3 M C - L 10 1:lB-L 5 ... (1 ,B-dinitro1:9E-L 3 tant and was isolated in crystalCBZ?) line form. The determination of its spectrophotometric prop8 . Unknown I11 C s e ext. 11C 10 1 : 4 EA-L ... erties permitted its quantitative estimation in the various 9. Unknown I T ... heated samples. Unknown I1 Same procedure ab in operation 5 has no real melting point but Abbreviations: CBZ = carbazole, B = benzene, L = ligroin 160-70' C . ) , E = ether, A = acetone, EA ethyl acetate. M C = methylene chloride, XG = nitroglycerin. chars betneen 300" and 360" C. * hlicrotonied samples were extracted for %. hours with methylene chloride in Roxhlet a p p a r a t u s . Its spectrum shows the comCompositions are given as ratios b v volume. .Idsorbent was new 2 : 1 silicic acid-Celite. Column dimensions x e r e 19 X 200 mm. with this exceptii,ii: plexity of several sharp mavima Prewr.8.h y s 0.2 V ml. of E , T' ml. of 1 : l A-E, 0.8 T ml. of E, a n d V ml. of L a n d operation 6 , 35 X 180 mu:. i; ml." i s defined as t h e volume of solrent required t o wet completely a was Tml. of I, (30-60' (2.). poutwash which seems tobe characteristic column of adsorbent. Elutions were with E unless specified otherwise. of carbazole and its derivatives. e Of t h e known compounds, 1-nitro-CBZ formed a bright yellow zone b u t others were qolorlass or very pale yellow. Unknown coinpounds formed yellow zones. Reagents u.ere used t o locate or delimit t h e zone more preT h e f o l l o ~ i n g evidence indicisely. Reagents have already been described (94, 2 6 ) . cates that unknown IIprobably is l,&diriitrocarbazole Figure 3 shows that, after the depletion of carbazole, the main reaction is the depletion of 3-nitrodata, however. are too scanty to permit any d e h i t e conclusiona. carbazole. A portion is converted t o 3,6dinitrocarbazole, and Unknon-n I\- was present in the 180-day sample. I t s spectrum i t might be supposed that other dinitro compounds such as 1,3-dinitrocarbazole and 3,8-dinitrocarbazole (which is equivalent which had a maximum a t 306 to 307 mp and a minimum a t 273 nip is less complex than t h a t of other carbazole derivatives. Ita to 1,6-dinitrocarbazole) would be formed. Because the substituchromatographic properties, its appreciable quantity, and iw tion of a second group into a compound which contains several aromatic rings tends to occur in an unsubstituted ring, the forappearance a t the later stages of the reactions of carbazole lead one t o suspect that unknown I V may be 1,3,6-trinitrocarbazole. mation of 1,6-dinitrocarbazole rather than l,%dinitrocarbazole is t o be expected, the more so because 2,4'-dinitrodiphenylamine, Unknown I11 was found only in minute amount. Its nonthe derivative analogous t o 1,6-dinitrocarbazole, is an important descript spectrum was without maxima or minima. It has been mentioned that heating caused the powder t o become progressively product of diphenylamine in smokeless powder. Furthermere, the chromatographic properties are those which might be predarker. However, after extraction with methylene chloride most of the color remained on the nitrocellulose residue. Urrdieted for 1,6-dinitrocarbazole. Because the literature records no information about 1 , 6 dinitrocarbazole, it has not been possible to characterize this TABLE T'. RESVLTSO F QUAKTITATIVE AN.4LYbES FOR DERIVATIVES O F CARBAZOLE compound further. IS POWDER C-390 HEATED AT 75" C. So little of unknown I could --Weight of Derivative. h l g . / G r a m of powder-^^be isolated that its study was Time of Unknown I1 Carbazole Heating, g-h-itrosoI S i t r o 3-A-itro3,B-Dinitro(1,d-dinitroAccounted limited to observation of its Days Carbazole carbazole carbazole carbazole carbazole carbazole?) for, % chromatographic properties and to qualitative determination of its spectral curve. The characteristics of the spectrum place it among simple derivatives of carbazole, and the Sample did not evolve red fumes b u t became so h a r d , brittle, a n d fissured t h a t i t had t o b e broken in a m o r t a r a n d pestle before extraction. chromatographic properties b Surface of sample was covered with a yellow material u,hich rva? foiind t o be 3,6-dinitrocarbazole; therefore might well be those of 1,3- or this result m a v be low. 1,s-d i n i t r o c a r b a z o 1e. T h e
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April 1951
INDUSTRIAL AND ENGINEERING CHEMISTRY
parison of its melting point and spectrum with those of synthetic material, and 4,4'-dinitrotriphenylamine by the agreement of its melting point with t h a t in the literature (4). T h e literature records t h a t 4,4',4"-trinitrotriphen?.lamine melts at 280" (14, 1 6 ) and a t 396" C. (5) and is very insoluble in the conimon solvents (16). T h e tentative idrntification of the trinitro compound rests, therefore, on the observed insolubility and on the fact t h a t , &B the major product. from 4,4'-dinitiotriphn~yla~nine, it is most reasonable t o assume that the syninietyiral trinitro derivative would result.
945
evidently is 4,4',4"-trinitrotriphen~-lsmineis formed. -\t any stage the suni of the minor derivatives is at most of the order of 10% of the main products.
I
1
I
I
1
80
70
60
50 40
Time of Heating. nays
---Weight
of Derivatiye, I I y . 'Gram of Poh-der44,4'-Di4,4',4"Minor
Sitro-
nitroTPA
... ...
ill
0.02 4.2 5 9 8.0 8.2 4.7 0.91
10'' 1.34
.,.
0 12 18 30 -16
TPA 10 4 2 0
0 7 8 75
TPA
...
.laniine must br converted completely to the dinitro isonivr txxfore what
30
20
MINOR D E R I V A T I V E S
I O
15
30
45
60
75
90
T I M E OF H E A T I N G AT 7 5 ' C
105 I
120
135
DAYS
Figure 4. F o r m a t i o n and Depletion of 'I'riptienj I a m i n e atid Derivatibes i n Powder C-ti3 Ileatrrl ut i5' C .
Thp H-ell defined spectra indicate, that the minor compounils :irr not nondescript suhstancrs such as are formid f r o m wiitr:iIit?. If earh is 3 difkrent derivative of triphenylamine, it is difficwlt to imagine what thc structures :ire, since only aftrr the trinitro stiigr has h r r i i i,rxched does the third phenyl group pcrmit an iiiim~:isc~ in the numl,cr of isomers ovrr t l i o s ~\vhich could lit> fornitd fi,oni diphenylamine. Sirice the fornintioii of .\--iiitroso tlrrivatives of ti,i~,hf,iiyl:iiiiiil(, is prrcludrti, it semis probablr t h a t the moleculv is dirrc,tlJ. nitr:itcd t o forin the derivatives i s o l i i t d The percentage of the original triphenylamiiie which ma!. lw accountcxd for (75 to SOYo) is conaidrrablp atlove that of o t h r r stabilizilrs. Thus, the values are: foi, diphenylamine. 50 to 00%: for cmtralite. 30 to 40%; for acartlite, 40%; and for carl)azolr., 60-70y00. If the quantities rquivnlent to the minor dcrivntivrs are taktm into account, thc 1'c'cover)- is even better. 8inc.e this spectrophotometric d a t a f o I ~-nitrotriphenplaniinc arid 4,4'diiiitI.oti,ii,henylamiiic are not too ar.c*uratr~lyknown, there i d (>rroi,iii thc c-altdated recovery. ACKZOX
i x n c UE\T
Thc, authors :icknowledgr \r-ith pleasure theif, ind(~I,tc(lii(wt < ) I ? o h i . t I 3 Core., under n h o s ~supvrvision the, work \vas e:trric,il out, anti to Linus Pauling who, as Official Investigator, m:idt. many interesting suggestions. Philip F, 1f'ilt:ox anti IAUIXI.. Fong assistcd in certain phiises of the work.
28, 233, 284 ( 1 0 3 3 ) . i Z i Ihilstein, " H a n d b u c h der o r g a n i s c h e n C h e m i e , " 4 t h
d,, \.(iI.
INDUSTRIAL AND ENGINEERING CHEMISTRY
946
(13) Eikhman, R. K., Lukashevich, V. 0.. aiitl Si1at.w. E:. .IOrg. ., Chem. I n d . (C'.S.S.R.), 6 , 93 (1939). Hem, R . , Ber., 23, 2536 (1890). Heydrich, C., Ibid., 18, 2156 (1885). Kirby, W.,J . Soc. Chem. I n d . . 40, 2741' ( 1 9 2 l j . Marqueyrol, l f . , M e m . poudres, 23, 158 (1928). Menon, B. IC., Menon, E. V., and Peacock. I). II., J . Chenr. Soc., 1942, 509. (19) Morgan, G. T., and Mitchell, J. G . , Ibid., 1931, 32S3. (20) Piccard, J., and Larsen, L., J. Am. Chem. Soc., 39, 2006 (19171. (21) Reudler, J. F. L.. Rec. trav. chim., 33, 35 (1914). (22) Ryan, H., and O'Toole, P. K., Sci. Pmc. Roy. I l i i h l i n ivoc.. 17, 139 (1923). (23) Schroeder, W.A , , Ann. .V. 1.. d c a d . Sci., 49, 204 19-1-Si. (14) (15) (16) (17) (18)
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Vol. 43, No. 4
,$chroeder, IT. A, Malmberg, E. IT.,Fong. L. L., Trueblood, K. N., Landerl, J. D., and Hoerger, E., IND. E s c . CHEM.,
41, 2818 (1949). ( 2 5 ) Schroeder. W. A , , M'ilson, 31. K., Green, C., Wileox, 1'. E., Mills, R. P., and Trueblood, K. N., Ibid., 42, 539 (1950). 4.26) Tonegutti, AI., ALti V coiiyr. noz. c h i r p . p u r a applicatn Rome, 1935, Pt. 11, 899 (1936). ' < 2 i ) Tonegutti, M.,Z.Q ~ S .Schiess- u. ASprengsto.fw., 32, 300 (1Y37). 128) \Vhitner, T. C., J . A m . Chenr. SOC.. 46, 23326 (1024). RECEIVED J u n e 12, 1950. Contribution 1-129 from the Gates a n d Crellin Laboratories of Chemistry. This paper is based in whole on work dona f o r the S a w Department, Bureau of Ordnance, under Contract NOrd!?lid27 with the California Institute of Technologv.
Isobaric Heat Capacities at
Bubble Point TZ-HEXANE,METHYLCYCLOPENTANE, AND n-OCTANE T. J . C O N S O L L I . B. t i . SAGE, 4411W. N. LACEY California
E
f n , * t i t utr oj 7echnoIog3, Pusodenu 4. Culif.
X P E R I kl E S T AL
I n order t o extend the range of temperatures for which the calorirneter h n i b and the heat capacities of organic liquids of industrial imporcontents for tlie large and measurements of the heat capacities of n-hexane, tance are a ~ a i l a b l e ,a set of calorimetric measurements small samplesof each hydrowas made. carbon studied, nnd for t h e methylcyclopentane, and These d a t u establish tl1e isobaric heat capacities a t snioll temperature intervals n-octane in the liquid phase bubble point, fur 11-hexanr, nieth: lcyc:lopcntane, and n used they were taken as have been reported in t h e literature. T h e studies by octane a t temperatures from 110" to 200" F. The data are cqual to q J d T and qr.!dT in agrerment with earlier measurrrnerlts and are of adefor the mean value of temParks et al. ( I O ) , Huffman ef al. ( 6 ) , and Douslin and quate accuracy for most engineering n orh. iwrnture in the intt,rval. Huffman (4) cstablished Jleasuremcrits of this type arc important in extending T h e other terms S('I'VC t o the range of temperatures for whie!l free energies, eno1Jt:tiri thc isolxiri(, hcat t h e behavior of n-hexane in the liquid phase a t teinthalpies, arid entropies of these c o m p o u n d s can be esti(::LlJ:lCit>. til(' lJIlbkJ1e peratures below 80 a F. mated. Such heat capacitj- data, when coupled with point from t.llcz i ~ o i ~ l ~ o r i v ~~l~~:~~llr~l~l~~llt~. There are available ( 3 , 6 ) directly measured experimental ~ o l u n i e t r i cdata or suitmeasurements of methylable correlations, permit the thermodj nanlic properties >lATERI .\ L S cyclopentane in t h e liquid t o br deterniined as a function of statr. phase at t,emperaturesbelow l h e n-hexane W ~ P ob80" F. D a t a on n-octane tairied from the Phillips Petroleunl co. and was EPorted cnntain over 99 mole % nwere obtained b y Parks et al. (lo), l l u f f m a net al. ( 6 ) ,and Osborne hexane. This material was subjrcted t o two distillations in a 30G~~~~~~~(9)a,hich established the heat capacity at temperplate column a t B reflux ratio of approximately 5 t o 1. At least atures u p t o 95" F. T h e present work includes measurements 10% of the initial overhead and a similar quantity of,material of bhe isobaric heat capacity of the buhlile point liquid iron] 80" remaining in the kettle were discarded in each fractionation. T h e variation of the temperature at t.he top of the column wa8 t o 200" F. for these three substances. observed be less t h a n 0.1 F. during the fractionation Of the Calorimetric measurements were nlatle in the t\x-o-phase regiorl sample. T h e refractive index a s measured on an Abbe refractom with a n isochoric instrument ( I , 2, 12, 14 I . X measured quantity et,,r at 770 F, was 1,3722 for the lines of sodium as comof energy was added electrically t o the citlorinieter and contents, pared with a critically chosen value of 1.37226 (If). The meth31 1 ntane likewise was obtained from the and t,he change in temperature noted. This proredwe J W , ~ rePhillips Petroi&:o(!$, and v a s reported to contain more than peated throughout t h e teniperaturr interval Ijetn-ecm 80 O a d 99 niole % methylcyclopentane, This material was first frttc.200" F. for t h e hydrocarbons investigated. A tlieriiiotl~.n:iinic ratio of 5 to 1; tioni,kd in a 30-p~ateglass colulm at a analysis of this process ( 1 4 ) leads t o the followirlg e q u : t t i o l i relatabout 10% of the initial overhead was discarded and a like of material remained in the kettle. T h e intermedia.te ing the experimentally measured quantit ipP t tire ~ ~c.:,lJ:lc.itif.s ~ : ~ amount t overhead liquid w:ts passed through a column, 1 inch in diamiJter, a t t h e bubble point: packed for a distance of 5 feet with silica gel supplied t)y the Ilavison Chemical Corp. and identified as 659528-2000. T h e Sr - P! initial SO% of the effluent was collected and passed through a dT dT l i d - I; second column of the gel, the first 80% of this sample then kjeirig ml - m2 twated in the same manner a third time. The partially purified nietliylcyclopent,ane thus obtained v a s subjected t o a second disd P , , ( V d d T' - T 7 tillation identical to the first. Independent measurements made b upon a sample of the purified methylcyclopentane indicated a TdT -'1' v d rrfractive index a t 68" F. of 1.40973 and a freezing point of (I) -224.39" F. The correspondlng critical chosen vilues (11) are 1.40970' and -224.40" F. Ths refractive index a t 77" F T h e experimentally d e t e r m i n d quantiticss. (21 A T nlld Q? 1.4068. as c0m~ar.d to ail itcreptrd value of 1.40700 :It this represent the net energy required per uriit trmpc3raturc change of trnipcxrature. ?.
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