MTDR IZISE-\I' \TCR STSTEJI
00 1
It E 1.:1.: It 1:z c1:s (1) (3) (3) (4)
LISD, S. C , : ,J. A l i i . C'liciii. Soc. 41, 31-51 (l9lOj. LISD,8. C., ASTI E.~RDWI:I,L,D. c'.: J. -1m. Cheni. Soc. 47, 2684 (1925). LISD, S. C , . A S D UARUXELL,D. C . : .J. .11n. Chem. Soc, 48, 1 5 5 (19.6). ROIESBLLII,c'. : J . Plij-s. Clieiii. 37, 53-8 (1933).
THE H\71>R~IZISE-TT~11TERSYSTElI' P A P L €1. ~ I O I I I t ?A N D I>. F. AUDRIETH
Soyex L n b o r c t l u ~C J Chcmistty, ~ I-niio.sity of Illinois, T'rbana, Illinois Reccil,cd Dcccmbcr 16>1948
tem liytilazinc-n-nter litis l m n investigated o w r the entire conccntruin ortlcr to verify tlie existence of ;L solid monohydrate of hyd~xzine, t o recletciniinc tlie freezing point of the :11ili~-droiisl m c , and to investigate the possildjty of c~~neentrnting dilute hydrazine d u t i o n s 1,- cooling and rcmoi.ing jt-atcr in the form of ice. Concentlntion of tlie dilute aqueous solution of liydrazinr., ohtained in the ctctl l ~ yfi~ictionaldistillation. The pui4ied salt- and minion liqiior is mriched n.it 11 i w p e e t to 1iyclr:izine in t h e e s u c c c ~ s i ~ 1.i per w n t , then tci 30 p c cent, ~ and finally to a product contnining 80-100 pcr caent lijdrazine hydrate ( 3 ) . Lhta iircwntcd hy Seniisliin is) for tlic freezing pointy of tlilutti d u t i o n s of hydrazine suggested that it sho~ilcll i c possi1)Ie t o effect a ;itiIi.-tnntial concentration of such solutions \\-ith respect t o their hydixzinc. c o n t e i ~ tI)>- f'ri.czing out \vnter. Prcliniinary esperimentd trials did sh that sonic concentration is po,sSihlt., hiit not t u the x&nt anticipntecl. It therefore c*onc,iiidctl that the iwo1detl datLr miist he n error. 1he present inyostipntion \\x> uiidwtaken in part t o resoh-e these liscrepancies. r 7
ESPI:RIMElrT.\L
A . JIaftr.ia1.s
Cornmerc~inllj-nvailuhle 8.i per cent hydrazinc hydrate IVLI? used as the starting naterial. I t v x s found t o lie of high purity and ]\-as used directly for ni:ilting ome of tlie niorc diliite hytlrnzine solutions. Dehydration and concentration o yield eseentinlly mliyclroiis hydrazine i9'3.(i per cent) \\-ere achieved by adding From p:ii-t of :I thesis presented bj- P a u l Herman 1 I o h r to the F:tculty of the G r a d u a t e cliool of tlie L-iiiversity of Illinois i r i parti:rl fulfillment of the requiremerits for t h e degree ' Master of Science, Julie, 1945. n ' e s t e m C:irtritlge Compnny Research Fellow in Chemistry a t the University of Illinois, 1-17-45.
902
PAUL 13. XIOHR AND L. F. AUDRIETH
a sufficient amount of sodium hydroxide to form the monohydrate TI ith the water present and then fractionating the mixture under reduced preswre. &illdilutions were made using doubly distilled Tv-ater. Every precaution n-as observed t o avoid contact of both the dilute and the concentrated solutions of hydrazine T.IBLE 1 Freezinq p o i n t s for the s i j s t e m hijdrazine-water ~-~~ ~
SZHI
BUNYO
FREEZING
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lIETaOD
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5 6
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
mole per t cent~
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5 40 5.40
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3 11 -3.80 I 3.11 -3.80 1 6 4 0 i 371 -430 7 GO 4.43 -5.30 449 I - 5 4 0 1 770 5 10 -6 40 I 8.70 1 11 9 7 06 1 -9.80 1 12.6 7.51 -10 3 8 32 -12 8 13 9 8.58 -12 7 14 3 -19 1 18 4 11 2 19 0 11 6 -20 3 11 6 -20 -1 19.0 -22 0 19 7 12 1 12 2 -22 2 1 19 9 -22 3 20 3 12 5 13 3 -24 7 21 4 22 2 13 8 -25 3 1 23 4 i 14 7 I -30.3 i -30 8 15 2 24 1 -33 3 I 15 6 24 8 26 0 16 5 -37.3 i -34 9 16 6 26 2 17.6 -41 6 I 27 5 -44 3 28 4 i 18 2 29.6 19 2 -46 3 23 7 -65 9 35 6 31 4 -75 8 45.0 1
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per weigh1
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29 30 , 31 32 33 ' 34 I 35 36 37 1 38 39 40 41 42 i 13
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44
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45 , 46 47 -18 I 49 I 50 ' 51 52 53 54 55 56 ' ~
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49.3 57.4 58.1 59.9 60.6 63.1 64.2 64.7 66.5 66.6 67.6 69.2 69.6 70.3 70.4 70.7 72.0 72.6 74.8 75.0 81.0 84.1 85.1 90.1 97.9 98.4 99.0 99.6
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lmole per cent
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35.4 -61.7 43.0 ' -53.7 43.9 -53.4 -52.6 45.8 -52.2 46.5 49.1 -51.7 50.2 -51.7 -52.0 50.8 52.8 -52.2 -52.7 52.9 -52.6 54.0 -50.3 55.8 56.2 -52.8 -46.8 57.1 57.1 -46.2 -44.2 57.8 -40.2 59.1 59.8 ' -40.2 62.5 , -34.1 62.8 -32.7 70.5 -20.4 74.9 -15.6 76.2 ' -14.8 83.6 i -8.70 96.4 -0.10 0.20 97.1 0.90 98.2 99.3 1.60
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3 3 2 2 2 3 2 2 2 2 3 3 2 3 3 3 3 3 3 3 3 2 3 3 2 2 3
2
* S u m b e r designations indicate t h e method used t o determine t h e freezing point or composition of t h e liquid phase a t a given temperature: 1, sample of liquid phase removed by means of filter stick and analyzed; 2, d a t a based on time-temperature cooling curves; 3, average of freezing point-melting point. See text for details. n-ith the atmosphere in ordpr t o prevent oxidation and absorption of carbon dioxide. Transfers and dilution\ n ere macle in a nitrogen ntmoyihere. All solutions 11 ere andyzcd for hydrazine citlier by titration against standard acid v ith methyl red a- indicator or o\;idimctric:illy uqing the iodate procedure with inteinul indicator (61.
112. -Ippni.nt~isatid procediire Melting-point (and freezing-point) tletermiiiation;; \\-ere carried out uiitlcr i i i t i q e n in a closed, tlo~thlt~-~\-alled, &is c ~ 1 1fitted with a mec1iaiiic:il stirrcar. I emperatures were measured 11-ith a calibrated alcohol thermometer grat1u:itcd in 0.2" and with a tliemomopilc which had heen calibrated at the freezing points of ineimry and carbon trtrachloridr. The tlatn given in tahle 1 and depicted graphically in figurc 1 irere ohtained hy three different methods. In the inore dilute regions the sample v w cooled slon-Iy to n tiefinite temperature and held at this point for at least, 1 111,. t o : w w e - 7
--,
FIG.1 . llelting-point diagram for t h e system hydrazine-water. present data.
- - > datn bl- Semishin;
attainment of equilibrium htn-een the solid and liquid phases. Aisumplc of the liquid phase was then witlidran-n for analysis by applying suction t o a precooled filter stick. T h e procedure TWP then repeated on the same sample either by cooling or by \\-arming to some other temperature, although no morC t h a n four samples \\.ere withd~~nn-n from any one solution. Results obtained in this manner ~ w r echerl.;ed for other ronipositions in the same concentration range 147 plotting tini-temperatuie cooling cvrves. Separate samples \\-ere used in all casts for solutions containing over 30 per cent hydrazine by u-eight. Timetemperature cooling cur\-ei \\-ere determined in the concentration range u-here the monohydrnte is o1)tninetl :is the c~,yt:Jiincphase. Solutions containing still higher conwntratioiis of liytli~azine(from GO t o 80 per cent) 11-ere found t o siiperroo1 so mar1;edly that coii.4tlerable difficulty ~ \ x sesperienced in using either of
DISCI-SSIOS r 7
I hc (lata for fiwzing points of I i \ ~ l ~ x z i~-\\-:itei, nr mixtiircs \\-ere obtained over i h c entire cmcentixt ion ~ x i g e~ z c ~ fpo it, ~1:itionscontaining 35-49 per cent Iiyc~rxzinc~. Fiwzing points in ihis ( * o n w n rxt t ion rnnge \\-er(l not only found t o t>xtrimcly lo\v, hut soliitions 1 , c ~ a : i r n c . x.tsi-y \-isrmis; cven the addition of ice tills tlicl not i n t l i i c c ~c The (1iit:i definitely YPI' I W of :I, inonohydrate of hydrazine Tvith a melting point, at -51 . i " C ' . 'l'\\.o t~riirrtic~.: \\TIT also dioivn to exist: one contains 09 pel* ccnt ( X molc pt'r ( * ( t i i t ) h ~ - c l r a z i n t \\.hilt ~, the other is not defined since it is in i h r x ra~igeof conccntixt ion3 \\.lien. melting points m i l d not he determined. Extrapolation of the f'rwzing point from $49.6per vent t o 100 per rent hydrazine gives a \-:iluc of 2.0"('. for t lie frwziiig point of anhydrous h>-drazine. This figure agrees \\.it11 the \.alric~ iqioi'ted by I3ruhl ( I ) and hy Curtius (3), but is higher than that determined hy other investigators ( 2 , 1,7 , 9,S).3 Comparison of the niclting-point diagram Imsed (a)on the experimental results presented by the authors and (6) on those previously reported hy Semishin reveals excellent agreemcnt for solutions rich in hydrazine, but marked deviations appear as t h e solutions becomc more dilute. The points plotted by the autho1.s in the region of tlie nionohyclr:ite shoi\- a very gradual curve ivitli a maximum at a cornposition corresponding to the formation of the monohydrate. Semishin's data are depicted pi~nyliicnll\-;is ti1.o straight lines intersecting sharply at a composition corresponding to i t monohydrate n-ith the result that a higher melting point (-46.8"C.) is obtained. The redetermined freezing points in tlic dilute hydrazine range drop much inore rapidly x i t h increasing hytlrazine conceiit'rations than had been recorded by Semishin. I-sili. Cheni. A165, 241 (1033).
THE S o L u m x n - OF XSTI~IOST(III) FLT-OIIIDE ISOKGAYIC COlII'UI-XDS1 DOSA1.D JT. B1iJ*:CI
