COT\4MX-NICIITION TO T H E EDITOR1 O S REPORTS Bl- F.E. JOSES IS THE SOT7EMHEK, 1944, ISSCE OF THE J O L R S - i L OF 1’H\7SICXI, C’HEJIISTR’1~ O S STITDIES OF STSTEJIS INT’OT~T7TSG CaO-~21?0?-~:C)i-T~?O-~a?O-H~O l q COXSTITTX”8 F. E. Jones nierits liiglic,5l praise for a11 o~itstantlingc~ontril~~ition t o the chemistry of cements as presented in his reports on the iybtem (‘aO-zl120s -CaS04-H20 a t 25°C. (J. Phys. Cheni. 48,34 (1944)) and the t\\o related cluinai 1 per cent of potassium hydroxide (J. Phys. Chern. 48, 356 (1944)) and 1 pci cent of sodium hydroxitlc ( J . Phy.. C‘hem. 48, 395 (1914)), respectively, as fifth components. In the report on the systeni Cia0~.1120a-Ca~O~-Sa?~~-H20 (loc. u t . ) refercncc is made b y Jones to a statement in a discuqqion ((+. 1, Kalouvk: &hi. Concretc Inst. 12 (Proceedings 37),692 (1941)) bawd on requltq given in a dissertation 1)y the present m i t e r (G. I,. Kalousek: Dissertation, 1-niversity of Xaryland, 1911). I t is stated in this later discussion that the lrork “indicated that thc stable wlfate-bearing conipounds in the presence of Sa0T-T a l e niemlwi of :I qolid d i i t i o n 1
Iicceivcd May 20, 19-15.
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COSlSIU1VIC.~TION TO THE EDITOR
w i e s having 3CaU.A1?03.CaSO4. 12H?O and 3 C ‘ a 0 . ~ ~ 1 ? 0 3 . C a ( O H ) 2 . 1a.~ H z 0 cnd nieniberc: ,Joiit* concliidc~i n hi. report t h a t a t a sodium hydroside or potassium liydio\idc c ouccntratioii oi I ~ x cent ~ i the ~ c~onipound3 C a 0 .A1103. 3C‘:iS04.:32f-T20(tii-uli:it(>l the onl> i t n l , l ( ~ciilfate phase :and supgeqts that solid solution. 11111 o c ( w a s :I uictn.t,il)le phase as in the qnateinary system Ca0-.11?07-C’a~0~-H~~). Inasmuch a. the difference in conclusion may be traced to a ditl’crcmccot choicc iegarrling ci itcria for stable equilibrium, the following comment. appeal pelrtinent. 111 diwii+ig ilit. quat c.inai!: ~ y ~ t c .Tone% i n states, “, . , it thusappearsprobable t 1iat 3C’:iO . l I , O i ?A ( ), 32H-1 init idly ioi*mc~lmay (’\ cnt\i:~lly changc cwriiplotc.ly t o w l i t l - 0 l u i i o i i . ” 1q:itlioi oi i \\ o implications is cwntained in tlii5 -tatt.n~cwt: (! i tlic, t i i - i i l t : t t c , i- inc.ta~tal,le; or ( 2 ) tlie third solid phaw, .K‘aO -41?03.~ i H ~ l)c~ide, 0, C’a(OH)?that is required for invariance, does not appear In the latter c a i e the d i d wlntion formed woulcl be metastable with respect t o 3C‘aO . U J 3 . 6 H 2 0 . Jones’s interpretation i b gii en Iwtei in tlic discussion of the quinary system C’~t0-.~1?03-C‘as(>~-liO-H?O at 25°C.. in xhich he states, *‘. . .at G, for stable rquilibrium, iorniation of 3CaO , A203GH20 chould occur. From analogy with 1)ehavior in the quaternary system Ca0-~~1?O3-CaSO4-H?0, however, i t seems proljnhle that t h e fundamentally stable phase (3Ca0 ..11203. 6H20) TI ill not : ~ p p ~ a:it r , any rate for consitlcrahle time, and that equilibria will pass into :I iiiotait:hlc region I\liere formntion of a solid sollition of general formula zC’a() . y.&OJ . x C ‘ u S O I . aci coiimicnw~,ant1 an appropriate metastable ec~uili1)riuiiii i sct up.” The same summary hold^ true for the findings in the quinary system Ca0-~11203-CaSO~-Saz0-I-Iz0 a t 25°C‘. I t is seen, therefore, t h a t if 3 C a 0 LU,03.GH,0 appears and is the stable phase in the presence of calcium hydroxide in the yuinaiy system, the trisulfate is likenise a stable phase. The composition of the solid solution I\ o d d be varialile as rspressed by Jones, and z in the general formula given is not restlicted to a T alue of 3, y being awigned a value of 1. The deterniiiiation oi the houndai ;r. Ca(OH)2-trisulfate (or monosulfatc, 3Ca0 .&O3. CaSO?.121Iz0)-.*lime ahiminate hydrate” in the system CaOX1203-S03-San0-H20 at 25°C. \\as undertaken by the writer (G. I>. Kalousek: Dissertation, University of Maryland, 1941). The sodium hydroxide concentration wa5 Yaried betn cen 0.0 and about 0.5 S (0.0-20 g. per liter), and the solid phases ~ \ c r eprecipitated in all tests b y mixing aliquots of aqueous solution< of the constituents. I n addition t o the two k n w n sulfatebearing compounds, anothci suliate phasc (solid solution 3Ca0. ,ll20J.Cas04 * 12H20-3Ca0 .l120d C‘a(0II)J.1213-0, \\ hich T\ ah isolated and identified) liatl to be considered. ‘l’he reiiilts of mixture.: agitated occasionally and allon ed seven to nine \leeks to age shouecl that in the range of sodium hydroxide concentration of about 0 . 2 to 0.5 N the three phases for the boundarywere Ca(OH),trisulfate-solid solution. I n not a single preparation in this range \vas there found any of tlic compound 3CaO . A l l ~ 0 3 ~ G H 2Companion 0. mixtures in the same sodium hydi o d e range I\ ere prepared and set aside. .lfter eighteen months thPy I\ ere ex:tmiiictl for 3CaO .,lI2O3.(iH20,hiit none was found. ?‘lit$ ”
14
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+
3
3
407
S E n - HOOKS
other phases (solid solution and trisulfate), except for slight carbonation, appeared t o be about the same as in the seven- to nine-week tests. I n the range of sodium hydroxide concentration of 0.0 to about 0.15 S , hydrous alumina appeared as a third phase but, since the time of seven to nine 11-eeks seemed short for attainment of equilibrium for a gelatinous phase, no conclusions ivere dran-n. Long-time tests were not carried out in this range. The absence of 3Ca0.XI203. GHzO in the prolonged tests indicates either that equilibrium x a s reached, and therefore, the solid solution is actually a stable phase, or that the compound in question forms very slon-ly indeed. Jones’s conclusion that 3Ca0 .Al2O3.GH2Ois the stable phase in the quinary 3ystem was actually based on analogy to findings in the quaternary system. In vieiv of the evidence just given, the question arises nhether possibly the hexagonal structure is not stabilized by the sulfate ion in the presence of the stated concentrations of sodium hydroxide and that in reality it is the stable structure (Le., the solid solution is the stable phase). Further experimental n-ork concerned Jvith long-time tests appears to lie necessaiy before a summary conclusion can be made as to n-hich is the stable phase. ,Jones’s deduction that the trisulfate is formed initially in hydrating cements was not borne out by tests carried out by the riter and reported in tlctail in the dissertation (loc. cit.). The platy, hexagonal forms instead \\ ere precipitated initially from aqueous solutions, simulating in composition those in hydrating cwnents. These phases persisted as such for period? of 1 to 40 days Ixforc starting to convert to the trisulfate. However, only trisulfatc preripitntcd from similar mixtures of solutions designed to yield 1000 g. of the trisulfate, when thew solutions were seeded with as little as 0.002 g. of this conipound. The writer is now a nieniber of the staff of the Toledo C’alsipore Laboratory of the Research Department of the On-enq-Illinoiq Glass Company, and permission for publication of this communication is granted hy the Director of Research. His investigations on these subjects, hon-ever, w r e performed at the Sational Bureau of Standards in Tashington, I>. C. (;I;oRoc
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OMens-llliiiois (;law (’ompany Toledo, Ohio
NEW BOOKS Outlzxe o j Ilie Ainiiio Acids u/id Proteins. MELVILLE SIHY-UN, Editor. 251 pp. Sen. York: Reinhold Publishing Corporation, 1944. Price: $4.00. This comparatively small volume contains a surprising aniouiit of information and is highly recoininended as an introduction t o or a brief survey of the field. Eleven people, in addition t o the editor, have contributed material, and each speaks with authority in his particular field. The purpose of the book is t o outline briefly the essentials of the chemistry and the biochemistry of the proteins and the amino acids. The authors hRvc skillfully
