NOTES
1528
Vol. 63
could not be detected, nor could mercuric oxide, the product of the reaction of isopropyl hydroperoxide with mercury.8 Furthermore, such a hydroperoxide formed by abstraction of hydrogen could not be the main precursor of isopropyl alcohol in this system, since every abstraction from isopropyl iodide has been shown to result in propylene formation. The present results show the yield of isopropyl alcohol to be about three times that of propylene. The same reasoning leads to the conclusion that the alcohol cannot be formed entirely by abstraction by isopropoxy radicals. No decomposition products of this radical were detected, and it may not be present in this system. The acetone and isopropyl alcohol can be explained partially by means of Ziso-CaH702 = iso-C,H,OH
+ CH3COCH3 + 02
(4)
a step similar to that suggested for the interaction of a-phenethylperoxy radica1s.g This requires that part of the acetone be converted into unidentifiable products, a possibility consistent with the erratic yields observed. Acknowledgment.-The author wishes to thank Dr. W. Albert Noyes, Jr., for encouragement and guidance in this work. (8) N. V. Fok and A. B. Nalbandyan, Dok. Akad. Nauk,S S S R , 86, 589 (1952);N. R. C. TT-396. (9) G . A. Russell, J . Bm. Chem. Soc.. 79,3871 (1967).
COMPOSITION OF THE SOLID PHASE I N THE NaaP301O-CaClz-HzO SYSTEM BY W. J. DIAMOND' AND J. E. GROVE Received January 14. 1960
Fig. 1. Two hundred-ml. samples of solutions 0.002 M in CaCh o made up and mixed and 0.0002 to 0.0018 M in ~ s P a O lwere for 5 minutes at 25 =k 1.1 . Previous experiments had established that equilibrium was essentially established in less than 5 min.6 Three 50 lambda samples were withdrawn by micro ipet and deposited on aluminum planchets. These were 8 i e d and counted for radioactivity with a Nuclear Chicago Ultrascaler 192. Fifty d. of the solution was passed twice through a dried and weighed 0.45 Millipore filter disk supported on the standard Millipore filtration e uipment with vacuum system. The filter disk was remove%, dried for 1 hour at 50°, placed in a desiccator for one hour and reweighed. These conditions were found to be adequate to obtain a constant weight precipitate. Three 50 lambda samples of filtrate were deposited on plnchets, dried and counted for radioactivity.
Results Quimbyz published the phase equilibrium diaData are plotted in Fig. 1. The weights of gram for the &++-sodium tripolyphosphate system in aqueous solution as determined by Gray precipitate reported are for the 50-ml. samples and Lemmerman. Moisture contents of the precip- which were filtered. The filtrate counts are the itates were reported and some conclusions were average of three samples corrected for background. drawn as to sodium concentration in the precipi- In all samples, count on the initial mixture was tates. Bonneman-Bemia3 reported a salt, NaCa2- 1130 & 30 couizts/minute (95% confidence limits P & & & O , as the product of reaction of equi- for any single determination). Consistency of molar quantities of NasP3OI0and CaClz at room this value over the range of tripolyphosphate contemperature. Quimby2 also suggested the pos- centration used indicates that self-absorption of sibility of a basic precipitate, Cae(PsOlo)(OH). the soft 0-emission was small and in any case 5H20. The experiments reported herein were constant. Therefore, the ratio of filtrate counts to designed to determine the ratio of Ca++ to (P301~)-ainitial counts can be utilized for calculation of in these precipitates by a combination of gravi- Ca++ concentration in the filtrate and the precipitate. metric and radiometric techniques. The phase boundary shown in Fig. 1 was deExperimental termined by a Fisher Nefluorophotorneter and 0.008 M sodium tripolyphosphate stock solution was pre- correlates reasonably well with the weight of prepared by dissolving the recrystallized powder in distilled water. This high purity product (96.24% NasPaO,o)4 was cipitate and radioactivity data. supplied by Westvaco Mineral Products Division of Food Discussion Machinery and Chemicals Corporation. The radioactive If a single solid phase is assumed, the reaction calcium chloride solution (0.01 M ) was prepared by dissolving Fisher U.S.P.CaC12.2H20in distilled water and adding taking place may be supposed to be represented by radioactive Ca-45 as the chloride (Union Carbide Nuclear the equation Company's Ca-45-P-2). (1) Brunswick-Balke-Collender Company, Muskegon, Michigan.
(2) 0. T. Quimby, THISJOURNAL, S8, 603 11954).
(3) P. Bonneman-Bemia, Ann. Chem., 16, 395 (1941). (4) L. E. Netherton, A . R. Wreath and D. N. Bernhard, Anal. Cliern., 87, 8GO (1955).
xCa++
+ 2/(P3010)-~+ zHzO
Ca,(P30dVdLO .C (1) since Quimby2 has shown that the precipitate ( 5 ) W, J. Diamond, THISJOURNAL, 63, 123 (1959).
5
a
NOTES
Sept., 1959 contains no sodium except a t concentrations near the phase boundary. For convenience the water is regarded as water of hydration, although it is recognized that the time and temperature of drying do not necessarily eliminate all absorbed moisture. The ratio x/y (Table I) is calculated from
"'
wt. of Ca in ppt. ~ 3 0 1 0 in ppt.
= wt. of
(mol. wt.P3010) at. wt. Ca
(2)
(mol. wt. P3010) (3) at. wt. Ca
TABLE I NasPsOi concn., mrnoles/l.
Wt. of ppt.,
Wt. of Ca in
g.
PPt.9 g.
0 0.0124 .0236 .0300 .0308 .0216 .0036
.... 0.0029 ,0053 ,0069 .0075 .0053 .0005
.0008
....
0.2
.4 .6 .8 1.0 1.2 1.4 1.6 1.8
....
0
% He0
X/Y
20.3 20.3 20.3 16.2 16.2 16.2
2.57 2.45 2.53 2.57 2.61 1.27
..
..
.. ..
.. ..
yo H20 was determined for 4 samples in each of the water percentage ranges defined by Quimby. The averages of these values were assigned to the samples above. These calculations yield a ratio z/y constant within experimental error, in the range from 0.4 t o 1.2 mmoles/l. of sodium tripolyphosphate. The data for Na5P3010concentrations greater than 1.2 mmoles/l. do not conform t o this ratio, as would be expected, because of the known presence of sodium in the precipitates.2 With x/y = 2.5, the simplest whole number ratio of Ca to P3010is 5:2 and the simplest (empirical) formula with 20% H20is Cas(P3O1o)2.l0H20. Using LaPine atomic models, the only molecule which could be constructed with the simplest ratio was
1529
+
NatCal(Ps010)~ N ~ s P ~ O K ?JftaCa3(P301& J.
+ NaaCaP3010 (6)
The uniformity of the Ca/PaOlo ratio in the range of 0.4 t o 1.2 mmoles/l. of NaaPoOlois contrary to the finding of Quimby and would appear to indicate a uniform chemical composition in this range. However, in Fig. 1, the tripolyphosphate concentration for optimum weight of precipitate approximately corresponds to that reported by Quimby as separating the amorphous precipitates wlth 20-21% water and the crystalline precipitates with 16-17% water.
Conclusions A constant ratio of 2.55 for Ca/PaOlo was found for the precipitates formed by the reaction of solutions containing 2 mmoles/l. of CaClzwith solutions containing 0.4 to 1.2 mmoles of sodium tripolyphosphate/liter a t 25". The empirical formula Ca6(P3010):! would satisfy this ratio. DIFFUSION OF ALLYL CHLORIDE I N POLYVINYL ACETATE AT 40' BY AKIRAKISHIMOTO AND KINYAMATSUMOTO Physical Chemistry Laboratory, Department of Fdaheries, University o Kyoto, Maizuru, Japan Received January 16, 1060
It is often reported that integral diffusion coefficients D of systems of organic vapor and polymer (amorphous or primarily amorphous) above their glass transition temperatures increase exponentially with increasing penetrant concentration C. These coefficients at the limit of C = 0 are quantities of great physical interest which are expected to be eventually correlated with polymer-solvent interactions; and they are generally determined by extrapolating the observed exponential relation (which gives a straight line on a log D vs. C plot) graphically down to zero concentration. Recently, Mearesl made accurate measurements of D for the system polyvinyl acetate (PVAc) and allyl chloride at 40" by using the steady-state method and compared his results with those obtained for the same system by Kokes and Long2 who used the transient-state method (measurements of rates of P O0 sorption a_nd desorption). He found that his O'PO values of D not only showed a marked deviation I I(a) 1w (1) ](a) 1 from the exponential concentration dependence -P=O O=P-o-ca-o-J=O o=P-o which the data of Kokes and Long had obeyed, but I I 1 I 0-Ca-0 0-Ca-0 also gave at zero concentration a value which was The transition from the above molecule to the about one-half of that extrapolated from the rechelate (CaP3010)-3could be explained in terms sults of the latter authors. The considerable of simple chelation of both the ring Ca between the difference in the magnitude of fj as well as its con1 and 3 phosphorus and the Ca joining the 1,l- centration dependence found by these investigaphosphorus by additional sodium tripolyphosphate. tors may not be unexpected because the temperature used was not sufficiently above the glass ca~(P3010)~ 3NaJ'a010 5NaaCaPs010 (4) transition point of the polymer (28-30'). At such The presence of sodium in the precipitates near the a temperature the macro-Brownian motion of the phase boundary2.was not examined but could be polymer chains is not yet so rapid and active that explained easily by postulating intermediate re- the time effect as discussed by Crank and Park3 may be involved in transient-state measurements; actions as shown by the equations steady-state measurements are apparently free Ca6(PsOlo)2 Na~PaOlo
4%
+
+
and
NazCa4(PaO10)z 4
+ Na&aPaOlo
(5)
(1) P.Meares, J . PoEymer Sci., Z7,391 (1958). (2) R.J. Kokes and F. A. Long, J . A m . Chsm. SOC.,75,8142 (1953). (3) J. Crank and 0.El. Park, Trane. Faraday Soc., 47,1072 (1951).
