I lists the average results obtained from a minimum of three determinations of each compound. The trinitrofluorenone complexes of &-naphthol and 8-naphthol are dibasic, and the values listed for the neutralization equivalents are one half the molecular weight. The neutralization equivalents of the other complexes are synonymous with their molecular weights. The use of indicators in this determination is not warranted as all solutions become highly colored in the course of the titration. Although both trinitrofluorenone and trinitrofluorenone complexes are titratable by the described procedure, no differentiation between trinitrofluorenone and the comnlex is nossible. Therefore, i t is essential that the complexes be completely free of excess trinitrofluorenoneifaccurateresultsareto be expected. The complexes prepared from acetic acid media should also be thoroughly dried as even trace amounts of occluded acetic acid lead to erroneous results. Tetrabutylammonium h y d r o x i d e
iioOc
/
may also be used, but more precise results are realized in pyridine solution.
/
LITERATURE CITED
(1) Cundiff, R. H., Markunas, P. C., ANAL.CHEM.28, 792 (1956). (2) Ibid., 34, 584 (1962). (3) Fritz, J. S., Moye, A. J., Richard, &I. J., Zbid., 29, 1685 (1957). (4) Gordon, H. T., Huraux, M.J., Zbid.,
""
31.302 11959).
-k 600
I +4 39
+2 0 0
Figure 1. Titration of fluoranthenetrinitrofluorenone complex in pyridine so,ution with o.o, ammonium hydroxide
,,
. . O., J . Am. Chem.xoc: 69,' 1225 (194f). (8) Orchin, hI., Woolfolk, E. O., Ibid., 68, 1727 (1946). (9) Robinson, W. T., Cundiff, R. H., Sensabaugh, A. J., hfarkunas, P. C., Talanta 3, 307 (1960). (10) Robinson, W. T., Sensabaugh, A. J., Markunas, P. C., ANAL. CHEM. 35, 770 (1963). (11) Sensabaugh, A. J., Cundiff, R. H., Rfarkunas, P. C., AXL. CHEW 30, 1445 (1958).
ROBERT H. CUNDIFF P. c. kI.4RKCX.4S
(0.1N) may also be used as a titrant if sufficient sample is available. Other nonaqueous solvents such as acetone
Research Department R. J. Reynolds Tobacco Co. Winston-Salem, iY. C.
Purification of Plutonium Sulfate Tetrahydrate by Recrystallization and Ion Exchange SIR: d recent paper by Pietri (2) indicated that the relatively scarce and expensive high-purity plutonium (99.96+%) was not required for the preparation of pure plutonium sulfate tetrahydrate. a proposed analytical standard for plutonium. Experimental data are presented here to show that the tetrahydrate may be prepared in high purity even from grossly impure plutonium waste solutions (>IO% impurities) by successive recrystallization or by anion exchange purification. EXPERIMENTAL
Plutonium Solution. An aqueous laboratory waste solution was used which contained approximately 1-I4 sulfuric, 3.W hydrochloric, and 4-If nitric acids, and t h e metal impurities in the concentrations listed in Table I. Recrystallization Studies. Four aliquots of t h e waste solution containing about 5 grams of plutonium were used to prepare four lots of Pu(SO4)2. 4Hs0 by controlled crystallization from sulfuric acid solution according to the published procedure (2). Teflon vessels were used in place of glassware. A portion from each lot of the prepared compound was removed for impurity analysis and the remainder was recrystallized. This recrystallization and sampling procedure was repeated an 1324
ANALYTICAL CHEMISTRY
additional four times. All solutions were filtered between crystallizations. Ion Exchange Purification. Another four aliquots (2 grams of plutonium each) from t h e above waste
Table I.
Element
ffArne Ba Be Cr Cs cu Fe K Li
Waste soln. 200 1%
0.4% 0,4% 70 1.4%
0.2% 0.1% 1.4% 1%
20 0.4%
Purity of Plutonium Sulfate Tetrahydrate
Impurities, p.p.m.aj* (unless otherwise specified) Crystallization I
0.4 240 0.2% 600 ND 270 200 200 0.8%
0.2% 1
2
