116 NOTES compounds, and lattice sizes. Vaughan, however, has described a new, denser hexagonal UzNa (Laz03 type), which occurred in a mixture of nitrides obtained on heating massive U in Ns between 500 and 915'. EvanslO has suggested that this is a coherency structure, but Trzebiatowski, et u Z . , ~ ~have found that annealing the cubic Mnz03-type C 2 S 3a t temperatures >1000" led to a new denser UsN3 phase. Recently Bugh and Bauer12 have stated that only the three compounds found by Rundle occur and that the solubility of Nz in solid U is RbF > K F > NaF. In fact, no evidence was found for any interaction of difluoramine with NaF, CaF2, or Acknowledgments.-This investigation was supNiF2 down to -80'. ported by Public Health Service Research Grant CA4A complete study of the CsF-HNF2 system was not 07064-01 from the National Cancer Institute. We are carried out because of the explosive properties of the indebted to the National Science Foundation for a complex. Condensing difluoramine over CsF and allowPredoctoral Fellowship to C. H . Y . ing some difluoramine to escape from the system resulted in a dissociation pressure of about 1.5 mm. a t -65.8', a higher pressure than the 0.8 mm. observed with R b F a t this temperature. However, removal of CONTRIBUTION FROM THE CHEMISTRY RESEARCH SECTIOS about 50% of the coniplexed difluoramine caused an ROCKETDYNE, A DIVISIONOF NORTHAMERICAN abrupt drop in the dissociation pressure to less than 0.05 AvIxrIox, Isc., CANOGA PARK,CALIFORNIA mm. On warming, this complex invariably exploded before i t reached 0 ' . Difluoramine: Preparation of In addition to the gas-solid reaction shown in (1) it Difluorsdiazine and Addition Compounds was found that aqueous K F (pH 8.6) effected the smooth with Alkali Metal Fluorides dehydrofluorination of HNF2. A nominally 25% solution of K F in water consumed HNF2 rapidly with the BY EMILA . LAWTOX, DONALD PILIPOVICH, formation of both isomers of NzFa in approximately 75y0 A N D R. D. WILSON yield, as in the equation Received July 20, 1964
2F-
Difluoramine is amphoteric, as witnessed by its formation of a complex with boron trichloride1 and the formation of 1:1 complexes with weak bases such as alkyl ethers2 We have found that difluoramine also forms complex compounds with the more basic alkali metal fluorides. At higher temperatures, difluoramine is converted smoothly and in excellent yield to difluorodiazine as in eq. l.3 With the ready availability of di2MF
+ 2Hh-Fz --f 2 M F . H F + NzFz
(1) R. C. Petry, J . A m . Chepn. Soc., 83, 2400 (1960). (2) E. A. Lawton and J. Q. Weber, ibid., 8 6 , 3595 (1963). (3) E. A. Lawton and D. Pilipovich, U. S. Patent 3,109,711 (1963).
(1)
+ 2HNFz
----f
2HFz-
+ NzFz
It is interesting to note, however, that experiments carried out with HNF2 and standard buffer solutions (Na2B40TK3P04) a t pH 8.0 and 9.0, respectively, resulted in only 20'% yields. These results indicate that F- may be particularly effective in the dehydrofluorination reaction, but ex(4) Difluoramine is released in high yield by adding sulfuric acid drop-bydrop t o t h e fluorinated urea liquids, described by Lawton and Weber,2 or t o difluorourea: E. A. Lawton, E. F. C. Cain, D. F. Sheehan, and M. Warner, J . Znoug. Nz~cl.Chem., 17, 188 (1961). (5) C. B. Colburn, "Nitrogen Fluorides a n d Their Inorganic Derivatives," chapter in "Advances in Fluorine Chemistry," Vol. 3, Butterworths, Washington, D. C., 1963, p. 103. (6) C. B. Colburn, F. A. Johnson, A. Kennedy, K. McCallurn, L. C. Metzger, and C. 0. Parker, J . A m . Chem. Soc., 81,6397 (1959). (7) H. Dubb, C. Greenough, a n d E. C. Curtis, to be submitted.
