HYDROXYLAMINE COMPLEXES OF SOME INORGANIC SALTS R .
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MOE,
Aerojet-General Corp., Sacramento, Calif.
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KLOTZ,
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D I MILO
95813
Preparation and characterization of some hydroxylamine complexes of various inorganic salts are described. Hydroxylammonium perchlorate forms complexes witlh both one and two hydroxylamine molecules, while the nitrate forms only a nionocomplex. These complexes are in general less hygroscopic than the salt itself. Complexes formed by lithium, magnesium, calcium, and barium perchlorates and by calcium chloride were also investigated.
WHILE studying
the effects of certain amines on hydroxylammonium perchlorate in ethyl acetate solution, the formation of solid mono- and dihydroxylamine complexes of the h ydroxylammonium perchlorate was observed. After identification and study of these complexes, the formation of hydroxylamine complexes with other salts was investigated. The general principle utilized in the search for the complexes was that the hydroxylamine complexes were formed by salts which formed hydrates. Hydroxylamine complexes were first observed by Lossen (187l), who reported the formation of the compounds 2NHrOH HC1 and 31\JH20H‘2HC1, although the existence of the latter was questioned by Dunstan and Goulding (1896). Further efforts (Adams, 1902; Audrieth, 1930; Piloty and Ruff, 1897) led to discoveries of additional complexes. Adams (1902) and Audrieth (1930) both recognized the similarity of these complexes to hydrates. Subsequently, little work was described until recent patents (Flynn and Stayer, 1967; Groves, 1964) described the preparation of hydroxylamine complexes of lithium and magnesium perchlorates.
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Experimental
Materials. Reagent grade chemicals were used as received. Hydroxylamine sulfate (General Aniline and Film) was recrystallized from water and N,N-diallylmelamine (American Cyanamid) was recrystallized from acetone prior to using. Hydroxylammonium perchlorate was prepared from barium perchlorate and hydroxylammonium sulfate. Hydroxylammonium nitrate was prepared from hydroxylammoniurn sulfate and calcium nitrate. Hydroxylamine was prepared by a modification of the Hurd method (1939), in which ethanol was substituted for butanol. (“?OH C1O4)~N1-I2OH.To 4.85 grams (0.0365 mole) of ”?OH C104 dissolved in 300 ml. of diethyl ether or chloroform was added, with stirring, 20 ml. of ethanol The precontaining 1.21 grams (0.0366 mole) of “,OH. cipitate was filtered and dried to give a quantitative yield of the monohydroxylamine complex.
’ Present
address, Chico State College, Chico, Calif,
(NH30H ClO4).2NH20H. To 250 ml. of ethanol containing 63 grams (0.474 mole) of hydroxylammonium perchlorate was added 440 ml. of ethanol containing 31 grams (0.95 mole) of hydroxylamine. After cooling overnight, the solid dihydroxylamine complex was removed by filtration and recrystallized from 700 ml. of ethanol a t 50” C. The complexes of hydroxylammoniurn perchlorate were also prepared by the in situ release of hydroxylamine from the salt by the addition of amines with pK, similar to hydroxylamine. The purity of the complexes depended on the solubility of the amine perchlorate. The amines used were aniline, phenylhydrazine, N,N-dimethylaniline, N,N-diallylmelamine, and quinoline. A typical preparation with these amines is as follows: N,N-Diallylmelamine (136.6 grams, 0.67 mole), recrystallized from acetone, was dissolved in 2000 ml. of ethyl acetate a t 55°C. and was added to a filtered solution of hydroxylammoniurn perchlorate (177 grams, 1.33 moles) in 500 ml. of ethyl acetate. The mixture was allowed to stand for 2 hours and filtered while still warm (35’ C.). The solid hydroxylammoniurn perchlorate monohydroxylamine was washed twice with 100 ml. of ethyl acetate. (“?OH SOs).NH20H. T o 55 grams (0.57 mole) of N H 3 0 H NO? dissolved in 250 ml. of ethanol was added a solution of 18.8 grams (0.57 mole) of XH20H in 350 ml. of ethanol. The solid was recrystallized from ethanol. General Method of Preparing Hydroxylamine Complexes of Other Inorganic Salts. T o 0.01 mole of the salt dissolved in 20 ml. of ethanol was added enough hydroxylamine (2M in ethanol) to maintain the required molar ratios. In all instances, an immediate precipitate was formed. The mixtures were cooled in an ice bath for 4 hours and filtered. The solid products were dried in a nitrogen atmosphere over phosphorus(\;) oxide. Results and Discussion
The hydroxylamine complexes prepared and some of their properties are listed in Tables I and 11. Generally the complexes were less hygroscopic than the salts from which they were derived. For instance, while the hydroxylammonium perchlorate gained 11.7 weight ‘L in 60 hours a t ambient conditions, its complexes showed no weight gain. V O L . 8 N O . 2 JUNE 1 9 6 9
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Table I. Yields and Physical Data for Hydroxylamine Complexes
Yield, Compound
CIC
",OH ClO, (XH?OH CIO,j.I%HzOH (",OH ":OH
65'
2.06 1.93' 1.97' 1.78
70
1.70
100
1.75
70',n 100'
ClO,).ZNH,OH
NO3
LiNOn. KH?OH
Density, G.1 M1.
Equivalent Weight Theory Found
Uiferential Thermal Analysis", Temp., C. Endotherm Exotherm
133c 16?
133 166.5
55, 88 75, 100
180 120
99.8O 2028 65' 129'
103 199.5 72 129
85
110
67
75
...
95, 140
...
170
"Heating rate, 1P per minute; temperature at which exotherm and endotherm begin. 'Titration u'ith base. 'Prepared b> addition of iV,N-diallylmelamine to iVHIOH C104. dAnalysis. Calcd. for N2HiC10s: H , 4.21; N , 16.83; Cl, 21.30. Found: H, 4.37; N , 16.53; Cl, 21.03. 'Prepared by addition of "?OH to salts. 'Analysis. Calcd. for N,HloCIO:: H , 5.04; N,21.1; C1, 17.8. Found: H , 5.49: N , 21 3;C1, 17.6. Titration with acid. Table II. Hydroxylamine Complexes of Various Inorganic Salts
">OH
Salt. Mole Ratio Found in Used complex by initially TGA
Salt LiC10, Mg(C10,)I Ca(C104)2 Ba(C10, j
CaCL
1 2 3 2 4 8 1 3 7.5 1
3 7.5 1 2 3 4 8
3.2 5.2 5.0 5.5 2.8 5.8 5.3 2.9 3.3 3.2
Equivalent Weight by Titration Theoretical Found 139O 86b 68' 77.6d 112.7' 80Ad 145' 144O
88O 70' 3.3
90 71 75 78 77 73 106 79 80 154 147 142 92 86 78 77 72
'Based on 1:1 complex. Based on 2:l complex. Based on 3:l complex. a Based on 5:l complex.
The hydroxylammonium perchlorate dihydroxylamine could be prepared by allowing the appropriate moles of reactants to crystallize from solution, whereas attempts to prepare the monohydroxylamine complex by the same method resulted in low yields of the dihydroxylamine complex. The monohydroxylamine could be prepared only by precipitating the complex from a suitable solvent. Attempts to recrystallize the monohydroxylamine complex resulted in formation of the dihydroxylamine complex. However, the dihydroxylamine complex was not stable and when the recrystallized material was exposed to the atmosphere a t room temperature, the dihydroxylamine complex lost one mole of hydroxylamine over a period of about 14 days and the mono complex was obtained. The hydroxylammonium perchlorate monohydroxylamine was kept with no sign of moisture absorption or further decomposition a t room temperature. The preparation of the complexes of hydroxylammonium nitrate yielded only the monohydroxylamine complex, regardless of the amount of hydroxylamine used.
198
I & E C PRODUCT RESEARCH A N D DEVELOPMENT
The data for the complexes of lithium perchlorate were interpreted to indicate that the tri complex was the only reasonably stable complex a t room temperature. The thermal gravimetric analysis (TGA) of the material made with 3 moles of hydroxylamine and 1 mole of lithium perchlorate showed a weight loss corresponding to that required for the loss of 3 moles of hydroxylamine per mole of lithium perchlorate. Other workers have reported a stable dihydroxylamine complex of lithium perchlorate (Groves, 1964), but this is not consistent with the similarity of hydroxylamine complexm to hydrates, since lithium perchlorate forms only a stable trihydrate. The addition of 1 mole equivalent of hydroxylamine to lithium nitrate formed the stable monohydroxylamine complex of lithium nitrate, as confirmed by thermal gravimetric analysis. The data for calcium chloride in Table I1 are inconclusive, but seem to indicate the formation of CaCl?.3 K H 2 0 H even though calcium chloride is reported to form mono-, di-, tetra-, and hexahydrates (Sidgwick, 1950). Calcium and magnesium perchlorates formed complexes containing 5 moles of hydroxylamine. Other workers (Groves, 1964) have reported MgC10,.2NH20H, but this was not confirmed in our work. Barium perchlorate formed a trihydroxylamine complex even with a 7.5 to 1 starting ratio of hydroxylamine to salt. Literature Cited
Adams, M., A m . Chem. J . 28, 198 (1902). Audrieth, L. F., Transactions of Illinois State Academy of Science, 22nd Annual Meeting, Macomb, Ill., May 3-4, 1929, Vol. XXII, p. 385, April 1930. Dunstan, W. R., Goulding, E., J . Chem. SOC.69, 842 (1896). Flynn, J. P., Stayer, E. J. (to Dow Chemical Co.,) U.S. Patent3,305,413 (Feb. 21, 1967); C A 66, 97092e (1967). Groves, K. 0. (to Dow Chemical Co.), U. S. Patent 3,148,940 (Sept. 15, 1964); CA 61, 15701g (1964). Hurd, C. D., Inorg. S y n t h . 1, 82 (1939). Lossen, W., A n n . 160, 242 (1871). Piloty, O., Ruff, O., Ber. 30, 1656 (1897). Sidgwick, N. V., "The Chemical Elements and Their Compounds," Vol. I, p. 252, Oxford University Press, London, 1950. RECEIVED for review October 3, 1968 ACCEPTED January 27,1969
