MECHANISM OF THE ISOTHERMAL DECOMPOSITION OF POTASSIUM PERCHLORATE<sup>1</sup>

Stern, Kurt H.; Bufalini, Marijon

doi:10.1021/j100840a517

Cited by 9 publications

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“…The inability to oxygenate chlorates to perchlorates by high-pressure treatment with molecular 0216•35 despite the favorable thermodynamic potential for such reactions would indicate the need for the participation of a kinetically more reactive form of oxygen to achieve the conversion. 31 In this same regard, it should be pointed out that despite the thermodynamic potential for oxygenation of Li20 by molecular 02 at moderate pressures, it has not been possible to bring about this reaction by application of even very high pressures of 02, whereas the peroxygenation of Li20 can be performed in decomposing LiC104 melts as demonstrated here. Thus, an appreciable body of chemical evidence exists to support the kinetic view for the presence of 0 atoms in decomposing perchlorates.14'17•29'31…”

Section: Discussion Of Resultsmentioning

confidence: 82%

“…Furthermore, a clear resolution between heterogeneous and homogeneous catalytic effects remains to be performed, although this investigation indicates homogeneous solution effects to be important only in the LiC104-Mn02 system. l4,l7-29, 31 For the pure RICIOl salts the degree of C12 release during decomposition follows the order Li >> Ka > K > Rb, Cs = 0 (Table 11). The direct transfer of 0 atoms to Mn metal is suggested by the formation of MnB04 in an 80 mole % Lic104-20 mole % Mn mixture maintained for several hours at 225'.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…A more general explanation might be based on the autoionization of perchlorate melts, much as occurs with molten nitrates37•38 NO,-^N02+ + O2" (31) Thus, for the perchlorates the self-ionization equilibrium might be represented as CIO4-…”

Section: Discussion Of Resultsmentioning

confidence: 99%

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The Differential Thermal Analysis of Perchlorates. VII. Catalytic Decompositions of the Alkali Metal Perchlorates by Manganese Dioxide

Markowitz¹,

Boryta²

1965

J. Phys. Chem.

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The thermal stabilities of the pure alkali metal perchlorates (MCIOI) and of admixtures with 10 mole % RhOz catalyst follow the order Li < Na < K, Rb, Cs. For both pure and catalyst-containing materials, rapid decomposition is preceded by liquid phase formstion. Analyses of molten perchlorates near their fusion temperatures show that fusion is coincident with decomposition except for LiClO, which has a congruent melting point; the simultaneous occurrence of fusion and decomposition is in contrast to the behavior manifested by RIC103 salts, each of which possesses a congruent melting point and a significant range of liquid phase stability. Catalysis of Mc101 pyrolysis by basic substances yielding 02ion, in conjunction with other evidence, suggests the presence of 0 atoms in decomposing perchlorates. A proposed mechanism for Clz evolution from lIC104 melts (order of extent of Clz release: Li >> Xa > K > Rb, Cs = 0) stipulates an autoionization equilibrium of the type C104-4 c103+ + 02-, so that Clz release occurs through the reaction Clod-+ ClO3+ -+ [C1207] -+ Clz + 7/z02. Such a scheme removes acidic oxides (e.g., P206, B203, W03, Moo3, etc.) from consideration as true catalysts inasmuch as they function by removal of oxide ions and hence undergo specific, irreversible reactions with RIC104 salts. In this regard, MnOZ is primarily a true catalytic agent for MC104 decomposition, but it also does appear to undergo a small amount of chemical reaction with LiClO,, in particular, to foster Clz evolution, viz., LiC104 + MnOz 4 Li?tfnOz + l/zClz + 2OZ.(1) "Gmelins Handbuch der anorganischen Chemie," 8 Auflage, System No. 6, "Chlor," Verlag Chemie, G.m.b.h., Berlin, 1926, pp.

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Section: Discussion Of Resultsmentioning

confidence: 82%

Section: Discussion Of Resultsmentioning

confidence: 99%

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The Differential Thermal Analysis of Perchlorates. VII. Catalytic Decompositions of the Alkali Metal Perchlorates by Manganese Dioxide

Markowitz¹,

Boryta²

1965

J. Phys. Chem.

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“…The conductivity (a) is expressed by a = H ne (10) where p is the mobility, n is the concentration of conduction electrons and e is the charge of an electron, a increases with n, which is a function of the concentra-tion of donor centers (Eq. (11)).…”

Section: Preparation Of Fe20z Catalysts the Results Of Dta Experimenmentioning

confidence: 99%

Phenomenological study of the catalytic thermal decomposition of potassium perchlorate by iron(II) oxides with different preparing histories

Furuichi

Ishii

Kobayashi

1974

Journal of Thermal Analysis

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The catalytic decomposition of KC10~ by Fe203, obtained by calcination of Fe(II) salts at different temperatures, was investigated by DTA, TG, X-ray and IR. A sample without catalyst was found to begin fusion and decomposition simultaneously, and to form an intermediate, KC10~. Addition of catalysts resulted in solid-phase decomposition before fusion of KC10~, and in a small amount of KC10~. The difference in catalytic effect observed for different catalysts was less in the molten-phase decomposition than in the solid phase. The initial decomposition temperature (Ti) increased with the temperature of preparation of the catalyst and showed a definitive relationship with the crystallite size of the catalyst. The change of Ti is discussed on the basis of the n-type semiconductive properties of the catalyst.Several investigators have studied the thermal decomposition of pure KC104, and the decomposition catalyzed by metal oxides and halogenides [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Rudloff and Freeman [18] employed thirteen metal oxides in a systematic investigation of their catalytic effects on the decomposition, by means of DTA, TG and electrical conductivity methods, and concluded that (a) the catalytic activity increased with the p-type semiconductive character of the catalyst, (b) in some cases, for example Cr203, the catalyst itself was oxidized irreversibly to a higher oxidation state during the decomposition, and (c) since the higher the electrical conductivity of the oxides, the higher the resultant catalytic activity, the decomposition might proceed through a charge-transfer mechanism, being at least in part ionic. Furthermore, they reported the interesting fact that Fe203, although an n-type semiconductor, exhibited a catalytic activity comparable with that of p-type semiconductors.Otto and Fry [1] described that the isothermal decomposition of KC104 containing Fe203 was unimolecular, that the rate constant was proportional to the amount of catalyst added, and that the sample in the course of decomposition was free from chlorate.In a series of studies on the thermal decomposition of alkali metal perchlorates, Markowitz and Boryta [14] gave the heats of crystallographic transition, fusion and decompositions of KC104, and also suggested that the role of MnO 2 as catalyst was the abstraction of atomic oxygen produced in the primary decomposition step.3* o r . Thermal Anal 6, 1974

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Influence of temperatures and starting materials used to prepare α-Fe2O3 on its catalytic activity at the thermal decomposition of KClO4

1977

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MECHANISM OF THE ISOTHERMAL DECOMPOSITION OF POTASSIUM PERCHLORATE¹

Cited by 9 publications

References 0 publications

The Differential Thermal Analysis of Perchlorates. VII. Catalytic Decompositions of the Alkali Metal Perchlorates by Manganese Dioxide

The Differential Thermal Analysis of Perchlorates. VII. Catalytic Decompositions of the Alkali Metal Perchlorates by Manganese Dioxide

Phenomenological study of the catalytic thermal decomposition of potassium perchlorate by iron(II) oxides with different preparing histories

Influence of temperatures and starting materials used to prepare α-Fe2O3 on its catalytic activity at the thermal decomposition of KClO4

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MECHANISM OF THE ISOTHERMAL DECOMPOSITION OF POTASSIUM PERCHLORATE1

Cited by 9 publications

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The Differential Thermal Analysis of Perchlorates. VII. Catalytic Decompositions of the Alkali Metal Perchlorates by Manganese Dioxide

The Differential Thermal Analysis of Perchlorates. VII. Catalytic Decompositions of the Alkali Metal Perchlorates by Manganese Dioxide

Phenomenological study of the catalytic thermal decomposition of potassium perchlorate by iron(II) oxides with different preparing histories

Influence of temperatures and starting materials used to prepare α-Fe2O3 on its catalytic activity at the thermal decomposition of KClO4

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MECHANISM OF THE ISOTHERMAL DECOMPOSITION OF POTASSIUM PERCHLORATE¹