Melting, potassium perchlorate decomposition

This reaction is quite vigorous, and becomes violent at temperatures above 500°C [2]. The actual decomposition mechanism may be more complex than equation 3.1 suggests. Intermediate formation of potassium perchlorate has been reported at temperatures just above the melting point, with the perchlorate then decomposing to yield potassium chloride and oxygen [5]. 

Because of its higher melting point and less-exothermic decomposition, potassium perchlorate produces mixtures that are less sensitive to heat, friction, and impact than those made withKClO] [2]. Potassium perchlorate can be used to produce colored flames (such as red when combined with strontium nitrate), noise (with aluminum, in "flash and sound" mixtures), and light (in photoflash mixtures with magnesium). 

Potassium perchlorate is a white, non-hygroscopic crystalline material with a melting point of 6101C, considerably higher than the 356°C melting point of KCIO 3 It undergoes decomposition at high temperature... 

The apparatus constant shall be determined as follows. First prepare the melting curves for pure tin, indium, potassium nitrate, and potassium perchlorate. Next using the value of heat of fusion found in the literature, determine the relationship between the temperature and the apparatus constant Calculate the apparatus constant at the extrapolated decomposition temperature, and, in the abovementioned equation, use the value so obtained. 

Unexpectedly we find that the bromate(V) ion in acid solution (i.e. effectively bromic(V) acid) is a more powerful oxidising agent than the chlorate(V) ion, CIO3. The halates(V) are thermally unstable and can evolve oxygen as one of the decomposition products. Potassium chlorate(V), when heated, first melts, then resolidifies due to the formation of potassium chlorate(VII) (perchlorate) ... 

All the halates decompose on heating, usually above their melting point. In the presence of a transition metal catalyst such as Mn02, the decomposition of KCIO3 to chloride and oxygen starts at 70 °C and is the source of pure oxygen in laboratory preparation. In a series of the halates with the same cation, the thermal stability decreases in the sequence of [lOs]" > [0103] > [Br03] . Potassium chlorate is used in the mixture of safety matches, in pyrotechnic formulations, and as intermediates in the production of perchlorates. 

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