Hyponitrite, decomposition

Admixtures are 1-2% nitrogen and NO, which can be removed by passing bivalent iron sulfate through the solution. Moreover, N20 is also produced by nitrates and nitrites reduction under definite conditions or by hyponitrite decomposition. 

Nitrous oxide may also be obtained by the controlled reduction of nitrates or nitrites, decomposition of hyponitrites, or thermal decomposition of hydroxylamine. 

While di-i-butyl (34) and dicumyl hyponitrites (35) have proved convenient sources of Tbutoxy and cumyloxy radicals respectively in the laboratory,71 72 115"117 the utilization of hyponitrites as initiators of polymerization has been limited by difficulties in synthesis and commercial availability. Dialkyl hyponitrites (16) show only weak absorption at A>290 ntn and their photochemistry is largely a neglected area. The triplet sensitized decomposition of these materials has been investigated by Mendenhall et a .11 s... 

Tertiary hyponitrites are not particularly susceptible to induced decomposition. However, the same is not true of primary and secondary hyponitrites. Isopropyl hyponitrite is reported123 to undergo induced decomposition by a mechanism involving initial abstraction of a a-hydrogen (Scheme 3.24). 

Oxygen-centered radicals are arguably the most common of initiator-derived species generated during initiation of polymerization and many studies have dealt with these species. The class includes alkoxy, hydroxy and aeyloxy radicals and tire sulfate radical anion (formed as primary radicals by homolysis of peroxides or hyponitrites) and alkylperoxy radicals (produced by the interaction of carbon-centered radicals with molecular oxygen or by the induced decomposition of hydroperoxides). 

The reactions of /-butoxy radicals are amongst the most studied of all radical processes. These radicals are generated by thermal or photochemical decomposition of peroxides or hyponitrites (Scheme 3.75). 

The action of sodium on ammonium nitrate results in a violent explosion. It is assumed to be caused by the decomposition of a hyponitrite formed as follows ... 

The mode of decomposition of Oi -alkylated diazeniumdiolates bound to carbonyls is also exceptional because they can undergo rearrangement to hyponitrites before decomposition (Scheme 3.15) [163]. 

According to A. Hantzsch and L. Kaufmann,1 if dry ammonia be passed into the ethereal soln. of hyponitrous acid, ammonium hydrohyponitrite, (NH4)HN202, or NH4O.N N.OH, is formed in colourless crystals which melt with turbulent decomposition at 64°-65°. The salt spontaneously decomposes into ammonia, nitrous oxide, and water. The salt dissolves in water with an alkaline reaction. Ammonium hyponitrite, NH4O.N H.ONH4, cannot be prepared directly, but... 

Sodium hyponitrite is readily soluble in water, the concentrated solution being stable in presence of a large proportion of sodium hydroxide. On crystallization the salt is deposited as pentahydrate, this substance losing its water of crystallization in a desiccator or on exposure to air. The anhydrous salt is the more stable form it melts with decomposition at 300° C. The cryoscopic method gives the double molecular formula, Na2N202. 

Amorphous sodium rrans-hyponitrite (NajNjOj), heated in a DSC in the absence of oxygen, decomposed [72] suddenly at various temperatures between 633 and 663 K with the formation of a viscous froth that later changed to a white residual solid. The reaction (NajNjOj NajO + NjO) may be accompanied by the formation of nitrite (NajNjOj + Oj — 2NaN02) and further oxidation to nitrate due to breakdown of NjO to oxygen by an unidentified mechanism. When Na2N202 is heated in oxygen the decomposition temperature is lowered by oxidation of N202 to N02 and subsequently to NOj. ... 

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