Just thinking of the reaction of SN with intense heat ie fire - I'm definitely no expert nor am I a chemist but I wonder….
SN reaction to fire
A yellowish white crystalline solid. Noncombustible but will accelerate the burning of combustible material. If large quantities are involved in a fire or if the combustible material is finely divided, an explosion may result. If contaminated by ammonium compounds, spontaneous decomposition can occur and the resulting heat may ignite surrounding combustible material. Prolonged exposure heat may result in an explosion. Toxic oxides of nitrogen are produced in fires involving this material. Used as a food preservative, and to make other chemicals.
Special Hazards of Combustion Products: Toxic oxides of nitrogen may form in fires.
Behavior in Fire: May increase intensity of fire if in contact with combustible material. May melt and flow at elevated temperatures. (USCG, 1999)
Reactivity Profile
SODIUM NITRITE is an oxidizing agent. Mixtures with phosphorus, tin(II) chloride or other reducing agents may react explosively [Bretherick 1979 p. 108-109]. If contaminated by ammonium compounds, spontaneous decomposition can occur and resulting heat may ignite surrounding combustible material. Reacts with acids to form toxic nitrogen dioxide gas. Mixing with liquid ammonia forms dipotassium nitrite, which is very reactive and easily explosive [Mellor 2, Supp. 3:1566 1963]. Melting together wilh an ammonium salt leads to a violent explosion [Von Schwartz 1918 p. 299]. A mixture with potassium cyanide may cause an explosion. Noncombustible but accelerates the burning of all combustible material. If large quantities are involved in fire or if the combustible material is finely divided, an explosion may result. When a little ammonium sulfate is added to fused potassium nitrite, a vigorous reaction occurs attended by flame [Mellor 2:702. 1946-47].
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