Combustion, spontaneous

Change in the way a reaction occurs because of inappropriate temperatures. At 20 C nitric acid converts mesitylene into 3,5-dimethylbenzoic acid without danger, but at 115°C the explosive 1,3,5-tris(nitromethyl)benzene is formed. Excessive heating of thiophosphoryl trichloride with pentaerythritol at 160°C leads to the formation of phosphine, which combusts spontaneously. 

Diborane forms complex hydrides with lithium, which combust spontaneously in... 

Hydrazine is an unstable substance because of its positive enthalpy of formation. It decomposes when heated. The decomposition can cause an inflammation even in the absence of air. It can also combust spontaneously in the presence of various materials from clothes to soil (see tables in Part Three the self-ignition temperatures vary according to the materials in contact with hydrazine). Also, violent decomposition of hydrazine in a steel reactor occurs when in a carbon dioxide atmosphere. 

Hydrazine combusts spontaneously In contact with dinitrogen tetroxide. As with nitric acid, this property made it suitable as a propellant for rockets from the N2O4/N2NNH2 system. 

Nitrous oxide/hydrazine mixture combusts spontaneously. 

Ammonia combusts spontaneously when it is mixed with fluorine. This system has been considered as a propellant for rockets. If ammonia is in the form of an aqueous solution, the mixture detonates as soon as it is formed. 

With nitric acid sodium combusts spontaneously. 

Powdered aluminium can create explosive suspensions in air in the presence of an ignition source. It can combust spontaneously if the powder is moist. Aluminium powder detonates spontaneously in liquid oxygen. 

Aluminium forms a complex that combusts spontaneously in air with diborane. 

Aluminium borohydride in the gaseous state has a positive enthalpy of formation, so it can be assumed to be rather unstable. It combusts spontaneously in contact with air, but detonates if water traces are present. The same thing happens in contact with water at 20°C. 

Powdered silicon can combust when water is present. It creates suspensions in air, which detonate violently when there is an ignition source present. The silicon/lithium alloy can combust spontaneously in air. 

Silicon combusts spontaneously in fluorine.The temperature reaches 1400°C. 

This gas combusts spontaneously in contact with air. Its enthalpy of formation is positive and makes it unstable. 

An air/nitric acid/phosphorus mixture in the gaseous state combusts spontaneously. The same is true for hot phosphorus or in the molten state when nitrogen oxides are present. 

Phosphine combusts spontaneously in contact with nitrogen oxides. 

The mixtures of sodium with phosphorus, phosphoryl trichloride or with phosphorus pentachloride combust spontaneously and/or detonate. There is an instantaneous ignition when powdered aluminium is mixed with trichloride or phosphorus pentachloride. 

Sulphur combusts spontaneously in fluorine at ambient temperature. Different sulphur chlorides (S2CI2 then SCy are formed with chlorine. The reaction is not considered dangerous. 

Hydrogen sulphide combusts spontaneously in the presence of oxygen when the mixture is at a temperature of 280-360 . Under controlled conditions this reaction is used to make suiphur from hydrogen sulphide. When soda lime is present, the interaction with pure oxygen is explosive whereas air simply causes soda lime to glow. 

In the presence of fluorine, sulphur dioxide combusts spontaneously or detonates. The seriousness of the result is supposed to depend on the order in which the compounds are added. Note that the action of chlorine leads to sulphuryl chloride and was not mentioned as being dangerous. 

Potassium peroxodisulphate decomposes violently when it is heated above 100°C by releasing oxygen. The same violent decomposition takes place at temperatures lower than 100°C, if water is present. The salt combusts spontaneously if soda is present. 

The situation does not improve with mixtures with the hydrides of the elements. Thus, a detonation occurred during contact between water and chlorine due to an accidental spark. Phosphine, silane and diborane all combust spontaneously in chlorine (their behaviour is the same in oxygen). With hydrogenated nitrogenous compounds ammonia, hydrazine, hydroxylamine, ammonium salts (especially ammonium chloride), and also sulphamic acid (these last two in an acid medium) there is ignition or even detonation. 

The sodium chlorite/sodium hydrosulphite mixture combusts spontaneously. This is explained by the fact that sulphur-containing salts catalyse the decomposition of chlorite. 

In the presence of air, the carbide combusts spontaneously. With water this substance detonates. Another accident involved powdered amorphous carbon mixed with potassium and heated to a high temperature. Ignition followed by detonation was attributed to the presence of the superoxide on the metal surface. If the suggested interpretation is correct, this accident illustrates the comment made previously. 

Moist potassium peroxodisulphate was accidentally exposed to traces of potassium hydroxide. It combusted spontaneously, causing the installations to catch fire. It is impossible to put out a fire involving this peroxydic compound with carbon dioxide or extinguishing powders although these agents are suitable for fires of chemical substances. Only water, which is usually not recommended in this case, can put out this type of fire. 

Pieces of calcium combust spontaneously in contact with gaseous fluorine. With chlorine the result is the same with powdered calcium. 

It is very difficult to handle since it combusts spontaneously in air. The fire is difficult to put out and requires special extinguishing agents. With liquid oxygen the reaction leads to a violent detonation. The surface texture of titanium seems to be an important element in the violence of the effects obtained. 

In the powdered state, the metal, which is obtained by the action of magnesium on vanadium trichloride, combusts spontaneously in air. 

Divanadium trioxide combusts spontaneously in air. For some authors this behaviour is observed at ambient temperature, for others, heating is necessary. 

There are pyrophoric forms of iron, which combust spontaneously in air if they are heated above 180°C. 

Iron combusts spontaneously in liquid fluorine. With chlorine, heating is necessary to cause thread iron to combust. 

Iron (II) oxide and especially that made by reducing the other oxides, combusts spontaneously if it is heated to 200°C. It also strongly catalyses the combustion of carbon in air. This behaviour can explain the spontaneous inflammable property of the products of burning iron oxalate, which contain this oxide and carbon. When they are placed on the hand and thrown into the air, they form very spectacular showers of sparks. It combusts in contact with liquid oxygen in the presence of carbon. 

Synthetic sulphide combusts spontaneously in air when it is impure and has caused numerous accidents. The same goes for pyrites in the powdered state and that contain humidity traces. In the absence of humidity, powder pyrites can combust on heating. The temperature of this ignition can be dramatically lowered if it contains carbon. 

With chlorine vapour, zinc in leaf form combusts spontaneously. Zinc glows in contact with fluorine vapour. 

A veterinary preparation made with diarsenic trioxide, sodium nitrate and ferrous sulphate combusted spontaneously. 

Whether hydrogen bromide is anhydrous or in an aqueous solution, it combusts spontaneously when in contact with fluorine. It reacts rapidly with ozone even around -100°C. The reaction speeds up before detonating. 

In air and even more so in oxygen, rubidium combusts spontaneously. There was no mention of any potential formation of superoxide as was the case for potassium. 

Halogens, (fluorine, chlorine and bromine) in the gaseous state, cause rubidium to combust spontaneously. With liquid bromine, it is very difficult to avoid detonation. 

Rubidium reacts with carbon and forms a carbide RbCa, which combusts spontaneously in air. 

Fine powdered strontium combusts spontaneously in air. It reacts more violently with water than calcium and produces hydrogen and strontium hydroxide. 

Niobium combusts spontaneously in fluorine when it is cold and in chlorine at... 

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