Dioxane flash point

Breakage of glassware allowed 92% sulfuric acid into a heating bath containing hot Synperonic NX (nearly anhydrous ethoxylated nonylphenol, a liquid surfactant). Hydrolysis of the latter lowered the flashpoint and the bath ignited (possibly from formation of dioxane, flash point 12°C). 

DIOXAN (123-91-1) Forms explosive mixture with air (flash point 54°F/12°C). Can form unstable peroxides when exposed to air or moisture. Peroxides can be detonated by heat, friction, or impact. Violent reaction with silver perchlorate, sulfur trioxide, strong oxidizers, strong acids. Incompatible with aliphatie amines, amides, caustics, isocyanates, Raney nickel catalyst, decaborane, triethynylaluminum. Flow or agitation of substance may generate electrostatic charges due to low conductivity. Attacks many plastics. 

Again, there is no hard line between what is safe and what is not, but solvents with flash point of less than -18°C are not used. A solvent with a flash point above -18°C can be used but special precautions must be taken such as grounding of all drums and reactors to prevent buildup of electrostatic electricity and excluding all other sources of ignition. All other solvents (toxic or flash point <-18°C) must be replaced. For example, chlorinated solvents (chloroform, carbon tetrachloride), which are carcinogenic, can be replaced with ethyl acetate. Solvents such as pentane (flammable) or hexane (forms electrostatic charges) are replaced with heptanes. Benzene (a carcinogen) is replaced with toluene or xylene. Diethyl ether is replaced with t-butyl methyl ether and dioxane with tetrahydrofiiran. 

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