Dangerous reactions thermal effects

Before or simultaneously to the chemical lesion induction, these very concentrated corrosives can cause a ceU necrosis by dehydration and/or by thermal effect. Once more, this justifies the necessity to wash as soon as possible and to optimize the decontamination. This includes washing and physical mechanical rinsing in a better control of the dangerous potential degradation products of the chemical reaction. 

The feedback effect of heat evolution on the rate of exothermic reactions may cause thermal runaway. This is a major issue in the operation of industrial reactors, as the loss of control of a chemical reactor constitutes a serious hazard everybody has in mind the SEVESO accident or those which occured recently in the Swiss industry. Thermal instability is due to the irreducible coupling between heat accumulation and the quasi-exponential increase of reaction rate as a function of temperature accounted for by Arrhenius equation. This problem can be studied by the methods of non linear dynamics. Here again, characteristic times make it possible to establish simple criteria which give at least an order of magnitude for dangerous and safe ranges of operation. 

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