Autoignition temperature, 48. Note

Note that many original contributions are presented in this book (on mixture flash points and autoignition temperatures). 

The critical condition is given by point c with Tc being the critical temperature. It should be noted that the critical heat loss rate, Ql2, depends not just on the vessel size but also on the surrounding temperature, T. Hence, the slope and the T intersection of Q in Equation (4.4), as tangent to Qr, will give a different Tc. We shall see that the Arrhenius character of the reaction rate will lead to T0 7X. This is called the autoignition temperature. The mathematical analysis is due to Semenov [3]. 

Fig. 7.17. Influence of NO2 on ignition delay-times in a rapid compression machine [141], Fractional ignition delays are shown for various post-compression temperatures. Note that at the higher temperatures NO2 enhances autoignition at small concentrations while hindering it at greater concentrations. Stoichiometric mixture of 90% iso-octane/10% n-hep-tane, total concentration 3.2 x 10 mol cm . ...

Note The measured autoignition temperature of dichlorosilane is above 212°F (100°C), but accumulated ... 

The fuel element of the fire/explosion triad can be any flammable material. Degree of flammability is indicated by a material s explosive or flammable limits, its flash point, and its autoignition temperature. These, with other combustion properties, are documented in the standard references previously noted. 

Note 2 Warning—Compressed gas under high pressure. Use with extreme caution in the presence of combustible material, since the autoignition temperatures of most organic compounds in air are drastically reduced at elevated pressures. See Annex A2.I. 

Note 4 Warning—Do not perform this test with air at temperatures in exces of the autoignition temperature of the test specimen as determined by Test Method E 659 or Test Method D 2883, or both. 

PHENYLETHYLENE (100-42-5) CgHg Forms explosive mixture with air [explosion limits in air (vol %) 1.1 to 6.1 flash point 88°F/31°C autoignition temp 914°F/490°C Fire Rating 3]. Unless inhibited (often with teri-butylcatechol however, it should be noted that the presence of an inhibitor may only lessen the possibility of polymerization), polymerization may occur and container may explode. Polymerization can be caused by elevated temperatures above 151°F/66°C contact with azoisobutyronitrile, butyl lithium, oxidizers, peroxides and hydroperoxides (dibenzoyl... 

---