Xylene ignition temperature

The low activity state which is characterized by the high ignition temperature, can be transformed into high activity state after 10-20 ramps up and down cycles. This state was stable while the catalyst was in operation. Under isotherm condition (3000 ppm xylene, 20 vol. % oxygen, flow rate 500 cm min and at 260°C) during 8 hours on stream the catalytic activity of sample (II) remained constant and only CO2 was formed. 

Fire Hazards - Flash Point (deg. F) 84 CC (solution) Flammable Limits in Air (%) 1.1 - 6.4 Fire Extinguishing Agents Foam, dry chemical, or carbon dioxide Fire Extinguishing Agents Not To Be Used Water may be ineffective fecial Hazards of Combustion Products Toxic vapors are generated when heated Behavior in Fire Solution in xylene may produce corrosive products when heated Ignition Temperature (deg. F) 986 (solution) Electrical Hazard Not pertinent Burning Rate 5.8 mm/min. 

The third and final hydrocarbon family to be discussed is known as the aromatic hydrocarbons, sometimes referred to as the BTX fraction (benzene, toluene, xylene). One additional aromatic beyond the BTX fraction is called styrene and will be covered as the fourth aromatic compound. Aromatics as a group are toxic and flammable. They have moderate boiling and flash points, narrow flammable ranges, high ignition temperatures, and are nonpolar. 

A flammable chemical substance is a solid, liquid, vapor, or gas that ignites easily and burns rapidly in air. Many of the flammable chemicals used in laboratories are flammable liquids and organic solvents. The vapors of these chemical substances form ignitable mixtures with air. Based on the flash points of these chemicals, classifications are made. The flash point of a chemical substance is defined as the lowest temperature at which a fuel-air mixture present above the surface of a liquid will ignite, if an ignition source is present. The common flammable chemical substances include, but are not restricted to, acetone, benzene, cyclohexane, ethanol, ethyl acetate, ethyl ether, gasoline, hexane, isopropyl alcohol, methanol, propanol, tetrahydro-furan and toluene, and xylene. 

A marked contrast is observed in the behaviour of the simplest aromatic hydrocarbon-air mixtures at high pressures. No cool-flame phenomena or an ignition peninsula in the (p-Ta) diagram are observed. These are found only when sufficiently reactive aliphatic side-chains are associated with the aromatic ring. Burgoyne et al. [129] showed this to be the case for n-propylbenzene in a closed vessel (Fig. 6.18). The ortho- and meta-isomers of the xylenes also showed a similar reactivity. Benzene, toluene and ethylbenzene were found to undergo spontaneous ignition at temperatures only above 700 K. 

The chance of ignition from static electricity is especially high when handling liquids that have vapours above their LEL and below their UEL, since the sparks tend to take place near the liquid surface where the vapour will neither be too rich nor too lean to catch fire. At ambient temperatures toluene, heptane and octane are particularly liable to electrostatic ignition, whereas benzene, n-hezane, m-xylene and n-nonane at normal ambient temperatures are outside their explosive range. 

C. The specific heat is 1.70-2.10 kj/(kg K), melting enthalpy is 60-90 kj/g, specific electric resistance is 10 -10 fl/m. PP fibers are soluble only at temperatures above 100°C in tetraline, decaline, xylene, chlorobenzene. No toxic products are formed at ignition. Fibers are oleophilic, resistant to acids, alkali and they are thermostable to 100-120 C. 

The dishes are heated gently over a bunsen until the xylene has evaporated and the temperature then raised until the polymer starts to decompose. Careful heating is maintained such that the vapours never ignite and heating is continued until all light volatile matter has been removed. The dishes are transferred to a cold electric muffle and ashed overnight at 500°C then weighed. 

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