Benzene ignition temperature

Benzene is a clear, colorless, flammable liquid with a pleasant characteristic odor, bp 80.1°C, flash point -11.1°C, and ignition temperature 538°C. Benzene has been found to be very toxic and is on the list of Known to Be Human Carcinogens published every two years by the Department of Health and Human Services under the National Toxicology Program (NTP). There are four top 50 chemicals on this worst carcinogen list benzene 1,3-butadiene ethylene oxide and vinyl chloride. There are also four chemicals in the top 50 on the Reasonably Anticipated to Be Human Carcinogens list acrylonitrile, ethylene dichloride, formaldehyde, and propylene oxide. 

Toluene is a colorless, flammable liquid with a benzene-like odor, bp 110.8°C, flash point 4.4°C, ignition temperature 552°C, and TLV (TWA) = 50 ppm. 

Benzene s molecular formula is C6H6, but it does not behave like hexane, hexene, or any of their isomers. One would expect it to be similar to these other six-carbon hydrocarbons in its properties. Table 4 provides a comparison between benzene, hexane and 1-hexene. The table shows that there are major differences between benzene and the straight-chain hydrocarbons of die same carbon content. Hexene s ignition temperature is very near to hexane s. The flash point difference is not great, however, there are significant differences in melting points. The explanation for these differences is structure which in the case of benzene is a cyclical form with alternating double bonds. 

It dissolves with difficulty in water, moderately well in chloroform and benzene, and readily in hot alcohol. Its ignition temperature is 160°C. 

Many articles have described the measurement of spontaneous ignition temperatures of various fuels and pure hydrocarbons by a variety of methods (11,25,31, 44> 63, 85, 86). Jackson gives the spontaneous ignition temperatures of 94 pure hydrocarbons and 15 fuels and commercial fluids. He states that benzene has the highest value of any of the materials tested (42). A comprehensive survey of methods of determining spontaneous ignition temperatures of liquid fuels and a tabulation of data is given by Mullins (64). 

Recently Livengood, Toong, Rona, Taylor, and Black used an externally heated hot spot to induce surface ignition in a motored engine (53). Under the conditions of these experiments, benzene required a somewhat higher hot-spot temperature for surface ignition than iso-octane, but the difference in temperature was far less than the difference between the spontaneous ignition temperatures of the two hydrocarbons as determined in the laboratory. 

Benzene (C6H6, boiling point 80°C, density 0.8789, flash point -11°C, ignition temperature 538°C), is a volatile, colorless, and flammable liquid aromatic hydrocarbon possessing a distinct, characteristic odor. Benzene is practically insoluble in water (0.07 part in 100 parts at 22°C) and fully miscible with alcohol, ether, and numerous organic liquids. 

Toluene (C6H5CH3, boiling point 110.8°C, density 0.8548, flash point 4.4°C, ignition temperature 552°C) is a colorless, flammable liquid with a benzenelike odor that is essentially insoluble in water but is fully miscible with alcohol, ether, chloroform, and many other organic liquids. Toluene dissolves iodine, sulfur, oils, fats, resins, and phosgene. When ignited, toluene burns with a smoky flame. Unlike benzene, toluene cannot be easily purified by crystallization. 

It has been shown that alcohols like benzene have ignition temperatures higher than corresponding normal paraffin hydrocarbons and that they are also excellent non-knocking fuels. 

Alcohols do not form peroxides when undergoing oxidation, oxidize at relatively high temperatures, and comprise non-knocking fuels.45 Aromatic compounds as benzene and toluene have relatively high ignition temperatures and are excellent non-knocking fuels. 

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. 

Benzene is the parent member of the aromatic hydrocarbon family. It is a colorless to light yellow liquid with a characteristic aromatic odor. Benzene is nonpolar and bums with incomplete combustion, producing a smoky fire. The flammable range is 1.5 to 8% in air. Benzene is also toxic, with a TLV of 10 ppm, and is a known carcinogen. Concentrations of 8000 ppm for 30 to 60 min are fatal. Its boiling point is 176°F, and the flash point is 12°F. The ignition temperature is 928°F. Its vapor density is... 

Four important tests which are used to characterize an engine fuel are the spontaneous ignition temperature (SIT), flash point, fire point, and smoke point. These tests are standardized, and specialized fuels have specific requirements as defined by these tests. The SIT is dependent on the composition of the fuel and the conditions of the walls of the cylinder. Diesel fuels require low SIT with short delay times of the order of 1-2 ms. The SIT of heptane (CN = 60) is 330°C, whereas benzene with CN = —10 has a SIT of 420°C. 

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