Octane, flammability properties

Octane (CAS 111-65-9) Vapors mildly irritating to eyes and respiratory tract. A CNS depressant at very high concentrations. 300 ppm 1000 ppm [LEL] 0 3 0 Coloriess liquid. Gasoline-like odor and irritation are good warning properties. Vapor pressure is 11 mm Hg at 20 C (68 F). Flammable. 

Among the 16 million that have been made, there are all kinds of molecules with amazingly varied properties. What do they look like They may be crystalline solids, oils, waxes, plastics, elastics, mobile or volatile liquids, or gases. Familiar ones include sugar, a cheap natural compound isolated from plants as hard white crystals when pure, and petrol, a mixture of colourless, volatile, flammable hydrocarbons. Isooctane is a typical example and gives its name to the octane rating of petrol. 

From an engineering perspective, in assessing the required characteristics of the biofuels themselves, one must consider a variety of chemical, physical, and environmental properties. These include factors such as total energy content, ease of ignition (quantified by octane and cetane numbers), heat release rates, evaporative spray characteristics (vapor pressures), flammability safety (flash point), flow properties (viscosity), density, miscibility, fuel toxicity, emissions, impact on engine parts, and stability in storage. 

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