Benzene is an organic chemical compound with the formula C6H6 that is classified as an aromatic hydrocarbon. Benzene is a colorless, toxic, carcinogenic, flammable liquid with a sweet odor that has a high evaporation rate and is responsible for the aroma around gas stations.
Benzene in the industry is obtained by catalytic modification. This method is a chemical process used in an oil refinery to convert crude oil into liquid products with high octane number and aromatic hydrocarbons. In this process, a mixture of hydrocarbons, mainly propane and butane, is combined with hydrogen gas and then exposed to a catalyst of platinum chloride or rhenium chloride at a temperature of 500 degrees and a pressure of 8 to 50 atmospheres, in which case the aliphatic hydrocarbons of the rings Form and lose hydrogen to form aromatic hydrocarbons.Aromatic reaction products are separated by extraction with some solvents such as diethylene glycol and sulfolan, and benzene is separated from other aromatics by distillation. Benzene can also be made from phenol, halo benzene and benzoic acid and its salts.
Applications of benzene:
It is mainly used as a raw material for the production of other chemicals such as ethylbenzene, cumin, cyclohexane, nitrobenzene and alkyl benzene. More than half of all benzene production is converted to ethylbenzene, a styrene precursor used to make polymers and plastics such as polystyrene and EPS. 20% of benzene production is used to produce cumin used for phenol production and acetone for resin and adhesives. Cyclohexane consumes 10% of the world’s benzene production in the production of nylon fibers that are processed into engineering fabrics and plastics. Small amounts of benzene are used to make some plastics, lubricants, paints, detergents, drugs, explosives, and pesticides. Toluene is now often used as a substitute for benzene for example as a fuel additive. The properties of benzene and toluene are similar but toluene is less toxic.