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The Chemical Compound Benzene

 

Benzene is a compound that comes from the gum benzoin, an aromatic resin. The acidic material was named flowers of benzoin, and the hydrocarbon derived from it was named benzene. Michael Faraday isolated and identified benzene in 1825 from oily residue left over from the production of illuminating gas. Eilhard Mitscherlich produced benzene in 1833 by distilling benzoic acid from gum benzoin.

Benzene

Benzene is a chemical compound with many diverse uses. It is used as a solvent, an intermediate in chemical synthesis, and as a constituent of motor fuels. Benzene is produced as a by-product of gasoline production at refineries. In the United States, benzene is used to make ethylbenzene, which accounts for 52% of the Benzene demand in 2008.

Exposure to benzene can cause different types of tumors in lab animals. In laboratory studies, benzene can also alter the chromosomes of bone marrow cells, which are commonly found in leukemia cells. Benzene is found in many consumer products, and may be harmful for people in high exposure. Moreover, exposure to high levels of benzene can cause a variety of blood cancers, including leukemia.
Benzene structure

Benzene has a hexagonal planar structure with carbon-carbon bonds of the same length. It does not undergo addition reactions or contain simple pi bonds. As the name suggests, benzene does not undergo any addition reactions. In the structure of the molecule, the carbon atoms are bonded to two other carbons and one hydrogen. The carbon-carbon bonds of benzene are intermediates, each spanning 120 degrees in length.

The benzene structure was first proposed by Friedrich August Kekule in 1865. The German chemist claimed that it was derived from a dream in which he saw a snake biting its own tail. The structure he proposed had alternating C-C single bonds and C-C double bonds. It was subsequently referred to as cyclohexa-1,3,5-triene. However, Kekule’s theory was not supported by all available evidence.

Benzene’s molecular orbital description

The molecular orbital description of benzene can be explained in two different ways. First, it can be shown in terms of AO contribution, where the open shapes of orbitals correspond to yellow and blue colors. Secondly, it can be shown as a superposition of two similar molecular orbitals. In both cases, the atomic distances between neighboring carbon atoms are the same.

Benzene has a mirror line from C-1 through the carbon opposite. When the mirror line is reflected, the molecule has a symmetric orbital and an anti-symmetric orbital. Asymmetric orbitals have a maximum density of electrons on one side, while an anti-symmetric orbital has a minimum density of electrons. Despite the name, benzene’s MO is symmetric and is the most stable of all cycloal molecules.
Benzene’s toxicity

The government’s Shanghai Health Study, a five-year project funded by the largest petrochemical companies and the API lobby, purported to examine benzene’s toxicity. Its three major inquiries focused on whether benzene is linked to non-Hodkin lymphoma, the progression of various diseases caused by benzene, and biological markers of toxicity. Yet, the study was largely misleading.

Despite growing evidence of benzene’s toxicity, companies have continued to manufacture it, despite the risk. Benzene is a colorless, flammable solvent that’s commonly used in industrial settings. Its exposure puts firefighters, service station attendants, and other workers at risk of serious health problems, including acute myeloid leukemia, as well as a host of other diseases.

Benzene’s sulfonation

Benzene’s sulfanation is a trimolecular electrophilic substitution that produces a sulfonic acid, oleum, or an aprotic solvent. The process is spontaneous and occurs in a receptacle, which is either a gas or a liquid. SO3 is an electrophile, and a proton-exchange model has been developed to calculate the reaction rate. Several kinetic models of benzene’s sulfonation have been developed, but there are several important flaws in them.

Sulfur trioxide, an electrophile in the sulfonation process, is formed from fuming concentrated sulfuric acid. The proton-absorbed sulfonium ion from sulfuric acid is then attacked by the benzene ring. Afterward, the positively charged sigma complex undergoes multiple rearrangements, giving rise to a resonant ring.

Benzene’s origin

Benzene is a chemical that was first discovered in 1825, when a man named Michael Faraday isolated a chemical called benzene from coal tar. Michael Faraday named the compound benzene and the hydrocarbon it is derived from benzoic acid, which was originally produced by pyrolysis of whale oil. In 1865, a German professor named August Kekule isolated and identified the chemical, and shortly afterward, he produced benzene by distilling the acid benzoic from coal tar. Benzene is a carcinogen and is widely used today.

Benzene’s origin is actually a complex process. Benzene is produced as a by-product of catalytic cracking, a process intended to convert large petroleum molecules into smaller ones. However, the origin of benzene is much more complicated than this. Benzene is actually obtained by catalytic reforming, a process in which alkanes are first converted to cycloalkanes, and then dehydrogenated to aromatic compounds. In addition to catalytic reforming, Hofmann’s work was influential to Charles Mansfield, who later used this process to produce benzene.