BenzeneBenzeneCreated by: Created by:

Tomáš MachulaTomáš Machula

Filák AntonínFilák Antonín

BenzeneBenzene BenzeneBenzene, also known as , also known as CC66HH66, , PhPhHH, and , and benzolbenzol, is an , is an organicorganic chemicalchemical

compoundcompound which is a which is a colorlesscolorless and and flammableflammable liquid with a pleasant, liquid with a pleasant, sweet smell. sweet smell.

Benzene is a known Benzene is a known carcinogencarcinogen. It is a component of . It is a component of gasolinegasoline. It is an . It is an important industrial important industrial solventsolvent and precursor in the production of and precursor in the production of drugsdrugs, , plasticsplastics, gasoline, synthetic , gasoline, synthetic rubberrubber, and , and dyesdyes. .

Benzene is a natural constituent of Benzene is a natural constituent of crudecrude oiloil, but it is usually synthesized , but it is usually synthesized from other compounds present in petroleum. from other compounds present in petroleum.

Benzene is an Benzene is an aromaticaromatic hydrocarbonhydrocarbon, and the second [, and the second [nn]-]-annuleneannulene ([6]- ([6]-annulene).annulene).

gasoline - benzín dyes – barviva rubber – guma crude - surový

Properties of BenzeneProperties of Benzene

General General SystematicSystematic namename Benzene Benzene Other names BenzolOther names Benzol MolecularMolecular formulaformula C6H6 C6H6 MolarMolar massmass 78.11 g/mol 78.11 g/mol Appearance Colorless liquidAppearance Colorless liquid CAS CAS numbernumber [71-43-2] [71-43-2]

HazardsHazards R-R-phrasesphrases R45, R46, R11, R36/38, R45, R46, R11, R36/38,

R48/23/24/25, R65R48/23/24/25, R65 S-S-phrasesphrases S53, S45 S53, S45

PropertiesProperties DensityDensity and and phasephase 0.8786 g/cm³ 0.8786 g/cm³ SolubilitySolubility in in waterwater 1.79 g/l (25 °C) 1.79 g/l (25 °C) MeltingMelting point point 5.5 °C (278.6 K) 5.5 °C (278.6 K) BoilingBoiling point point 80.1 °C (353.2 K) 80.1 °C (353.2 K) ViscosityViscosity 0.652 0.652 cPcP at 20 °C at 20 °C

StructureStructure MolecularMolecular shapeshape Planar Planar DipoleDipole moment moment 0 0 DD

HistoryHistory Benzene was discovered in Benzene was discovered in 18251825 by by

the the EnglishEnglish scientist scientist Michael Michael FaradayFaraday, , who isolated it from oil gas and gave who isolated it from oil gas and gave it the name it the name bicarburet of hydrogenbicarburet of hydrogen. . In In 18331833, the , the GermanGerman chemist chemist EilhardEilhard MitscherlichMitscherlich produced it via the produced it via the distillationdistillation of of benzoicbenzoic acidacid (from (from gum gum benzoinbenzoin) and ) and limelime. Mitscherlich gave . Mitscherlich gave the compound the name the compound the name benzinbenzin. In . In 18451845, the English chemist , the English chemist Charles Charles MansfieldMansfield, working under , working under August August WilhelmWilhelm von von HofmannHofmann, isolated , isolated benzene from benzene from coalcoal tartar. Four years . Four years later, Mansfield began the first later, Mansfield began the first industrial-scale production of industrial-scale production of benzene, based on the coal-tar benzene, based on the coal-tar method.method. Michael Faraday

ProductionProduction Benzene may result whenever Benzene may result whenever carboncarbon-rich materials -rich materials

undergo incomplete undergo incomplete combustioncombustion. It is produced naturally in . It is produced naturally in volcanoesvolcanoes and and forestforest firesfires, and is also a component of , and is also a component of cigarettecigarette smoke. smoke.

Up until Up until WorldWorld WarWar II II, most benzene was produced as a , most benzene was produced as a byproduct of byproduct of cokecoke production in the production in the steelsteel industry. industry. However, in the However, in the 1950s1950s, increased demand for benzene, , increased demand for benzene, especially from the growing especially from the growing plasticsplastics industry, necessitated industry, necessitated the production of benzene from petroleum. Today, most the production of benzene from petroleum. Today, most benzene comes from the benzene comes from the petrochemicalpetrochemical industry, with only industry, with only a small fraction being produced from coal.a small fraction being produced from coal.

Three chemical processes contribute equally to industrial Three chemical processes contribute equally to industrial benzene production: benzene production: catalyticcatalytic reformingreforming, , toluenetoluene hydrodealkylation, and hydrodealkylation, and steamsteam crackingcracking..

Byproduct – vedlejší produkt

UsesUses In the 19th and early 20th centuries, benzene was used as an In the 19th and early 20th centuries, benzene was used as an

aftershave because of its pleasant smell. Prior to the aftershave because of its pleasant smell. Prior to the 1920s1920s, , benzene was frequently used as an industrial solvent, especially benzene was frequently used as an industrial solvent, especially for degreasing metal. As its toxicity became obvious, other for degreasing metal. As its toxicity became obvious, other solvents replaced benzene in applications that directly exposed solvents replaced benzene in applications that directly exposed the user to benzene.the user to benzene.

As a gasoline additive, benzene increases the As a gasoline additive, benzene increases the octane octane ratingrating and and reduces reduces knockingknocking. As a result, gasoline often contained several . As a result, gasoline often contained several percent benzene before the percent benzene before the 1950s1950s, when , when tetraethyltetraethyl leadlead replaced replaced it as the most widely used antiknock additive. However, with the it as the most widely used antiknock additive. However, with the global phaseout of leaded gasoline, benzene has made a global phaseout of leaded gasoline, benzene has made a comeback as a gasoline additive in some nations. By far the comeback as a gasoline additive in some nations. By far the largest use of benzene is as an intermediate to make other largest use of benzene is as an intermediate to make other chemicals. The most widely produced derivatives of benzene are chemicals. The most widely produced derivatives of benzene are styrenestyrene, which is used to make polymers and plastics, , which is used to make polymers and plastics, phenolphenol for for resins and adhesives (via resins and adhesives (via cumenecumene), and ), and cyclohexanecyclohexane, which is , which is used in Nylon manufacture. Smaller amounts of benzene are used used in Nylon manufacture. Smaller amounts of benzene are used to make some types of rubbers, lubricants, dyes, detergents, to make some types of rubbers, lubricants, dyes, detergents, drugs, explosives and pesticides.drugs, explosives and pesticides.

Health EffectsHealth Effects Breathing very high levels of benzene can result in Breathing very high levels of benzene can result in deathdeath, while , while

high levels can cause drowsiness, dizziness, rapid heart rate, high levels can cause drowsiness, dizziness, rapid heart rate, headachesheadaches, tremors, confusion, and unconsciousness. Eating or , tremors, confusion, and unconsciousness. Eating or drinking foods containing high levels of benzene can cause drinking foods containing high levels of benzene can cause vomiting, irritation of the vomiting, irritation of the stomachstomach, dizziness, sleepiness, , dizziness, sleepiness, convulsions, rapid heart rate, and death.convulsions, rapid heart rate, and death.

The major effect of benzene from The major effect of benzene from chronicchronic (long term) exposure is (long term) exposure is to the to the bloodblood. Benzene damages the . Benzene damages the bone bone marrowmarrow and can cause a and can cause a decrease in red blood cells leading to anemia. It can also cause decrease in red blood cells leading to anemia. It can also cause excessive bleeding and depress the immune system, increasing excessive bleeding and depress the immune system, increasing the chance of infection.the chance of infection.

The US Occupational Safety and Health Administration (OSHA) has The US Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit of 1 part of benzene per million set a permissible exposure limit of 1 part of benzene per million parts of air (1 ppm) in the workplace during an 8-hour workday, parts of air (1 ppm) in the workplace during an 8-hour workday, 40-hour workweek.40-hour workweek.

Exposure – vystaveni

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