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Cumene process

 
Cumene Process

 
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Cumene process
 
 
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Cumene process is an industrial process
Industrial process

Industrial processes are procedures involving chemistry or mechanization steps to aid in the manufacture of an item or items, usually carried out on a very large scale....
 for developing phenol
Phenol

Phenol, also known as carbolic acid, is a toxic, white crystalline solid with a sweet tarry odor, commonly referred to as a "hospital smell"....
 and acetone
Acetone

Acetone is the organic compound with the chemical formula OC2. This colorless, mobile, flammable liquid is the simplest example of the ketones....
 from benzene
Benzene

Benzene, or benzol, is an organic compound chemical compound and a known carcinogen with the molecular formula Carbon6Hydrogen6....
 and propylene
Propylene

Propene, also known as propylene, is an saturation organic chemistry having the chemical formula Carbon3Hydrogen6. It has one covalent bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance....
. The term stems from cumene
Cumene

Cumene is the common name for isopropylbenzene, an organic compound that is an aromatic hydrocarbon. It is a constituent of crude oil and refined fuels....
 (isopropyl benzene), the intermediate material during the process.

This process converts two relatively cheap starting materials, benzene
Benzene

Benzene, or benzol, is an organic compound chemical compound and a known carcinogen with the molecular formula Carbon6Hydrogen6....
 and propylene
Propylene

Propene, also known as propylene, is an saturation organic chemistry having the chemical formula Carbon3Hydrogen6. It has one covalent bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance....
, into two more valuable ones, phenol and acetone. Other reactants required are oxygen
Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
 from air and small amounts of a radical initiator
Radical initiator

In chemistry, radical initiators are substances that can produce radical under mild conditions and promote radical polymerization reactions. These substances generally possess weak bonds—bonds that have small bond dissociation energy....
. Most of the worldwide production of phenol and acetone is now based on this method.

The overall chemical process is summarised below.
ene and propylene are compressed together to a pressure of 30 standard atmospheres
Atmospheric pressure

Atmospheric pressure is sometimes defined as the force per unit area exerted against a surface by the weight of air above that surface at any given point in the Earth's atmosphere....
 at 250 °C
Celsius

Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death....
 (482° F
Fahrenheit

Fahrenheit is a temperature scale named after the physicist Daniel Gabriel Fahrenheit , who proposed it in 1724. Today, the scale has largely been replaced by the Celsius scale; it is still in use for non-scientific purposes in the United States and a few other countries such as Belize....
) in presence of a catalytic Lewis acid
Lewis acid

A Lewis acid is a chemical compound, A, that can accept a pair of electrons from a Lewis base, B, that acts as an electron-pair donor, forming an adduct, AB.Gilbert N....
.






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Encyclopedia


Cumene process is an industrial process
Industrial process

Industrial processes are procedures involving chemistry or mechanization steps to aid in the manufacture of an item or items, usually carried out on a very large scale....
 for developing phenol
Phenol

Phenol, also known as carbolic acid, is a toxic, white crystalline solid with a sweet tarry odor, commonly referred to as a "hospital smell"....
 and acetone
Acetone

Acetone is the organic compound with the chemical formula OC2. This colorless, mobile, flammable liquid is the simplest example of the ketones....
 from benzene
Benzene

Benzene, or benzol, is an organic compound chemical compound and a known carcinogen with the molecular formula Carbon6Hydrogen6....
 and propylene
Propylene

Propene, also known as propylene, is an saturation organic chemistry having the chemical formula Carbon3Hydrogen6. It has one covalent bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance....
. The term stems from cumene
Cumene

Cumene is the common name for isopropylbenzene, an organic compound that is an aromatic hydrocarbon. It is a constituent of crude oil and refined fuels....
 (isopropyl benzene), the intermediate material during the process.

This process converts two relatively cheap starting materials, benzene
Benzene

Benzene, or benzol, is an organic compound chemical compound and a known carcinogen with the molecular formula Carbon6Hydrogen6....
 and propylene
Propylene

Propene, also known as propylene, is an saturation organic chemistry having the chemical formula Carbon3Hydrogen6. It has one covalent bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance....
, into two more valuable ones, phenol and acetone. Other reactants required are oxygen
Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
 from air and small amounts of a radical initiator
Radical initiator

In chemistry, radical initiators are substances that can produce radical under mild conditions and promote radical polymerization reactions. These substances generally possess weak bonds—bonds that have small bond dissociation energy....
. Most of the worldwide production of phenol and acetone is now based on this method.

The overall chemical process is summarised below.

Technical description

Benzene and propylene are compressed together to a pressure of 30 standard atmospheres
Atmospheric pressure

Atmospheric pressure is sometimes defined as the force per unit area exerted against a surface by the weight of air above that surface at any given point in the Earth's atmosphere....
 at 250 °C
Celsius

Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death....
 (482° F
Fahrenheit

Fahrenheit is a temperature scale named after the physicist Daniel Gabriel Fahrenheit , who proposed it in 1724. Today, the scale has largely been replaced by the Celsius scale; it is still in use for non-scientific purposes in the United States and a few other countries such as Belize....
) in presence of a catalytic Lewis acid
Lewis acid

A Lewis acid is a chemical compound, A, that can accept a pair of electrons from a Lewis base, B, that acts as an electron-pair donor, forming an adduct, AB.Gilbert N....
. Phosphoric acid
Phosphoric acid

Phosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula Hydrogen3PhosphorusOxygen4....
 is often favored over aluminium
Aluminium

Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13....
 halide
Halide

A halide is a binary compound, of which one part is a halogen atom and the other part is an chemical element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound....
s. Cumene is formed in the gas-phase Friedel-Crafts alkylation
Friedel-Crafts reaction

The Friedel-Crafts reactions are a set of organic reaction developed by Charles Friedel and James Crafts in 1877. There are two main types of Friedel-Crafts reactions: alkylation reactions and acylation reactions....
 of benzene by propylene:

Cumene is oxidized in air which removes the tertiary benzylic hydrogen from cumene and hence forms a cumene radical
Radical (chemistry)

In chemistry, radicals are atoms, molecules or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly chemical reaction, so radicals are likely to take part in chemical reactions....
:

This cumene radical then bonds
Chemical bond

A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds....
 with an oxygen molecule to give cumene hydroperoxide radical, which in turn forms cumene hydroperoxide (C6H5C(CH3)2-O-O-H) by abstracting benzylic hydrogen from another cumene molecule. This latter cumene converts into cumene radical and feeds back into subsequent chain formations of cumene hydroperoxides. A pressure of 5 atm is used to ensure that the unstable peroxide is kept in liquid state.

Cumene hydroperoxide is then hydrolysed
Hydrolysis

Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
 in an acid
Acid

An acid is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion Activity greater than in pure water, i.e....
ic medium to give phenol
Phenol

Phenol, also known as carbolic acid, is a toxic, white crystalline solid with a sweet tarry odor, commonly referred to as a "hospital smell"....
 and acetone
Acetone

Acetone is the organic compound with the chemical formula OC2. This colorless, mobile, flammable liquid is the simplest example of the ketones....
. In the first step, the terminal hydorperoxy oxygen atom is protonated. This is followed by a step in which the phenyl group migrates from the benzyl carbon to the adjacent oxygen and a water molecule is lost, producing a resonance
Resonance (chemistry)

Resonance in chemistry is a key component of valence bond theory used to graphically represent and mathematically model certain types of molecular structures when no single, conventional Lewis structure can satisfactorily represent the observed structure or explain its properties....
 stabilized tertiary carbocation
Carbocation

A carbocation is an ion with a positively-charged carbon atom. The charged carbon atom in a carbocation is a "sextet", i.e. it has only six electrons in its outer Electron shell#Valence shell instead of the eight valence electrons that ensures maximum stability ....
. The concerted mechanism of this step is similar to the mechanisms of the Baeyer-Villiger oxidation
Baeyer-Villiger oxidation

The Baeyer-Villiger oxidation is an organic reaction in which a ketone is redox to an ester by treatment with peroxy acids or hydrogen peroxide....
 and also the oxidation step of hydroboration-oxidation.

As shown below, the resulting carbocation
Carbocation

A carbocation is an ion with a positively-charged carbon atom. The charged carbon atom in a carbocation is a "sextet", i.e. it has only six electrons in its outer Electron shell#Valence shell instead of the eight valence electrons that ensures maximum stability ....
 is then attacked by water, a proton is then transferred from the hydroxy oxygen to the ether oxygen, and finally the ion falls apart into phenol and acetone.

The products are extracted by distillation
Distillation

Distillation is a method of separation process mixtures based on differences in their Volatility in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
.

See also

  • Chemical synthesis
    Chemical synthesis

    In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product , or several products. This happens by physics and chemical manipulations usually involving one or more reactions....
  • Dow process
    Dow process

    The Dow process is the electrolysis method of bromine extraction from brine, and was Herbert Henry Dow's second revolutionary process for generating bromine commercially....
  • Friedel Crafts alkylation
  • Baeyer-Villiger oxidation
    Baeyer-Villiger oxidation

    The Baeyer-Villiger oxidation is an organic reaction in which a ketone is redox to an ester by treatment with peroxy acids or hydrogen peroxide....
  • Concerted reaction
    Concerted reaction

    In chemistry, a concerted reaction is a chemical reaction in which all bond breaking and bond making occurs in a single step. Reactive intermediates or other unstable high energy intermediates are not involved....
  • Raschig process
    Raschig process

    The Raschig process is a chemical process for producing hydroxylamine . The process converts ammonium carbonate to ammonium nitrite, and this is converted to hydroxylamine disulfonate and thence to hydroxylamine sulfate....
     (also produces phenol)


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