Pentene
Encyclopedia
Pentene refers to all the alkenes with chemical formula
. Each contains one double bond
within its molecular structure. There are a total of five different compounds in this class, differing from each other by whether the carbon atoms are attached linearly or in a branched structure, and whether the double bond has a cis or trans form.
. Most often 1-pentene is made as a byproduct of catalytic or thermal cracking of petroleum
, or during production of ethylene
and propylene
via thermal cracking of hydrocarbon fractions. It is rarely isolated as a separate compound. Instead, it is most often blended into gasoline
or, in a mixture with other hydrocarbons, alkylated
with isobutane
to make gasoline.
The only commercial manufacturer of 1-pentene is Sasol Ltd
, where it is separated from crude made by the Fischer-Tropsch process
.
2-Pentene has two geometric isomers, cis-2-pentene and trans-2-pentene. cis-2-Pentene is used in olefin metathesis
.
Alternative names for 1-pentene include amylene, n-amylene, and n-pentene. Alternative names for 2-pentene include beta-n-amylene and sym-methylethylethylene.
Isoamylene is one of three main byproducts of deep catalytic cracking (DCC), a relatively new concept that is very similar to the operation of the fluid catalytic cracking
(FCC). The DCC uses vacuum gas oil (VGO) as a feedstock to produce primarily propylene
, isobutylene
, and isoamylene. The rise in demand for polypropylene
has encouraged the growth of the DCCU, which is operated very much like an FCCU. Isobutylene
and isoamylene are feedstocks necessary for the production of the much debated gasoline blending components methyl tert-butyl ether
(MTBE) and tert-amyl methyl ether (TAME).
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
. Each contains one double bond
Double bond
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...
within its molecular structure. There are a total of five different compounds in this class, differing from each other by whether the carbon atoms are attached linearly or in a branched structure, and whether the double bond has a cis or trans form.
Straight-chain isomers
1-Pentene is an alpha-olefinAlpha-olefin
Alpha-olefins are a family of organic compounds which are olefins or alkenes with a chemical formula CxH2x, distinguished by having a double bond at the primary or alpha position...
. Most often 1-pentene is made as a byproduct of catalytic or thermal cracking of petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
, or during production of ethylene
Ethylene
Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...
and propylene
Propylene
Propene, also known as propylene or methylethylene, is an unsaturated organic compound having the chemical formula C3H6. It has one double bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance.-Properties:At room temperature and...
via thermal cracking of hydrocarbon fractions. It is rarely isolated as a separate compound. Instead, it is most often blended into gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
or, in a mixture with other hydrocarbons, alkylated
Alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene . Alkylating agents are widely used in chemistry because the alkyl group is probably the most common group encountered in...
with isobutane
Isobutane
Isobutane, also known as methylpropane, is an isomer of butane. It is the simplest alkane with a tertiary carbon. Concerns with depletion of the ozone layer by freon gases have led to increased use of isobutane as a gas for refrigeration systems, especially in domestic refrigerators and freezers,...
to make gasoline.
The only commercial manufacturer of 1-pentene is Sasol Ltd
Sasol
Sasol Ltd. is a South African company involved in mining, energy, chemicals and synfuels. In particular, they produce petrol and diesel profitably from coal and natural gas using Fischer-Tropsch process...
, where it is separated from crude made by the Fischer-Tropsch process
Fischer-Tropsch process
The Fischer–Tropsch process is a set of chemical reactions that convert a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. The process, a key component of gas to liquids technology, produces a petroleum substitute, typically from coal, natural gas, or biomass for use as synthetic...
.
2-Pentene has two geometric isomers, cis-2-pentene and trans-2-pentene. cis-2-Pentene is used in olefin metathesis
Olefin metathesis
Olefin metathesis or transalkylidenation is an organic reaction that entails redistribution of alkylene fragments by the scission of carbon - carbon double bonds in olefins . Its advantages include the creation of fewer sideproducts and hazardous wastes. Yves Chauvin, Robert H. Grubbs, and Richard R...
.
Alternative names for 1-pentene include amylene, n-amylene, and n-pentene. Alternative names for 2-pentene include beta-n-amylene and sym-methylethylethylene.
Branched-chain isomers
The branched isomers are 2-methylbut-1-ene, 3-methylbut-1-ene (isopentene), and 2-methylbut-2-ene (isoamylene).Isoamylene is one of three main byproducts of deep catalytic cracking (DCC), a relatively new concept that is very similar to the operation of the fluid catalytic cracking
Fluid catalytic cracking
Fluid catalytic cracking is the most important conversion process used in petroleum refineries. It is widely used to convert the high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils to more valuable gasoline, olefinic gases, and other products...
(FCC). The DCC uses vacuum gas oil (VGO) as a feedstock to produce primarily propylene
Propylene
Propene, also known as propylene or methylethylene, is an unsaturated organic compound having the chemical formula C3H6. It has one double bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance.-Properties:At room temperature and...
, isobutylene
Isobutylene
Isobutylene is a hydrocarbon of significant industrial importance. It is a four-carbon branched alkene , one of the four isomers of butylene. At standard temperature and pressure it is a colorless flammable gas.-Uses:...
, and isoamylene. The rise in demand for polypropylene
Polypropylene
Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes...
has encouraged the growth of the DCCU, which is operated very much like an FCCU. Isobutylene
Isobutylene
Isobutylene is a hydrocarbon of significant industrial importance. It is a four-carbon branched alkene , one of the four isomers of butylene. At standard temperature and pressure it is a colorless flammable gas.-Uses:...
and isoamylene are feedstocks necessary for the production of the much debated gasoline blending components methyl tert-butyl ether
Methyl tert-butyl ether
Methyl tert-butyl ether, also known as methyl tertiary butyl ether and MTBE, is an organic compound with molecular formula 3COCH3. MTBE is a volatile, flammable, and colorless liquid that is immiscible with water. It has a minty odor vaguely reminiscent of diethyl ether, leading to unpleasant taste...
(MTBE) and tert-amyl methyl ether (TAME).