In
organic chemistryOrganic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
, a
hydrocarbon is an
organic compoundAn organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
consisting entirely of
hydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
and
carbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
. Hydrocarbons from which one hydrogen atom has been removed are
functional groupIn organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
s, called
hydrocarbyls.
Aromatic hydrocarbonAn aromatic hydrocarbon or arene is a hydrocarbon with alternating double and single bonds between carbon atoms. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent...
s (arenes),
alkaneAlkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
s,
alkeneIn organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
s,
cycloalkaneCycloalkanes are types of alkanes that have one or more rings of carbon atoms in the chemical structure of their molecules. Alkanes are types of organic hydrocarbon compounds that have only single chemical bonds in their chemical structure...
s and
alkyneAlkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...
-based compounds are different types of hydrocarbons.
The majority of hydrocarbons found naturally occur in crude oil, where decomposed organic matter provides an abundance of carbon and hydrogen which, when bonded, can
catenateCatenation is the ability of a chemical element to form a long chain-like structure via a series of covalent bonds. Catenation occurs most readily in carbon, which forms covalent bonds with other carbon atoms. Catenation is the reason for the presence of a large number of organic compounds in nature...
to form seemingly limitless chains.
Types of hydrocarbons
The classifications for hydrocarbons defined by
IUPAC nomenclature of organic chemistryThe IUPAC nomenclature of organic chemistry is a systematic method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry . Ideally, every possible organic compound should have a name from which an unambiguous structural formula can be drawn. ...
are as follows:
- Saturated hydrocarbons (alkane
Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
s) are the simplest of the hydrocarbon species and are composed entirely of single bonds and are saturated with hydrogen. The general formula for saturated hydrocarbons is CnH2n+2 (assuming non-cyclic structures). Saturated hydrocarbons are the basis of petroleum fuels and are found as either linear or branched species. Hydrocarbons with the same molecular formula but different structural formulaThe structural formula of a chemical compound is a graphical representation of the molecular structure, showing how the atoms are arranged. The chemical bonding within the molecule is also shown, either explicitly or implicitly...
e are called structural isomers. As given in the example of 3-methylhexane and its higher homologuesIn chemistry, homology refers to the appearance of homologues. A homologue is a compound belonging to a series of compounds differing from each other by a repeating unit, such as a methylene group, a peptide residue, etcetera....
, branched hydrocarbons can be chiralA chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....
. Chiral saturated hydrocarbons constitute the side chains of biomolecules such as chlorophyllChlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
and tocopherolTocopherols are a class of chemical compounds of which many have vitamin E activity. It is a series of organic compounds consisting of various methylated phenols...
.
- Unsaturated hydrocarbon
Unsaturated hydrocarbons are hydrocarbons that have double or triple covalent bonds between adjacent carbon atoms. Those with at least one double bond are called alkenes and those with at least one triple bond are called alkynes...
s have one or more double or triple bonds between carbon atoms. Those with double bond are called alkeneIn organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
s. Those with one double bond have the formula CnH2n (assuming non-cyclic structures). Those containing triple bonds are called alkyneAlkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...
s, with general formula CnH2n-2.
- Cycloalkanes are hydrocarbons containing one or more carbon rings to which hydrogen atoms are attached. The general formula for a saturated hydrocarbon containing one ring is CnH2n.
- Aromatic hydrocarbon
An aromatic hydrocarbon or arene is a hydrocarbon with alternating double and single bonds between carbon atoms. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent...
s, also known as areneArene or Arênê or Arène may refer to:*an aromatic hydrocarbon*Arene , a genus of marine snails in the family Areneidae*Arene , the wife of Aphareus and mother of Idas and Lynceus in Greek mythology...
s, are hydrocarbons that have at least one aromatic ring.
Hydrocarbons can be gases (e.g.
methaneMethane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
and
propanePropane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
), liquids (e.g.
hexaneHexane is a hydrocarbon with the chemical formula C6H14; that is, an alkane with six carbon atoms.The term may refer to any of four other structural isomers with that formula, or to a mixture of them. In the IUPAC nomenclature, however, hexane is the unbranched isomer ; the other four structures...
and
benzeneBenzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
), waxes or low melting solids (e.g. paraffin wax and
naphthaleneNaphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...
) or polymers (e.g.
polyethylenePolyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
,
polypropylenePolypropylene , 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...
and
polystyrenePolystyrene ) also known as Thermocole, abbreviated following ISO Standard PS, is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry...
).
General properties
Because of differences in molecular structure, the empirical formula remains different between hydrocarbons; in linear, or "straight-run" alkanes, alkenes and alkynes, the amount of bonded hydrogen lessens in alkenes and alkynes due to the "self-bonding" or catenation of carbon preventing entire saturation of the hydrocarbon by the formation of double or triple bonds.
This inherent ability of hydrocarbons to bond to themselves is referred to as
catenationCatenation is the ability of a chemical element to form a long chain-like structure via a series of covalent bonds. Catenation occurs most readily in carbon, which forms covalent bonds with other carbon atoms. Catenation is the reason for the presence of a large number of organic compounds in nature...
, and allows hydrocarbon to form more complex molecules, such as
cyclohexaneCyclohexane is a cycloalkane with the molecular formula C6H12. Cyclohexane is used as a nonpolar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which being intermediates used in the production of nylon...
,and in rarer cases, arenes such as
benzeneBenzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
. This ability comes from the fact that bond character between carbon atoms is entirely non-polar,in that the distribution of electrons between the two elements is somewhat even due to the same electronegativity values of the elements (~0.30), and does not result in the formation of an electrophile.
Generally, with catenation comes the loss of the total amount of bonded hydrocarbons and an increase in the amount of energy required for bond cleavage due to strain exerted upon the molecule;in molecules such as cyclohexane, this is referred to as
ring strainIn organic chemistry, ring strain is the tendency of a cyclic molecule, such as cyclopropane, to destabilize when its atoms are in non-favorable high energy spatial orientations...
, and occurs due to the "destabilized" spatial electron configuration of the atom.
In simple chemistry, as per
valence bond theoryIn chemistry, valence bond theory is one of two basic theories, along with molecular orbital theory, that were developed to use the methods of quantum mechanics to explain chemical bonding. It focuses on how the atomic orbitals of the dissociated atoms combine to give individual chemical bonds...
, the carbon atom must follow the "
4-hydrogen rule",which states that the maximum number of atoms available to bond with carbon is equal to the number of electrons that are attracted into the outer shell of carbon.In terms of shells, carbon consists of an incomplete outer shell, which comprises 4 electrons,and thus has 4 electrons available for covalent or dative bonding.
Hydrocarbons are hydrophobic and are
lipidLipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
s.
Some hydrocarbons also are abundant in the solar system. Lakes of liquid methane and ethane have been found on
TitanTitan , or Saturn VI, is the largest moon of Saturn, the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found....
, Saturn's largest moon, confirmed by the Cassini-Huygens Mission. Hydrocarbons are also abundant in nebulae forming polycyclic aromatic hydrocarbons - PAH compounds.
Simple hydrocarbons and their variations
Number of
carbon atoms |
Alkane Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
|
AlkeneIn organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
|
Alkyne Alkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...
|
Cycloalkane Cycloalkanes are types of alkanes that have one or more rings of carbon atoms in the chemical structure of their molecules. Alkanes are types of organic hydrocarbon compounds that have only single chemical bonds in their chemical structure...
|
Alkadiene |
| 1 |
Methane Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
|
– |
– |
– |
– |
| 2 |
EthaneEthane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas....
|
Ethene (ethylene) |
EthyneAcetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...
(acetylene) |
– |
– |
| 3 |
PropanePropane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
|
Propene (propylene) |
Propyne Methylacetylene is an alkyne with the chemical formula H3C≡CH. It is a component of MAPP gas along with its isomer 1,2-propadiene , which is commonly used in gas welding...
(methylacetylene) |
CyclopropaneCyclopropane is a cycloalkane molecule with the molecular formula C3H6, consisting of three carbon atoms linked to each other to form a ring, with each carbon atom bearing two hydrogen atoms...
|
PropadienePropadiene is the organic compound with the formula H2C=C=CH2. It is the simplest allene, a compound with conjoined C=C double bonds. Propadiene's common name is allene...
(allene) |
| 4 |
ButaneButane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...
|
Butene (butylene) |
Butyne Butyne may refer to either of two isomeric organic chemical compounds:*1-Butyne *2-Butyne...
|
CyclobutaneCyclobutane is an organic compound with the formula 4. Cyclobutane is a colourless gas and commercially available as a liquefied gas. Derivatives of cyclobutane are called cyclobutanes...
|
Butadiene 1,3-Butadiene is a simple conjugated diene with the formula C4H6. It is an important industrial chemical used as a monomer in the production of synthetic rubber. When the word butadiene is used, most of the time it refers to 1,3-butadiene....
|
| 5 |
PentanePentane is an organic compound with the formula C5H12 — that is, an alkane with five carbon atoms. The term may refer to any of three structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, pentane means exclusively the n-pentane isomer; the other two being called...
|
Pentene 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...
|
Pentyne |
CyclopentaneCyclopentane is a highly flammable alicyclic hydrocarbon with chemical formula 510 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and below the plane. It occurs as a colorless liquid with a petrol-like odor. Its melting point is −94 °C...
|
Pentadiene (piperylene) |
| 6 |
Hexane Hexane is a hydrocarbon with the chemical formula C6H14; that is, an alkane with six carbon atoms.The term may refer to any of four other structural isomers with that formula, or to a mixture of them. In the IUPAC nomenclature, however, hexane is the unbranched isomer ; the other four structures...
|
Hexene Hexene is a higher olefin, or alkene with a formula C6H12. The "Hex" is derived from the fact that there are 6 carbon atoms in the molecule, while the "ene" suffix denotes that two carbon atoms are connected via a double bond. There are several isomers of hexene, depending on the position of the...
|
Hexyne |
CyclohexaneCyclohexane is a cycloalkane with the molecular formula C6H12. Cyclohexane is used as a nonpolar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which being intermediates used in the production of nylon...
|
Hexadiene |
| 7 |
Heptanen-Heptane is the straight-chain alkane with the chemical formula H3C5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale...
|
Heptene Heptene is a higher olefin, or alkene with the formula C7H14.The commercial product is a liquid that is a mixture of isomers. It is used as an additive in lubricants, as a catalyst, and as a surfactant. This chemical is also known as heptylene....
|
Heptyne |
Cycloheptane Cycloheptane is a cycloalkane with the molecular formula C7H14. Cycloheptane is used as a nonpolar solvent for the chemical industry and as an intermediate in the manufacture of chemicals and pharmaceutical drugs. It may be derived by Clemmensen reduction from cycloheptanone. Cycloheptane vapour is...
|
Heptadiene |
| 8 |
Octane Octane is a hydrocarbon and an alkane with the chemical formula C8H18, and the condensed structural formula CH36CH3. Octane has many structural isomers that differ by the amount and location of branching in the carbon chain...
|
Octene Octene is an alkene with the formula . Several isomers of octene are known, depending on the position of the double bond and the branching of the carbon chain....
|
Octyne |
CyclooctaneCyclooctane is a cycloalkane with the molecular formula 8. It is a simple colourless hydrocarbon, but it is often a reference compound for saturated eight-membered ring compounds in general.- Conformation :...
|
Octadiene |
| 9 |
Nonane Nonane is a linear alkane hydrocarbon with the chemical formula C9H20.Nonane has 35 structural isomers. Tripropylene is a mixture of three specific isomers of nonane.Its substituent form is nonyl. Its cycloalkane counterpart is cyclononane, ....
|
Nonene Nonene is an alkene with the molecular formula C9H18. Many structural isomers are possible, depending on the location of the C=C double bond and the branching of the other parts of the molecule. Industrially, the most important nonenes are trimers of propene...
|
Nonyne |
Cyclononane Cyclononane is an alicyclic hydrocarbon consisting of a ring of nine carbon atoms. Its molecular formula is C9H18. Its empirical formula is CH2....
|
Nonadiene |
| 10 |
Decane Decane is an alkane hydrocarbon with the chemical formula CH38CH3.75 structural isomers of decane exist, all of which are flammable liquids. Decane is one of the components of gasoline . Like other alkanes, it is nonpolar and therefore will not dissolve in polar liquids such as water...
|
Decene Decene is an alkene with the formula . Decene contains a chain of ten carbon atoms with one double bond. There are many isomers of decene depending on the position and geometry of the double bond. 1-Decene is the only isomer of industrial importance...
|
Decyne 1-Decyne is an alkyne hydrocarbon with the chemical formula C10H18....
|
Cyclodecane Cyclodecane is a cycloalkane with the chemical formula C10H20....
|
Decadiene |
Usage
Hydrocarbons are one of the Earth's most important energy resources. The predominant use of hydrocarbons is as a combustible
fuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
source. In their solid form, hydrocarbons take the form of asphalt.
Mixtures of volatile hydrocarbons are now used in preference to the chlorofluorocarbons as a
propellantA propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...
for
aerosol sprayAerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles. This is used with a can or bottle that contains a liquid under pressure. When the container's valve is opened, the liquid is forced out of a small hole and emerges as an aerosol or mist...
s, due to chlorofluorocarbon's impact on the
ozone layerThe ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to the life forms on Earth...
.
MethaneMethane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
[1C] and
ethaneEthane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas....
[2C] are gaseous at ambient temperatures and cannot be readily liquefied by pressure alone.
PropanePropane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...
[3C] is however easily liquefied, and exists in 'propane bottles' mostly as a liquid.
ButaneButane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...
[4C] is so easily liquefied that it provides a safe, volatile fuel for small pocket lighters.
PentanePentane is an organic compound with the formula C5H12 — that is, an alkane with five carbon atoms. The term may refer to any of three structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, pentane means exclusively the n-pentane isomer; the other two being called...
[5C] is a clear liquid at room temperature, commonly used in chemistry and industry as a powerful nearly odorless
solventA solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
of waxes and high molecular weight organic compounds, including greases.
HexaneHexane is a hydrocarbon with the chemical formula C6H14; that is, an alkane with six carbon atoms.The term may refer to any of four other structural isomers with that formula, or to a mixture of them. In the IUPAC nomenclature, however, hexane is the unbranched isomer ; the other four structures...
[6C] is also a widely used non-polar, non-aromatic solvent, as well as a significant fraction of common
gasolineGasoline , 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...
.
The [6C] through [10C] alkanes, alkenes and isomeric cycloalkanes are the top components of
gasolineGasoline , 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...
, naptha,
jet fuelJet fuel is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is clear to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1 which are produced to a standardized international specification...
and specialized industrial solvent mixtures. With the progressive addition of carbon units, the simple non-ring structured hydrocarbons have higher viscosities, lubricating indices, boiling points, solidification temperatures, and deeper color. At the opposite extreme from [1C] methane lie the heavy tars that remain as the
lowest fraction in a crude oil refining retort. They are collected and widely utilized as roofing compounds, pavement composition, wood preservatives (the
creosoteCreosote is the portion of chemical products obtained by the distillation of a tar that remains heavier than water, notably useful for its anti-septic and preservative properties...
series) and as extremely high viscosity sheer-resisting liquids.
Burning hydrocarbons
Hydrocarbons are currently the main source of the world’s
electric energyElectric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
and heat sources (such as home heating) because of the energy produced when burnt. Often this energy is used directly as heat such as in home heaters, which use either
oilAn oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
or
natural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
. The hydrocarbon is burnt and the heat is used to heat water, which is then circulated. A similar principle is used to create electric energy in power plants.
Common properties of hydrocarbons are the facts that they produce steam, carbon dioxide and heat during combustion and that oxygen is required for combustion to take place. The simplest hydrocarbon, methane, burns as follows:
- CH4 + 2 O2 → 2 H2O + CO2 + Energy
Another example of this property is propane:
- C3H8 + 5 O2 → 4 H2O + 3 CO2 + Energy
- CnH2n+2 + (3n+1)/2 O2 → (n+1) H2O + n CO2 + Energy
Burning of hydrocarbons is an example of
exothermicAn exothermic reaction is a chemical reaction that releases energy in the form of light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation:-Overview:...
chemical reaction.
Petroleum
Extracted hydrocarbons in a liquid form are referred to as
petroleumPetroleum 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...
(literally "rock oil") or
mineral oilA mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....
, whereas hydrocarbons in a gaseous form are referred to as
natural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
. Petroleum and natural gas are found in the Earth's subsurface with the tools of
petroleum geologyPetroleum geology refers to the specific set of geological disciplines that are applied to the search for hydrocarbons .-Sedimentary basin analysis:...
and are a significant source of fuel and raw materials for the production of
organic chemicalsOrganic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
.
The extraction of liquid hydrocarbon fuel from
sedimentary basinThe term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. As the sediments are buried, they are subjected to increasing pressure and begin the process of lithification...
s is integral to modern
energy developmentEnergy development is the effort to provide sufficient primary energy sources and secondary energy forms for supply, cost, impact on air pollution and water pollution, mitigation of climate change with renewable energy....
. Hydrocarbons are
minedMining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
from
tar sandsBituminous sands, colloquially known as oil sands or tar sands, are a type of unconventional petroleum deposit. The sands contain naturally occurring mixtures of sand, clay, water, and a dense and extremely viscous form of petroleum technically referred to as bitumen...
and
oil shaleOil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...
, and potentially extracted from sedimentary methane hydrates. These reserves require distillation and upgrading to produce
synthetic crudeSynthetic crude is the output from a bitumen/extra heavy oil upgrader facility used in connection with oil sand production. It may also refer to shale oil, an output from an oil shale pyrolysis. The properties of the synthetic crude depend on the processes used in the upgrading. Typically, it is...
and petroleum.
Oil reservesThe total estimated amount of oil in an oil reservoir, including both producible and non-producible oil, is called oil in place. However, because of reservoir characteristics and limitations in petroleum extraction technologies, only a fraction of this oil can be brought to the surface, and it is...
in sedimentary rocks are the source of hydrocarbons for the energy,
transportTransport or transportation is the movement of people, cattle, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations...
and
petrochemicalPetrochemicals are chemical products derived from petroleum. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as corn or sugar cane....
industry.
Hydrocarbons are economically important because major
fossil fuelFossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
s such as
coalCoal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
, petroleum and
natural gasNatural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
, and its derivatives such as
plasticA plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
s,
paraffinIn chemistry, paraffin is a term that can be used synonymously with "alkane", indicating hydrocarbons with the general formula CnH2n+2. Paraffin wax refers to a mixture of alkanes that falls within the 20 ≤ n ≤ 40 range; they are found in the solid state at room temperature and begin to enter the...
,
waxthumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
es,
solventA solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
s and oils are hydrocarbons. Hydrocarbons – along with NOx and
sunlightSunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
– contribute to the formation of
tropospheric ozoneOzone is a constituent of the troposphere . Photochemical and chemical reactions involving it drive many of the chemical processes that occur in the atmosphere by day and by night...
and
greenhouse gasA greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
es.
See also
- Abiogenic petroleum origin
Abiogenic petroleum origin is a largely abandoned hypothesis that was proposed as an alternative to theory of biological petroleum origin. It was relatively popular in the past, but it went largely forgotten at the end of the 20th century after it failed to predict the location of new wells.The...
- Biohydrocarbon
- Energy storage
Energy storage is accomplished by devices or physical media that store some form of energy to perform some useful operation at a later time. A device that stores energy is sometimes called an accumulator....
- Fractional distillation
Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of distillation...
- Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
- Hydrocarbon mixtures
Hydrocarbon mixtures are a group of various volatile, highly flammable, mixtures used chiefly as nonpolar solvents.-Composition:Hydrocarbon mixtures are composed of petroleum ethers and other hydrocarbons...
- Hydrocarbons on other planets
Basic hydrocarbons are ubiquitous in the atmospheres of Jupiter and Saturn. The parent molecule, methane , undergoes photochemical reactions which convert it to chain molecules such as acetylene , ethylene , and ethane . The atmosphere of Saturn's largest moon, Titan, contains higher mass...
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