Hydrocarbon

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Ball-and-stick model of the methane molecule, CH4. Methane is part of a homologous series known as the alkanes, which contain single bonds only. Methane-3D-balls.png
Ball-and-stick model of the methane molecule, CH4. Methane is part of a homologous series known as the alkanes, which contain single bonds only.

In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. [1] :620 Hydrocarbons are examples of group 14 hydrides. Hydrocarbons from which one hydrogen atom has been removed are functional groups called hydrocarbyls. [2] Hydrocarbons are generally colourless and hydrophobic with only weak odours. Because of their diverse molecular structures, it is difficult to generalize further. Most anthropogenic emissions of hydrocarbons are from the burning of fossil fuels including fuel production and combustion. Natural sources of hydrocarbons such as ethylene, isoprene, and monoterpenes come from the emissions of vegetation. [3]

Contents

Types

As defined by IUPAC nomenclature of organic chemistry, the classifications for hydrocarbons are:

  1. Saturated hydrocarbons are the simplest of the hydrocarbon species. They are composed entirely of single bonds and are saturated with hydrogen. The formula for acyclic saturated hydrocarbons (i.e., alkanes) is CnH2n+2. [1] :623 The most general form of saturated hydrocarbons is CnH2n+2(1-r), where r is the number of rings. Those with exactly one ring are the cycloalkanes. Saturated hydrocarbons are the basis of petroleum fuels and are found as either linear or branched species. Substitution reaction is their characteristics property (like chlorination reaction to form chloroform). Hydrocarbons with the same molecular formula but different structural formulae are called structural isomers. [1] :625 As given in the example of 3-methylhexane and its higher homologues, branched hydrocarbons can be chiral. [1] :627 Chiral saturated hydrocarbons constitute the side chains of biomolecules such as chlorophyll and tocopherol. [4]
  2. Unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms. Those with double bond are called alkenes. Those with one double bond have the formula CnH2n (assuming non-cyclic structures). [1] :628 Those containing triple bonds are called alkyne. Those with one triple bond have the formula CnH2n−2. [1] :631
  3. Aromatic hydrocarbons, also known as arenes, are hydrocarbons that have at least one aromatic ring. 10% of total nonmethane organic carbon emission are aromatic hydrocarbons from the exhaust of gasoline-powered vehicles. [5]

Hydrocarbons can be gases (e.g. methane and propane), liquids (e.g. hexane and benzene), waxes or low melting solids (e.g. paraffin wax and naphthalene) or polymers (e.g. polyethylene, polypropylene and polystyrene).

The term 'aliphatic' refers to non-aromatic hydrocarbons. Saturated aliphatic hydrocarbons are sometimes referred to as 'paraffins'. Aliphatic hydrocarbons containing a double bond between carbon atoms are sometimes referred to as 'olefins'.

Simple hydrocarbons and their variations

Variations on hydrocarbons based on the number of carbon atoms
Number of
carbon atoms
Alkane (single bond) Alkene (double bond) Alkyne (triple bond) Cycloalkane Alkadiene
0 Hydrogen(H2)
1 Methane
2 Ethane Ethene (ethylene) Ethyne (acetylene)
3 Propane Propene (propylene) Propyne (methylacetylene) Cyclopropane Propadiene (allene)
4 Butane Butene (butylene) Butyne Cyclobutane Butadiene
5 Pentane Pentene Pentyne Cyclopentane Pentadiene (piperylene)
6 Hexane Hexene Hexyne Cyclohexane Hexadiene
7 Heptane Heptene Heptyne Cycloheptane Heptadiene
8 Octane Octene Octyne Cyclooctane Octadiene
9 Nonane Nonene Nonyne Cyclononane Nonadiene
10 Decane Decene Decyne Cyclodecane Decadiene
11 Undecane Undecballene Undecyne Cycloundecane Undecadiene
12 Dodecane Dodecene Dodecyne Cyclododecane Dodecadiene

Usage

Oil refineries are one way hydrocarbons are processed for use. Crude oil is processed in several stages to form desired hydrocarbons, used as fuel and in other products. ShellMartinez-refi.jpg
Oil refineries are one way hydrocarbons are processed for use. Crude oil is processed in several stages to form desired hydrocarbons, used as fuel and in other products.
Tank wagon 33 80 7920 362-0 with hydrocarbon gas at Bahnhof Enns (2018). 2018-05-04 (303) Tank wagon 33 80 7920 362-0 with hydrocarbon gas at Bahnhof Enns.jpg
Tank wagon 33 80 7920 362-0 with hydrocarbon gas at Bahnhof Enns (2018).

The predominant use of hydrocarbons is as a combustible fuel source. Methane is the predominant component of natural gas. The C6 through C10 alkanes, alkenes and isomeric cycloalkanes are the top components of gasoline, naphtha, jet fuel 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 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 (bitumen), wood preservatives (the creosote series) and as extremely high viscosity shear-resisting liquids.

Some large-scale nonfuel applications of hydrocarbons begins with ethane and propane, which are obtained from petroleum and natural gas. These two gases are converted either to syngas [6] or to ethylene and propylene. [7] [8] These two alkenes are precursors to polymers, including polyethylene, polystyrene, acrylates, [9] [10] [11] polypropylene, etc. Another class of special hydrocarbons is BTX, a mixture of benzene, toluene, and the three xylene isomers. [12] Global consumption of benzene, estimated at more than 40,000,000 tons (2009). [13]

Hydrocarbons are also prevalent in nature. Some eusocial arthropods, such as the Brazilian stingless bee, Schwarziana quadripunctata , use unique hydrocarbon "scents" in order to determine kin from non-kin. The chemical hydrocarbon composition varies between age, sex, nest location, and hierarchal position. [14]

There is also potential to harvest hydrocarbons from plants like Euphorbia lathyri and Euphorbia tirucalli as an alternative and renewable energy source for vehicles that use diesel. [15] Furthermore, endophytic bacteria from plants that naturally produce hydrocarbons have been used in hydrocarbon degradation in attempts to deplete hydrocarbon concentration in polluted soils. [16]

Reactions

The noteworthy feature of hydrocarbons is their inertness, especially for saturated members. Otherwise, three main types of reactions can be identified:

Free-radical reactions

Substitution reactions only occur in saturated hydrocarbons (single carbon–carbon bonds). Such reactions require highly reactive reagents, such as chlorine and fluorine. In the case of chlorination, one of the chlorine atoms replaces a hydrogen atom. The reactions proceed via free-radical pathways.

CH4 + Cl2 → CH3Cl + HCl
CH3Cl + Cl2 → CH2Cl2 + HCl

all the way to CCl4 (carbon tetrachloride)

C2H6 + Cl2 → C2H5Cl + HCl
C2H4Cl2 + Cl2 → C2H3Cl3 + HCl

all the way to C2Cl6 (hexachloroethane)

Substitution

Of the classes of hydrcarbons, aromatic compounds uniquely (or nearly so) undergo substitution reactions. The chemical process practiced on the largest scale is an example: the reaction of benzene and ethylene to give ethylbenzene.

Addition reactions

Addition reactions apply to alkenes and alkynes. In this reaction a variety of reagents add "across" the pi-bond(s). Chlorine, hydrogen chloride, water, and hydrogen are illustrative reagents. Alkenes and some alkynes also undergo polymerization, alkene metathesis, and alkyne metathesis.

Oxidation

Hydrocarbons are currently the main source of the world's electric energy and heat sources (such as home heating) because of the energy produced when they are combusted. [17] Often this energy is used directly as heat such as in home heaters, which use either petroleum or natural gas. The hydrocarbon is burnt and the heat is used to heat water, which is then circulated. A similar principle is used to create electrical 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

In inadequate supply of air, carbon monoxide gas and water vapour are formed:

2 CH4 + 3 O2 → 2 CO + 4 H2O

Another example is the combustion of propane:

C3H8 + 5 O2 → 4 H2O + 3 CO2 + energy

And finally, for any linear alkane of n carbon atoms,

CnH2n+2 + 3n + 1/2 O2 → (n + 1) H2O + n CO2 + energy.

Partial oxidation characterizes the reactions of alkenes and oxygen. This process is the basis of rancidification and paint drying.

Origin

Natural oil spring in Korna, Slovakia. Korna natural oil seep 1.JPG
Natural oil spring in Korňa, Slovakia.

The vast majority of hydrocarbons found on Earth occur in petroleum, coal, and natural gas. Petroleum (literally "rock oil" – petrol for short) and coal are generally thought to be products of decomposition of organic matter. In contrast to petroleum, is coal, which is richer in carbon and poorer in hydrogen. Natural gas is the product of methanogenesis. [18] [19]

A seemingly limitless variety of compounds comprise petroleum, hence the necessity of refineries. These hydrocarbons consist of saturated hydrocarbons, aromatic hydrocarbons, or combinations of the two. Missing in petroleum are alkenes and alkynes. Their production requires refineries. Petroleum-derived hydrocarbons are mainly consumed for fuel, but they are also the source of virtually all synthetic organic compounds, including plastics and pharmaceuticals. Natural gas is consumed almost exclusively as fuel. Coal is used as a fuel and as a reducing agent in metallurgy.

Abiological hydrocarbons

A small fraction of hydrocarbon found on earth is thought to be abiological. [20]

Some hydrocarbons also are widespread and abundant in the solar system. Lakes of liquid methane and ethane have been found on Titan, Saturn's largest moon, confirmed by the Cassini-Huygens Mission. [21] Hydrocarbons are also abundant in nebulae forming polycyclic aromatic hydrocarbon (PAH) compounds. [22]

Bioremediation

Bioremediation of hydrocarbon from soil or water contaminated is a formidable challenge because of the chemical inertness that characterize hydrocarbons (hence they survived millions of years in the source rock). Nonetheless, many strategies have been devised, bioremediation being prominent. The basic problem with bioremediation is the paucity of enzymes that act on them. Nonetheless the area has received regular attention. [23] Bacteria in the gabbroic layer of the ocean's crust can degrade hydrocarbons; but the extreme environment makes research difficult. [24] Other bacteria such as Lutibacterium anuloederans can also degrade hydrocarbons. [25] Mycoremediation or breaking down of hydrocarbon by mycelium and mushrooms is possible. [26] [27]

Safety

Hydrocarbons are generally of low toxicity, hence the widespread use of gasoline and related volatile products. Aromatic compounds such as benzene are narcotic and chronic toxins and are carcinogenic. Certain rare polycyclic aromatic compounds are carcinogenic. Hydrocarbons are highly flammable.

Environmental impact

Burning hydrocarbons as fuel, which produces carbon dioxide and water, is a major contributor to anthropogenic global warming. Hydrocarbons are introduced into the environment through their extensive use as fuels and chemicals as well as through leaks or accidental spills during exploration, production, refining, or transport of fossil fuels. Anthropogenic hydrocarbon contamination of soil is a serious global issue due to contaminant persistence and the negative impact on human health. [28]

When soil is contaminated by hydrocarbons, it can have a significant impact on its microbiological, chemical, and physical properties. This can serve to prevent, slow down or even accelerate the growth of vegetation depending on the exact changes that occur. Crude oil and natural gas are the two largest sources of hydrocarbon contamination of soil. [29]

See also

Related Research Articles

Alkane Class of simple organic hydrocarbons

In organic chemistry, an alkane, or paraffin (a historical name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemical formula CnH2n+2. The alkanes range in complexity from the simplest case of methane (CH4), where n = 1 (sometimes called the parent molecule), to arbitrarily large and complex molecules, like pentacontane (C50H102) or 6-ethyl-2-methyl-5-(1-methylethyl) octane, an isomer of tetradecane (C14H30).

Aromatic compounds are those chemical compounds that contain one or more rings with pi electrons delocalized all the way around them. In contrast to compounds that exhibit aromaticity, aliphatic compounds lack this delocalization. The term "aromatic" was assigned before the physical mechanism determining aromaticity was discovered, and referred simply to the fact that many such compounds have a sweet or pleasant odour; however, not all aromatic compounds have a sweet odour, and not all compounds with a sweet odour are aromatic. Aromatic hydrocarbons, or arenes, are aromatic organic compounds containing solely carbon and hydrogen atoms. The configuration of six carbon atoms in aromatic compounds is called a "benzene ring", after the simple aromatic compound benzene, or a phenyl group when part of a larger compound.

Aliphatic compound

In organic chemistry, hydrocarbons are divided into two classes: aromatic compounds and aliphatic compounds, also known as non-aromatic hydrocarbons. Aliphatics can be cyclic; however, hydrocarbons with conjugated pi-systems that obey Hückel's rule are instead considered to demonstrate aromaticity. Aliphatic compounds can be saturated, like hexane, or unsaturated, like hexene and hexyne. Open-chain compounds contain no rings of any type, and are thus aliphatic.

Alkene Chemical compound

In chemistry, an alkene is a hydrocarbon that contains a carbon–carbon double bond.

Alkyne Acyclic hydrocarbon

In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical 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. Like other hydrocarbons, alkynes are generally hydrophobic.

Petrochemical

Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.

Ethane is an organic chemical compound with chemical formula C
2
H
6
. At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by-product of petroleum refining. Its chief use is as feedstock for ethylene production.

Hydrogenation Chemical reaction between molecular hydrogen and another compound or element

Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, often an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogenation reduces double and triple bonds in hydrocarbons.

Cracking (chemistry)

In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of a large alkane into smaller, more useful alkenes. Simply put, hydrocarbon cracking is the process of breaking a long chain of hydrocarbons into short ones. This process requires high temperatures.

Unsaturated hydrocarbon

Unsaturated hydrocarbons are hydrocarbons that have double or triple covalent bonds between adjacent carbon atoms. The term "unsaturated" means more hydrogen atoms may be added to the hydrocarbon to make it saturated. The configuration of an unsaturated carbons include straight chain, such as alkenes and alkynes, as well as branched chains and aromatic compounds.

Halogenation is a chemical reaction that involves the addition of one or more halogens to a compound or material. The pathway and stoichiometry of halogenation depends on the structural features and functional groups of the organic substrate, as well as on the specific halogen. Inorganic compounds such as metals also undergo halogenation.

Propene, also known as propylene or methyl ethylene, is an unsaturated organic compound with the chemical formula . It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. It is a colorless gas with a faint petroleum-like odor

The Fischer–Tropsch process is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. These reactions occur in the presence of metal catalysts, typically at temperatures of 150–300 °C (302–572 °F) and pressures of one to several tens of atmospheres. The process was first developed by Franz Fischer and Hans Tropsch at the Kaiser-Wilhelm-Institut für Kohlenforschung in Mülheim an der Ruhr, Germany, in 1925.

Steam reforming or steam methane reforming is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen production. The reaction is represented by this equilibrium:

Wilkinsons catalyst Chemical compound

Wilkinson's catalyst is the common name for chloridotris(triphenylphosphine)rhodium(I), a coordination complex of rhodium with the formula [RhCl(PPh3)3] (Ph = phenyl). It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in tetrahydrofuran or chlorinated solvents such as dichloromethane. The compound is widely used as a catalyst for hydrogenation of alkenes. It is named after chemist and Nobel laureate Sir Geoffrey Wilkinson, who first popularized its use.

Organopalladium chemistry is a branch of organometallic chemistry that deals with organic palladium compounds and their reactions. Palladium is often used as a catalyst in the reduction of alkenes and alkynes with hydrogen. This process involves the formation of a palladium-carbon covalent bond. Palladium is also prominent in carbon-carbon coupling reactions, as demonstrated in tandem reactions.

Catalytic reforming is a chemical process used to convert petroleum refinery naphthas distilled from crude oil into high-octane liquid products called reformates, which are premium blending stocks for high-octane gasoline. The process converts low-octane linear hydrocarbons (paraffins) into branched alkanes (isoparaffins) and cyclic naphthenes, which are then partially dehydrogenated to produce high-octane aromatic hydrocarbons. The dehydrogenation also produces significant amounts of byproduct hydrogen gas, which is fed into other refinery processes such as hydrocracking. A side reaction is hydrogenolysis, which produces light hydrocarbons of lower value, such as methane, ethane, propane and butanes.

Hydrodesulfurization (HDS) is a catalytic chemical process widely used to remove sulfur (S) from natural gas and from refined petroleum products, such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils. The purpose of removing the sulfur, and creating products such as ultra-low-sulfur diesel, is to reduce the sulfur dioxide emissions that result from using those fuels in automotive vehicles, aircraft, railroad locomotives, ships, gas or oil burning power plants, residential and industrial furnaces, and other forms of fuel combustion.

Group 14 hydrides are chemical compounds composed of hydrogen atoms and group 14 atoms.

Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. It is the principal industrial method for producing the lighter alkenes, including ethene and propene. Steam cracker units are facilities in which a feedstock such as naphtha, liquefied petroleum gas (LPG), ethane, propane or butane is thermally cracked through the use of steam in steam cracking furnaces to produce lighter hydrocarbons. The propane dehydrogenation process may be accomplished through different commercial technologies. The main differences between each of them concerns the catalyst employed, design of the reactor and strategies to achieve higher conversion rates.

References

  1. 1 2 3 4 5 6 Silberberg, Martin (2004). Chemistry: The Molecular Nature Of Matter and Change. New York: McGraw-Hill Companies. ISBN   0-07-310169-9.
  2. IUPAC Goldbook hydrocarbyl groups Archived 7 January 2010 at the Wayback Machine
  3. Dewulf, Jo. "Hydrocarbons in the Atmosphere" (PDF). Retrieved 26 October 2020.
  4. Meierhenrich, Uwe. Amino Acids and the Asymmetry of Life Archived 2 March 2017 at the Wayback Machine . Springer, 2008. ISBN   978-3-540-76885-2
  5. Barnes, I. "TROPOSPHERIC CHEMISTRY AND COMPOSITION (Aromatic Hydrocarbons)" . Retrieved 26 October 2020.
  6. Liu, Shenglin; Xiong, Guoxing; Yang, Weisheng; Xu, Longya (1 July 2000). "Partial Oxidation of Ethane to Syngas over Supported Metal Catalysts". Reaction Kinetics and Catalysis Letters. 70 (2): 311–317. doi:10.1023/A:1010397001697. ISSN   1588-2837. S2CID   91569579.
  7. Ge, Meng; Chen, Xingye; Li, Yanyong; Wang, Jiameng; Xu, Yanhong; Zhang, Lihong (1 June 2020). "Perovskite-derived cobalt-based catalyst for catalytic propane dehydrogenation". Reaction Kinetics, Mechanisms and Catalysis. 130 (1): 241–256. doi:10.1007/s11144-020-01779-8. ISSN   1878-5204. S2CID   218496057.
  8. Li, Qian; Yang, Gongbing; Wang, Kang; Wang, Xitao (2020). "Preparation of carbon-doped alumina beads and their application as the supports of Pt–Sn–K catalysts for the dehydrogenation of propane". Reaction Kinetics, Mechanisms and Catalysis. 129 (2): 805–817. doi:10.1007/s11144-020-01753-4. S2CID   212406355.
  9. Naumann d'Alnoncourt, Raoul; Csepei, Lénárd-István; Hävecker, Michael; Girgsdies, Frank; Schuster, Manfred E.; Schlögl, Robert; Trunschke, Annette (2014). "The reaction network in propane oxidation over phase-pure MoVTeNb M1 oxide catalysts". J. Catal. 311: 369–385. doi:10.1016/j.jcat.2013.12.008. hdl: 11858/00-001M-0000-0014-F434-5 .
  10. Hävecker, Michael; Wrabetz, Sabine; Kröhnert, Jutta; Csepei, Lenard-Istvan; Naumann d'Alnoncourt, Raoul; Kolen'Ko, Yury V.; Girgsdies, Frank; Schlögl, Robert; Trunschke, Annette (2012). "Surface chemistry of phase-pure M1 MoVTeNb oxide during operation in selective oxidation of propane to acrylic acid". J. Catal. 285: 48–60. doi:10.1016/j.jcat.2011.09.012. hdl: 11858/00-001M-0000-0012-1BEB-F .
  11. Kinetic studies of propane oxidation on Mo and V based mixed oxide catalysts (PDF). TU Berlin. 2011.
  12. Li, Guixian; Wu, Chao; Ji, Dong; Dong, Peng; Zhang, Yongfu; Yang, Yong (1 April 2020). "Acidity and catalyst performance of two shape-selective HZSM-5 catalysts for alkylation of toluene with methanol". Reaction Kinetics, Mechanisms and Catalysis. 129 (2): 963–974. doi:10.1007/s11144-020-01732-9. ISSN   1878-5204. S2CID   213601465.
  13. The Future of Benzene and Para-Xylene after Unprecedented Growth In 2010 Archived 2011-10-05 at the Wayback Machine . From a ChemSystems report in 2011.
  14. Nunes, T.M.; Turatti, I.C.C.; Mateus, S.; Nascimento, F.S.; Lopes, N.P.; Zucchi, R. (2009). "Cuticular Hydrocarbons in the Stingless Bee Schwarziana quadripunctata (Hymenoptera, Apidae, Meliponini): Differences between Colonies, Castes and Age" (PDF). Genetics and Molecular Research. 8 (2): 589–595. doi:10.4238/vol8-2kerr012. PMID   19551647. Archived (PDF) from the original on 26 September 2015.
  15. Calvin, Melvin (1980). "Hydrocarbons from plants: Analytical methods and observations". Naturwissenschaften. 67 (11): 525–533. Bibcode:1980NW.....67..525C. doi:10.1007/BF00450661. S2CID   40660980 . Retrieved 26 October 2020.
  16. Pawlik, Malgorzata (2017). "Hydrocarbon degradation potential and plant growth-promoting activity of culturable endophytic bacteria of Lotus corniculatus and Oenothera biennis from a long-term polluted site". Environmental Science and Pollution Research International. 24 (24): 19640–19652. doi:10.1007/s11356-017-9496-1. PMC   5570797 . PMID   28681302.
  17. World Coal, Coal and Electricity Archived 22 October 2015 at the Wayback Machine . World Coal Association
  18. Clayden, J., Greeves, N., et al. (2001) Organic Chemistry Oxford ISBN   0-19-850346-6 p. 21
  19. McMurry, J. (2000). Organic Chemistry 5th ed. Brooks/Cole: Thomson Learning. ISBN   0-495-11837-0 pp. 75–81
  20. Sephton, M. A.; Hazen, R. M. (2013). "On the Origins of Deep Hydrocarbons". Reviews in Mineralogy and Geochemistry. 75 (1): 449–465. Bibcode:2013RvMG...75..449S. doi:10.2138/rmg.2013.75.14.
  21. NASA's Cassini Spacecraft Reveals Clues About Saturn Moon Archived 2 September 2014 at the Wayback Machine . NASA (12 December 2013)
  22. Guzman-Ramirez, L.; Lagadec, E.; Jones, D.; Zijlstra, A. A.; Gesicki, K. (2014). "PAH formation in O-rich planetary nebulae". Monthly Notices of the Royal Astronomical Society. 441 (1): 364–377. arXiv: 1403.1856 . Bibcode:2014MNRAS.441..364G. doi:10.1093/mnras/stu454. S2CID   118540862.
  23. Lim, Mee Wei; Lau, Ee Von; Poh, Phaik Eong (2016). "A comprehensive guide of remediation technologies for oil contaminated soil — Present works and future directions". Marine Pollution Bulletin. 109 (1): 14–45. doi:10.1016/j.marpolbul.2016.04.023. PMID   27267117.
  24. Mason OU, Nakagawa T, Rosner M, Van Nostrand JD, Zhou J, Maruyama A, Fisk MR, Giovannoni SJ (2010). "First investigation of the microbiology of the deepest layer of ocean crust". PLOS ONE. 5 (11): e15399. Bibcode:2010PLoSO...515399M. doi:10.1371/journal.pone.0015399. PMC   2974637 . PMID   21079766.
  25. Yakimov, M. M.; Timmis, K. N.; Golyshin, P. N. (2007). "Obligate oil-degrading marine bacteria". Curr. Opin. Biotechnol. 18 (3): 257–266. CiteSeerX   10.1.1.475.3300 . doi:10.1016/j.copbio.2007.04.006. PMID   17493798.
  26. Stamets, Paul (2008). "6 ways mushrooms can save the world" (video). TED Talk. Archived from the original on 31 October 2014.
  27. Stamets, Paul (2005). "Mycoremediation" . Mycelium Running: How Mushrooms Can Help Save the World. Ten Speed Press. p.  86. ISBN   9781580085793.
  28. "Microbial Degradation of Alkanes (PDF Download Available)". ResearchGate. Archived from the original on 24 February 2017. Retrieved 23 February 2017.
  29. "Additives Affecting the Microbial Degradation of Petroleum Hydrocarbons", Bioremediation of Contaminated Soils, CRC Press, pp. 353–360, 9 June 2000, doi:10.1201/9781482270235-27, ISBN   978-0-429-07804-0