59-448: Picene is a hydrocarbon found in the pitchy residue obtained in the distillation of peat tar and of petroleum . This is distilled to dryness and the distillate repeatedly recrystallized from cymene . It may be synthetically prepared by the action of anhydrous aluminium chloride on a mixture of naphthalene and 1,2-dibromoethane , or by distilling a-dinaphthostilbene. It crystallizes in large colorless plates which possess
118-579: A hydrocarbon is an organic compound consisting entirely of hydrogen and carbon . Hydrocarbons are examples of group 14 hydrides . Hydrocarbons are generally colourless and hydrophobic ; their odor is usually faint, and may be similar to that of gasoline or lighter fluid . They occur in a diverse range of molecular structures and phases: they can be gases (such as methane and propane ), liquids (such as hexane and benzene ), low melting solids (such as paraffin wax and naphthalene ) or polymers (such as polyethylene and polystyrene ). In
177-400: A nuclear fission reactor ; nuclear fuel can refer to the material or to physical objects (for example fuel bundles composed of fuel rods ) composed of the fuel material, perhaps mixed with structural, neutron moderating , or neutron reflecting materials. When some of these fuels are struck by neutrons, they are in turn capable of emitting neutrons when they break apart. This makes possible
236-442: A blue fluorescence . It is soluble in concentrated sulfuric acid with a green color. Chromic acid in glacial acetic acid solution oxidizes it to picene- quinone , picene-quinone carboxylic acid , and finally to phthalic acid . When intercalated with potassium or rubidium and cooled to below 18 K, picene has been reported to exhibit superconductive properties. However, due to the apparent inability to reproduce this work,
295-414: A common thermoplastic material. Addition reactions apply to alkenes and alkynes. It is because they add reagents that they are called unsaturated. In this reaction a variety of reagents add "across" the pi-bond(s). Chlorine, hydrogen chloride, water , and hydrogen are illustrative reagents. Polymerization is a form of addition. Alkenes and some alkynes also undergo polymerization by opening of
354-426: A double bond between carbon atoms are sometimes referred to as 'olefins'. The predominant use of hydrocarbons is as a combustible fuel source. Methane is the predominant component of natural gas. C through C alkanes, alkenes, cycloalkanes, and aromatic hydrocarbons are the main components of gasoline , naphtha , jet fuel , and specialized industrial solvent mixtures. With the progressive addition of carbon units,
413-403: A mixture of propane and butane , both of which are easily compressible gases under standard atmospheric conditions. It offers many of the advantages of compressed natural gas (CNG) but is denser than air, does not burn as cleanly, and is much more easily compressed. Commonly used for cooking and space heating, LP gas and compressed propane are seeing increased use in motorized vehicles. Propane
472-436: A pivotal part of our contemporary society, with most countries in the world burning fossil fuels in order to produce power, but are falling out of favor due to the global warming and related effects that are caused by burning them. Currently the trend has been towards renewable fuels, such as biofuels like alcohols. Chemical fuels are substances that release energy by reacting with substances around them, most notably by
531-425: A reservoir). The first known use of fuel was the combustion of firewood by Homo erectus nearly two million years ago. Throughout most of human history only fuels derived from plants or animal fat were used by humans. Charcoal , a wood derivative, has been used since at least 6,000 BCE for melting metals. It was only supplanted by coke , derived from coal, as European forests started to become depleted around
590-918: A self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor , or at a very rapid uncontrolled rate in a nuclear weapon . The most common fissile nuclear fuels are uranium-235 ( U) and plutonium-239 ( Pu). The actions of mining, refining, purifying, using, and ultimately disposing of nuclear fuel together make up the nuclear fuel cycle . Not all types of nuclear fuels create energy from nuclear fission. Plutonium-238 and some other elements are used to produce small amounts of nuclear energy by radioactive decay in radioisotope thermoelectric generators and other types of atomic batteries . In contrast to fission, some light nuclides such as tritium ( H) can be used as fuel for nuclear fusion . This involves two or more nuclei combining into larger nuclei. Fuels that produce energy by this method are currently not utilized by humans, but they are
649-529: A single C–C bond it is alkane metathesis , for a double C–C bond it is alkene metathesis (olefin metathesis), and for a triple C–C bond it is alkyne metathesis . The vast majority of hydrocarbons found on Earth occur in crude oil , petroleum, coal , and natural gas. Since thousands of years they have been exploited and used for a vast range of purposes. Petroleum ( lit. ' rock oil ' ) and coal are generally thought to be products of decomposition of organic matter. Coal, in contrast to petroleum,
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#1732772408837708-466: A source of energy. The International Energy Agency (IEA) predicts that fossil fuel prices will decline, with oil stabilizing around $ 75 to $ 80 per barrel as electric vehicle adoption surges and renewable energy expands. Additionally, the IEA anticipates a notable increase in liquefied natural gas capacity, enhancing Europe’s energy diversification. The amount of energy from different types of fuel depends on
767-468: A two neutral radical atoms ( homolytic fission ). all the way to CCl 4 ( carbon tetrachloride ) all the way to C 2 Cl 6 ( hexachloroethane ) Aromatic compounds, almost uniquely for hydrocarbons, undergo substitution reactions. The chemical process practiced on the largest scale is the reaction of benzene and ethene to give ethylbenzene : The resulting ethylbenzene is dehydrogenated to styrene and then polymerized to manufacture polystyrene ,
826-516: A way to make heavy oil fractions usable as liquid fuels. Many liquid fuels play a primary role in transportation and the economy. Some common properties of liquid fuels are that they are easy to transport and can be handled easily. They are also relatively easy to use for all engineering applications and in home use. Fuels like kerosene are rationed in some countries, for example in government-subsidized shops in India for home use. Conventional diesel
885-696: Is also potential to harvest hydrocarbons from plants like Euphorbia lathyris and E. tirucalli as an alternative and renewable energy source for vehicles that use diesel. Furthermore, endophytic bacteria from plants that naturally produce hydrocarbons have been used in hydrocarbon degradation in attempts to deplete hydrocarbon concentration in polluted soils. Saturated hydrocarbons are notable for their inertness. Unsaturated hydrocarbons (alkanes, alkenes and aromatic compounds) react more readily, by means of substitution, addition, polymerization. At higher temperatures they undergo dehydrogenation, oxidation and combustion. The cracking of saturated hydrocarbons
944-400: Is called autoxidation , begins with the formation of hydroperoxides (ROOH). Combustion of hydrocarbons is currently the main source of the world's energy for electric power generation , heating (such as home heating), and transportation. 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
1003-424: Is decreasing as heating technology and the availability of good quality fuel improves. In some areas, smokeless coal is often the only solid fuel used. In Ireland, peat briquettes are used as smokeless fuel. They are also used to start a coal fire. Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy , usually producing kinetic energy . They must also take
1062-460: Is equivalent to 44 ⁄ 12 (this is the ratio of the molecular/atomic weights) or 3.7 tonnes of CO 2 . Carbon dioxide is one of the greenhouse gases that enhances radiative forcing and contributes to global warming , causing the average surface temperature of the Earth to rise in response, which the vast majority of climate scientists agree will cause major adverse effects . Fuels are
1121-482: Is estimated at more than 58 million metric tons, which will increase to 60 million tons in 2022. Hydrocarbons are also prevalent in nature. Some eusocial arthropods, such as the Brazilian stingless bee, Schwarziana quadripunctata , use unique cuticular hydrocarbon "scents" in order to determine kin from non-kin. This hydrocarbon composition varies between age, sex, nest location, and hierarchal position. There
1180-545: Is possible. Hydrocarbons are generally of low toxicity, hence the widespread use of gasoline and related volatile products. Aromatic compounds such as benzene and toluene are narcotic and chronic toxins, and benzene in particular is known to be carcinogenic . Certain rare polycyclic aromatic compounds are carcinogenic. Hydrocarbons are highly flammable . Fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work . The concept
1239-463: Is richer in carbon and poorer in hydrogen. Natural gas is the product of methanogenesis . 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
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#17327724088371298-399: Is similar to gasoline in that it is a mixture of aliphatic hydrocarbons extracted from petroleum . Kerosene is used in kerosene lamps and as a fuel for cooking, heating, and small engines. Natural gas , composed chiefly of methane , can only exist as a liquid at very low temperatures (regardless of pressure), which limits its direct use as a liquid fuel in most applications. LP gas is
1357-616: Is the main industrial route to alkenes and alkyne . These reactions require heterogeneous catalysts and temperatures >500 °C. Widely practice conversions of hydrocarbons involves their reaction with oxygen. In the presence of excess oxygen, hydrocarbons combust. With, however, careful conditions, which have been optimized for many years, partial oxidation results. Useful compounds can obtained in this way: maleic acid from butane , terephthalic acid from xylenes , acetone together with phenol from cumene (isopropylbenzene), and cyclohexanone from cyclohexane]]. The process, which
1416-398: Is the paucity of enzymes that act on them. Nonetheless, the area has received regular attention. Bacteria in the gabbroic layer of the ocean's crust can degrade hydrocarbons; but the extreme environment makes research difficult. Other bacteria such as Lutibacterium anuloederans can also degrade hydrocarbons. Mycoremediation or breaking down of hydrocarbon by mycelium and mushrooms
1475-409: Is the third most commonly used motor fuel globally. Fuel gas is any one of a number of fuels that are gaseous under ordinary conditions. Many fuel gases are composed of hydrocarbons (such as methane or propane ), hydrogen , carbon monoxide , or mixtures thereof. Such gases are sources of potential heat energy or light energy that can be readily transmitted and distributed through pipes from
1534-597: Is used to heat water, which is then circulated. A similar principle is used to create electrical energy in power plants . Both saturated and unsaturated hydrocarbons undergo this process. 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: In inadequate supply of air, carbon black and water vapour are formed: And finally, for any linear alkane of n carbon atoms, Partial oxidation characterizes
1593-1010: Is widespread public debate about how carbon neutral these fuels are. Fossil fuels are hydrocarbons , primarily coal and petroleum ( liquid petroleum or natural gas ), formed from the fossilized remains of ancient plants and animals by exposure to high heat and pressure in the absence of oxygen in the Earth's crust over hundreds of millions of years. Commonly, the term fossil fuel also includes hydrocarbon-containing natural resources that are not derived entirely from biological sources, such as tar sands . These latter sources are properly known as mineral fuels . Fossil fuels contain high percentages of carbon and include coal, petroleum, and natural gas. They range from volatile materials with low carbon: hydrogen ratios like methane , to liquid petroleum to nonvolatile materials composed of almost pure carbon, like anthracite coal. Methane can be found in hydrocarbon fields, alone, associated with oil, or in
1652-541: The Solar System . Lakes of liquid methane and ethane have been found on Titan , Saturn 's largest moon, as confirmed by the Cassini–Huygens space probe. Hydrocarbons are also abundant in nebulae forming polycyclic aromatic hydrocarbon compounds. Burning hydrocarbons as fuel, which produces carbon dioxide and water , is a major contributor to anthropogenic global warming . Hydrocarbons are introduced into
1711-454: The fossil fuel industries, hydrocarbon refers to naturally occurring petroleum , natural gas and coal , or their hydrocarbon derivatives and purified forms. Combustion of hydrocarbons is the main source of the world's energy. Petroleum is the dominant raw-material source for organic commodity chemicals such as solvents and polymers. Most anthropogenic (human-generated) emissions of greenhouse gases are either carbon dioxide released by
1770-441: The stoichiometric ratio , the chemically correct air and fuel ratio to ensure complete combustion of fuel, and its specific energy , the energy per unit mass. 1 MJ ≈ 0.28 kWh ≈ 0.37 HPh . (The fuel-air ratio (FAR) is the reciprocal of the air-fuel ratio (AFR).) λ is the air-fuel equivalence ratio, and λ =1 means that it is assumed that the fuel and the oxidising agent (oxygen in air) are present in exactly
1829-468: The 18th century. Charcoal briquettes are now commonly used as a fuel for barbecue cooking. Crude oil was distilled by Persian chemists , with clear descriptions given in Arabic handbooks such as those of Muhammad ibn Zakarīya Rāzi . He described the process of distilling crude oil/petroleum into kerosene , as well as other hydrocarbon compounds, in his Kitab al-Asrar ( Book of Secrets ). Kerosene
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1888-561: The absorption of a proton or neutron . In most stars the fuel is provided by hydrogen, which can combine to form helium through the proton-proton chain reaction or by the CNO cycle . When the hydrogen fuel is exhausted, nuclear fusion can continue with progressively heavier elements, although the net energy released is lower because of the smaller difference in nuclear binding energy. Once iron-56 or nickel-56 nuclei are produced, no further energy can be obtained by nuclear fusion as these have
1947-579: The area around modern Baku , Azerbaijan . These fields were described by the Arab geographer Abu al-Hasan 'Alī al-Mas'ūdī in the 10th century, and by Marco Polo in the 13th century, who described the output of those wells as hundreds of shiploads. With the development of the steam engine in the United Kingdom in 1769, coal came into more common use, the combustion of which releases chemical energy that can be used to turn water into steam. Coal
2006-495: The burning of fossil fuels , or methane released from the handling of natural gas or from agriculture. As defined by the International Union of Pure and Applied Chemistry 's nomenclature of organic chemistry , hydrocarbons are classified as follows: The term 'aliphatic' refers to non-aromatic hydrocarbons. Saturated aliphatic hydrocarbons are sometimes referred to as 'paraffins'. Aliphatic hydrocarbons containing
2065-600: The correct proportions so that they are both fully consumed in the reaction. Nuclear fuel is any material that is consumed to derive nuclear energy . In theory, a wide variety of substances could be a nuclear fuel, as they can be made to release nuclear energy under the right conditions. However, the materials commonly referred to as nuclear fuels are those that will produce energy without being placed under extreme duress. Nuclear fuel can be "burned" by nuclear fission (splitting nuclei apart) or fusion (combining nuclei together) to derive nuclear energy. "Nuclear fuel" can refer to
2124-593: The earliest fuel employed by humans is wood. Evidence shows controlled fire was used up to 1.5 million years ago at Swartkrans , South Africa. It is unknown which hominid species first used fire, as both Australopithecus and an early species of Homo were present at the sites. As a fuel, wood has remained in use up until the present day, although it has been superseded for many purposes by other sources. Wood has an energy density of 10–20 MJ / kg . Recently biofuels have been developed for use in automotive transport (for example bioethanol and biodiesel ), but there
2183-524: 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. 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
2242-647: The form of methane clathrates . Fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the Earth's crust over millions of years. This biogenic theory was first introduced by German scholar Georg Agricola in 1556 and later by Mikhail Lomonosov in the 18th century. It was estimated by the Energy Information Administration that in 2007 primary sources of energy consisted of petroleum 36.0%, coal 27.4%, natural gas 23.0%, amounting to an 86.4% share for fossil fuels in primary energy consumption in
2301-420: The fuel itself, or to physical objects (for example bundles composed of fuel rods ) composed of the fuel material, mixed with structural, neutron moderating , or neutron-reflecting materials. Nuclear fuel has the highest energy density of all practical fuel sources. The most common type of nuclear fuel used by humans is heavy fissile elements that can be made to undergo nuclear fission chain reactions in
2360-431: The generation of renewable energy is therefore under way to help meet increased energy needs. The burning of fossil fuels produces around 21.3 billion tonnes (21.3 gigatonnes ) of carbon dioxide (CO 2 ) per year, but it is estimated that natural processes can only absorb about half of that amount, so there is a net increase of 10.65 billion tonnes of atmospheric carbon dioxide per year (one tonne of atmospheric carbon
2419-495: 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. 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
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2478-459: The highest nuclear binding energies. Any nucleii heavier than Fe and Ni would thus absorb energy instead of giving it off when fused. Therefore, fusion stops and the star dies. In attempts by humans, fusion is only carried out with hydrogen ( H (deuterium) or H (tritium)) to form helium-4 as this reaction gives out the most net energy. Electric confinement ( ITER ), inertial confinement (heating by laser) and heating by strong electric currents are
2537-641: The illumination that accompanies combustion . Fuels are also used in the cells of organisms in a process known as cellular respiration , where organic molecules are oxidized to release usable energy. Hydrocarbons and related organic molecules are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are also utilized. Fuels are contrasted with other substances or devices storing potential energy , such as those that directly release electrical energy (such as batteries and capacitors ) or mechanical energy (such as flywheels , springs, compressed air, or water in
2596-468: The main source of fuel for stars . Fusion fuels are light elements such as hydrogen whose nucleii will combine easily. Energy is required to start fusion by raising the temperature so high that nuclei can collide together with enough energy that they stick together before repelling due to electric charge. This process is called fusion and it can give out energy. In stars that undergo nuclear fusion, fuel consists of atomic nuclei that can release energy by
2655-509: The multiple bonds to produce polyethylene , polybutylene , and polystyrene . The alkyne acetylene polymerizes to produce polyacetylene . Oligomers (chains of a few monomers) may be produced, for example in the Shell higher olefin process , where α-olefins are extended to make longer α-olefins by adding ethylene repeatedly. Some hydrocarbons undergo metathesis , in which substituents attached by C–C bonds are exchanged between molecules. For
2714-452: The point of origin directly to the place of consumption. Fuel gas is contrasted with liquid fuels and from solid fuels, though some fuel gases are liquefied for storage or transport. While their gaseous nature can be advantageous, avoiding the difficulty of transporting solid fuel and the dangers of spillage inherent in liquid fuels, it can also be dangerous. It is possible for a fuel gas to be undetected and collect in certain areas, leading to
2773-509: The popular methods. Most transportation fuels are liquids, because vehicles usually require high energy density . This occurs naturally in liquids and solids. High energy density can also be provided by an internal combustion engine . These engines require clean-burning fuels. The fuels that are easiest to burn cleanly are typically liquids and gases. Thus, liquids meet the requirements of being both energy-dense and clean-burning. In addition, liquids (and gases) can be pumped, which means handling
2832-779: The process of combustion . Chemical fuels are divided in two ways. First, by their physical properties, as a solid, liquid or gas. Secondly, on the basis of their occurrence: primary (natural fuel) and secondary (artificial fuel) . Thus, a general classification of chemical fuels is: Solid fuel refers to various types of solid material that are used as fuel to produce energy and provide heating , usually released through combustion. Solid fuels include wood , charcoal , peat , coal , hexamine fuel tablets , and pellets made from wood (see wood pellets ), corn , wheat , rye and other grains . Solid-fuel rocket technology also uses solid fuel (see solid propellants ). Solid fuels have been used by humanity for many years to create fire . Coal
2891-401: The reactions of alkenes and oxygen. This process is the basis of rancidification and paint drying . Benzene burns with sooty flame when heated in air: Saturated hydrocarbons react with chlorine and fluorine . In the case of chlorination, one of the chlorine atoms replaces a hydrogen atom. The reactions proceed via free-radical pathways , in which the halogen first dissociates into
2950-575: The risk of a gas explosion . For this reason, odorizers are added to most fuel gases so that they may be detected by a distinct smell. The most common type of fuel gas in current use is natural gas . Biofuel can be broadly defined as solid, liquid, or gas fuel consisting of, or derived from biomass . Biomass can also be used directly for heating or power—known as biomass fuel . Biofuel can be produced from any carbon source that can be replenished rapidly e.g. plants. Many different plants and plant-derived materials are used for biofuel manufacture. Perhaps
3009-499: The shape of their container; the fumes of liquid fuels are flammable, not the fluids. Most liquid fuels in widespread use are derived from the fossilized remains of dead plants and animals by exposure to heat and pressure inside the Earth's crust. However, there are several types, such as hydrogen fuel (for automotive uses), ethanol , jet fuel and bio-diesel , which are all categorized as liquid fuels. Emulsified fuels of oil in water, such as orimulsion , have been developed as
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#17327724088373068-737: The simple non-ring structured hydrocarbons have higher viscosities , lubricating indices, boiling points, and solidification temperatures. 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 material ( bitumen ), wood preservatives (the creosote series) and as extremely high viscosity shear-resisting liquids. Some large-scale non-fuel applications of hydrocarbons begin with ethane and propane, which are obtained from petroleum and natural gas. These two gases are converted either to syngas or to ethylene and propylene respectively. Global consumption of benzene in 2021
3127-517: 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 . A small fraction of hydrocarbon found on earth, and all currently known hydrocarbon found on other planets and moons, is thought to be abiological . Hydrocarbons such as ethylene, isoprene, and monoterpenes are emitted by living vegetation. Some hydrocarbons also are widespread and abundant in
3186-464: The superconducting nature of doped picene has been met with heavy scepticism. Picene is also a major constituent of the hydrocarbon mineral idrialite . [REDACTED] This article incorporates text from a publication now in the public domain : Chisholm, Hugh , ed. (1911). " Picene ". Encyclopædia Britannica . Vol. 21 (11th ed.). Cambridge University Press. p. 581. Hydrocarbon In organic chemistry ,
3245-550: The world. Non-fossil sources in 2006 included hydroelectric 6.3%, nuclear 8.5%, and others ( geothermal , solar , tidal , wind , wood , waste ) amounting to 0.9%. World energy consumption was growing about 2.3% per year. Fossil fuels are non-renewable resources because they take millions of years to form, and reserves are being depleted much faster than new ones are being made. So we must conserve these fuels and use them judiciously. The production and use of fossil fuels raise environmental concerns. A global movement toward
3304-438: Was also produced during the same period from oil shale and bitumen by heating the rock to extract the oil, which was then distilled. Rāzi also gave the first description of a kerosene lamp using crude mineral oil, referring to it as the "naffatah". The streets of Baghdad were paved with tar , derived from petroleum that became accessible from natural fields in the region. In the 9th century, oil fields were exploited in
3363-605: Was later used to drive ships and locomotives . By the 19th century, gas extracted from coal was being used for street lighting in London. In the 20th and 21st centuries, the primary use of coal is to generate electricity , providing 40% of the world's electrical power supply in 2005. Fossil fuels were rapidly adopted during the Industrial Revolution , because they were more concentrated and flexible than traditional energy sources, such as water power. They have become
3422-433: Was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy, such as nuclear energy (via nuclear fission and nuclear fusion ). The heat energy released by reactions of fuels can be converted into mechanical energy via a heat engine . Other times, the heat itself is valued for warmth, cooking , or industrial processes, as well as
3481-409: Was the fuel source which enabled the Industrial Revolution , from firing furnaces , to running steam engines . Wood was also extensively used to run steam locomotives . Both peat and coal are still used in electricity generation today. The use of some solid fuels (e.g. coal) is restricted or prohibited in some urban areas, due to unsafe levels of toxic emissions. The use of other solid fuels as wood
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