Hydrogenation is a class of chemical reactions which result an addition of hydrogen (H₂) usually to unsaturated organic compounds. Typical substrates include alkenes, alkynes, ketones, nitriles, and imines.^[1] Most hydrogenations involve the direct addition of diatomic hydrogen (H₂) but some involve the alternative sources of hydrogen, not H₂: these processes are called transfer hydrogenations. The reverse reaction, removal of hydrogen, is called dehydrogenation. Vapours of hydrogen chloride in a beaker and ammonia in a test tube meet to form a cloud of a new substance, ammonium chloride A chemical reaction is a process that results in the interconversion of chemical substances. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... The term saturation generally means thoroughly full, and can refer to the following: In chemistry, see saturation (chemistry) for a number of meanings. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic (see below for more on the definition controversy... An alkene is one of the three classes of unsaturated hydrocarbons that contain at least one carbon-carbon double bond and have the general molecular formula of CnH2n (the other two being alkynes and arenes). ... The structural formula of 2-butyne, a simple alkyne-containing molecule Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms, with the formula CnH2n-2. ... Ketone group A ketone(key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group. ... A nitrile is any organic compound which has a -C≡N functional group. ... An imine is a functional group or chemical compound containing a carbon-nitrogen double bond. ... Transfer hydrogenation is the addition of hydrogen (H2; dihydrogen in inorganic and organometallic chemistry) to a molecule from a source other than gaseous H2. ... Hydrogenation is a chemical reaction in which unsaturated bonds between carbon atoms are reduced by attachment of a hydrogen atom to each carbon. ...

The classical example of a hydrogenation is the addition of hydrogen on unsaturated bonds between carbon atoms, converting alkenes to alkanes. Numerous important applications are found in the petrochemical, pharmaceutical and food industries. Health concerns associated with the hydrogenation of unsaturated fats to produce saturated fats and trans fats is an important aspect of current consumer awareness. Hydrogenation differs from protonation or hydride addition (e.g. use of sodium borohydride): in hydrogenation, the products have the same charge as the reactants. The chemical structure of ethylene, the simplest alkene. ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ... An alkene is one of the three classes of unsaturated hydrocarbons that contain at least one carbon-carbon double bond and have the general molecular formula of CnH2n (the other two being alkynes and arenes). ... An alkane in organic chemistry is a type of hydrocarbon in which the molecule has the maximum possible number of hydrogen atoms and so has no double bonds (they are saturated). ... Petrochemicals are chemical products made from raw materials of petroleum (hydrocarbon) origin. ... An unsaturated fat is a fat or fatty acid in which there are one or more double bonds in the fatty acid chain. ... Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. ... A trans fatty acid (commonly shortened to trans fat) is an unsaturated fatty acid molecule that contains a trans double bond between carbon atoms, which makes the molecule less kinked compared to cis fat. Research suggests a correlation between diets high in trans fats and diseases like atherosclerosis and coronary... Protonation is the addition of a proton (H+) to an atom, molecule, or ion. ... A hydride is a compound of hydrogen with more electropositive elements. ... Sodium borohydride, also known as sodium tetrahydroborate, has the chemical formula NaBH4. ...

The hydrogenation process

Hydrogenation has three components: the unsaturated substrate, the hydrogen (or hydrogen source) and, invariably, a catalyst. The largest scale technological uses of H₂ are the hydrogenation and hydrogenolysis reactions associated with both heavy and fine chemicals industries. Hydrogenation is the addition of H₂ to unsaturated organic compounds such as alkenes to give alkanes and aldehydes to give alcohols. Hydrogenolysis is the cleavage of C-X (X = O, S, N) bonds by H₂ to give C-H and H-X bonds. Large-scale applications of hydrogenolysis reactions are associated with the upgrading of fossil fuels. Hydrogenation and hydrogenolysis reactions require metal catalysts, often those composed of platinum or similar precious metals. It is a curious fact that under mild conditions, H₂ reacts directly with no organic compound in the absence of such catalysts. Hydrogenolysis is a chemical reaction in which a compound is decomposed -- a molecule is broken into smaller molecules by the reaction of hydrogen. ... The term saturation generally means thoroughly full, and can refer to the following: In chemistry, see saturation (chemistry) for a number of meanings. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic (see below for more on the definition controversy... The chemical structure of ethylene, the simplest alkene. ... Chemical structure of methane, the simplest alkane Alkanes are chemical compounds that consists only of the elements carbon (C) and hydrogen (H) (i. ... An aldehyde. ... Functional group of an alcohol molecule. ...

The addition of H₂ to an alkene affords an alkane in the protypical reaction: The chemical structure of ethylene, the simplest alkene. ... Chemical structure of methane, the simplest alkane Alkanes are chemical compounds that consists only of the elements carbon (C) and hydrogen (H) (i. ...

RCH=CH₂ + H₂ → RCH₂CH₃ (R = alkyl, aryl)

An alkyl is a univalent radical containing only carbon and hydrogen atoms arranged in a chain. ... In the context of organic molecules, aryl refers to any member of the set of functional groups or substituents that are derived from a simple aromatic ring. ...

Catalysts

With rare exception, no reaction below 480 °C occurs between H₂ and organic compounds in the absence of metal catalysts. The catalyst simultaneously binds both the H₂ and the unsaturated substrate and facilitates their union. Platinum group metals, particularly platinum, palladium, rhodium and ruthenium, are highly active catalysts. Highly active catalysts operate at lower temperatures and lower pressures of H₂. Non-precious metal catalysts, especially those based on nickel (such as Raney nickel and Urushibara nickel) have also been developed as economical alternatives but they are often slower or require higher temperatures. The trade-off is activity (speed of reaction) vs. cost of the catalyst and cost of the apparatus required for use of high pressures. General Name, Symbol, Number platinum, Pt, 77 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... General Name, Symbol, Number palladium, Pd, 46 Chemical series transition metals Group, Period, Block 10, 5, d Appearance silvery white metallic Standard atomic weight 106. ... General Name, Symbol, Number rhodium, Rh, 45 Chemical series transition metals Group, Period, Block 9, 5, d Appearance silvery white metallic Atomic mass 102. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... Raney nickel is an amorphous solid composed of finely divided grains of a nickel/aluminium alloy. ...

Two broad families of catalysts are known - homogeneous and heterogeneous. Homogeneous catalysts dissolve in the solvent that contains the unsaturated substrate. Heterogeneous catalysts are solids that are suspended in the same solvent with the substrate or are treated with gaseous substrate. In the pharmaceutical industry and for special chemical applications, soluble ""homogeneous"" catalyst are sometimes employed, such as the rhodium-based compound known as Wilkinson's catalyst, or the iridium-based Crabtree's catalyst. Homogeneous catalysis is a chemistry term which describes catalysis where the catalyst is in the same phase (ie. ... General Name, Symbol, Number rhodium, Rh, 45 Chemical series transition metals Group, Period, Block 9, 5, d Appearance silvery white metallic Atomic mass 102. ... Wilkinsons catalyst 1 is the common name for chlorotris(triphenylphosphine)rhodium(I), named after the late organometallic chemist and 1973 Nobel Laureate, Sir Geoffrey Wilkinson. ... General Name, Symbol, Number iridium, Ir, 77 Chemical series transition metals Group, Period, Block 9, 6, d Appearance silvery white Atomic mass 192. ... Crabtrees catalyst is the name given to a complex of iridium with cyclooctadiene, tris-cyclohexylphosphine, and pyridine. ...

The activity and selectivity of catalysts can be adjusted by changing the environment around the metal, i.e. the coordination sphere. Different faces of a crystalline heterogeneous catalyst display distinct activities, for example. Similarly, heterogeneous catalysts are affected by their supports, i.e. the material upon with the heterogeneous catalyst is bound. Homogeneous catalysts are affected by their ligands. In many cases, highly empirical modifications involve selective "poisons." Thus, a carefully chosen catalyst can be used to hydrogenate some functional groups without affecting others, such as the hydrogenation of alkenes without touching aromatic rings, or the selective hydrogenation of alkynes to alkenes using Lindlar's catalyst. For prochiral substrates, the selectivity of the catalyst can be adjusted such that one enantiomeric product is produced. cis-[CoCl2(NH3)4]+ The colored atoms form a coordination sphere around the ion of cobalt The primary or first coordination sphere, or simply coordination sphere of a metal ion in a coordination complex is the set of ligands immediately atached to the ion. ... Examples of directions Miller indices are a notation used to describe lattice planes and directions in a crystal. ... In chemistry, a ligand is an atom, ion, or molecule (see also: functional group) that generally donates one or more of its electrons through a coordinate covalent bond to, or shares its electrons through a covalent bond with, one or more central atoms or ions (these ligands act as a... Alkynes are hydrocarbons that have at least one triple bond between carbon atoms. ... A Lindlar catalyst is a palladium heterogeneous catalyst on calcium carbonate poisoned, deactivated, or conditioned by lead acetate, CaCO3, or lead. ... Refers to an atom in a molecule (usually a carbon atom) that would become chiral if one of two identical substituents is replaced by a new ligand; i. ...

Hydrogenolysis

The catalytic hydrogenation of organic sulfur compounds to form gaseous hydrogen sulfide (H₂S) is very widely used in petroleum refineries, petrochemical plants and other industries to desulfurize various final products, intermediate products and process feedstocks by converting sulfur compounds to gaseous hydrogen sulfide which is then easily removed by distillation. The gaseous hydrogen sulfide is subsequently recovered in an amine treater and finally converted to elemental sulfur in a Claus process unit. In those industries, desulfurization process units are often referred to as hydrodesulfurizers (HDS) or hydrotreaters (HDT). In the petroleum refining and petrochemical industries, cobalt-molybdenum or nickel-molybdenum catalysts are commonly used for hydrogenation and hydrogenolysis catalysts. General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Standard atomic weight 32. ... Hydrogen sulfide (hydrogen sulphide in British English), H2S, is a colorless, toxic, flammable gas that is responsible for the foul odor of rotten eggs and flatulence. ... View of Shell Oil Refinery in Martinez, California. ... Petrochemicals are chemical products made from raw materials of petroleum (hydrocarbon) origin. ... Oil desulfurization is a widely used precombustion method for reducing sulfur dioxide emissions from oil-burning power plants. ... Laboratory distillation set-up using, without a fractionating column 1: Heat source 2: Still pot 3: Still head 4: Thermometer/Boiling point temperature 5: Condenser 6: Cooling water in 7: Cooling water out 8: Distillate/receiving flask 9: Vacuum/gas inlet 10: Still receiver 11: Heat control 12: Stirrer speed... Amine gas treating refers to a group of processes that use aqueous solutions of various amines to remove hydrogen sulfide (H2S) and carbon dioxide (CO2) from gases. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Standard atomic weight 32. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Hydrodesulfurization is one means of lowering the sulfur content of liquids from oil/coal. ... A hydrotreater is a common process unit in an oil refinery that is used to treat products such as gasoline, kerosene, diesel, and intermediates such as gasoil. ...

Mechanism of reaction

Because of its technological relevance, metal-catalyzed “activation” of H₂, has been the subject of considerable study, focusing on the reaction mechanisms of by which metals mediate these reactions.^[2] First of all isotope labeling using deuterium can be used to determine the regiochemistry of the addition: In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs. ... It has been suggested that Isotopic tracer be merged into this article or section. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of Earth of approximately one atom in 6500 of hydrogen (~154 PPM). ... In chemistry, regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions. ...

RCH=CH₂ + D₂ → RCHDCH₂D

Essentially, the metal binds to both components to give an intermediate alkene-metal(H)₂ complex. The general sequence of reactions is:

• binding of the hydrogen to give a dihydride complex ("oxidative addition"):

L_nM + H₂ → L_nMH₂

• binding of alkene:

L_nM(η²H₂) + CH₂=CHR → L_n-1MH₂(CH₂=CHR) + L

• transfer of one hydrogen atom from the metal to carbon (migratory insertion)

L_n-1MH₂(CH₂=CHR) → L_n-1M(H)(CH₂-CH₂R)

• transfer of the second hydrogen atom from the metal to the alkyl group with simultaneous dissociation of the alkane ("reductive elimination")

L_n-1M(H)(CH₂-CH₂R) → L_n-1M + CH₃-CH₂R

Preceding the oxidative addition of H₂ is the formation of a dihydrogen complex. Dihydrogen complexes are coordination complexes containing intact H2 as a ligand. ...

Hydrogen sources

The obvious source of H₂ is the gas itself, often under pressure. Hydrogen can also be transferred from hydrogen-donor molecules, such as hydrazine,^[3][4] dihydronaphthalene, dihydroanthracene, isopropanol, and formic acid.^[5][6] Transfer hydrogenation can be metal catalysed. Hydrogenation does proceeds from some hydrogen donors without catalysts, examples being diimide and aluminium isopropoxide. Hydrazine is the chemical compound with formula N2H4. ... Isopropyl alcohol or isopropanol is a common name for 2-propanol, an alcohol commonly used for application to the skin, and popularly referred to as rubbing alcohol. ... Formic acid (systematically called methanoic acid) is the simplest carboxylic acid. ... Transfer hydrogenation is the addition of hydrogen (H2; dihydrogen in inorganic and organometallic chemistry) to a molecule from a source other than gaseous H2. ... In chemistry, azo compounds generally have a molecular formula of the form R-N=N-R, in which R and R can be either aromatic or aliphatic. ... Aluminium isopropoxide is an inorganic compound and the adduct of aluminum and isopropyl alcohol. ...

Temperatures

The reaction is carried out at different temperatures and pressures depending upon the substrate. Hydrogenation is a strongly exothermic reaction. In the hydrogenation of vegetable oils and fatty acids, for example, the heat released is about 25 kcal per mole (105 kJ/mol), sufficient to raise the temperature of the oil by 1.6-1.7 °C per iodine number drop. In thermodynamics, the word exothermic describes a process or reaction that releases energy in the form of heat. ... The iodine number in chemistry is the mass of iodine in grams that is consumed by 100 grams of a chemical substance. ...

Hydrogenation in the food industry

Hydrogenation is widely applied to the processing of vegetable oils and fats. Complete hydrogenation converts unsaturated fatty acids to saturated ones. In practice the process is not usually carried to completion. Since the original oils usually contain more than one double bond per molecule (that is, they are poly-unsaturated), the result is usually described as partially hydrogenated vegetable oil; that is some, but usually not all, of the double bonds in each molecule have been reduced . This is done by adding hydrogen atoms which bond to the carbon, thus occupying a place in the outer orbital of the carbon which would have otherwise been used to bond with the next carbon in the fatty acid chain. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... An unsaturated fat is a fat or fatty acid in which there are one or more double bonds in the fatty acid chain. ... In nutrition, monounsaturated fats are fatty acids with one double-bonded carbon in the molecule, with all of the others single-bonded carbons, in contrast to polyunsaturated fatty acids which have more than one double bond. ... // In nutrition, polyunsaturated fat is an abbreviation of polyunsaturated fatty acid. ... A trans fatty acid (commonly shortened to trans fat) is an unsaturated fatty acid molecule that contains a trans double bond between carbon atoms, which makes the molecule less kinked compared to cis fat. Research suggests a correlation between diets high in trans fats and diseases like atherosclerosis and coronary... Omega-3 fatty acids are a family of polyunsaturated fatty acids which have in common a carbon-carbon double bond in the ω-3 position. ... Omega-6 fatty acids are fatty acids where the term omega-6 signifies that the first double bond in the carbon backbone of the fatty acid, counting from the end opposite the acid group, occurs in the sixth carbon-carbon bond. ... Omega-9 fatty acids are a class of unsaturated fatty acids which have a C=C double bond in the ω-9 position. ... Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. ... Interesterified fats are oils (such as soybean oil) that have been chemically modified. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... Essential fatty acids, or EFAs, are fatty acids that cannot be constructed within an organism from other components (generally all references are to humans) as there are no known biochemical pathways capable of producing them. ... Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. ... Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ...

Hydrogenation results in the conversion of liquid vegetable oils to solid or semi-solid fats, such as those present in margarine. Changing the degree of saturation of the fat changes some important physical properties such as the melting point, which is why liquid oils become semi-solid. Semi-solid fats are preferred for baking because the way the fat mixes with flour produces a more desirable texture in the baked product. Since partially hydrogenated vegetable oils are cheaper than animal source fats, they are available in a wide range of consistencies, and have other desirable characteristics (e.g., increased oxidative stability (longer shelf life)), they are the predominant fats used in most commercial baked goods. Fat blends formulated for this purpose are called shortenings. It has been suggested that this article or section be merged with cooking oil. ... Margarine in a tub Margarine (pronunciation: ), as a generic term, can indicate any of a wide range of butter-substitutes. ... Shortening is a semisolid fat used in food preparation, especially baked goods, and is so called because it inhibits the formation of long gluten strands in wheat-based doughs, giving them a short texture (as in shortbread). ...

Health implications

Main article: trans fat

A side effect of incomplete hydrogenation having implications for human health is the isomerization of the remaining unsaturated carbon bonds. The cis configuration of these double bonds predominates in the unprocessed fats in most edible fat sources, but incomplete hydrogenation partially converts these molecules to trans isomers, which have been implicated in circulatory diseases including heart disease (see trans fats). The catalytic hydrogenation process favors the conversion from cis to trans bonds because the trans configuration has lower energy than the natural cis one. At equilibrium, the trans/cis isomer ratio is about 2:1. Food legislation in the US and codes of practice in EU has long required labels declaring the fat content of foods in retail trade, and more recently, have also required declaration of the trans fat content. A trans fatty acid (commonly shortened to trans fat) is an unsaturated fatty acid molecule that contains a trans double bond between carbon atoms, which makes the molecule less kinked compared to cis fat. Research suggests a correlation between diets high in trans fats and diseases like atherosclerosis and coronary... In chemistry, isomerization is the transformation of a molecule into a different isomer. ... CIS usually refers to: Commonwealth of Independent States, a modern-day political entity consisting of 11 former Soviet Union Republics CIS is also an acronym for: Canadian Interuniversity Sport Cancer Information Service Carcinoma in situ Centre for Independent Studies Center for Immigration Studies Chinese International School Cisalpino Citizenship & Immigration Services... Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ... In chemistry, geometric isomerism is a form of stereoisomerism and describes the orientation of functional groups at the ends of a bond around which no rotation is possible. ... Heart disease is an umbrella term for a number of different sexes diseases which affect the heart and is the leading cause of death in the United States as of 2006. ... A trans fatty acid (commonly shortened to trans fat) is an unsaturated fatty acid molecule that contains a trans double bond between carbon atoms, which makes the molecule less kinked compared to cis fat. Research suggests a correlation between diets high in trans fats and diseases like atherosclerosis and coronary...

In 2006, New York City adopted the US’s first major municipal ban on most artificial trans fats in restaurant cooking.

History

The earliest hydrogenation is that of platinum catalyzed addition of hydrogen to oxygen in the Döbereiner's lamp, a device commercialized as early as 1823. The French chemist Paul Sabatier is considered the father of the hydrogenation process. In 1897 he discovered that the introduction of a trace of nickel as a catalyst facilitated the addition of hydrogen to molecules of gaseous carbon compounds in what is now known as the Sabatier process. For this work Sabatier won half of the 1912 Nobel Prize in Chemistry. Wilhelm Normann was awarded a patent in Germany in 1902 and in Britain in 1903 for the hydrogenation of liquid oils using hydrogen gas, which was the beginning of what is now a very large industry world wide. The commercially very important Haber-Bosch process (ammonia hydrogenation) was first described in 1905 and less so Fischer-Tropsch process (carbon monoxide hydrogenation) in 1922. Another commercial application is the oxo process (1938), a hydrogen mediated coupling of aldehydes with alkenes. Wilkinson's catalyst was the first homogeneous catalyst developed in the 1960s and Noyori asymmetric hydrogenation (1987) one of the first applications in asymmetric synthesis. General Name, Symbol, Number platinum, Pt, 77 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... In chemistry and biology, catalysis is the acceleration (increase in rate) of a chemical reaction by means of a substance, called a catalyst, that is itself not consumed by the overall reaction. ... Döbereiners Lamp is a lighter invented by the German chemist Johann Wolfgang Döbereiner. ... Paul Sabatier (November 5, 1854 – August 14, 1941) was a French chemist, born at Carcassonne. ... The Sabatier process involves the reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst to produce methane and water. ... This is a list of Nobel Prize laureates in Chemistry from 1901 to 2006. ... Wilhelm Normann (1870 - 1939) (sometimes also spelled Norman) was a German chemist who introduced the hydrogenation of fats in 1901, which had a profound influence on the production of margerine. ... The Haber Process (also Haber-Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... // The Fischer-Tropsch process is a catalyzed chemical reaction in which carbon monoxide and hydrogen are converted into liquid hydrocarbons of various forms. ... Hydroformylation, also known as oxo synthesis, is an important industrial process for the production of aldehydes from alkenes. ... Wilkinsons catalyst 1 is the common name for chlorotris(triphenylphosphine)rhodium(I), named after the late organometallic chemist and 1973 Nobel Laureate, Sir Geoffrey Wilkinson. ... Homogeneous catalysis is a chemistry term which describes catalysis where the catalyst is in the same phase (ie. ... The Noyori asymmetric hydrogenation is a chemical reaction described as an asymmetric reduction of β-keto-esters. ... This article or section does not adequately cite its references or sources. ...

A 2007 review article advocated the use of more hydrogenations in C-C coupling reactions like the oxo process.^[7]

See also

• Dehydrogenation
• Transfer hydrogenation
• Hydrogenolysis
• Hydrodesulfurization, Hydrotreater and Oil desulfurization

Hydrogenation is a chemical reaction in which unsaturated bonds between carbon atoms are reduced by attachment of a hydrogen atom to each carbon. ... Transfer hydrogenation is the addition of hydrogen (H2; dihydrogen in inorganic and organometallic chemistry) to a molecule from a source other than gaseous H2. ... Hydrogenolysis is a chemical reaction in which a compound is decomposed -- a molecule is broken into smaller molecules by the reaction of hydrogen. ... Hydrodesulfurization is one means of lowering the sulfur content of liquids from oil/coal. ... A hydrotreater is a common process unit in an oil refinery that is used to treat products such as gasoline, kerosene, diesel, and intermediates such as gasoil. ... Oil desulfurization is a widely used precombustion method for reducing sulfur dioxide emissions from oil-burning power plants. ...

References