Hydrogenation is a chemical reaction in which unsaturated bonds between carbon atoms are reduced by attachment of a hydrogen atom to each carbon. The process thus results in the saturation of the carbon atoms, meaning that each carbon atom has 4 other atoms attached to it. Numerous important applications are found in the pharmaceutical and petrochemical industries. A chemical reaction is a process involving one, two, or more substances, such as compounds or atoms. ... The term saturation generally means thoroughly full, and can refer to the following: In chemistry, see saturation (chemistry) for a number of meanings. ... A chemical bond is the phenomenon of atoms being held together in molecules, crystals or in solid metal. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Redox reactions include all chemical processes in which atoms have their oxidation number (oxidation state) changed. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...

Hydrogenation is widely applied to the processing of fats and oils. Complete hydrogenation converts unsaturated fatty acids to saturated ones. In practice the process is not usually carried to completion. Since the original oils typically 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. Hydrogenation results in the conversion of liquid vegetable oils to solid or semi-solid fats, such as margarine. Changing the degree of saturation of the fat changes important physical properties such as melting point, which is why the liquids 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 much less expensive than most other fats with similar characteristics, and because they have other desirable characteristics leading to longer shelf life, they are the predominant fat used in most commercial baked goods. In chemistry, especially biochemistry, a fatty acid is a carboxylic acid (or organic acid), often with a long aliphatic tail (long chains), either saturated or unsaturated. ... The term saturation generally means thoroughly full, and can refer to the following: In chemistry, see saturation (chemistry) for a number of meanings. ... Oil is a generic term for organic liquids that are not miscible with water. ... A great guy, who has put so much into celeb-forum. ... Margarine is a generic term used to indicate any of a wide range of butter substitutes. ...

Processes accomplishing the reverse are called "dehydrogenation" or "partial dehydrogenation."

A side effect of incomplete hydrogenation which has 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 of most foods. But hydrogenation often converts these molecules to trans isomers, which in fats have been implicated in heart disease ( see trans fats ). The catalytic hydrogenation process favors the conversion from cis to trans bonds because the trans conformation is lower energy than the natural cis conformation. In chemistry, isomerization is the transformation of a molecule into a different isomer. ... CIS is an abbreviation of: Commonwealth of Independent States Canadian Interuniversity Sport Contact Image Sensor CompuServe Information Service Chinese International School Confederacy of Independent Systems (Star Wars) Continuous injection system Communication Information Services Card Information Structure Cisalpino See also uses of the word cis. ... 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. ... Trans is a Latin word meaning across, beyond or on the opposite side and is the opposite of cis, which means on the same side. In chemistry, a bond not subject to free rotation in which the greater radical on both ends is on the opposite side of the bond... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently. ... There are different forms of heart disease: Coronary heart disease Ischaemic heart disease Cardiovascular disease The study of the heart (and diseases of the heart) is Cardiology This is a disambiguation page, a list of pages that otherwise might share the same title. ... 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...

Hydrogenation typically uses hydrogen gas as a reactant and an undissolved (or "heterogeneous") metal catalyst, such as nickel, palladium or platinum. Otherwise, the "homogeneous" rhodium-based catalyst known as Wilkinson's catalyst is often used. The reaction is usually carried out at elevated temperature and pressure. Such reactions belong to organic chemistry. General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... A gas is one of the four main phases of matter (after solid and liquid, and followed by plasma), that subsequently appear as a solid material that is subjected to increasingly higher temperatures. ... In chemistry, the reactants are the substances that exist at the start of a chemical reaction. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds, and metals are sometimes described as a lattice of positive ions (cations) in a cloud of electrons. ... A catalyst (Greek: καταλύτης, catalytēs) is a substance that accelerates the rate (speed) of a chemical reaction without itself being transformed or consumed by the reaction (see also catalysis). ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... General Name, Symbol, Number palladium, Pd, 46 Chemical series transition metals Group, Period, Block 10, 5, d Appearance silvery white metallic Atomic mass 106. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Atomic mass 195. ... Homogeneous catalysis is a chemistry term which describes catalysis where the catalyst is in the same phase (ie. ... Rh redirects here. ... 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. ... Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds that by definition contain carbon. ...

The French chemist Paul Sabatier greatly facilitated the industrial use of hydrogenation. In 1897, he discovered that the introduction of a trace of nickel as a catalyst facilitated the addition of hydrogen to molecules of carbon compounds. Paul Sabatier was born at Carcassonne in southern France on November 5, 1854. ...

See also

• hydrogenolysis
• hydrodeoxygenation.

Hydrogenolysis is a chemical reaction in which a compound is decomposed -- a molecule is broken into smaller molecules by the reaction of hydrogen. ...

External links

• Parr Instrument Company - Hydrogenation Apparatus manufacturer