en.wikipedia.org/wiki/Hydrogenation 1/12

Catalysed hydrogenation

Process type Chemical

Industrial

sector(s)

Food industry, petrochemical

industry, pharmaceutical industry,

agricultural industry

Main

technologies

or sub-

processes

Various transition metal catalysts,

high-pressure technology

Feedstock Unsaturated substrates and

hydrogen or hydrogen donors

Product(s) Saturated hydrocarbons and

derivatives

Inventor Paul Sabatier

Year of

invention

1897

HydrogenationFrom Wikipedia, the free encyclopedia

Hydrogenation – to treat with hydrogen – is a chemicalreaction between molecular hydrogen (H2) and another

compound or element, usually in the presence of a catalyst.The process is commonly employed to reduce or saturateorganic compounds. Hydrogenation typically constitutes theaddition of pairs of hydrogen atoms to a molecule, generally analkene. Catalysts are required for the reaction to be usable;non-catalytic hydrogenation takes place only at very hightemperatures. Hydrogenation reduces double and triple bonds

in hydrocarbons.[1]

Because of the importance of hydrogen, many relatedreactions have been developed for its use. Mosthydrogenations use gaseous hydrogen (H2), but some involve

the alternative sources of hydrogen, not H2: these processes

are called transfer hydrogenations. The reverse reaction,removal of hydrogen from a molecule, is calleddehydrogenation. A reaction where bonds are broken whilehydrogen is added is called hydrogenolysis, a reaction that mayoccur to carbon-carbon and carbon-heteroatom (oxygen,nitrogen or halogen) bonds. Hydrogenation differs fromprotonation or hydride addition: in hydrogenation, the products have the same charge as the reactants.

Hydrogenation of unsaturated fats produces saturated fats. In the case of partial hydrogenation, trans fats may begenerated as well.

Contents

1 Process1.1 Substrate

1.2 Catalysts

1.2.1 Homogeneous catalysts1.2.2 Heterogeneous catalysts

1.3 Hydrogen sources1.4 Transfer hydrogenation

1.5 Electrolytic hydrogenation

2 Thermodynamics and mechanism2.1 Heterogeneous catalysis

2.2 Homogeneous catalysis3 Inorganic substrates

4 Industrial applications

4.1 In the food industry4.1.1 Health implications

en.wikipedia.org/wiki/Hydrogenation 2/12

4.2 Hydrogenation of coal

5 History

5.1 Heterogeneous catalytic hydrogenation5.2 Homogeneous catalytic hydrogenation

6 Metal-free hydrogenation7 Equipment used for hydrogenation

7.1 Batch hydrogenation under atmospheric conditions

7.2 Batch hydrogenation at elevated temperature and/or pressure7.3 Flow hydrogenation

7.4 Industrial reactors8 See also

9 References

10 Further reading11 External links

Process

Hydrogenation has three components, the unsaturated substrate, the hydrogen (or hydrogen source) and, invariably,a catalyst. The reduction reaction is carried out at different temperatures and pressures depending upon the substrateand the activity of the catalyst.

Substrate

The addition of H2 to an alkene affords an alkane in the prototypical reaction:

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

Hydrogenation is sensitive to steric hindrance explaining the selectivity for reaction with the exocyclic double bondbut not the internal double bond.

An illustrative example of a hydrogenation reaction is the addition of hydrogen to maleic acid to form succinic acid.[2]

Numerous important applications of this petrochemical are found in pharmaceutical and food industries.

An important characteristic of alkene and alkyne hydrogenations, both the homogeneously and heterogeneouslycatalyzed versions, is that hydrogen addition occurs with "syn addition", with hydrogen entering from the least

hindered side.[3] Typical substrates are listed in the table

Substrates for and products of hydrogenation

substrate product comments

alkene,

en.wikipedia.org/wiki/Hydrogenation 3/12

R2C=CR'2 alkane, R2CHCHR'2 many catalysts, major application is margarine

alkyne,

RCCRalkene, cis-RHC=CHR' over-hydrogenation to alkane can be problematic

aldehyde,

RCHO

primary alcohol,

RCH2OHeasy substrate

ketone,R2CO

secondary alcohol,R2CHOH

more challenging than RCHO, prochiral for unsymmetrical ketones

ester,RCO2R'

two alcohols, RCH2OH

+ R'OHchallenging substrate

imine,

RR'CNR"amine, RR'CHNHR"

easy substrate, often use transfer hydrogenation, actual precursor is N-

protonated

amide,RC(O)NR'2

amine, RCH2NR'2 challenging substrate

nitrile, RCNprimary amine,

RCH2NH2product amine reactive toward precursor nitrile in some cases

nitro, RNO2 amine, RNH2commercial applications use heterogeneous Ni and Ru catalysts; major

application is aniline[4][5]

Catalysts

With rare exceptions, no reaction below 480 °C (750 K or 900 °F) occurs between H2 and organic compounds in

the absence of metal catalysts. The catalyst binds both the H2 and the unsaturated substrate and facilitates their

union. Platinum, palladium, rhodium, and ruthenium form highly active catalysts, which operate at lower temperaturesand 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 highertemperatures. The trade-off is activity (speed of reaction) vs. cost of the catalyst and cost of the apparatus required

for use of high pressures. Notice that the Raney-nickel catalysed hydrogenations require high pressures:[6][7]

Two broad families of catalysts are known - homogeneous catalysts and heterogeneous catalysts. Homogeneouscatalysts dissolve in the solvent that contains the unsaturated substrate. Heterogeneous catalysts are solids that aresuspended in the same solvent with the substrate or are treated with gaseous substrate.

Homogeneous catalysts

en.wikipedia.org/wiki/Hydrogenation 4/12

Illustrative homogeneous catalysts include the rhodium-based compound known as Wilkinson's catalyst and the

iridium-based Crabtree's catalyst. An example is the hydrogenation of carvone:[8]

Hydrogenation is sensitive to steric hindrance explaining the selectivity for reaction with the exocyclic double bondbut not the internal double bond.

The activity and selectivity of homogeneous catalysts is adjusted by changing the ligands. For prochiral substrates, theselectivity of the catalyst can be adjusted such that one enantiomeric product is favored. Asymmetric hydrogenation

is also possible via heterogeneous catalysis on a metal that is modified by a chiral ligand.[9]

Heterogeneous catalysts

Heterogeneous catalysts for hydrogenation are more common industrially. As in homogeneous catalysts, the activityis adjusted through changes in the environment around the metal, i.e. the coordination sphere. Different faces of acrystalline heterogeneous catalyst display distinct activities, for example. Similarly, heterogeneous catalysts areaffected by their supports, i.e. the material upon with the heterogeneous catalyst is bound.

In many cases, highly empirical modifications involve selective "poisons". Thus, a carefully chosen catalyst can beused to hydrogenate some functional groups without affecting others, such as the hydrogenation of alkenes withouttouching aromatic rings, or the selective hydrogenation of alkynes to alkenes using Lindlar's catalyst. For example,when the catalyst palladium is placed on barium sulfate and then treated with quinoline, the resulting catalyst reducesalkynes only as far as alkenes. The Lindlar catalyst has been applied to the conversion of phenylacetylene to

styrene.[10]

Asymmetric hydrogenation is also possible via heterogeneous catalysis on a metal that is modified by a chiral

ligand.[9]

Hydrogen sources

For hydrogenation, the obvious source of hydrogen is H2 gas itself, which is typically available commercially within

the storage medium of a pressurized cylinder. The hydrogenation process often uses greater than 1 atmosphere ofH2, usually conveyed from the cylinders and sometimes augmented by "booster pumps". Gaseous hydrogen is

produced industrially from hydrocarbons by the process known as steam reforming.[11]

Transfer hydrogenation

en.wikipedia.org/wiki/Hydrogenation 5/12

Hydrogen also can be extracted ("transferred") from "hydrogen-donors" in place of H2 gas. Hydrogen donors, which

often serve as solvents include hydrazine, dihydronaphthalene, dihydroanthracene, isopropanol, and formic acid.[12]

In organic synthesis, transfer hydrogenation is useful for the asymmetric reduction of polar unsaturated substrates,such as ketones, aldehydes, and imines.

Electrolytic hydrogenation

Polar substrates such as ketones can be hydrogenated electrochemically, using protic solvents and reducing

equivalents as the source of hydrogen.[13]

Thermodynamics and mechanism

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 °Cper iodine number drop. The mechanism of metal-catalyzed hydrogenation of alkenes and alkynes has been

extensively studied.[14] First of all isotope labeling using deuterium confirms the regiochemistry of the addition:

RCH=CH2 + D2 → RCHDCH2D

Heterogeneous catalysis

On solids, the accepted mechanism is the Horiuti-Polanyi mechanism:[15][16]

1. Binding of the unsaturated bond, and hydrogen dissociation into atomic hydrogen onto the catalyst2. Addition of one atom of hydrogen; this step is reversible

3. Addition of the second atom; effectively irreversible under hydrogenating conditions.

In the second step, the metallointermediate formed is a saturated compound that can rotate and then break down,again detaching the alkene from the catalyst. Consequently, contact with a hydrogenation catalyst necessarily causescis-trans-isomerization, because the isomerization is thermodynamically favorable. This is a problem in partialhydrogenation, while in complete hydrogenation the produced trans-alkene is eventually hydrogenated.

For aromatic substrates, the first bond is hardest to hydrogenate because of the free energy penalty for breaking thearomatic system. The product of this is a cyclohexadiene, which is extremely active and cannot be isolated; inconditions reducing enough to break the aromatization, it is immediately reduced to a cyclohexene. The cyclohexeneis ordinarily reduced immediately to a fully saturated cyclohexane, but special modifications to the catalysts (such asthe use of the anti-solvent water on ruthenium) can preserve some of the cyclohexene, if that is a desired product.

Homogeneous catalysis

In many homogeneous hydrogenation processes,[17] the metal binds to both components to give an intermediatealkene-metal(H)2 complex. The general sequence of reactions is assumed to be as follows or a related sequence of

steps:

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

LnM + H2 → LnMH2

binding of alkene:

en.wikipedia.org/wiki/Hydrogenation 6/12

LnM(η2H2) + CH2=CHR → Ln-1MH2(CH2=CHR) + L

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

Ln-1MH2(CH2=CHR) → Ln-1M(H)(CH2-CH2R)

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

Ln-1M(H)(CH2-CH2R) → Ln-1M + CH3-CH2R

Preceding the oxidative addition of H2 is the formation of a dihydrogen complex.

Inorganic substrates

The hydrogenation of nitrogen to give ammonia is conducted on a vast scale by the Haber-Bosch process,consuming an estimated 1% of the world's energy supply.

Oxygen can be partially hydrogenated to give hydrogen peroxide, although this process has not beencommercialized.

Industrial applications

Catalytic hydrogenation has diverse industrial uses. Most frequently, industrial hydrogenation relies on heterogeneous

catalysts.[11]

In petrochemical processes, hydrogenation is used to convert alkenes and aromatics into saturated alkanes(paraffins) and cycloalkanes (naphthenes), which are less toxic and less reactive. For example, mineral turpentine isusually hydrogenated. Hydrocracking of heavy residues into diesel is another application. In isomerization andcatalytic reforming processes, some hydrogen pressure is maintained to hydrogenolyze coke formed on the catalystand prevent its accumulation.

Hydrogenation is a useful reaction for converting more oxidized oxygen and nitrogen compounds such as aldehydes,imines and nitriles into the corresponding saturated compounds, i.e. alcohols and amines. Primary alcohols can besynthesized from aldehydes by hydrogenation. Thus, alkyl aldehydes, which can be synthesized with the oxo processfrom carbon monoxide and an alkene, can be converted to alcohols. E.g. 1-propanol is produced frompropionaldehyde, produced from ethene and carbon monoxide. Xylitol, a polyol, is produced by hydrogenation ofthe sugar xylose, an aldehyde. Primary amines can be synthesized by hydrogenation of nitriles, while nitriles arereadily synthesized from cyanide and a suitable electrophile. For example, isophorone diamine, a precursor to thepolyurethane monomer isophorone diisocyanate, is produced from isophorone nitrile by a tandem nitrilehydrogenation/reductive amination by ammonia, wherein hydrogenation converts both the nitrile into an amine and theimine formed from the aldehyde and ammonia into another amine.

In the food industry

en.wikipedia.org/wiki/Hydrogenation 7/12

Partial hydrogenation of a typical plant oil to a typical

component of margarine. Most of the C=C double

bonds are removed in this process, which elevates the

melting point of the product.

The largest scale application of hydrogenation is for the processing of vegetable oils. Typical vegetable oils arederived from polyunsaturated fatty acids (containing more than one carbon-carbon double bonds). Their partialhydrogenation reduces most but not all, of these carbon-carbon double bonds. The degree of hydrogenation is

controlled by restricting the amount of hydrogen, reaction temperature and time, and the catalyst.[18]

Hydrogenation converts liquid vegetable oils into solid orsemi-solid fats, such as those present in margarine.Changing the degree of saturation of the fat changes someimportant physical properties such as the melting range,which is why liquid oils become semi-solid. Solid or semi-solid fats are preferred for baking because the way the fatmixes with flour produces a more desirable texture in thebaked product. Because partially hydrogenated vegetableoils are cheaper than animal source fats, are available in awide range of consistencies, and have other desirablecharacteristics (e.g., increased oxidative stability/longershelf life), they are the predominant fats used as shorteningin most commercial baked goods.

Health implications

Main article: Trans fat

A side effect of incomplete hydrogenation havingimplications for human health is the isomerization of someof the remaining unsaturated carbon bonds. The cis configuration of these double bonds predominates in theunprocessed fats in most edible fat sources, but incomplete hydrogenation partially converts these molecules to transisomers, which have been implicated in circulatory diseases including heart disease. The conversion from cis to transbonds is favored because the trans configuration has lower energy than the natural cis one. At equilibrium, thetrans/cis isomer ratio is about 2:1. Food legislation in the US and codes of practice in EU have long required labelsdeclaring the fat content of foods in retail trade and, more recently, have also required declaration of the trans fatcontent. The use of trans fats in human food products has been effectively banned in Denmark (since 2003) andSwitzerland (2008). In the US, local legislation banned trans fats from restaurants and public kitchens in New YorkCity (since 2005) and California. Other countries and regions have introduced mandatory labeling of trans fats on

food products and appealed to the industry for voluntary reductions.[19][20]

Hydrogenation of coal

Main article: Bergius process

History

Heterogeneous catalytic hydrogenation

The earliest hydrogenation is that of platinum catalyzed addition of hydrogen to oxygen in the Döbereiner's lamp, adevice commercialized as early as 1823. The French chemist Paul Sabatier is considered the father of thehydrogenation process. In 1897, building on the earlier work of James Boyce, an American chemist working in themanufacture of soap products, he discovered that the introduction of a trace of nickel as a catalyst facilitated theaddition of hydrogen to molecules of gaseous hydrocarbons in what is now known as the Sabatier process. For this

en.wikipedia.org/wiki/Hydrogenation 8/12

work Sabatier shared the 1912 Nobel Prize in Chemistry. Wilhelm Normann was awarded a patent in Germany in1902 and in Britain in 1903 for the hydrogenation of liquid oils, which was the beginning of what is now a world wideindustry. The commercially important Haber-Bosch process, first described in 1905, involves hydrogenation ofnitrogen. In the Fischer-Tropsch process, reported in 1922 carbon monoxide, which is easily derived from coal, ishydrogenated to liquid fuels.

Also in 1922, Voorhees and Adams described an apparatus for performing hydrogenation under pressures above

one atmosphere.[21] The Parr shaker, the first product to allow hydrogenation using elevated pressures andtemperatures, was commercialized in 1926 based on Voorhees and Adams’ research and remains in widespreaduse. In 1924 Murray Raney developed a nickel fine powder catalyst named after him which is still widely used inhydrogenation reactions such as conversion of nitriles to amines or the production of margarine.

Homogeneous catalytic hydrogenation

The history of homogeneous hydrogenation has been assigned to the development the Meerwein–Ponndorf–Verleyreduction of ketones using aluminium alkoxides. In the 1930s, Calvin discovered that copper(II) complexes oxidizedH2. The 1960s witnessed the development of well defined homogeneous catalysts using transition metal complexes,

e.g., Wilkinson's catalyst (RhCl(PPh3)3). Soon thereafter Schrock and Obsorne's discovered that cationic Rh and Ircatalyze the hydrogenation of alkenes and carbonyls. In the 1970s, asymmetric hydrogenation was demonstrated in

the synthesis of L-DOPA and the 1990s saw the invention of Noyori asymmetric hydrogenation.[22] Thedevelopment of homogeneous hydrogenation was influenced by work started in the 1930s and 1940s on the oxo

process and Ziegler-Natta polymerization.[23]

Metal-free hydrogenation

For all practical purposes, hydrogenation requires a metal catalyst. Hydrogenation can, however, proceed from somehydrogen donors without catalysts, illustrative hydrogen donors being diimide and aluminium isopropoxide. Somemetal-free catalytic systems have been investigated in academic research. One such system for reduction of ketones

consists of tert-butanol and potassium tert-butoxide and very high temperatures.[24] The reaction depicted belowdescribes the hydrogenation of benzophenone:

A chemical kinetics study[25] found this reaction is first-order in all three reactants suggesting a cyclic 6-memberedtransition state.

en.wikipedia.org/wiki/Hydrogenation 9/12

Another system for metal-free hydrogenation is based on the phosphine-borane, compound 1, which has been calleda frustrated Lewis pair. It reversibly accepts dihydrogen at relatively low temperatures to form the phosphonium

borate 2 which can reduce simple hindered imines.[26]

The reduction of nitrobenzene to aniline has been reported to be catalysed by fullerene, its mono-anion, atmospheric

hydrogen and UV light.[27]

Equipment used for hydrogenation

Today's bench chemist has three main choices of hydrogenation equipment:

Batch hydrogenation under atmospheric conditionsBatch hydrogenation at elevated temperature and/or pressure

Flow hydrogenation

Batch hydrogenation under atmospheric conditions

The original and still a commonly practised form of hydrogenation in teaching laboratories, this process is usuallyeffected by adding solid catalyst to a round bottom flask of dissolved reactant which has been evacuated usingnitrogen or argon gas and sealing the mixture with a penetrable rubber seal. Hydrogen gas is then supplied from aH2-filled balloon. The resulting three phase mixture is agitated to promote mixing. Hydrogen uptake can be

monitored, which can be useful for monitoring progress of a hydrogenation. This is achieved by either using agraduated tube containing a coloured liquid, usually aqueous copper sulfate or with gauges for each reaction vessel.

Batch hydrogenation at elevated temperature and/or pressure

Since many hydrogenation reactions such as hydrogenolysis of protecting groups and the reduction of aromaticsystems proceed extremely sluggishly at atmospheric temperature and pressure, pressurised systems are popular. Inthese cases, catalyst is added to a solution of reactant under an inert atmosphere in a pressure vessel. Hydrogen isadded directly from a cylinder or built in laboratory hydrogen source, and the pressurized slurry is mechanicallyrocked to provide agitation, or a spinning basket is used. Heat may also be used, as the pressure compensates forthe associated reduction in gas solubility.

Flow hydrogenation

en.wikipedia.org/wiki/Hydrogenation 10/12

Flow hydrogenation has become a popular technique at the bench and increasingly the process scale. This techniqueinvolves continuously flowing a dilute stream of dissolved reactant over a fixed bed catalyst in the presence ofhydrogen. Using established HPLC technology, this technique allows the application of pressures from atmosphericto 1,450 psi (100 bar). Elevated temperatures may also be used. At the bench scale, systems use a range of pre-packed catalysts which eliminates the need for weighing and filtering pyrophoric catalysts.

Industrial reactors

Catalytic hydrogenation is done in a tubular plug-flow reactor (PFR) packed with a supported catalyst. Thepressures and temperatures are typically high, although this depends on the catalyst. Catalyst loading is typically muchlower than in laboratory batch hydrogenation, and various promoters are added to the metal, or mixed metals areused, to improve activity, selectivity and catalyst stability. The use of nickel is common despite its low activity, due toits low cost compared to precious metals.

Gas Liquid Induction Reactors (Hydrogenator) are also used for carrying out catalytic hydrogenation.[28]

See also

Carbon neutral fuel

Dehydrogenation

Transfer hydrogenationHydrogenolysis

Hydrodesulfurization, hydrotreater and oil desulfurizationTimeline of hydrogen technologies

Josiphos ligands

References

1. ^ Hudlický, Miloš (1996). Reductions in Organic Chemistry. Washington, D.C.: American Chemical Society. p. 429.ISBN 0-8412-3344-6.

2. ^ Catalytic Hydrogenation of Maleic Acid at Moderate Pressures A Laboratory Demonstration Kwesi Amoa 1948

Journal of Chemical Education • Vol. 84 No. 12 December 2007

3. ^ Advanced Organic Chemistry Jerry March 2nd Edition

4. ^ D.R.Patel, Hydrogenation of nitrobenzene using polymer bound Ru(III) complexes as catalyst, Ind. Jr. of Chem.Tech., 7, 2000, 280

5. ^ D. R. Patel, Hydrogenation of nitrobenzene using polymer anchored Pd(II) complexes as catalyst. J of MolecularCatalysis. 130, 1998, 57

6. ^ C. F. H. Allen and James VanAllan (1955), "m-Toylybenzylamine"

(http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0827), Org. Synth.; Coll. Vol. 3: 827

7. ^ A. B. Mekler, S. Ramachandran, S. Swaminathan, and Melvin S. Newman (1973), "2-Methyl-1,3-Cyclohexanedione" (http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV5P0567), Org. Synth.; Coll.

Vol. 5: 743

8. ^ S. Robert E. Ireland and P. Bey (1988), "Homogeneous Catalytic Hydrogenation: Dihydrocarvone"

(http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV6P0459), Org. Synth.; Coll. Vol. 6: 459

9. a b Mallat, T.; Orglmeister, E.; Baiker, A. (2007). "Asymmetric Catalysis at Chiral Metal Surfaces". Chemical

Reviews 107 (11): 4863–90. doi:10.1021/cr0683663 (http://dx.doi.org/10.1021%2Fcr0683663). PMID 17927256(//www.ncbi.nlm.nih.gov/pubmed/17927256).

10. ^ H. Lindlar and R. Dubuis (1973), "Palladium Catalyst for Partial Reduction of Acetylenes"

(http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV5P0880), Org. Synth.; Coll. Vol. 5: 880

a b Paul N. Rylander, "Hydrogenation and Dehydrogenation" in Ullmann's Encyclopedia of Industrial Chemistry,

en.wikipedia.org/wiki/Hydrogenation 11/12

11. a b Paul N. Rylander, "Hydrogenation and Dehydrogenation" in Ullmann's Encyclopedia of Industrial Chemistry,Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a13 487 (http://dx.doi.org/10.1002%2F14356007.a13+487)

12. ^ van Es, T.; Staskun, B. "Aldehydes from Aromatic Nitriles: 4-Formylbenzenesulfonamide" Org. Syn., Coll. Vol. 6,p. 631 (1988). (Article (http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0631))

13. ^ Navarro, Daniela Maria do Amaral Ferraz; Navarro, Marcelo (2004). "Catalytic Hydrogenation of Organic

Compounds without H2 Supply: An Electrochemical System". Journal of Chemical Education 81 (9): 1350.doi:10.1021/ed081p1350 (http://dx.doi.org/10.1021%2Fed081p1350).

14. ^ Kubas, G. J., "Metal Dihydrogen and σ-Bond Complexes", Kluwer Academic/Plenum Publishers: New York, 2001

15. ^ Gallezot, Pierre. "Hydrogenation - Heterogeneous" in Encyclopedia of Catalysis, Volume 4, ed. Horvath, I.T., JohnWiley & Sons, 2003.

16. ^ Horiuti, Iurô; Polanyi, M. (1934). "Exchange reactions of hydrogen on metallic catalysts". Transactions of the

Faraday Society 30: 1164. doi:10.1039/TF9343001164 (http://dx.doi.org/10.1039%2FTF9343001164).

17. ^ Johannes G. de Vries, Cornelis J. Elsevier, eds. The Handbook of Homogeneous Hydrogenation Wiley-VCH,Weinheim, 2007. ISBN 978-3-527-31161-3

18. ^ Ian P. Freeman "Margarines and Shortenings" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_145 (http://dx.doi.org/10.1002%2F14356007.a16_145)

19. ^ "Deadly fats: why are we still eating them?" (http://www.independent.co.uk/life-style/health-and-wellbeing/healthy-living/deadly-fats-why-are-we-still-eating-them-843400.html). The Independent. 2008-06-10. Retrieved 2008-06-16.

20. ^ "New York City passes trans fat ban" (http://www.msnbc.msn.com/id/16051436/). msnbc. 2006-12-05. Retrieved2010-01-09.

21. ^ http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1922/44/i06/f-pdf/f_ja01427a021.pdf

22. ^ C. Pettinari, F. Marchetti, D. Martini "Metal Complexes as Hydrogenation Catalysts" Comprehensive CoordinationChemistry II, 2004, volume 9. pp. 75–139. doi:10.1016/B0-08-043748-6/09125-8 (http://dx.doi.org/10.1016%2FB0-08-043748-6%2F09125-8)

23. ^ Ngai, Ming-Yu; Kong, Jong-Rock; Krische, Michael J. (2007). "Hydrogen-Mediated C−C Bond Formation: A

Broad New Concept in Catalytic C−C Coupling1". The Journal of Organic Chemistry 72 (4): 1063–72.doi:10.1021/jo061895m (http://dx.doi.org/10.1021%2Fjo061895m). PMID 17288361(//www.ncbi.nlm.nih.gov/pubmed/17288361).

24. ^ Walling, Cheves.; Bollyky, Laszlo. (1964). "Homogeneous Hydrogenation in the Absence of Transition-Metal

Catalysts". Journal of the American Chemical Society 86 (18): 3750. doi:10.1021/ja01072a028(http://dx.doi.org/10.1021%2Fja01072a028).

25. ^ Berkessel, Albrecht; Schubert, Thomas J. S.; Müller, Thomas N. (2002). "Hydrogenation without a Transition-Metal Catalyst: On the Mechanism of the Base-Catalyzed Hydrogenation of Ketones". Journal of the American

Chemical Society 124 (29): 8693–8. doi:10.1021/ja016152r (http://dx.doi.org/10.1021%2Fja016152r).PMID 12121113 (//www.ncbi.nlm.nih.gov/pubmed/12121113).

26. ^ Chase, Preston A.; Welch, Gregory C.; Jurca, Titel; Stephan, Douglas W. (2007). "Metal-Free Catalytic

Hydrogenation". Angewandte Chemie International Edition 46 (42): 8050. doi:10.1002/anie.200702908(http://dx.doi.org/10.1002%2Fanie.200702908).

27. ^ Li, Baojun; Xu, Zheng (2009). "A Nonmetal Catalyst for Molecular Hydrogen Activation with Comparable Catalytic

Hydrogenation Capability to Noble Metal Catalyst". Journal of the American Chemical Society 131 (45): 16380–2.doi:10.1021/ja9061097 (http://dx.doi.org/10.1021%2Fja9061097). PMID 19845383(//www.ncbi.nlm.nih.gov/pubmed/19845383).

28. ^ Joshi, J.B.; Pandit, A.B.; Sharma, M.M. (1982). "Mechanically agitated gas-liquid reactors". Chemical Engineering

Science 37 (6): 813. doi:10.1016/0009-2509(82)80171-1 (http://dx.doi.org/10.1016%2F0009-2509%2882%2980171-1).

Further reading

Jang ES, Jung MY, Min DB (2005). "Hydrogenation for Low Trans and High Conjugated Fatty Acids"(http://members.ift.org/NR/rdonlyres/27B49B9B-EA63-4D73-BAB4-42FEFCD72C68/0/crfsfsv4n1p00220030ms20040577.pdf) (PDF). Comprehensive Reviews in Food

Science and Food Safety 1.

en.wikipedia.org/wiki/Hydrogenation 12/12

examples of hydrogenation from Organic Syntheses:

Organic Syntheses, Coll. Vol. 7, p.226 (1990). (http://orgsynth.org/orgsyn/pdfs/CV7P0226.pdf)Organic Syntheses, Coll. Vol. 8, p.609 (1993). (http://orgsynth.org/orgsyn/pdfs/CV8P0609.pdf)Organic Syntheses, Coll. Vol. 5, p.552 (1973). (http://orgsynth.org/orgsyn/pdfs/CV5P0552.pdf)

Organic Syntheses, Coll. Vol. 3, p.720 (1955). (http://orgsynth.org/orgsyn/pdfs/CV4P0603.pdf)Organic Syntheses, Coll. Vol. 6, p.371 (1988). (http://orgsynth.org/orgsyn/pdfs/CV6P0371.pdf)

early work on transfer hydrogenation: Davies, R. R.; Hodgson, H. H. J. Chem. Soc. 1943, 281. Leggether,B. E.; Brown, R. K. Can. J. Chem. 1960, 38, 2363. Kuhn, L. P. J. Am. Chem. Soc. 1951, 73, 1510.

Fred A. Kummerow (2008). Cholesterol Won't Kill You, But Trans Fat Could. Trafford.ISBN 142513808 Check |isbn= value (help).

External links

"The Magic of Hydro" Popular Mechanics, June 1931, pp. 107–109 (http://books.google.com/books?id=4OIDAAAAMBAJ&pg=-PA107&dq=Popular+Science+1930+plane+%22Popular+Mechanics%22&hl=en&ei=NCt4TtDKIqnf0QG

65_3-Cw&sa=X&oi=book_result&ct=book-thumbnail&resnum=6&ved=0CEIQ6wEwBTge#v=onepage&q&f=true) – early article for the general publicon hydrogenation of oil produces in the 1930s

Retrieved from "http://en.wikipedia.org/w/index.php?title=Hydrogenation&oldid=575071822"Categories: Addition reactions Homogeneous catalysis Chemical engineering Industrial processes Hydrogen

Oil refining Oil shale technology Synthetic fuel technologies

This page was last modified on 30 September 2013 at 00:24.Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By

using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.