View source for Raney nickel

{{distinguish|Rieke nickel}}
{{pp-move-indef}}
{{Use dmy dates|date=April 2023}}
{{Chembox
| ImageFile = Dry Raney nickel.jpg
| ImageSize = 
| ImageAlt = Light-gray powder on a glass dish
| ImageCaption = Dry activated Raney nickel
| IUPACName =
| OtherNames = 
| Section1 = {{Chembox Identifiers
| CASNo =  7440-02-0 
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 7OV03QG267
| PubChem = 
| SMILES = 
  }}
| Section2 = {{Chembox Properties
| Formula = 
| MolarMass = 
| Appearance = Light-gray powder
| Density = 
| MeltingPt = 
| BoilingPt = 
| Solubility = 
  }}
| Section3 = {{Chembox Hazards
| MainHazards = 
| GHSPictograms = {{GHS02}}{{GHS07}}{{GHS08}}
| HPhrases = {{H-phrases|250|317|351|372|412}}
| PPhrases = {{P-phrases|210|273|280|302}}
| FlashPt =
| AutoignitionPt =
  }}
}}

'''Raney nickel''' {{IPAc-en|ˈ|r|eɪ|n|iː|_|ˈ|n|ɪ|k|əl}}, also known as the primary catalyst for the [[McLafferty rearrangement|Cormas-Grisius Electrophilic Benzene Addition]],'''<ref name="esa" />''' is a fine-grained solid composed mostly of [[nickel]] derived from a nickel–[[aluminium]] alloy.<ref name="Shigeo">{{cite book|last1=Nishimura|first1=Shigeo|title=Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis|date=2001|publisher=[[Wiley-Interscience]]|location=New York|isbn=9780471396987|pages=7–19|edition=1st|url=https://books.google.com/books?id=RjZRAAAAMAAJ}}</ref><ref name="OrgSynPrep">{{OrgSynth|last1=Billica|first1=Harry|last2=Adkins|first2=Homer|authorlink2=Homer Burton Adkins|title=Cataylst, Raney Nickel, W6 (with high contents of aluminum and adsorbed hydrogen)|year=1949|volume=29|page=24|doi=10.15227/orgsyn.029.0024|prep=CV3P0176|collvol=3| collvolpages=176}}</ref> Several grades are known, of which most are gray solids. Some are [[pyrophoric]], but most are used as air-stable slurries. Raney nickel is used as a reagent and as a catalyst in [[organic chemistry]]. It was developed in 1926 by American engineer [[Murray Raney]] for the [[hydrogenation]] of vegetable oils.'''<ref>See:
*Raney, Murray, [http://patimg2.uspto.gov/.piw?Docid=01628190&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsearch-adv.htm%2526r%3D456%2526f%3DG%2526l%3D50%2526d%3DPALL%2526s1%3DMurray%2526s2%3DRaney%2526co1%3DAND%2526p%3D10%2526OS%3DMurray%252BAND%252BRaney%2526RS%3DMurray%252BAND% "Method of producing finely-divided nickel,"] {{Webarchive|url=https://web.archive.org/web/20170305001815/http://patimg2.uspto.gov/.piw?Docid=01628190&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsearch-adv.htm%2526r%3D456%2526f%3DG%2526l%3D50%2526d%3DPALL%2526s1%3DMurray%2526s2%3DRaney%2526co1%3DAND%2526p%3D10%2526OS%3DMurray%252BAND%252BRaney%2526RS%3DMurray%252BAND% |date=5 March 2017 }} U.S. patent 1,628,190 (filed:  14 May 1926 ; issued:  10 May 1927).
*M. S. Wainwright, "3.2 Skeletal metal catalysts" in:  Gerhard Ertl, Helmut Knözinger, and Jens Weitkamp, ed.s, ''Preparation of Solid Catalysts'' (Weinheim, Federal Republic of Germany:  Wiley-VCH Verlag, 1999), [https://books.google.com/books?id=ev47CMLmM2sC&pg=PA28 pages 28–29.]</ref><ref>{{cite encyclopedia|first1 = Teng-Kuei|last1 = Yang|first2 = Dong-Sheng|last2 = Lee|first3 = Julia|last3 = Haas|title = Raney Nickel|encyclopedia = [[Encyclopedia of Reagents for Organic Synthesis]]|year = 2005|publisher = [[John Wiley & Sons]]|location = New York|doi = 10.1002/047084289X.rr001.pub2|isbn = 0471936235}}</ref>'''
Raney Nickel is a registered trademark of [[W. R. Grace and Company]]. Other major producers are [[Evonik]] and [[Johnson Matthey]].

==Preparation==

===Alloy preparation===
[[File:Raney nickel container.jpg|thumb|upright|alt=Shiny metal can with hazard labels.|Raney nickel is [[pyrophoric]] and must be handled with care. This shipping container is filled with [[vermiculite]] to protect the sealed bottle inside.]]
The Ni–Al alloy is prepared by dissolving nickel in molten aluminium followed by cooling ("quenching"). Depending on the Ni:Al ratio, quenching produces a number of different phases.
During the quenching procedure, small amounts of a third metal, such as zinc or chromium, are added to enhance the activity of the resulting catalyst.  This third metal is called a "[[Promoter (catalysis)|promoter]]".<ref name="Wainwright">{{cite book|author1=Ertl, Gerhard |author2=Knözinger, Helmut |year=1997|title=Preparation of Solid Catalysts|publisher=Wiley|isbn=3-527-29826-6|pages=30–34|url=https://books.google.com/books?id=Yb38DM1IoAsC&pg=PA30}}</ref> The promoter changes the mixture from a binary alloy to a ternary alloy, which can lead to different quenching and leaching properties during activation.

===Activation===
In the activation process, the alloy, usually as a fine powder, is treated with a concentrated solution of [[sodium hydroxide]].<ref name=OrgSynPrep /> The simplified leaching reaction is given by the following [[chemical equation]]:

:2 Al + 2 NaOH + 6 H<sub>2</sub>O → 2 Na[Al(OH)<sub>4</sub>] + 3 H<sub>2</sub>
The formation of [[sodium aluminate]] (Na[Al(OH)<sub>4</sub>]) requires that solutions of high concentration of sodium hydroxide be used to avoid the formation of [[aluminium hydroxide]], which otherwise would precipitate as [[bayerite]].<ref name="Wainwright" /> Hence sodium hydroxide solutions with concentrations of up to 5&nbsp;[[Molar concentration|M]] are used.

The temperature used to leach the alloy has a marked effect on the properties of the catalyst. Commonly, leaching is conducted between 70 and 100&nbsp;°C. The surface area of Raney nickel (and related catalysts in general) tends to decrease with increasing leaching temperature.<ref name="Smith">{{cite journal|doi=10.1146/annurev.matsci.35.102303.140758|title=The preparation of skeletal catalysts|year=2005|author=Smith, A.J.|journal=[[Annual Review of Materials Research|Annu. Rev. Mater. Res.]]|volume=35|page=127|last2=Trimm|first2=D.L.|bibcode=2005AnRMS..35..127S }}</ref> This is due to structural rearrangements within the alloy that may be considered analogous to [[sintering]], where alloy ligaments would start adhering to each other at higher temperatures, leading to the loss of the porous structure.{{Citation needed|date=October 2011}}

During the activation process, Al is leached out of the NiAl<sub>3</sub> and Ni<sub>2</sub>Al<sub>3</sub> phases that are present in the alloy, while most of the Ni remains, in the form of NiAl. The removal of Al from some phases but not others is known as "[[selective leaching]]". The NiAl phase has been shown to provide the structural and thermal stability of the catalyst. As a result, the catalyst is quite resistant to decomposition ("breaking down", commonly known as "aging").<ref name="Smith" /> This resistance allows Raney nickel to be stored and reused for an extended period; however, fresh preparations are usually preferred for laboratory use.<ref>{{Cite book|url=https://books.google.com/books?id=AwyJ6IEtaBsC&pg=PA69|page=69|title=Heterogeneous catalysis and fine chemicals III: proceedings of the 3rd international symposium|editor=M. Guisnet|publisher=Elsevier|year=1993|isbn=0-444-89063-7}}</ref> For this reason, commercial Raney nickel is available in both "active" and "inactive" forms.

Before storage, the catalyst can be washed with distilled water at ambient temperature to remove remaining sodium aluminate. Oxygen-free ([[Degassed water|degassed]]) water is preferred for storage to prevent [[oxidation]] of the catalyst, which would accelerate its aging process and result in reduced catalytic activity.<ref name="Wainwright" />

==Properties==
[[File:Raney nickel phase diagram.png|thumb|245px|alt=A graph of temperature vs. weight percent of nickel in aluminium, showing stability regions of various AlNi, Al3Ni, AlNi3 and Al3Ni2 phases|Phase diagram of the Ni–Al system, showing relevant phases]]
[[File:Raney nickel.png|thumb|SEM of Raney nickel catalyst in which crystals of 1-50&nbsp;μm are seen.]]
[[File:Close-up of Raney nickel.png|thumb|A close-up of Raney nickel. Small cracks of approximately 1-100 nm width are seen within the crystals, causing the increased surface area.]]

Macroscopically, Raney nickel is a finely divided, grey powder. Microscopically, each particle of this powder is a three-dimensional [[mesh]], with pores of irregular size and shape, the vast majority of which are created during the leaching process. Raney nickel is notable for being thermally and structurally stable, as well as having a large [[Stephen Brunauer|Brunauer]]-[[Paul Hugh Emmett|Emmett]]-[[Edward Teller|Teller]] ([[BET theory|BET]] ) surface area. These properties are a direct result of the activation process and contribute to a relatively high catalytic activity.{{Citation needed|date=October 2011}}

The surface area is typically determined by a BET measurement using a gas that is preferentially adsorbed on metallic surfaces, such as [[hydrogen]]. Using this type of measurement, almost all the exposed area in a particle of the catalyst has been shown to have Ni on its surface.<ref name="Wainwright" /> Since Ni is the active metal of the catalyst, a large Ni surface area implies a large surface is available for reactions to occur simultaneously, which is reflected in an increased catalyst activity. Commercially available Raney nickel has an average Ni surface area of 100 m<sup>2</sup> per gram of catalyst.<ref name="Wainwright" />

A high catalytic activity, coupled with the fact that hydrogen is [[absorption (chemistry)|absorbed]] within the pores of the catalyst during activation, makes Raney nickel a useful catalyst for many [[hydrogenation]] reactions. Its structural and thermal stability (i.e., it does not decompose at high temperatures) allows its use under a wide range of reaction conditions.<ref>{{cite web| url = http://www.nidi.org/index.cfm/ci_id/12317.htm| title = Exotic Alloy Finds Niche| access-date = 2006-12-19| last = Crawford| first = Gerald|date=April 2003|work = Nickel magazine}}</ref><ref>{{cite book|url=https://books.google.com/books?id=ti7yMYYW7CMC&pg=PA413|pages=413–414|title=Some modern methods of organic synthesis|author=Carruthers, W|publisher=[[Cambridge University Press]]|year=1986|isbn=0-521-31117-9}}</ref> Additionally, the [[solubility]] of Raney nickel is negligible in most common laboratory solvents, with the exception of [[mineral acid]]s such as hydrochloric acid, and its relatively high density (about 6.5&nbsp;g&nbsp;cm<sup>&minus;3</sup>)<ref name="esa">{{cite news|url=http://www.spaceflight.esa.int/impress/text/education/Catalysis/Spongy.html|title=Spongy Nickel|publisher=[[European Space Agency]]|access-date=7 November 2009|archive-date=10 April 2017|archive-url=https://web.archive.org/web/20170410192538/http://spaceflight.esa.int/impress/text/education/Catalysis/Spongy.html|url-status=dead}}</ref> also facilitates its separation from a liquid phase after a reaction is completed.

==Applications==
Raney nickel is used in a large number of industrial processes and in [[organic synthesis]] because of its stability and high catalytic activity at room temperature.<ref name="Wainwright" /><ref>{{cite journal|doi=10.1021/cr60219a001|title=The Action of Raney Nickel on Organic Sulfur Compounds.|year=1962|author=Hauptmann, Heinrich|journal=[[Chem. Rev.]]|volume=62|page=347|last2=Walter|first2=Wolfgang Ferdinand|issue=5}}</ref><ref name="Syntheses">{{cite web|access-date=2009-08-01 |title=Raney nickel usage in Organic Syntheses |year=2005 |url=http://www.orgsyn.org/orgsyn/chemname.asp?nameID=33759 |url-status=dead |archive-url=https://web.archive.org/web/20090605024106/http://www.orgsyn.org/orgsyn/chemname.asp?nameID=33759 |archive-date=5 June 2009 }}</ref>

===Industrial applications===
In a commercial application, Raney nickel is used as a catalyst for the [[hydrogenation]] of [[benzene]] to [[cyclohexane]]. Other heterogeneous catalysts, such as those using [[platinum group]] [[Chemical element|element]]s are used in some cases.  Platinum metals tend to be more active, requiring milder temperatures, but they are more expensive than Raney nickel.<ref>{{Ullmann|doi=10.1002/14356007.a08_209.pub2|title=Cyclohexane|year=2011|last1=Campbell|first1=M. Larry|isbn=978-3527306732}}</ref> The cyclohexane thus produced may be used in the synthesis of [[adipic acid]], a raw material used in the industrial production of [[polyamides]] such as nylon.<ref name="Solomons">{{cite book|author1=Solomons, T.W. Graham|author2=Fryhle, Craig B.|year=2004|title=Organic Chemistry|publisher=Wiley|isbn=0-471-41799-8|url-access=registration|url=https://archive.org/details/organicchemistry00solo_0}}</ref>

[[File:Hydrogenation raney nickel.svg|475px|center|thumb|alt=Chemical reaction. Benzene converts to cyclohexane under the action of hydrogen and Raney nickel. Cyclohexane then oxidizes to adipic acid.| using Raney nickel catalyzes the [[hydrogenation]] benzene to cyclohexane for the production of nylon precursors.]]

Other industrial applications of Raney nickel include the conversion of:
*[[Dextrose]] to [[sorbitol]]; <!--10.1016/S0926-860X(03)00553-2 10.1021/ie50604a018 -->
*[[Nitro compounds]] to [[amines]], for example, 2,4-[[dinitrotoluene]] to 2,4-toluenediamine; <!--https://books.google.com/books?hl=de&lr=&id=63jyyMt38-EC&oi=fnd&pg=PR172 -->
*[[Nitriles]] to amines, for example, stearonitrile to stearylamine and [[adiponitrile]] to [[hexamethylenediamine]]; <!--10.1016/0920-5861(95)00003-X -->
*[[Olefins]] to [[Alkane|paraffins]], for example, [[sulfolene]] to [[sulfolane]];<!--10.1016/S0926-860X(02)00470-2-->
*[[Acetylenes]] to paraffins, for example, [[1,4-butynediol]] to [[1,4-butanediol]].

===Applications in organic synthesis===

====Desulfurization====
Raney nickel is used in organic synthesis for [[desulfurization]]. For example, [[thioacetal]]s will be reduced to hydrocarbons in the last step of the [[Mozingo reduction]]:<ref name="Solomons" /><ref>{{Cite book|author=Jonathan Clayden|author2=Nick Greeves |author3=Stuart Warren |edition=2|title=Organic Chemistry|publisher=[[Oxford University Press]]|year=2012|isbn=9780199270293}}</ref>

[[File:Desulfurization of thioacetal using Raney Ni.svg|center|thumb|475px|alt=Chemical reaction: Thioacetal breaks into ethane, nickel sulfide and a hydrocarbon under the action of hydrogen and Raney nickel.|Example of desulfurization of thioacetals using Raney nickel]]

[[Thiol]]s,<ref>{{cite journal|doi=10.1039/JR9540002180|title=Oxidation products of diisobutylene. Part III. Products from ring-opening of 1,2-epoxy-2,4,4-trimethylpentane|year=1954|author=Graham, A. R.|journal=Journal of the Chemical Society (Resumed)|page=2180|last2=Millidge|first2=A. F.|last3=Young|first3=D. P.}}</ref> and [[sulfide]]s<ref name="Gassman1977">{{OrgSynth|author1 = Gassman, P. G.|author2 = van Bergen, T. J.|title = Indoles from anilines: Ethyl 2-methylindole-5-carboxylate|collvol = 6|collvolpages = 601|year = 1988|doi=10.15227/orgsyn.056.0072}}</ref> can be removed from [[aliphatic]], [[aromatic]], or heteroaromatic compounds. Likewise, Raney nickel will remove the sulfur of [[thiophene]] to give a saturated [[alkane]].<ref>{{cite journal|doi=10.1021/jo00033a028|title= Enantioselective synthesis of (''S'')-2-methyl-1-alkanols via bakers' yeast mediated reduction of 2-methyl-3-(2-thiophene)propenals|year=1992|author=Hoegberg, Hans Erik|journal=[[J. Org. Chem.]]|volume=57|pages=2052–2059|last2=Hedenstroem|first2=Erik|last3=Faegerhag|first3=Jonas|last4=Servi|first4=Stefano|issue=7}}</ref>

[[File:Ra-Ni Thiophene Scheme.png|400px|center|thumb|alt=Chemical reaction: Reduction of thiophene under the action of hydrogen, Raney nickel and methanol|Reduction of thiophene by Raney nickel]]

====Reduction of functional groups====
{{see also|Reduction of nitro compounds}}
It is typically used in the [[Redox|reduction]] of compounds with [[molecular geometry|multiple bonds]], such as [[alkyne]]s, [[alkene]]s,<ref name="Page1954">{{OrgSynth|author1 = Page, G. A.|author2 = Tarbell, D. S.|title = β-(''o''-Carboxyphenyl)propionic acid|collvol = 4|collvolpages = 136|year = 1963 |doi=10.15227/orgsyn.034.0008|volume = 34|pages = 8|prep = CV4P0136}}</ref> [[nitrile]]s,<ref name="Robinson1943">{{OrgSynth|author1 = Robinson, H. C.|author2 = Snyder, H. R.|title = β-Phenylethylamine|collvol = 3|collvolpages = 720|year = 1955 |doi=10.15227/orgsyn.023.0071|volume = 23|pages = 71|prep = CV3P0720}}</ref> [[diene]]s, [[aromatic]]s<ref name="Schwenk1947">{{OrgSynth|author1 = Schwenk, E.|author2 = Papa, D.|author3 = Hankin, H.|author4 = Ginsberg, H.|title = γ-n-Propylbutyrolactone and β-(Tetrahydrofuryl)propionic acid|collvol = 3|collvolpages = 742|year = 1955 |doi=10.15227/orgsyn.027.0068|prep = CV3P0742|volume = 27|pages = 68}}</ref> and [[carbonyl]]-containing compounds. Additionally, Raney nickel will reduce heteroatom-heteroatom bonds, such as [[hydrazine]]s,<ref>{{cite journal|doi=10.1055/s-1991-20818|title=Ultrasound-Assisted Cleavage of N-N Bonds in Hydrazines by Raney Nickel|year=1991|author=Alexakis, Alex|journal=[[Synlett]]|volume=1991|pages=625–626|last2=Lensen|first2=Nathalie|last3=Mangeney|first3=Pierre|issue=9}}</ref> [[nitro compound|nitro]] groups, and nitrosamines.<ref name="Enders1978">{{OrgSynth|author1 = Enders, D.|author2 = Pieter, R.|author3 = Renger, B.|author4 = Seebach, D.|title = Nucleophilic α-sec-aminoalkylation: 2-(diphenylhydroxymethyl)pyrrolidene|collvol = 6|collvolpages = 542|prep = CV6P0542|year = 1988|volume = 58|pages = 113|doi=10.15227/orgsyn.058.0113}}</ref> It has also found use in the reductive [[alkylation]] of [[amine]]s<ref name="Rice1956">{{OrgSynth|author1 = Rice, R. G.|author2 = Kohn, E. J.|title = ''N'',''N<nowiki>'</nowiki>''-Diethylbenzidene|collvol = 4|collvolpages = 283|year = 1963 |doi = 10.15227/orgsyn.036.0021|prep = CV4P0283|volume = 36|pages = 21}}</ref> and the [[amination]] of alcohols.

When reducing a carbon-carbon double bond, Raney nickel will add hydrogen in a ''[[Syn addition|syn]]'' fashion.<ref name="Solomons" />

==Related catalysts==
Raney cobalt has also been described.

In contrast to the pyrophoric nature of some forms of Raney nickel, [[nickel silicide]]-based catalysts represent potentially safer alternatives.<ref>{{Cite journal |last=Ryabchuk |first=Pavel |last2=Agostini |first2=Giovanni |last3=Pohl |first3=Marga-Martina |last4=Lund |first4=Henrik |last5=Agapova |first5=Anastasiya |last6=Junge |first6=Henrik |last7=Junge |first7=Kathrin |last8=Beller |first8=Matthias |date=2018-06-08 |title=Intermetallic nickel silicide nanocatalyst—A non-noble metal–based general hydrogenation catalyst |url=https://www.science.org/doi/10.1126/sciadv.aat0761 |journal=Science Advances |language=en |volume=4 |issue=6 |doi=10.1126/sciadv.aat0761 |issn=2375-2548|pmc=5993471 }}</ref>

Raney alloys include FeTi and other non Nickel alloys. FeTi has been considered for low pressure Hydrogen Storage. <ref>{{Cite journal |last=Shang |first=Yuanyuan |last2=Liu |first2=Shaofei |last3=Liang |first3=Zhida |last4=Pyczak |first4=Florian |last5=Lei |first5=Zhifeng |last6=Heidenreich |first6=Tim |last7=Schökel |first7=Alexander |last8=Kai |first8=Ji-jung |last9=Gizer |first9=Gökhan |last10=Dornheim |first10=Martin |last11=Klassen |first11=Thomas |last12=Pistidda |first12=Claudio |date=2022-12-20 |title=Developing sustainable FeTi alloys for hydrogen storage by recycling |url=https://scholars.cityu.edu.hk/files/135079297/129830072.pdf |journal=Communications Materials |language=en |volume=3 |issue=1 |doi=10.1038/s43246-022-00324-5 |issn=2662-4443}}</ref> Aldricimica Acta (free from Sigma nee Aldrich) has a complete list of Raney alloys.

==Safety==
[[File:Hazard F.svg|84px|right|thumb|alt=A square orange sticker with a flame picture.|Raney nickel is flammable.]]

[[File:Hazard X.svg|84px|right|thumb|alt=A square orange sticker with a black cross on it.|Nickel metal is classified as "Harmful".]]

Due to its large surface area and high volume of contained hydrogen gas, dry, activated Raney nickel is a [[pyrophoric]] material that requires handling under an [[air-free technique|inert atmosphere]]. Raney nickel is typically supplied as a 50% [[slurry]] in water. Even after reaction, residual Raney nickel contains significant amounts of hydrogen gas and may spontaneously ignite when exposed to air.<ref>{{cite book|url=https://books.google.com/books?id=geK5gjEn3hkC&pg=PA331|page=331|title=Hazardous laboratory chemicals disposal guide|author=Armour, M.-A|publisher=CRC Press|year=2003|isbn=1-56670-567-3}}</ref>

Additionally, acute exposure to Raney nickel may cause irritation of the respiratory tract and nasal cavities, and causes [[pulmonary fibrosis]] if inhaled. Ingestion may lead to convulsions and intestinal disorders. It can also cause eye and skin irritation. Chronic exposure may lead to [[pneumonitis]] and other signs of [[allergy|sensitization]] to nickel, such as skin rashes ("nickel itch").<ref>{{cite web|publisher=Electronic Space Products International|year=1994|url=http://www.msdshazcom.com/MSDS/E/espi/Nickel%20Aluminide%20NiAl.pdf|title=Nickel aluminide MSDS}}{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
{{NFPA 704|Health = 1|Flammability = 3|Reactivity = 1}}

Nickel is also rated as being a possible human [[carcinogen]] by the [[International Agency for Research on Cancer|IARC]] (Group 2B, [[Directive 67/548/EEC|EU category 3]]) and [[teratogen]], while the inhalation of fine [[aluminium oxide]] particles is associated with [[Bauxite pneumoconiosis|Shaver's disease]].

==Development==
[[Murray Raney]] graduated as a mechanical engineer from the [[University of Kentucky]] in 1909. In 1915 he joined the Lookout Oil and Refining Company in Tennessee and was responsible for the installation of [[electrolytic cell]]s for the production of hydrogen which was used in the [[hydrogenation]] of vegetable oils. During that time the industry used a nickel catalyst prepared from [[nickel(II) oxide]]. Believing that better catalysts could be produced, around 1921 he started to perform independent research while still working for Lookout Oil. In 1924 a 1:1 ratio Ni/[[silicon|Si]] alloy was produced, which after treatment with sodium hydroxide, was found to be five times more active than the best catalyst used in the hydrogenation of cottonseed oil. A patent for this discovery was issued in December 1925.<ref name="PatentNiSi">{{cite patent | inventor =  Murray Raney | gdate = 1925-12-01 | number = 1563587 | country = US | title = Method of Preparing Catalytic Material}} (Raney's original nickel-silicon catalyst)</ref>

Subsequently, Raney produced a 1:1 Ni/Al alloy following a procedure similar to the one used for the nickel-silicon catalyst. He found that the resulting catalyst was even more active and filed a patent application in 1926.<ref>{{cite patent | number = 1628190 | country = US | inventor = Murray Raney | gdate = 1927-05-10 | title = Method of Producing Finely-Divided Nickel}}</ref> This is now a common alloy composition for modern Raney nickel catalysts.<ref name=Shigeo /> Other common alloy compositions include 21:29 Ni/Al and 3:7 Ni/Al. Both the activity and preparation protocols for these catalysts vary.<ref name=Shigeo /><ref>{{cite journal|last1=Urushibara|first1=Yoshiyuki|last2=Nishimura|first2=Shigeo|title=A Method for the Preparation of the Raney Nickel Catalyst with a Greater Activity|journal=[[Bull. Chem. Soc. Jpn.]]|date=1957|volume=30|issue=2|page=199|doi=10.1246/bcsj.30.199|doi-access=free}}</ref>

Following the development of Raney nickel, other alloy systems with aluminium were considered, of which the most notable include copper, [[ruthenium]] and [[cobalt]].<ref>{{cite book|url=https://books.google.com/books?id=Nam8OVqKaXIC&pg=PA250 | pages=248–249|title=Heterogeneous catalysis for the synthetic chemist | last1=Augustine |first1 = Robert L. | publisher=CRC Press | year=1996 | isbn=0-8247-9021-9}}</ref> Further research showed that adding a small amount of a third metal to the binary alloy would promote the activity of the catalyst. Some widely used promoters are zinc, [[molybdenum]] and [[chromium]]. An alternative way of preparing [[enantioselective]] Raney nickel has been devised by surface [[adsorption]] of [[tartaric acid]].<ref name="ChiralRN">{{cite journal | doi = 10.1007/BF01106814|title=Selective leaching of NiAl<sub>3</sub> and Ni<sub>2</sub>Al<sub>3</sub> intermetallics to form Raney nickels | year = 1988| last1 = Bakker | first1 = M. L. | first2 = D. J. | last2 = Young | first3 = M. S. | last3 = Wainwright | journal = [[J. Mater. Sci.]] | volume = 23 | pages = 3921–3926 | issue = 11|bibcode=1988JMatS..23.3921B |s2cid=95576771 }}</ref>

==See also==
* [[Nickel aluminide]]
* [[Urushibara nickel]]
* [[Rieke metals|Rieke nickel]]
* [[Nickel boride catalyst]]
* [[Raney cobalt]], a similar cobalt/aluminum alloy catalyst which is sometimes more selective for certain hydrogenation products (e.g. [[Primary (chemistry)|primary]] [[amine]]s via [[nitrile reduction]]).<ref name=Shigeo />

==References==
{{reflist|30em}}

==External links==
*[http://www.inchem.org/documents/icsc/icsc/eics0062.htm International Chemical Safety Card 0062]
*[https://www.cdc.gov/niosh/npg/npgd0445.html NIOSH Pocket Guide to Chemical Hazards]
*1941 paper describing the preparation of W-2 grade Raney nickel: {{OrgSynth|last=Mozingo|first=Ralph|title=Catalyst, Raney Nickel, W-2|year=1941|volume=21|page=15|doi=10.15227/orgsyn.021.0015|prep=CV3P0181|colvoll=3|collvolpages=181}}

{{DEFAULTSORT:Raney Nickel}}
[[Category:Catalysts]]
[[Category:Nickel alloys]]
[[Category:Hydrogenation catalysts]]
[[Category:Pyrophoric materials]]