:Kolbe electrolysis
{{Short description|Organic reaction}}
{{redirect|Kolbe reaction|the carboxylation of phenols|Kolbe–Schmitt reaction}}
{{Use dmy dates|date=April 2024}}
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The Kolbe electrolysis or Kolbe reaction is an organic reaction named after Hermann Kolbe.{{cite journal|doi=10.1039/cs9972600157|title=Trends in Organic Electrosynthesis|journal=Chemical Society Reviews|volume=26|issue=3|pages=157|year=1997|last1=Utley|first1=James}} The Kolbe reaction is formally a decarboxylative dimerisation of two carboxylic acids (or carboxylate ions). The overall reaction is:
:File:Electrólisis de Kolbe.png
If a mixture of two different carboxylates are used, all combinations of them are generally seen as the organic product structures:
: 3 R1COO− + 3 R2COO− → R1−R1 + R1−R2 + R2−R2 + 6 CO2 + 6 e−
The reaction mechanism involves a two-stage radical process: electrochemical decarboxylation gives a radical intermediate, which combine to form a covalent bond.{{cite journal
| title = Electrode Kinetic Aspects of the Kolbe Reaction
| first1 = A. K. |last1= Vijh |first2= B. E. |last2= Conway
| journal = Chem Rev
| year = 1967
| volume = 67
| issue = 6
| pages = 623–664
| doi = 10.1021/cr60250a003}} As an example, electrolysis of acetic acid yields ethane and carbon dioxide:
:CH3COOH → CH3COO− → CH3COO· → CH3· + CO2
:2CH3· → CH3CH3
Another example is the synthesis of 2,7-dimethyl-2,7-dinitrooctane from 4-methyl-4-nitrovaleric acid:{{OrgSynth | title = 2,7-Dimethyl-2,7-dinitrooctane | first1 = W. H. |last1= Sharkey |first2= C. M. |last2= Langkammerer | collvol = 5 | collvolpages = 445 | year = 1973 | prep = cv5p0445}}
:Kolbe electrolysis, synthesis of 2,7-Dimethyl-2,7-dinitrooctane
The Kolbe reaction has also been occasionally used in cross-coupling reactions.
In 2022, it was discovered that the Kolbe electrolysis is enhanced if an alternating square wave current is used instead of a direct current.{{Cite report |url=https://chemrxiv.org/engage/chemrxiv/article-details/635afdb2ca86b81d1ac683f4 |title=Overcoming the Limitations of Kolbe Coupling via Waveform-Controlled Electrosynthesis |last1=Hioki |first1=Yuta |last2=Costantini |first2=Matteo |date=2022-10-31 |publisher=Chemistry |doi=10.26434/chemrxiv-2022-3cj82-v2 |last3=Griffin |first3=Jeremy |last4=Harper |first4=Kaid |last5=Prado Merini |first5=Melania |last6=Nissl |first6=Benedikt |last7=Kawamata |first7=Yu |last8=Baran |first8=Phil}}{{Cite journal |last1=Hioki |first1=Yuta |last2=Costantini |first2=Matteo |last3=Griffin |first3=Jeremy |last4=Harper |first4=Kaid C. |last5=Merini |first5=Melania Prado |last6=Nissl |first6=Benedikt |last7=Kawamata |first7=Yu |last8=Baran |first8=Phil S. |date=2023-04-07 |title=Overcoming the limitations of Kolbe coupling with waveform-controlled electrosynthesis |url=https://www.science.org/doi/10.1126/science.adf4762 |journal=Science |language=en |volume=380 |issue=6640 |pages=81–87 |doi=10.1126/science.adf4762 |pmid=37023204 |issn=0036-8075|url-access=subscription }}
Applications
Kolbe electrolysis has a few industrial applications.{{cite book |doi=10.1002/14356007.a09_183.pub3 |chapter=Electrochemistry |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2009 |last1=Wendt |first1=Hartmut |last2=Vogt |first2=Helmut |last3=Kreysa |first3=Gerhard |last4=m. Kolb |first4=Dieter |last5=e. Engelmann |first5=Gerald |last6=Ziegler |first6=Jörg C. |last7=Goldacker |first7=Hubert |last8=Jüttner |first8=Klaus |last9=Galla |first9=Ulrich |last10=Schmieder |first10=Helmut |last11=Steckhan |first11=Eberhard |isbn=978-3-527-30673-2 }} In one example, sebacic acid has been produced commercially by Kolbe electrolysis of adipic acid.{{cite journal|title=Development of Kolbe Electrosynthesis of Sebacic Acid|last1=Seko|first1=Maomi|last2=Yomiyama|first2=Akira|last3=Isoya|first3=Toshiro|journal=CEER, Chemical Economy & Engineering Review|year=1979|volume=11|number=9|pages=48–50 }}
Kolbe electrolysis has been examined for converting biomass into biodiesel{{Cite journal |last1=Yuan |first1=Gang |last2=Wu |first2=Chan |last3=Zeng |first3=Guorong |last4=Niu |first4=Xiaopo |last5=Shen |first5=Guoqiang |last6=Wang |first6=Li |last7=Zhang |first7=Xiangwen |last8=Luque |first8=Rafael |last9=Wang |first9=Qingfa |date=2020-01-18 |title=Kolbe Electrolysis of Biomass-Derived Fatty Acids Over Pt Nanocrystals in an Electrochemical Cell |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201901443 |journal=ChemCatChem |language=en |volume=12 |issue=2 |pages=642–648 |doi=10.1002/cctc.201901443 |issn=1867-3880|url-access=subscription }}{{Cite journal |last1=Ho |first1=Calvin K. |last2=McAuley |first2=Kimberley B. |last3=Peppley |first3=Brant A. |date=2019-10-01 |title=Biolubricants through renewable hydrocarbons: A perspective for new opportunities |url=https://www.sciencedirect.com/science/article/pii/S1364032119304691 |journal=Renewable and Sustainable Energy Reviews |volume=113 |pages=109261 |doi=10.1016/j.rser.2019.109261 |issn=1364-0321|url-access=subscription }} and for grafting of carbon electrodes.{{Cite journal |last1=Andrieux |first1=Claude P. |last2=Gonzalez |first2=Felipe |last3=Savéant |first3=Jean-Michel |date=1997-05-01 |title=Derivatization of Carbon Surfaces by Anodic Oxidation of Arylacetates. Electrochemical Manipulation of the Grafted Films |url=https://pubs.acs.org/doi/10.1021/ja9636092 |journal=Journal of the American Chemical Society |language=en |volume=119 |issue=18 |pages=4292–4300 |doi=10.1021/ja9636092 |issn=0002-7863|url-access=subscription }}{{Cite journal |last1=Bélanger |first1=Daniel |last2=Pinson |first2=Jean |date=2011-06-20 |title=Electrografting: a powerful method for surface modification |url=https://pubs.rsc.org/en/content/articlelanding/2011/cs/c0cs00149j |journal=Chemical Society Reviews |language=en |volume=40 |issue=7 |pages=3995–4048 |doi=10.1039/C0CS00149J |pmid=21503288 |issn=1460-4744|url-access=subscription }}
See also
References
{{Reflist}}
Further reading
- {{cite journal
| title = Zersetzung der Valeriansäure durch den elektrischen Strom
|trans-title= Decomposition of valeric acid by an electric current
| first = Hermann |last= Kolbe
| journal = Annalen der Chemie und Pharmacie
| year = 1848
| volume = 64
| issue = 3
| pages = 339–341
| url = https://babel.hathitrust.org/cgi/pt?id=uiug.30112025847739;view=1up;seq=353
| doi = 10.1002/jlac.18480640346
| author-link = Adolph Wilhelm Hermann Kolbe| url-access = subscription
}}
- {{cite journal
| title = Untersuchungen über die Elektrolyse organischer Verbindungen
|trans-title= Investigations of the electrolysis of organic compounds
| first = Hermann |last= Kolbe
| journal = Annalen der Chemie und Pharmacie
| year = 1849
| volume = 69
| issue = 3
| pages = 257–294
| url = https://babel.hathitrust.org/cgi/pt?id=hvd.hx3bh3;view=1up;seq=271
| doi = 10.1002/jlac.18490690302
| author-link = Adolph Wilhelm Hermann Kolbe}}
External links
- {{cite web | title = Kolbe Electrolysis | publisher = Organic Chemistry Portal | url = https://www.organic-chemistry.org/namedreactions/kolbe-electrolysis.shtm | access-date = 2007-10-22}}
{{electrolysis}}