Cyclohexylbenzene
{{Chembox
| ImageFile = Cyclohexylbenzene.svg
| ImageSize =
| ImageAlt =
| PIN = Cyclohexylbenzene
| OtherNames = Phenylcyclohexane
|Section1={{Chembox Identifiers
| CASNo = 827-52-1
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = TRJ2SXT894
| PubChem = 13229
| ChemSpiderID = 12674
| EC_number = 212-572-0
| ChEMBL = 3278514
| StdInChI=1S/C12H16/c1-3-7-11(8-4-1)12-9-5-2-6-10-12/h1,3-4,7-8,12H,2,5-6,9-10H2
| StdInChIKey = IGARGHRYKHJQSM-UHFFFAOYSA-N
| SMILES = C1CCC(CC1)C2=CC=CC=C2
}}
|Section2={{Chembox Properties
| C=12|H=16
| MolarMass =
| Appearance = Colorless liquid
| Density = 0.982 g/cm3
| MeltingPtC = 7.3
| BoilingPtC = 240.1
| Solubility = }}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS07}}{{GHS08}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|302|304|315|319|410}}
| PPhrases = {{P-phrases|264|270|273|280|301+310|301+312|302+352|305+351+338|321|330|331|332+313|337+313|362|391|405|501}}
| MainHazards =
| FlashPt =
| AutoignitionPt = }}
}}
Cyclohexylbenzene (or phenylhexamethylene, as it was initially called) is the organic compound with the structural formula {{chem2|C6H5\sC6H11}}. It is a derivative of benzene with a cyclohexyl substituent (C6H11). It is a colorless liquid.
History and synthesis
Cyclohexylbenzene was first obtained in 1899 by Markovnikov's student Nikolay Kirsanov (1874–1921).{{Cite book |last=Быков |first=Георгий Владимирович |url=https://books.google.com/books?id=76RbAAAAIAAJ&q=%D1%84%D0%B5%D0%BD%D0%B8%D0%BB%D1%86%D0%B8%D0%BA%D0%BB%D0%BE%D0%B3%D0%B5%D0%BA%D1%81%D0%B0%D0%BD |title=История органической химии: Открытие важнейших органических соединений |date=1978 |publisher=Наука |pages=132 |language=ru}} He used a Friedel–Crafts alkylation of benzene with cyclohexyl chloride using a catalyst such as aluminum trichloride:{{Cite book |url=https://books.google.com/books?id=Y20MAQAAIAAJ&pg=RA1-PA79 |title=Журнал Русского физико-химического общества |date=1900 |publisher=Тип-ія Б. Демакова |pages=79 |language=ru}}
:{{chem2 | C6H6 + C6H11Cl -> C6H5\sC6H11 + HCl }}
Cyclohexylbenzene is now industrially produced by the acid-catalyzed alkylation of benzene with cyclohexene.{{cite journal|doi=10.1246/cl.2004.472|title=Novel Acidic Ionic Liquids Catalytic Systems for Friedel–Crafts Alkylation of Aromatic Compounds with Alkenes|journal=Chemistry Letters|volume=33|issue=4|pages=472–473|year=2004|last1=Qiao|first1=Kun|last2=Yokoyama|first2=Chiaki}}{{cite journal |doi=10.15227/orgsyn.019.0036|title=Cyclohexylbenzene |journal=Organic Syntheses |year=1939 |volume=19 |page=36|author=B. B. Corson, V. N. Ipatieff }} The process can proceed using benzene as the exclusive organic precursor. Its partial hydrogenation gives cyclohexene, which alkylates the unhydrogenated benzene.
It is also generated by the hydrodesulfurization of dibenzothiophene,{{cite journal|doi=10.1016/j.jcat.2011.12.018|title=Hydrodesulfurization of Dibenzothiophene and its Hydrogenated Intermediates over Bulk MoP|journal=Journal of Catalysis|volume=287|pages=161–169|year=2012|last1=Bai|first1=Jin|last2=Li|first2=Xiang|last3=Wang|first3=Anjie|last4=Prins|first4=Roel|last5=Wang|first5=Yao}} and ExxonMobil took a patent in 2009 for a process based on direct hydroalkylation of two benzene molecules.{{US patent|8178728B2}}
Applications
A route to phenol analogous to the cumene process begins with cyclohexylbenzene, which is oxidized to a hydroperoxide, akin to the production of cumene hydroperoxide. Via the Hock rearrangement, cyclohexylbenzene hydroperoxide cleaves to give phenol and cyclohexanone:
:{{chem2|C6H5\sC6H10OOH -> C6H5OH + OC6H10}}
Cyclohexanone is an important precursor to some nylons.{{cite web |url=https://www.acs.org/content/acs/en/pressroom/cutting-edge-chemistry/what-s-new-in-phenol-production-.html |title=What's New in Phenol Production? |last=Plotkin |first=Jeffrey S. |publisher=American Chemical Society |date=2016-03-21 |access-date=2018-01-02 |archive-url=https://web.archive.org/web/20191027122212/https://www.acs.org/content/acs/en/pressroom/cutting-edge-chemistry/what-s-new-in-phenol-production-.html |archive-date=2019-10-27 |url-status=dead }}{{Ullmann|doi=10.1002/14356007.a19_299.pub3|title=Phenol|year=2004|last1=Weber|first1=Manfred|last2=Weber|first2=Markus|last3=Kleine-Boymann|first3=Michael}}