:2,2'-Biphenol
{{Chembox
| Name = 2,2′-Biphenol
| ImageFile = 2,2'-biphenol.svg
| ImageSize = 182 px
| ImageAlt =
| PIN = [1,1′-Biphenyl]-2,2′-diol
| OtherNames = o,o′-Dihydroxybiphenyl
|Section1={{Chembox Identifiers
| CASNo = 1806-29-7
| PubChem = 15731
| EC_number = 217-303-0
| Gmelin = 51261
| UNII = PM2R53I3C9
| ChEBI = 28970
| ChemSpiderID = 14959
| ChEMBL = 183874
| KEGG = C03209
| Beilstein = 1638363
| StdInChI=1S/C12H10O2/c13-11-7-3-1-5-9(11)10-6-2-4-8-12(10)14/h1-8,13-14H
| StdInChIKey = IMHDGJOMLMDPJN-UHFFFAOYSA-N
| SMILES = C1=CC=C(C(=C1)C2=CC=CC=C2O)O
}}
|Section2={{Chembox Properties
| C=12|H=10|O=2
| MolarMass =
| Appearance = white solid
| Density =
| MeltingPtC = 109
| BoilingPtC = 320
| Solubility = }}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS05}}{{GHS07}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|302|315|318|319|335}}
| PPhrases = {{P-phrases|261|264|270|271|280|301+312|302+352|304+340|305+351+338|310|312|321|330|332+313|337+313|362|403+233|405|501}}
| MainHazards =
| FlashPt =
| AutoignitionPt = }}
}}
2,2′-Biphenol is an organic compound with the formula (C6H4OH)2. It is one of three symmetrical isomers of biphenol. A white solid, it is a precursor to diphosphite ligands that are used to support industrial hydroformylation catalysis.{{cite journal|doi=10.1021/ja00058a079|title=Practical, High-Yield, Regioselective, Rhodium-Catalyzed Hydroformylation of Functionalized α-Olefins|journal=Journal of the American Chemical Society|volume=115|pages=2066–2068|year=1993|last1=Cuny|first1=Gregory D.|last2=Buchwald|first2=Stephen L.|issue=5 }}{{cite journal|doi=10.1021/OM950549K|title=Bulky Diphosphite-Modified Rhodium Catalysts: Hydroformylation and Characterization|journal=Organometallics|volume=15|pages=835–847|year=1996|last1=Van Rooy|first1=Annemiek|last2=Kamer|first2=Paul C. J.|last3=Van Leeuwen|first3=Piet W. N. M.|last4=Goubitz|first4=Kees|last5=Fraanje|first5=Jan|last6=Veldman|first6=Nora|last7=Spek|first7=Anthony L.|issue=2 |url=http://dare.uva.nl/personal/pure/en/publications/bulky-diphosphite-modified-rhodium-catalyst-hydroformylation-and-characterization(c06c2654-cecb-4e97-84ba-f1fdfb51ad35).html}}
image:BiPhePhos.svg is representative diphosphite ligand derived from 2,2′-biphenol.]]
Synthesis
The chemical can be made by a hydrolysis reaction that opens the central ring of dibenzofuran. Alternatively, it can be produced from 2,4-di-tert-butylphenol in two steps. The first step entails oxidative coupling to give the 2,2′-biphenol with four tert-butyl substituents. This species then undergoes debutylation.{{Ullmann|author1=Fiege, H. |author2=Voges, H.-M. |author3=Hamamoto, T |author4=Umemura, S. |author5=Iwata, T. |author6=Miki, H. |author7=Fujita, Y. |author8=Buysch, H.-J. |author9=Garbe, D. |author10=Paulus, W. | title = Phenol Derivatives | year = 2000 | doi = 10.1002/14356007.a19_313}}