Pinacol

Not to be confused with Pinakol, a traditional beaded ornament created and occasionally worn by the Rungus female of Sabah, Malaysia.

Pinacol is a branched alcohol which finds use in organic syntheses. It is a diol that has hydroxyl groups on vicinal carbon atoms. A white solid that melts just above room temperature, pinacol is notable for undergoing the pinacol rearrangement in the presence of acid and for being the namesake of the pinacol coupling reaction.

Pinacol

Pinacol
Ball-and-stick model of pinacol
Names
Preferred IUPAC name 2,3-Dimethylbutane-2,3-diol
Other names 2,3-Dimethyl-2,3-butanediol Tetramethylethylene glycol 1,1,2,2-Tetramethylethylene glycol Pinacone
Identifiers
CAS Number	76-09-5 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:131185 Y
ChEMBL	ChEMBL3289669
ChemSpider	21109330 Y
ECHA InfoCard	100.000.849
EC Number	200-933-5
PubChem CID	6425
UNII	527QE7I5CO Y
CompTox Dashboard (EPA)	DTXSID3058793
InChI InChI=1S/C6H14O2/c1-5(2,7)6(3,4)8/h7-8H,1-4H3 Y Key: IVDFJHOHABJVEH-UHFFFAOYSA-N Y
SMILES CC(C)(O)C(C)(C)O CC(C)(O)C(C)(C)O
Properties
Chemical formula	C6H14O2
Molar mass	118.174 g/mol
Appearance	White solid
Density	0.967 g/cm3
Melting point	40 to 43 °C (104 to 109 °F; 313 to 316 K)
Boiling point	171 to 173 °C (340 to 343 °F; 444 to 446 K)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H228, H315, H319, H335
Precautionary statements	P210, P240, P241, P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501
Flash point	77 °C (171 °F; 350 K)
Safety data sheet (SDS)	External MSDS
Related compounds
Related compounds	Pinacolone
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Preparation

It may be produced by the pinacol coupling reaction from acetone:^[1]

Reactions

As a vicinal diol, it can rearrange to pinacolone by the pinacol rearrangement, e.g., by heating with sulfuric acid:^[2]

Pinacol can be used with borane and boron trichloride to produce useful synthetic intermediates such as pinacolborane, bis(pinacolato)diboron,^[3] and pinacolchloroborane.

See also

• Pinacol coupling reaction
• Pinacol rearrangement
• Semipinacol rearrangement