Cyclohexanol

Cyclohexanol[1]
IUPAC name	Cyclohexanol
Other names	Cyclohexyl Alcohol, hexahydrophenol, hydrophenol, hydroxycyclohexane, Naxol
Identifiers
CAS number	108-93-0 Y
EC-number	203-630-6
RTECS number	GV7875000
SMILES	C1CCC(CC1)O
InChI	1/C6H12O/c7-6-4-2-1-3-5-6/h6-7H,1-5H2
InChI key	HPXRVTGHNJAIIH-UHFFFAOYAN
ChemSpider ID	7678
Properties
Molecular formula	C6H12O
Molar mass	100.16 g/mol
Appearance	Colorless, viscous liquid. Hygroscopic
Density	0.962 g/mL, liquid
Melting point	25.4 °C, 299 K, 78 °F
Boiling point	160.8 °C, 434 K, 321 °F
Solubility in water	3.60 g/100 mL (20 °C)
Acidity (pKa)	16
Viscosity	41.07 mPa·s (30 °C)
Hazards
MSDS	MSDS for cyclohexanol
R-phrases	R20 R22 R37 R38
S-phrases	S24 S25
Flash point	67 °C
LD50	2.06 g/kg (oral, rat)
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Cyclohexanol is the organic compound with the formula (CH₂)₅CHOH. The molecule is related to cyclohexane ring by replacement of one hydrogen atom by a hydroxyl group.^[2] This compound exists as a deliquescent colorless solid, which, when very pure, melts near room temperature. Billions of kilograms are produced annually, mainly as a precursor to nylon.^[3]

Production

Cyclohexanol is produced by the oxidation of cyclohexane in air, typically using cobalt catalysts:^[3]

C₆H₁₂ + 1/2 O₂ → C₆H₁₁OH

This process co-forms cyclohexanone, and this mixture ("KA oil" for ketone-alcohol oil) is the main feedstock for the production of adipic acid. The oxidation involves radicals and the intermediacy of the hydroperoxide C₆H₁₁O₂H. Alternatively, cyclohexanol can be produced by the hydrogenation of phenol:

C₆H₅OH + 3 H₂ → C₆H₁₁OH

This process can also be adjusted to favor the formation of cyclohexanone.

Basic reactions

Cyclohexanol undergoes the main reactions expected for a secondary alcohol. Oxidation gives cyclohexanone, which is converted on a large scale in industry to the oxime, a precursor to caprolactam. As a laboratory exercise, this oxidation can be effected with chromic acid. Esterification affords the commercially useful derivatives dicyclohexyladipate and dicyclohexylphthalate, which are used as plasticizers. Heating in the presence of acid catalysts converts cyclohexanol to cyclohexene.^[3]

Applications

As indicated above, cyclohexanol is an important feedstock in the polymer industry, firstly as a precursor to Nylons, but also to various plasticizers. Small amounts are used as a solvent.

Safety

Cyclohexanol is somewhat toxic: the TLV for the vapor for 8 h is 50 ppm.^[3] Few studies have been done on its carcinogenicity, but one study on rats found it to have co-carcinogenic effects.^[4]

References

1. ^ Merck Index, 11th Edition, 2731.
2. ^ Lide, D. R., ed. (2005), CRC Handbook of Chemistry and Physics (86th ed.), Boca Raton (FL): CRC Press, ISBN 0-8493-0486-5 
3. ^ ^{a b c d} Michael Tuttle Musser "Cyclohexanol and Cyclohexanone" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.
4. ^ [1] Lucrecia Márquez-Rosado, Cristina Trejo-Solís 2, María del Pilar Cabrales-Romero, Evelia Arce-Popoca, Adolfo Sierra-Santoyo, Leticia Alemán-Lazarini, Samia Fatel-Fazenda, Claudia E. Carrasco-Legleu, Saúl Villa-Treviño, "Co-carcinogenic effect of cyclohexanol on the development of preneoplastic lesions in a rat hepatocarcinogenesis model", Molecular Carcinogenesis, Vol. 46, No. 7, Pages 524 - 533, March 2007.