Cyclohexanol
Encyclopedia
Cyclohexanol is the organic compound
with the formula
(C
H
2)5CHOH. The molecule is related to cyclohexane
ring by replacement of one hydrogen atom by a hydroxyl group
. 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
.
in air, typically using cobalt catalysts:
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
:
This process can also be adjusted to favor the formation of 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 plasticizer
s. Heating in the presence of acid catalysts converts cyclohexanol to cyclohexene
.
.
for the vapor for 8 h is 50 ppm
. Few studies have been done on its carcinogenicity, but one study on rats found it to have co-carcinogenic effects.
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
(C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
2)5CHOH. The molecule is related to cyclohexane
Cyclohexane
Cyclohexane is a cycloalkane with the molecular formula C6H12. Cyclohexane is used as a nonpolar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which being intermediates used in the production of nylon...
ring by replacement of one hydrogen atom by a hydroxyl group
Hydroxide
Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and a hydrogen atom held together by a covalent bond, and carrying a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, as a ligand, a nucleophile, and a...
. 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
Nylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...
.
Production
Cyclohexanol is produced by the oxidation of cyclohexaneCyclohexane
Cyclohexane is a cycloalkane with the molecular formula C6H12. Cyclohexane is used as a nonpolar solvent for the chemical industry, and also as a raw material for the industrial production of adipic acid and caprolactam, both of which being intermediates used in the production of nylon...
in air, typically using cobalt catalysts:
- C6H12 + 1/2 O2 → C6H11OH
This process co-forms cyclohexanone
Cyclohexanone
Cyclohexanone is the organic compound with the formula 5CO. The molecule consists of six-carbon cyclic molecule with a ketone functional group. This colorless oil has an odor reminiscent of peardrop sweets as well as acetone. Over time, samples assume a yellow color due to oxidation...
, and this mixture ("KA oil" for ketone-alcohol oil) is the main feedstock for the production of adipic acid
Adipic acid
Adipic acid is the organic compound with the formula 42. From the industrial perspective, it is the most important dicarboxylic acid: About 2.5 billion kilograms of this white crystalline powder are produced annually, mainly as a precursor for the production of nylon...
. The oxidation involves radicals and the intermediacy of the hydroperoxide C6H11O2H.
Alternatively, cyclohexanol can be produced by the hydrogenation
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...
of phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
:
- 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 cyclohexanoneCyclohexanone
Cyclohexanone is the organic compound with the formula 5CO. The molecule consists of six-carbon cyclic molecule with a ketone functional group. This colorless oil has an odor reminiscent of peardrop sweets as well as acetone. Over time, samples assume a yellow color due to oxidation...
, which is converted on a large scale in industry to the oxime
Oxime
An oxime is a chemical compound belonging to the imines, with the general formula R1R2C=NOH, where R1 is an organic side chain and R2 may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted oximes form a closely related family of compounds...
, a precursor to caprolactam
Caprolactam
Caprolactam is an organic compound with the formula 5CNH. This colourless solid is a lactam or a cyclic amide of caproic acid. Approximately 2 billion kilograms are produced annually...
. As a laboratory exercise, this oxidation can be effected with chromic acid
Chromic acid
The term chromic acid is usually used for a mixture made by adding concentrated sulfuric acid to a dichromate, which may contain a variety of compounds, including solid chromium trioxide. This kind of chromic acid may be used as a cleaning mixture for glass. Chromic acid may also refer to the...
. Esterification affords the commercially useful derivatives dicyclohexyladipate and dicyclohexylphthalate, which are used as plasticizer
Plasticizer
Plasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...
s. Heating in the presence of acid catalysts converts cyclohexanol to cyclohexene
Cyclohexene
Cyclohexene is a hydrocarbon with the formula C6H10. This cycloalkene is a colorless liquid with a sharp smell. It is an intermediate in various industrial processes...
.
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 solventSolvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
.
Safety
Cyclohexanol is somewhat toxic: the TLVThreshold Limit Value
The threshold limit value of a chemical substance is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse health effects. Strictly speaking, TLV is a reserved term of the American Conference of Governmental Industrial Hygienists...
for the vapor for 8 h is 50 ppm
PPM
- Culture :*Peter, Paul and Mary, a 1960s folk music trio*Picture Postcard Monthly, a magazine for collectors of postcards*Please Please Me, the first album by The Beatles- Health :*Permanent pacemaker or artificial pacemaker...
. Few studies have been done on its carcinogenicity, but one study on rats found it to have co-carcinogenic effects.