Industrial-grade 99.5% Cyclohexanol CAS 108-93-0

What is Cyclohexanol? How does it work?

Cyclohexanol is a secondary alcohol with the molecular formula C6H12O and the structural formula (CH2)5CHOH. It is formed by replacing one hydrogen atom of cyclohexane with a hydroxyl group and appears as a thick, transparent liquid. It is the foundation of the nylon industry: every year, millions of tons of cyclohexanol are oxidized into adipic acid and dehydrogenated into cyclohexanone. These derivatives become nylon‑66 and nylon‑6 fibres used in textiles, adipic acid for engineering plastics, and plasticizers for flexible PVC products.

Basic identification data

Molecular formula C6H12O

Molecular weight 100.16

CAS No. 108‑93‑0

EC No. 203‑630‑6

Industrial production method: Air oxidation of cyclohexane under cobalt catalysis, with cyclohexanone formed as a co‑product; the resulting mixture is known as KA oil. An alternative route is phenol hydrogenation. Cyclohexanol acts as a central intermediate within the cyclohexane‑cyclohexanol‑cyclohexanone industrial chain.

It is a colourless, viscous liquid. The high‑purity product melts at 25.93 °C and may form waxy crystals at room temperature. It has a camphor‑like odour and is hygroscopic. Density: 0.9624 g/mL; boiling point: 161.84 °C; slightly soluble in water (approximately 3.6 g/100 mL at 20 °C), freely soluble in organic solvents such as ethanol, diethyl ether, acetone, chloroform and ethyl acetate; refractive index: 1.4641; flash point: 67 °C; auto‑ignition temperature: 300 °C.

Cyclohexanol is a typical secondary alcohol. It can be catalytically dehydrogenated or oxidized to cyclohexanone (further oxidative cleavage yields adipic acid). It undergoes esterification with acids or acid anhydrides to form esters such as dicyclohexyl phthalate and cyclohexyl acetate. Under acid catalysis, it dehydrates to produce cyclohexene. As a moderately polar alcoholic solvent, it dissolves resins, oils and waxes. It must be kept away from ignition sources and oxidizing agents and stored in sealed, moisture‑proof containers.

From a reaction‑mechanism perspective, industrial‑grade cyclohexanol plays an irreplaceable role owing to four characteristic reaction pathways of its secondary alcoholic hydroxyl group: oxidation, dehydrogenation, esterification and dehydration, combined with its moderate polarity and solubility. Its mechanisms of action for different applications are described below:

1. Oxidative ring‑opening process for adipic acid production

Cyclohexanol (KA oil containing cyclohexanone) is oxidized by nitric acid or air. Its secondary alcoholic hydroxyl group is converted into a ketone group, and subsequent oxidation and cleavage of the cyclic structure produces adipic acid (nylon‑66 monomer). This constitutes the core reaction of the nylon industrial chain.

2. Dehydrogenation to Cyclohexanone – Reaction Mechanism

The nylon‑6 industrial chain relies on the dehydrogenation of cyclohexanol over catalysts such as copper and zinc (or the oxidation of cyclohexane) to yield cyclohexanone. Cyclohexanone is then converted into cyclohexanone oxime, which undergoes rearrangement to form caprolactam (nylon‑6 monomer).

3. Esterification Plasticization Mechanism

Macromolecular esters (dicyclohexyl phthalate, dicyclohexyl adipate) are synthesized by reacting cyclohexanol with phthalic anhydride, adipic acid and other raw materials. When incorporated into polymer molecular chains, these esters weaken intermolecular forces and reduce the glass‑transition temperature, softening rigid resins. They serve as plasticizers for plastics such as PVC.

4. Dissolution and Solvent Mechanism

Cyclohexanol functions as a moderately polar alcoholic solvent because it combines the polarity of the hydroxyl group with the lipophilic cyclohexyl skeleton. It dissolves alkyd resins, nitrocellulose, shellac, oils and waxes and is formulated into coatings and paint systems.

5. Olefin Formation via Dehydration Elimination Mechanism

Under acid catalysis, cyclohexanol undergoes elimination and dehydration to yield cyclohexene (elimination reaction). Cyclohexene is an important organic intermediate and can be further converted into a wide variety of fine chemicals.

To summarize, industrial cyclohexanol is the foundation of the nylon industry. Thanks to the oxidation, dehydrogenation, esterification and dehydration reactivity of its secondary alcoholic hydroxyl group, it is used to manufacture adipic acid and cyclohexanone and also as a feedstock for plasticizers and solvents. It runs through the core processes for nylon fibres, engineering plastics and fine chemicals.

II. What are the applications of industrial Cyclohexanol?

Industrial‑grade cyclohexanol serves the entire nylon industrial chain and is also applied in plastic additives, coatings, fine chemicals, flavours and fragrances, and analytical chemistry. Each application is outlined below by downstream end‑use area, including application field, related products and working principle:

1.Raw Material for Adipic Acid Production (Core application in the Nylon‑66 industrial chain)

Application areas: Nylon‑66 and polymer industries.

Related Products: adipic acid, nylon‑66 fibre, nylon‑66 engineering plastics, tyre cord, automotive airbag fabric, carpet fibre, adipate‑ester plasticizers, polyurethane feedstocks, food‑grade adipic acidulant, etc.

Why it works for this application: Cyclohexanol (KA oil containing cyclohexanone) undergoes oxidative ring‑opening with nitric acid or air to form adipic acid. Adipic acid is then polycondensed with hexamethylenediamine to produce nylon‑66. It is the core feedstock of the global nylon‑66 industrial chain and determines the supply of engineering plastics and high‑performance fibres.

2. Raw Material for Cyclohexanone and Caprolactam (Nylon‑6 industrial chain, core application)

Application areas: Nylon‑6 and solvent industries.

Related Products: cyclohexanone, caprolactam, nylon‑6 fibre, nylon‑6 engineering plastics, cyclohexanone oxime, co‑feedstock for adipic acid production, industrial cyclohexanone solvent, cleaning agents, etc.

Why it works for this application: Cyclohexanol is dehydrogenated to cyclohexanone. Cyclohexanone reacts with hydroxylamine to form cyclohexanone oxime, which undergoes the Beckmann rearrangement to yield caprolactam. Caprolactam undergoes ring‑opening polymerization to produce nylon‑6, a key intermediate along the value chain of nylon‑6 fibres and engineering plastics.

3. Ester Intermediates for Plasticizers (Plastic additive industry)

Application areas: Plastic additives and PVC processing.

Related products: dicyclohexyl phthalate (DCHP), dicyclohexyl adipate, cyclohexyl fatty acid esters, flexible PVC products, cellulose plasticizers, coating plasticizers, sealant plasticizers, etc.

Why it works for this application: Cyclohexanol reacts with phthalic anhydride, adipic acid and other substances to form macromolecular ester plasticizers. Once incorporated into polymer molecular chains, these esters weaken intermolecular forces and improve flexibility and processability. They represent an important class of plasticizers for flexible PVC articles.

4. Coatings and Paint Solvents (Coating industry)

Application areas: Paint and coating manufacturing.

Related Products: solvent for alkyd resin coatings, varnish and shellac solvent, nitrocellulose lacquer thinner, wood coatings, paint removers, ink solvents, resin solvents, leather finishing agents, etc.

Why it works for this application: Cyclohexanol is a moderately polar alcoholic solvent capable of dissolving alkyd resins, nitrocellulose and shellac. It has a moderate evaporation rate, improves coating levelling and gloss, and is widely used as a solvent in coatings and paint‑remover formulations.

5. Feedstock for Cyclohexene Production, Chemical Intermediate Sector

Application areas: Chemical intermediates and organic synthesis.

Related products: cyclohexene, cyclohexanol‑derived intermediates, adipaldehyde, cyclohexyl compounds, organic synthetic intermediates, pesticide intermediates, etc.

Why it works for this application: Under acid catalysis, cyclohexanol undergoes dehydration and elimination to yield cyclohexene. Cyclohexene contains a carbon‑carbon double bond and can undergo addition, oxidation and hydration reactions, making it a valuable intermediate for synthesizing numerous fine chemicals.

6. Reaction Medium and Extraction Solvent for Organic Synthesis (Fine‑chemical industry)

Application areas: Fine chemicals and organic synthesis.

Related Products: solvents for organic synthetic reactions, extraction solvents, recrystallization media, cleaning solvents, carrier liquids for chemical reactions, polymerization media, etc.

Why it works for this application: Cyclohexanol has mild chemical reactivity, a moderate boiling point (161.8 °C) and broad solvency. It acts as a reaction medium for many organic transformations and also serves as an extraction and recrystallization solvent, a common alcoholic solvent in fine‑chemical production.

7. Ester Fragrance Intermediates (Flavour and fragrance industry)

Application areas: Flavour and fragrance industry.

Related products: cyclohexyl acetate (fruity flavour), cyclohexanol esters, food flavours (banana, apple, etc.), daily‑use fragrances, cosmetic fragrances, soap fragrances, etc.

Why it works for this application: Cyclohexanol reacts with acetic acid to form cyclohexyl acetate and other esters possessing a sweet, fruity aroma. These esters are fragrance raw materials used to formulate fruit flavours for food and daily‑chemical products and deliver fresh, stable odours.

8. Analytical Reagents and Laboratory

Application areas: Research laboratories and analytical chemistry.

Related products: analytical‑grade cyclohexanol, chromatographic solvents, extraction reagents, solvents for standard‑solution preparation, laboratory cleaning solvents, teaching reagents, etc.

Why it works for this application: Reagent‑grade cyclohexanol has high purity and good solubility. It can be used as an analytical solvent and extracting agent and for preparing standard solutions to guarantee reliable experimental and detection results.

To summarize, industrial cyclohexanol (CAS 108‑93‑0) is the foundation of the nylon industry. The reactivity of its secondary alcoholic hydroxyl group toward oxidation, dehydrogenation, esterification and dehydration supports its well‑established applications across eight major sectors: adipic acid for nylon‑66, cyclohexanone and caprolactam for nylon‑6, plasticizer esters, coating solvents, cyclohexene intermediates, organic reaction media, ester fragrances, and analytical reagents. Among these fields, adipic‑acid and cyclohexanone production represent the largest consumption segments within the nylon industrial chain and supply raw materials for everyday products including nylon fibres, engineering plastics and flexible PVC. Cyclohexanol has moderate toxicity (occupational exposure limit 50 ppm in air) and is flammable (flash point 67 °C). It reacts violently with strong oxidizing agents. Strict ventilation and fire‑prevention measures must be implemented during industrial handling.