Cyclohexanone, Oxocyclohexane, Pimelic Ketone, Cyclohexyl Ketone, Ketohexamethylene, 108-94-1

CYCLOHEXANONE

Cyclohexanone / Oxocyclohexane / Pimelic Ketone / Cyclohexyl Ketone / Ketohexamethylene
CAS Number: 108-94-1
EC Number: 203-631-1

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

Cyclohexanone is a colorless to pale yellow, oily liquid with a characteristic sweet, minty odor reminiscent of acetone. It is one of the most important alicyclic ketones and is widely used as a solvent and as a precursor in the production of nylon and other polymers. Cyclohexanone is primarily produced by the oxidation of cyclohexane or by the hydrogenation of phenol. The compound is slightly soluble in water but is miscible with most common organic solvents including alcohols, ethers, esters, ketones, and aromatic hydrocarbons. It is a key intermediate in the production of caprolactam, which is used to produce Nylon 6, and adipic acid, which is used to produce Nylon 6,6. Cyclohexanone is also widely used as a solvent in paints, coatings, adhesives, and inks, and as a chemical intermediate in the synthesis of pharmaceuticals, herbicides, insecticides, plasticizers, and rubber chemicals.

2. PHYSICAL AND CHEMICAL PROPERTIES

Cyclohexanone is a colorless to pale yellow, oily liquid with a characteristic sweet, minty odor. It has a density of 0.947-0.950 g/cm³ at 20°C, making it slightly lighter than water. The melting point is -47°C, and the boiling point is 155.65°C. The flash point is 44°C (closed cup), classifying it as a moderately flammable liquid. The vapor pressure at 20°C is 5 mmHg, indicating moderate volatility. The vapor density is 3.38 (air=1), meaning its vapor is approximately 3.4 times heavier than air and may accumulate in low-lying areas. Cyclohexanone is slightly soluble in water (23-24 g/L at 20°C) but is miscible with most common organic solvents including alcohols, ethers, esters, ketones, and aromatic hydrocarbons. The low viscosity (2.3 cP) and good solvent properties make it an excellent solvent for many resins, polymers, and coatings.

3. CHEMICAL PROPERTIES AND REACTIONS

Cyclohexanone is a cyclic ketone that undergoes the characteristic reactions of ketones, including nucleophilic addition, condensation, oxidation, and reduction. Its chemical behavior is determined by the carbonyl group (C=O) and the cyclohexane ring.

Oxidation:

Cyclohexanone can be oxidized to adipic acid (hexanedioic acid) using strong oxidizing agents such as nitric acid:

C₆H₁₀O + 2 O₂ → HOOC-(CH₂)₄-COOH (adipic acid)

Adipic acid is a key monomer for Nylon 6,6 production.

Reduction:

Cyclohexanone can be reduced to cyclohexanol using hydrogenation (with metal catalysts) or using reducing agents such as sodium borohydride:

C₆H₁₀O + H₂ → C₆H₁₁OH (cyclohexanol)

Aldol Condensation:

Cyclohexanone undergoes aldol condensation to form 2-cyclohexylidenecyclohexanone (a dimer) under basic or acidic conditions.

Beckmann Rearrangement:

Cyclohexanone reacts with hydroxylamine to form cyclohexanone oxime, which undergoes Beckmann rearrangement to produce caprolactam (the precursor to Nylon 6):

C₆H₁₀O + NH₂OH → C₆H₁₀=N-OH (cyclohexanone oxime) → caprolactam (Beckmann rearrangement)

Wittig Reaction:

Cyclohexanone undergoes Wittig reactions with phosphorus ylides to form alkenes.

Grignard Reaction:

Cyclohexanone reacts with Grignard reagents to form tertiary alcohols.

Ketal Formation:

Cyclohexanone forms ketals with glycols under acid catalysis.

Halogenation:

Cyclohexanone undergoes α-halogenation reactions with halogens (chlorine, bromine) under acidic or basic conditions.

Photochemistry:

Cyclohexanone undergoes Norrish Type I and Type II photochemical reactions upon UV irradiation.

4. PRODUCTION METHODS

Cyclohexanone is produced industrially by several methods, primarily through the oxidation of cyclohexane or the hydrogenation of phenol.

Detailed Production Process (Cyclohexane Oxidation - Most Common):

1. Oxidation: Cyclohexane is oxidized with air in the presence of cobalt or manganese naphthenate catalysts at 150-170°C and 8-15 atm pressure.

   C₆H₁₂ + O₂ → C₆H₁₀O + H₂O (cyclohexanone)

   C₆H₁₂ + ½ O₂ → C₆H₁₁OH (cyclohexanol)

2. Separation: The reaction mixture (KA oil - ketone/alcohol oil) is separated and purified by distillation.

3. Dehydrogenation: Cyclohexanol is dehydrogenated to produce additional cyclohexanone:

   C₆H₁₁OH → C₆H₁₀O + H₂ (cyclohexanone)

4. Purification: The crude cyclohexanone is purified by fractional distillation to obtain high-purity product.

5. SPECIFICATIONS (INDUSTRIAL GRADE)

6. APPLICATIONS AND INDUSTRIAL USES

Cyclohexanone is a versatile chemical with a wide range of applications, with its most important use being in the production of nylon and other polymers.

6.1. Nylon Production (Most Important Application - ~75%)

Cyclohexanone is primarily used as a precursor in the production of caprolactam and adipic acid, which are the monomers for Nylon 6 and Nylon 6,6 respectively. The compound is first converted to cyclohexanone oxime by reaction with hydroxylamine. The oxime then undergoes Beckmann rearrangement in the presence of sulfuric acid to form caprolactam. Caprolactam is polymerized to produce Nylon 6, which is used in textiles, carpets, engineering plastics, and films. Adipic acid is produced by the oxidation of cyclohexanone (often in a mixture with cyclohexanol) with nitric acid. Adipic acid is then polymerized with hexamethylenediamine to produce Nylon 6,6, which is used in automotive parts, textiles, and consumer goods.

6.2. Solvent Applications

Cyclohexanone is an excellent solvent for many resins, polymers, and coatings due to its high solvency power and moderate evaporation rate. It is widely used as a high-boiling solvent in nitrocellulose, acrylic, alkyd, and epoxy resin coatings. It is also used in printing inks, adhesives, industrial degreasers, cleaners, and as a thinner for paints, varnishes, and lacquers.

6.3. Chemical Intermediate Applications

Cyclohexanone is an important chemical intermediate in the synthesis of various pharmaceuticals, herbicides, insecticides, plasticizers, rubber chemicals, dyes, pigments, fragrances, and flavors.

6.4. Other Applications

Cyclohexanone is also used as a spinning solvent for synthetic fibers, as a solvent in polymerization reactions, in metal extraction processes, and as a laboratory reagent.

7. HEALTH EFFECTS AND TOXICOLOGY

Cyclohexanone has moderate acute toxicity and can cause health effects through inhalation, skin contact, and ingestion. It is classified as an irritant and a potential narcotic.

7.1. Toxicological Data

7.2. Health Effects

Acute Exposure:

Chronic Exposure:

• Central Nervous System Effects: Prolonged or repeated exposure may cause headaches, dizziness, fatigue, memory impairment, and peripheral neuropathy.

• Skin Effects: Repeated skin contact may cause dermatitis and skin sensitization.

• Kidney and Liver Effects: Long-term high-level exposure may affect kidney and liver function.

• Reproductive Effects: Some studies suggest possible reproductive effects in animals at high doses.

8. FIRST AID MEASURES

9. SAFETY INFORMATION (GHS CLASSIFICATION)

Signal Word: WARNING

Hazard Statements (H-Codes):

Precautionary Statements (P-Codes):

10. FIREFIGHTING MEASURES

11. ACCIDENTAL RELEASE MEASURES

12. STORAGE AND HANDLING

Cyclohexanone should be stored in cool, dry, well-ventilated areas, away from ignition sources, heat, and incompatible materials (strong oxidizing agents, acids, bases, strong reducing agents). Containers should be tightly closed, grounded, and bonded to prevent static electricity accumulation. Storage areas should be equipped with fire suppression equipment and spill containment systems. The flash point of 44°C requires careful handling away from ignition sources. Shelf life under proper storage conditions is typically 12-24 months.

Handling Notes:

• Use in well-ventilated areas

• Keep away from ignition sources

• Avoid static electricity accumulation (ground all equipment)

• Avoid contact with eyes, skin, and clothing

• Avoid breathing vapor or mist

• Use only with appropriate personal protective equipment

• Avoid release to the environment

13. TRANSPORT INFORMATION

Cyclohexanone is classified as a dangerous good with UN number 1915. Hazard class is 3 (Flammable Liquid) and Packing Group III. During transport, it should be kept away from heat, sparks, open flames, and other ignition sources. Containers should be grounded and bonded. Proper labeling and documentation are required.

14. REGULATORY INFORMATION

Regulatory Status:

15. OTHER NAMES AND DATABASE IDENTIFIERS

Database Identifiers:

16. ENVIRONMENTAL INFORMATION

17. DOWNSTREAM AND UPSTREAM PRODUCTS

17.1. Raw Materials (Upstream)

17.2. Derivative Products (Downstream)

18. COMPARISON WITH OTHER COMMON SOLVENTS

19. INDUSTRY SUITABILITY TABLE

20. SUMMARY AND CRITICAL WARNINGS

SUMMARY:

Cyclohexanone (C₆H₁₀O, CAS 108-94-1) is a colorless to pale yellow, oily liquid with a characteristic sweet, minty odor. The molecular weight is 98.15 g/mol, density is 0.947-0.950 g/cm³, melting point is -47°C, boiling point is 155.65°C, and flash point is 44°C. It is slightly soluble in water (23-24 g/L at 20°C) and miscible with most common organic solvents. It is produced primarily by the oxidation of cyclohexane or the hydrogenation of phenol. Its most important application is in the production of caprolactam and adipic acid for Nylon 6 and Nylon 6,6 production (approximately 75% of consumption). It is also widely used as a solvent in paints, coatings, adhesives, inks, and as a chemical intermediate in pharmaceuticals, herbicides, insecticides, plasticizers, and rubber chemicals. From a health perspective, it is an irritant, harmful if swallowed or inhaled, and may cause respiratory irritation. It is classified as a flammable liquid with a flash point of 44°C. IARC Group 3 (not classifiable as to carcinogenicity to humans). UN 1915 (Class 3 - Flammable Liquid, Packing Group III). It is stored in cool, dry, well-ventilated areas away from ignition sources and incompatible materials. Packaging: 200 L drums, IBC tanks, or bulk tankers.

Key Properties:

Major Application Areas:

Key Safety Points:

• FLAMMABLE LIQUID: Flash point 44°C; keep away from all ignition sources

• IRRITANT: Causes skin and eye irritation; may cause respiratory irritation

• HARMFUL: Harmful if swallowed or inhaled

• VAPOR HAZARD: Vapors are heavier than air and may travel to ignition sources

• STORAGE: Store in cool, dry, well-ventilated area away from ignition sources

• PPE REQUIRED: Chemical-resistant gloves, goggles, protective clothing, respiratory protection if ventilation is inadequate

• ENVIRONMENTAL HAZARD: Avoid release to the environment

CRITICAL WARNINGS:

Nylon Production: Cyclohexanone is one of the most important industrial chemicals due to its role in nylon production. Approximately 75% of all cyclohexanone produced is used in the production of caprolactam (Nylon 6) and adipic acid (Nylon 6,6). The demand for cyclohexanone is closely tied to the demand for nylon fibers, engineering plastics, and films.

Flammability: With a flash point of 44°C, cyclohexanone is a moderately flammable liquid. Vapors are heavier than air (vapor density 3.38) and may travel considerable distances to ignition sources, causing flashback. Explosive limits range from 1.1-9.4% by volume in air. Static electricity accumulation can cause ignition. Use explosion-proof electrical equipment, proper grounding, and non-sparking tools.

Health Hazards: Cyclohexanone is an irritant and can cause skin and eye irritation. It is harmful if swallowed or inhaled. Prolonged or repeated exposure may cause central nervous system effects (headache, dizziness, fatigue, memory impairment) and peripheral neuropathy. The ACGIH TLV-TWA is 25 ppm (100 mg/m³), and the NIOSH IDLH is 700 ppm. Workplace exposure should be monitored and controlled.

Solvent Properties: Cyclohexanone is an excellent solvent for many resins, polymers, and coatings due to its high solvency power and moderate evaporation rate. It is particularly useful in nitrocellulose, acrylic, alkyd, and epoxy resin coatings. Its moderate evaporation rate allows for good film formation and leveling.

Chemical Reactivity: Cyclohexanone undergoes a variety of reactions including oxidation, reduction, aldol condensation, Beckmann rearrangement, Wittig reaction, Grignard reaction, ketal formation, and halogenation. These reactions make it a versatile intermediate for the synthesis of many important chemicals, including caprolactam, adipic acid, pharmaceuticals, herbicides, and insecticides.

Environmental Considerations: Cyclohexanone is readily biodegradable (60-80% degradation in 28 days) and has low bioaccumulation potential (LogP 0.81). However, it is moderately toxic to aquatic organisms (LC50, Fish, 96h: 527 mg/L). Release to the environment should be avoided. Waste should be disposed of according to local regulations; incineration at a permitted facility is recommended.

Important Disclaimer: This Technical Data Sheet (TDS) is for informational purposes only. The information provided is based on available data and is believed to be accurate. However, the user is solely responsible for determining the suitability of the product for their specific application and for complying with all applicable regulations and safety requirements. For complete safety, handling, storage, and regulatory compliance information, always refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. Users are responsible for testing the product in their own processes and applications. All local, national, and international regulations must be followed when working with cyclohexanone.