Cyclohexanone Handling, Storage & Lab Use Guidelines

Cyclohexanone is a widely used industrial and laboratory ketone solvent valued for its moderate polarity, selective solvation power, and broad compatibility with organic synthesis workflows.

CAS Number

108-94-1

Molecular Formula

C₆H₁₀O

Molecular Weight

98.14 g/mol

Boiling Point

155–156 °C at 760 mmHg

Flash Point

Approximately 44 °C (closed cup)

Appearance

Colorless to pale yellow liquid with a peppermint-like odor

Miscibility

Miscible with most organic solvents; slightly soluble in water

Physical & Chemical Properties

Cyclohexanone (CAS 108-94-1) is a cyclic ketone with the molecular formula C₆H₁₀O and a molecular weight of 98.14 g/mol. It is a colorless to pale yellow, flammable liquid with a characteristic peppermint-like or acetone-like odor. Key physical properties relevant to laboratory use include a boiling point of approximately 155–156 °C at 760 mmHg, a density of about 0.947 g/mL at 25 °C, and a refractive index of approximately 1.450. Its flash point of roughly 44 °C (closed cup) classifies it as a flammable liquid under GHS criteria.

Cyclohexanone is moderately polar (log P ≈ 0.81), making it an effective solvent for resins, lacquers, waxes, natural and synthetic rubbers, and many polymer systems. It is slightly soluble in water (~8 g/L at 20 °C) and fully miscible with common organic solvents including ethanol, diethyl ether, acetone, and ethyl acetate. Its moderate vapor pressure (~5 mmHg at 20 °C) means inhalation exposure must be managed in the laboratory setting.

Safe Handling & Personal Protective Equipment

Cyclohexanone is classified as a flammable liquid (GHS Category 3) and an irritant. It poses hazards through inhalation, skin contact, and eye contact. Researchers must observe the following handling precautions at all times:

• Ventilation: Always work with cyclohexanone inside a certified chemical fume hood. Avoid generating vapors in poorly ventilated spaces.
• Eye protection: Wear chemical splash goggles at minimum; a face shield is recommended when handling large volumes.
• Skin protection: Use solvent-resistant gloves (nitrile at least 0.3 mm thick or neoprene) and a lab coat. Cyclohexanone can penetrate some glove materials rapidly; replace gloves frequently during extended use.
• Respiratory protection: If engineering controls are insufficient to keep vapor levels below occupational exposure limits (typically 25–50 ppm TWA depending on jurisdiction), use an organic-vapor respirator cartridge rated for ketones.
• Ignition sources: Keep away from open flames, sparks, and hot surfaces. Use explosion-proof electrical equipment where concentrations may exceed the lower explosive limit (LEL ~1.1 vol% in air).

In case of skin contact, flush immediately with copious water for at least 15 minutes. In case of eye contact, irrigate immediately with water for at least 15 minutes and seek medical attention. If ingested or if symptoms of overexposure (headache, dizziness, narcosis) occur, remove the individual to fresh air and consult a poison control center.

Storage Requirements

Proper storage of cyclohexanone is essential to maintain reagent quality and laboratory safety. Follow these guidelines:

• Location: Store in a dedicated, well-ventilated flammable materials storage cabinet away from oxidizers, strong acids, strong bases, and sources of ignition.
• Temperature: Keep at room temperature (15–25 °C) or cool store (2–8 °C) away from direct sunlight. Avoid prolonged exposure to temperatures exceeding 30 °C, which accelerates peroxide formation in aged or impure stock.
• Container integrity: Keep containers tightly sealed when not in use to minimize vapor release and moisture ingress. Use original amber or light-protected glass or UN-rated HDPE containers.
• Segregation: Segregate from peroxide-forming reagents, reactive metals (sodium, potassium), and halogenated oxidants.
• Quantity limits: Limit bench-top quantities to the minimum needed for immediate use (typically ≤1 L). Larger quantities should remain in the flammable storage cabinet.
• Labeling: Clearly label all secondary containers with contents, concentration, date of receipt, date opened, and hazard warnings.

Cyclohexanone can slowly form peroxides upon prolonged air exposure, especially if contaminated with water or metals. Test stored material with peroxide test strips before use if the container has been opened multiple times or stored for extended periods exceeding six months.

Laboratory Applications & Purity Considerations

Cyclohexanone serves diverse roles in research and industrial laboratory settings:

• Solvent for organic synthesis: Used as a reaction medium for nucleophilic additions, condensation reactions (including aldol-type reactions where it acts as a substrate), and Baeyer–Villiger oxidations to produce ε-caprolactone.
• Polymer research: Excellent solvent for cellulose esters, polyvinyl chloride (PVC), polystyrene, and polyurethane resins, making it valuable for film casting, coating formulation, and polymer characterization work.
• Analytical chemistry: Used as a standard or co-solvent in UV-Vis and IR spectroscopy sample preparation. Its characteristic carbonyl absorption near 1715 cm⁻¹ in IR spectra serves as a useful calibration marker.
• Biochemistry & cell biology: Occasionally used as a co-solvent at low concentrations for dissolving lipophilic compounds, though researchers must validate cytotoxicity at the concentrations used.

Purity grade selection: For most synthetic applications, reagent-grade (≥99%) cyclohexanone is appropriate. For spectroscopic or analytical reference applications, HPLC-grade or spectrophotometric-grade material with defined UV cutoff values should be selected. Always consult the Certificate of Analysis (CoA) provided with the specific lot to confirm water content, peroxide levels, and residual metals before use in moisture-sensitive or metal-catalyzed reactions.

Waste Disposal & Environmental Considerations

Cyclohexanone waste must be managed in accordance with local, national, and institutional regulations for flammable organic solvents. The following best practices apply:

• Segregation: Collect cyclohexanone waste in clearly labeled, solvent-compatible (glass or HDPE) waste containers dedicated to halogen-free organic solvents. Do not mix with halogenated solvent waste streams.
• Container management: Keep waste containers closed when not actively adding waste. Store in a designated flammable waste accumulation area within regulatory time and quantity limits.
• Disposal route: Arrange disposal through a licensed hazardous waste contractor. Incineration in a high-temperature facility is the standard disposal method for cyclohexanone waste.
• Drain disposal prohibition: Do NOT pour cyclohexanone down the drain. It is harmful to aquatic organisms (GHS Aquatic Chronic Category 3) and may disrupt wastewater treatment processes.
• Spill response: For small spills, absorb with inert dry material (sand, vermiculite, or commercial absorbent). Collect and place in appropriate labeled waste containers. For large spills, evacuate the area, eliminate ignition sources, and contact your institutional emergency response team.

Always consult your institution's Environmental Health and Safety (EHS) office and the current Safety Data Sheet (SDS) for cyclohexanone before establishing disposal procedures.

Frequently asked questions

What personal protective equipment (PPE) is required when handling cyclohexanone?

At minimum, wear chemical splash goggles, solvent-resistant nitrile gloves (≥0.3 mm), and a lab coat when handling cyclohexanone. Work inside a certified fume hood and use an organic-vapor respirator if vapor concentrations may exceed occupational exposure limits. Replace gloves frequently, as cyclohexanone can penetrate some glove materials.

Can cyclohexanone be stored at room temperature, and how long is it stable once opened?

Yes, cyclohexanone can be stored at room temperature (15–25 °C) in a tightly sealed, light-protected container inside a flammable materials cabinet. Once opened, it is generally stable for at least six months if kept tightly closed and away from light and moisture; however, perform a peroxide test before use if the container has been opened repeatedly or stored beyond six months, as trace peroxide formation can occur.

Which purity grade of cyclohexanone should I choose for my application?

For general organic synthesis, reagent-grade cyclohexanone (≥99%) is suitable. For spectroscopic or analytical applications requiring a defined UV cutoff or low UV absorbance background, choose HPLC-grade or spectrophotometric-grade material. Always verify lot-specific parameters such as water content, peroxide levels, and residual metals by consulting the Certificate of Analysis before use in sensitive reactions.

Is cyclohexanone compatible with aqueous reaction systems?

Cyclohexanone has limited water solubility (approximately 8 g/L at 20 °C) and is not fully miscible with water. In biphasic aqueous-organic systems it forms a separate organic layer, which can be exploited for extraction purposes. If a homogeneous aqueous-organic mixture is needed, co-solvents such as ethanol or acetone may be added, though this will alter reaction conditions significantly.

How should a cyclohexanone spill be managed in the laboratory?

For small spills, immediately eliminate all ignition sources, then absorb the liquid with inert dry material such as sand or vermiculite. Collect the absorbed material in a labeled, sealable waste container for disposal through a licensed hazardous waste contractor. For large spills, evacuate the area, ventilate, eliminate ignition sources, and contact your institutional emergency response team; do not allow the material to enter drains or waterways.

References

1. Royal Society of Chemistry. Cyclohexanone. ChemSpider entry. Physical and chemical property data.
2. National Institute for Occupational Safety and Health (NIOSH). Cyclohexanone. NIOSH Pocket Guide to Chemical Hazards.
3. European Chemicals Agency (ECHA). Cyclohexanone REACH registration dossier. Physicochemical, toxicological and ecotoxicological data.
4. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. 4th ed. Wiley-Interscience, 1992.

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