Quick Answer

Yes, cyclohexanone is volatile - but only moderately so. It is classified as a moderately volatile industrial solvent, meaning it evaporates at room temperature but far more slowly than fast-evaporating solvents like acetone or MEK.

The key numbers explain why:

• Boiling point: 155.6°C - much higher than acetone (56°C)
• Vapor pressure: approximately 5.2 mmHg at 25°C - roughly 30–40 times lower than acetone's vapor pressure
• Flash point: approximately 44°C (closed cup) - classifying it as a combustible liquid rather than a highly flammable one

Because of this moderate evaporation rate, cyclohexanone is widely used in applications that require controlled drying and film formation rather than instant flash-off. This includes paint and coating formulations, nylon (caprolactam and adipic acid) production, resin and polymer manufacturing, and adhesive systems, where a slower solvent release improves surface finish, adhesion, and process control.

For buyers and formulators, "moderately volatile" translates directly into practical decisions: standard ventilated storage rather than refrigerated storage, standard flammable-liquid shipping classification, and predictable drying/curing windows in production.

What Does "Volatile" Mean?

In chemistry, volatility describes how readily a liquid turns into a vapor at a given temperature. It is purely a physical property tied to how easily molecules escape a liquid's surface into the air.

It's important to separate volatility from two properties it's often confused with:

• Volatility is not flammability. A liquid can evaporate quickly without being especially flammable (or vice versa). Flammability depends on flash point and vapor flammability limits, not evaporation rate alone.
• Volatility is not toxicity. How fast a substance evaporates says nothing directly about how hazardous its vapor is to breathe. A slow-evaporating liquid can still require respiratory protection, and a fast-evaporating one may be relatively low-risk in short exposures.

Volatility instead answers a narrower, practical question: how much of this liquid will end up in the air, and how fast? That single property drives decisions about ventilation, container design, drying times, and VOC (volatile organic compound) reporting - which is why it matters so much in industrial purchasing and process design.

Why Is Cyclohexanone Considered Moderately Volatile?

Cyclohexanone sits in the middle of the solvent volatility spectrum, and two physical properties explain why.

Boiling point (155.6°C). Boiling point is the clearest single predictor of relative volatility among similar solvents: the higher the boiling point, the more energy is needed to convert liquid to vapor, and the slower evaporation happens at room temperature. At 155.6°C, cyclohexanone's boiling point is nearly triple that of acetone (56°C) and almost double that of toluene (111°C).

Vapor pressure (~5.2 mmHg at 25°C). Vapor pressure measures how strongly a liquid "pushes" molecules into the surrounding air at a given temperature. Acetone's vapor pressure at the same temperature is around 180–230 mmHg - more than 30 times higher. Cyclohexanone's comparatively low vapor pressure means far fewer molecules escape into the air per unit of time, so a spill or open container releases vapor gradually rather than in a quick burst.

Put together, these two properties explain the practical behavior formulators and buyers actually observe: cyclohexanone evaporates noticeably slower than fast solvents, but it does not sit in the "low volatility" category occupied by high-boiling glycols or plasticizers. That middle position is precisely why it's described as moderately volatile.

cyclohexanone physical properties

Cyclohexanone vs. Other Common Solvents 

The pattern is consistent: as boiling point rises, evaporation slows and vapor pressure drops. Cyclohexanone's position - well above the "fast" solvents but below genuinely low-volatility compounds like glycol ethers - is exactly what makes it useful where formulators need working time, film-leveling time, or controlled drying, rather than instant evaporation.

Why Volatility Matters in Industrial Purchasing

For procurement and technical teams, a solvent's volatility isn't just a lab number - it directly shapes cost, compliance, and process decisions:

• Storage requirements: A flash point around 44°C means cyclohexanone needs cool, well-ventilated storage away from ignition sources, but not the specialized refrigerated storage that highly volatile, low-flash-point solvents require.
• Shipping classification: Its flash point and vapor pressure place it in standard flammable-liquid transport categories, which affects packaging, labeling, and carrier requirements for both domestic and export shipments.
• VOC considerations: Because it evaporates and contributes to volatile organic compound emissions, cyclohexanone use is subject to VOC reporting and control regulations in many jurisdictions - a factor buyers should confirm against local environmental rules.
• Process performance: Moderate volatility gives formulators more open time during application (coatings, resin processing) before the solvent flashes off, improving leveling, adhesion, and finish quality.
• Drying speed: Slower evaporation means longer drying/curing cycles compared with fast solvents - a trade-off production planning needs to account for in throughput scheduling.
• Worker exposure: Lower vapor pressure generally means lower ambient vapor concentration under the same conditions, but exposure limits (such as OSHA PELs) still apply and must guide ventilation design.

Safety and Storage Guidelines

Handling cyclohexanone safely follows standard industrial solvent practice, informed by OSHA and CDC/NIOSH guidance:

• Personal Protective Equipment (PPE): Chemical-resistant gloves, safety goggles or a face shield, and protective clothing are recommended to prevent skin and eye contact, which can cause irritation.
• Ventilation: Use local exhaust ventilation or work in well-ventilated areas to keep airborne vapor concentrations below occupational exposure limits.
• Storage temperature: Store in a cool, dry area away from heat sources and direct sunlight, in tightly closed, corrosion-resistant containers (typically steel or HDPE).
• Fire protection: Because its flash point classifies it as a combustible/flammable liquid, keep it away from open flames, sparks, and static discharge sources, and store it separately from strong oxidizers.
• Spill response: Contain spills with inert absorbent material, ventilate the area to disperse vapors, and avoid ignition sources during cleanup; dispose of waste according to local hazardous-waste regulations.

How Moderate Volatility Benefits Industrial Applications

Cyclohexanone's specific volatility profile isn't incidental - it's a major reason the compound is chosen over faster- or slower-evaporating alternatives across several industries:

• Paint and coatings: Moderate evaporation gives paint films time to level and flow before the solvent flashes off, reducing surface defects like orange peel and improving gloss and adhesion.
• Nylon production: As a key intermediate and process solvent in caprolactam and adipic acid manufacturing (precursors to nylon 6 and nylon 6,6), its stable liquid behavior at process temperatures supports controlled reaction and separation steps.
• Adhesives: A slower evaporation rate extends open/working time, giving adhesive formulators a longer window for application and bonding before the solvent fully evaporates.
• Pesticide and agrochemical formulations: Cyclohexanone's solvency power combined with moderate volatility helps active ingredients stay in solution during storage while still allowing the carrier solvent to evaporate appropriately after application.

FAQ

Is cyclohexanone highly volatile?

No. Cyclohexanone is moderately volatile. Its boiling point (155.6°C) and vapor pressure (~5.2 mmHg at 25°C) are both far below those of high-volatility solvents like acetone.

Is cyclohexanone flammable?

Yes, it is classified as a combustible/flammable liquid, with a flash point of approximately 44°C (closed cup). It should be stored away from heat, sparks, and open flame.

Does cyclohexanone evaporate quickly?

Not quickly compared to common fast solvents. It evaporates at room temperature but at a much slower rate than acetone, MEK, or ethyl acetate, due to its higher boiling point and lower vapor pressure.

Is cyclohexanone considered a VOC?

Yes, cyclohexanone is generally classified as a volatile organic compound and is subject to VOC emission regulations in many regions. Buyers should confirm specific reporting requirements with local environmental authorities.

Can cyclohexanone be stored at room temperature?

Yes. With a melting point of -47°C and a boiling point of 155.6°C, it remains stable as a liquid across normal ambient temperatures, provided it is kept in a cool, ventilated area away from ignition sources.

How does cyclohexanone compare with acetone?

Cyclohexanone is far less volatile than acetone. Its boiling point is nearly triple acetone's, and its vapor pressure is roughly 30–40 times lower, meaning it evaporates far more slowly and provides longer working time in formulations.

How should cyclohexanone be transported?

Due to its flash point, cyclohexanone is shipped as a flammable/combustible liquid under standard hazardous-materials regulations (e.g., UN 1915), requiring appropriate labeling, packaging, and carrier compliance for both domestic and international transport.