Names & Synonyms

Name of Substance

• cyclohexane

Superlist Name

• Benzene, hexahydro-
• Cyclohexane
• Cyclohexane [UN1145] [Flammable liquid]
• RCRA waste no. U056
• UN1145

Synonyms

• AI3-08222
• Benzene, hexahydro-
• Benzenehexahydride
• CCRIS 3928
• CTFA 06225
• Caswell No. 269
• Cicloesano [Italian]
• Cyclohexaan [Dutch]
• Cyclohexan [German]
• Cyclohexane
• Cyclohexane (ACGIH:OSHA)
• Cykloheksan [Polish]
• EINECS 203-806-2
• EPA Pesticide Chemical Code 025901
• HSDB 60
• Hexahydrobenzene
• Hexamethylene
• Hexanaphthene
• NSC 406835
• RCRA waste number U056

Systematic Name

• Cyclohexane
• Cyclohexane(DOT) (8CI)(9CI)

Classification Code

• Mutation data
• Skin / Eye Irritant
• TSCA Flag: T [Subject to a Section 4 test rule]

Superlist Classification Code

• Reportable Quantity (RQ) = 1000 lb
• TWA (300 ppm)
• TWA 300 mg/m3 (1050 ppm);

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Internet Locators

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• CGB
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• MA
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OSHA

Appearance and odor

Cyclohexane is a colorless liquid with a mild, sweet odor resembling that of chloroform or benzene. Air odor thresholds ranging from 25 to 300 parts per million (ppm) parts of air have been reported.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 84.18

2. Boiling point (at 760 mm Hg): 80.7 degrees C (177.26 degrees F)

3. Specific gravity: 0.78 at 20 degrees C (68 degrees F)

4. Vapor density: 2.90

5. Melting point: 6.47 degrees C (43.65 degrees F)

6. Vapor pressure at 20 degrees C (68 degrees F): 95 mm Hg

7. Solubility: Insoluble in water; soluble in alcohol, ether, acetone, benzene, and ligroin.

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to cyclohexane can occur through inhalation, ingestion, and eye or skin contact [Sittig 1991].

* Summary of toxicology

1. Effects on Animals: Cyclohexane is an eye and mucous membrane irritant; at high concentrations, it causes narcosis in experimental animals [Hathaway et al. 1991]. Exposure to high vapor concentrations causes convulsions, and ingestion of toxic doses causes diarrhea, circulatory collapse, and death [Gosselin 1984]. Rabbits exposed for 8 hours to 18,500 ppm survived; exposure to 26,000 ppm proved fatal after 1 hour. Exposure to 12,600 ppm resulted in lethargy, narcosis, increased respiratory rates, and convulsions. Rabbits exposed to 786 ppm for 50 6-hour exposures showed microscopic changes in liver and kidney tissue [ACGIH 1991]. Mice exposed to 18,000 ppm developed tremors in 5 minutes, disturbed equilibrium in 15 minutes, and recumbency in 25 minutes [Hathaway et al. 1991]. A monkey exposed to 1,243 ppm for 50 6-hour exposures showed no adverse effects during or after exposure, and postmortem examination showed no histological changes [NLM 1995].

2. Effects on Humans: Cyclohexane is an irritant of the eyes and mucous membranes in humans. By analogy with the effects in animals, exposure to high concentrations is expected to cause narcosis. Exposure to 300 ppm caused irritation to the eyes and mucous membranes in workers [Hathaway et al. 1991]. Exposure to higher concentrations is likely to cause dizziness, nausea, and other narcotic effects. On repeated contact, cyclohexane is a defatting agent. Cyclohexane has not been shown to cause the hematologic changes associated with exposure to benzene [Hathaway et al. 1991].

* Signs and symptoms of exposure

1. Acute exposure: Exposure to the vapors of cyclohexane causes irritation of the eyes and mucous membranes. If exposure is severe, nausea, vomiting, incoordination, and coma may occur [Hathaway et al. 1991].

2. Chronic exposure: Chronic dermal contact may cause a dry, scaly, fissured dermatitis [Sittig 1991; Hathaway et al. 1991].