Benzonitrile: A Close Look at Its Safety Data and Handling in the Modern Workplace

Identification

Chemical name: Benzonitrile
Synonyms: Cyanobenzene, Phenyl cyanide
Molecular formula: C7H5N
CAS Number: 100-47-0
Description: A colorless to pale yellow liquid, faint almond-like odor, soluble in organic solvents, slightly soluble in water.

Hazard Identification

Hazard classification: Harmful if inhaled, swallowed, or absorbed through the skin, toxic to aquatic life, flammable liquid and vapor.
Key risks: Can irritate the nose, throat, eyes, and skin, can depress the central nervous system, potential to cause lasting organ damage at high exposure, fire risk in the presence of open flames or static discharge.
Label elements: Exclamation mark symbol, flame symbol, environmental hazard symbol.
Primary exposure routes: Inhalation, skin contact, ingestion.

Composition / Information on Ingredients

Main ingredient: Benzonitrile — typically found at or near 100 percent concentration in pure form for industrial use.
Impurities: Trace amounts of related aromatic nitriles may occur; commercial samples sometimes include stabilizers or inhibitors.
Toxic components: Main hazard stems from benzonitrile itself; small presence of other nitrile compounds should be noted.

First Aid Measures

Inhalation: Move impacted person into fresh air, keep comfortable, monitor symptoms, seek medical attention if symptoms persist.
Skin contact: Remove contaminated clothing, gently wash exposed skin with soap and water, observe for irritation or burns, consult a health professional if needed.
Eye contact: Rinse cautiously with water for several minutes, remove contact lenses if present, continue rinsing, seek medical advice for persistent pain or vision changes.
Ingestion: Rinse mouth with water, call a physician or poison center rapidly, do not induce vomiting unless instructed by a professional.

Fire-Fighting Measures

Suitable extinguishing media: Use dry chemical, carbon dioxide, alcohol-resistant foam.
Major fire risks: Vapors form explosive mixtures with air, burning can release toxic gases including hydrogen cyanide and nitrogen oxides.
PPE for firefighters: Self-contained breathing apparatus, full protective clothing, fight fires upwind to avoid inhalation of vapors.
Additional tips: Cool containers with water spray to prevent rupture, watch for runoff carrying contamination into soil or drains.

Accidental Release Measures

Personal precautions: Remove unnecessary personnel, ventilate area, avoid breathing vapors, prevent skin and eye contact.
Containment: Absorb liquid spills with inert materials such as sand or vermiculite, collect for disposal in sealed containers.
Environmental precautions: Prevent entry into watercourses, soil, or drains; report significant spillage to local authorities.
Cleanup techniques: Small spills can be wiped up wearing gloves and goggles; larger spills need trained teams and air monitoring.

Handling and Storage

Handling: Work in a well-ventilated space, keep away from flames, sparks, or static; observe strict hygiene, do not eat, drink, or smoke in work area.
Storage: Store in tightly closed, clearly labeled containers in a cool, dry area away from incompatible materials like acids and oxidizers; use flame-proof storage if available.
Mixing concerns: Avoid heating or mixing with strong acids, bases, or oxidizing agents to prevent violent reactions or toxic byproducts.

Exposure Controls and Personal Protection

Engineering controls: Local exhaust ventilation, chemical fume hood, prevent vapor buildup.
Personal protective equipment: Chemical-resistant gloves (such as nitrile or neoprene), safety goggles, lab coats or aprons, in high exposure situations use respiratory protection.
Exposure limits: Specific occupational limits vary by region; some agencies suggest thresholds around 5 ppm for workplace air over an eight-hour shift.
Hygiene: Wash hands thoroughly after use, remove contaminated clothing, keep separate from street clothes.

Physical and Chemical Properties

Appearance: Colorless to light yellow liquid.
Boiling point: Around 191°C.
Melting point: Approximately -13°C.
Flash point: Near 72°C.
Vapor pressure: Modest at room temperature, about 1 mmHg at 25°C.
Solubility: Slightly in water, mixes well with ethanol, ether, acetone.
Density: About 1.01 g/cm³ at 20°C.
Odor: Bitter almond-like, somewhat pungent.

Stability and Reactivity

Chemical stability: Stable under ordinary storage and handling, sensitive to intense heat or flames.
Reactivity concerns: Can react with strong acids, bases, and oxidizing agents, leading to hazardous byproducts.
Hazardous decomposition: Breakdown may generate toxic gases such as hydrogen cyanide, nitrogen oxides at high temperature.
Incompatible materials: Avoid mixing with chloroformates, strong oxidizing or reducing agents, powdered metals.

Toxicological Information

Acute toxicity: Harmful or fatal in high doses through inhalation, ingestion, or skin contact; metabolism can generate cyanide in the body.
Symptoms: Headache, nausea, dizziness, difficulty breathing, confusion, severe exposures threaten heart and brain function.
Chronic risks: Prolonged low-level exposure linked to central nervous system effects and possible organ damage, animal testing points to impacts on blood and liver.
Irritation: Eyes and skin may show redness or burning after contact; sensitive individuals could react more strongly.

Ecological Information

Aquatic effects: Toxic to aquatic organisms, persistent in water, high concentrations can disturb aquatic life balance.
Soil behavior: Tends to percolate through soil, risk of groundwater contamination.
Degradation: Not readily biodegradable, breaks down slowly in the environment, photolysis offers some route for breakdown.
Bioaccumulation: Low potential in most species, but concern remains regarding chronic low-level impacts.

Disposal Considerations

Methods: Incinerate in approved chemical incinerators with afterburners and scrubbers; smaller quantities can be absorbed in sand or earth and delivered to hazardous waste facilities.
Do not pour: Avoid draining into sewers, surface or subsurface water; all disposal to be consistent with federal, state, and local regulations.
Container disposal: Triple rinse, destroy labels, puncture or crush before landfilling if allowed by local waste laws.

Transport Information

UN number: Recognized as a hazardous material for transport, assigned commonly to UN1648.
Proper shipping name: Benzonitrile.
Transport risk: Flammable liquid, toxic substance, requires special labeling, use only approved containers and means.
Packing Group: Usually falls under Group III -- substances presenting a low risk of immediate harm during transit, but still subject to control.
Mode restrictions: Some airlines and carriers refuse unaccompanied or bulk shipments.

Regulatory Information

Occupational safety: Monitored under a variety of workplace safety standards, including recommended exposure limits and requirements for worker training.
Chemical inventories: Listed as a regulated substance in many countries, triggering import, export, and reporting requirements.
Environmental protection: Under regulatory scrutiny for potential water and soil contamination, subject to discharge limitations and control orders.
Sara/Reach status: Obey all reporting duties for supply, use, and disposal under national and international rules.
Labelling: Hazard statements, precautionary statements, and pictograms needed on packaging in accordance with the Globally Harmonized System.