Toluene (Methylbenzene)

Overview

Toluene (CAS No: 108-88-3), also known as methylbenzene, is a colorless, water-insoluble aromatic hydrocarbon with a characteristic odor. It consists of a benzene ring with a methyl group attached, making it a key solvent and chemical intermediate in various industries.

Toluene is an excellent solvent for organic compounds and is used in paints, coatings, adhesives, and chemical synthesis. It serves as a starting material for producing benzene, xylene, TNT, and other chemicals. Its high octane number also makes it a valuable fuel additive.

Applications

Toluene has a wide range of industrial and consumer applications:

Technical Specifications

Safety Information

Hazard Symbols and Statements

Flammable Eye and skin irritation Central nervous system effects

Personal Protective Equipment

• Chemically resistant gloves (nitrile or Viton)
• Chemical safety goggles or face shield
• Respiratory protection with organic vapor filter
• Chemically resistant apron or work clothing
• Ensure adequate ventilation or local exhaust systems

Storage Conditions

• Store in a cool, well-ventilated, non-flammable area
• Keep away from ignition sources and sparks
• Store in tightly sealed original containers, protected from sunlight
• Keep separate from oxidizing agents
• Storage temperature: 15-25°C

Fire Fighting Measures

• Suitable extinguishing agents: Dry chemical, CO₂, alcohol-resistant foam
• Do not use water jets - may spread fire
• Trained personnel should intervene with appropriate respiratory protection
• For small fires, use dry chemical or CO₂
• For large fires, use water spray for cooling

Handling and Storage

Handling

• Ensure containers are tightly closed during transport
• Ground equipment to prevent static electricity buildup
• Provide adequate ventilation in transport vehicles
• Avoid eating, drinking, or smoking during handling
• Label transport containers as "Highly Flammable Liquid"

Storage

• Store in stainless steel, polyethylene, or glass containers
• Use polyethylene or Teflon for plastic containers
• Display "Flammable Liquid" signs in storage areas
• Use appropriate breather valves in storage tanks
• Use explosion-proof electrical systems for large-scale storage
• Prohibit smoking in storage areas

Spill Response

• Remove all ignition sources
• Use appropriate respiratory protection
• Absorb spill with sand, chemical absorbent, or other suitable materials
• Dispose of absorbed materials properly
• Clean spilled area with plenty of water and detergent
• For large spills, contact professional cleanup services

Regulatory Information

GHS Classification

• Flammable Liquid Category 2
• Skin Irritation Category 2
• Eye Irritation Category 2A
• Specific Target Organ Toxicity (Single Exposure) Category 3
• Respiratory Irritation

Key Regulations

• REACH: Registered
• CLP: Compliant
• OSHA: Subject to hazard communication standards
• NFPA 704: Health 2, Flammability 3, Reactivity 0
• EPA: Classified as VOC

International Regulations

• European Union: Subject to Directive 2008/58/EC
• USA: Subject to EPA VOC regulations
• China: Listed in IECSC
• Japan: Listed in ISHL
• Global: Not subject to Montreal Protocol

Environmental Information

Environmental Impact

Toluene degrades in the atmosphere via photochemical reactions (half-life 1-3 days). In water, it is moderately toxic to aquatic organisms. It rapidly evaporates and biodegrades in soil. It does not harm the ozone layer.

Biodegradation

• Air: Photochemical reactions with 1-3 days half-life
• Water: Microbial activity degrades it within 7-28 days
• Soil: Rapid biodegradation via microbial activity
• Biological Oxygen Demand (BOD): 2.1-2.4 g O₂/g Toluene

Waste Management

• Classified as hazardous waste
• Small quantities can be evaporated in licensed facilities
• Large quantities must be incinerated in licensed hazardous waste facilities
• Dispose in accordance with local regulations
• Prevent contamination of wastewater

Frequently Asked Questions

How is toluene produced?

Toluene is primarily produced during petroleum refining through catalytic reforming or from coal tar distillation. Industrial-scale methods include catalytic reforming and pyrolysis gasoline extraction. Global annual production exceeds 20 million tons.

What is the difference between toluene and benzene?

Toluene (C7H8) is formed by attaching a methyl group to a benzene (C6H6) ring. Benzene is more toxic and carcinogenic. Toluene is less toxic and can be used as a safer alternative in many applications. Their solvent properties are similar.

Does toluene damage plastics?

Toluene can dissolve or damage polystyrene, PVC, and some other plastics. Polyethylene and polypropylene are resistant to short-term exposure but should avoid prolonged contact. PTFE (Teflon) is resistant to toluene.

What is the shelf life of toluene?

When stored in tightly sealed containers, toluene has a shelf life of approximately 2 years. To prevent oxidation, minimize air exposure. Stability testing is recommended for long-term storage.

What should I do if toluene contacts skin?

Remove contaminated clothing immediately and wash with plenty of soap and water. Prolonged contact may cause dryness and irritation. If irritation persists, seek medical attention. For eye contact, rinse with water for at least 15 minutes and consult an eye specialist.