Xylene

Overview

Xylene (CAS No: 1330-20-7), also known as dimethylbenzene, is a colorless, flammable aromatic hydrocarbon with a distinctive, pungent odor. This organic compound contains a benzene ring with two methyl groups attached, making it a key industrial solvent.

Xylene exists in three isomeric forms (ortho-, meta-, and para-xylene). Commercial xylene is typically a mixture of these isomers. It has low solubility in water but is miscible with most organic solvents. Due to its high solvency power and moderate evaporation rate, it is widely used in the paint, coating, and printing ink industries.

Applications

Xylene has a wide range of industrial and consumer applications:

Technical Specifications

Safety Information

Hazard Symbols and Statements

Flammable Eye and Skin Irritation Respiratory Irritation

Personal Protective Equipment (PPE)

• Chemical-resistant gloves (nitrile or neoprene)
• Chemical safety goggles or face shield
• Respiratory protection with organic vapor filter
• Chemical-resistant apron or work clothing
• Adequate ventilation or local exhaust system

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: 15-30°C

Fire Fighting Measures

• Suitable extinguishers: Dry chemical, CO₂, alcohol-resistant foam
• Do not use water jet - may spread fire
• Intervene with proper respiratory protection by trained personnel
• Use dry chemical or CO₂ for small fires
• Use water spray for cooling in large fires

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 "Flammable Liquid"

Storage

• Store in stainless steel, polyethylene, or glass containers
• Label storage areas with "Flammable Liquid" signs
• Use appropriate breathing valves in storage tanks
• Use explosion-proof electrical systems for large-scale storage
• Prohibit smoking in storage areas
• Ensure grounding systems 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 material appropriately
• Clean the spill area with plenty of water and detergent
• Seek professional cleanup services for large spills

Regulatory Information

GHS Classification

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

Key Regulations

• REACH: Registered
• CLP: Compliant
• OSHA: Subject to Hazard Communication Standard
• 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

Xylene degrades in the atmosphere via photochemical reactions (half-life 1-2 days). It is toxic to aquatic organisms if released into water sources. It is biodegradable but moderately persistent in the environment.

Biodegradation

• Air: Photochemical reactions with 1-2 day half-life
• Water: Degrades via microbial activity within 1-4 weeks
• Soil: Moderate degradation via microbial activity
• Biological Oxygen Demand (BOD): 1.5-2.0 g O₂/g xylene

Waste Management

• Classified as hazardous waste
• Incinerate in licensed hazardous waste disposal facilities
• Dispose in accordance with local regulations
• Prevent release into wastewater
• Take precautions to avoid soil contamination

Frequently Asked Questions

How is xylene produced?

Xylene is primarily produced through petroleum refining and coal tar distillation. It is separated from the BTX (benzene, toluene, xylene) mixture obtained from the reforming process. Industrial-scale distillation and extraction processes are used.

What is the difference between xylene and toluene?

Xylene (C8H10) has a longer alkyl chain and higher boiling point than toluene (C7H8). Xylene evaporates more slowly and has higher solvency power. In terms of toxicity, xylene poses a slightly higher risk.

Does xylene damage plastics?

Xylene can dissolve or deform polystyrene, PVC, and some other plastics. Polyethylene and polypropylene are resistant to short-term exposure but should avoid prolonged contact.

What is the shelf life of xylene?

When stored properly in sealed containers, xylene has a shelf life of approximately 2 years. It should be tightly sealed to prevent water absorption and oxidation.

What should I do if xylene contacts skin?

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