Material Safety Data Sheet: Thionyl Chloride

Identification

Product Name: Thionyl Chloride
Chemical Formula: SOCl₂
Chemical Family: Inorganic acid chloride
CAS Number: 7719-09-7
Manufacturer: Common industrial chemical suppliers
Recommended Use: Intermediate in organic synthesis, pharmaceuticals, and agrochemicals
Emergency Contact: Refer to local and international emergency phone systems, for example CHEMTREC in the United States
Synonyms: Sulfurous dichloride, sulfur oxychloride
UN Number: 1836
Relevant Identified Uses: Laboratory reagent, chemical manufacturing
Restrictions on Use: Only for industrial and professional use

Hazard Identification

GHS Classification: Acute Toxicity (Oral, Dermal, Inhalation) Category 3; Skin Corrosion Category 1A; Specific Target Organ Toxicity (Single Exposure) Category 3
Pictograms: Corrosive, skull and crossbones
Signal Word: Danger
Hazard Statements: Fatal if inhaled, causes severe skin burns and eye damage, may cause respiratory irritation
Precautionary Statements: Avoid breathing dust, fumes, gas, mist, vapors, or spray; wash hands thoroughly; use only in well-ventilated area; wear protective gloves, clothing, and eye protection
Routes of Exposure: Inhalation, skin contact, eye contact, ingestion
Specific Hazards: Releases highly toxic gases on contact with water (hydrogen chloride and sulfur dioxide), very reactive and corrosive, fuming liquid

Composition / Information on Ingredients

Chemical Name: Thionyl Chloride
Concentration: 100% for pure substance, otherwise consult supplier
Molecular Weight: 118.97 g/mol
Impurities: Possible traces of sulfur monochloride, sulfur dichloride, or other reactive chlorinated compounds depending on manufacturing process
Ingredient Disclosure: No mixtures

First Aid Measures

Inhalation: Move to fresh air immediately, administer oxygen if breathing is difficult, seek medical attention right away
Skin Contact: Remove contaminated clothing, flush skin with plenty of water for at least 15 minutes, seek immediate medical care; do not use ointments
Eye Contact: Rinse with water for at least 15 minutes, lifting eyelids occasionally; get medical help urgently
Ingestion: Do not induce vomiting, rinse mouth with water, never give anything by mouth to an unconscious person, get medical assistance as fast as possible
Most Important Symptoms: Severe burning sensation, coughing, shortness of breath, eye and skin burns, possible delayed pulmonary edema
Advice for Physicians: Treat as corrosive inhalation and ingestion; monitor for chemical pneumonitis and secondary infections

Fire-Fighting Measures

Suitable Extinguishing Media: Dry powder, sand, or carbon dioxide, use large amount of water spray for small fires only if product is not reacting with water
Fire Hazards: Non-flammable but reacts violently with water; liberates hazardous vapors (hydrogen chloride, sulfur dioxide)
Special Hazards: Contact with water or moisture creates corrosive fumes, risk of container rupture at high temperature
Firefighting Instructions: Use self-contained breathing apparatus and chemical protective clothing, evacuate area if necessary
Decomposition Products: Hydrogen chloride, sulfur dioxide, possibly phosgene and other chlorinated gases

Accidental Release Measures

Personal Precautions: Use full chemical protective suit, avoid inhalation and skin contact, ventilate area
Environmental Precautions: Prevent product from entering sewers, waterways, or soil, contain spill with sand or inert material
Methods for Cleanup: Absorb using dry earth or vermiculite, keep away from water, neutralize cautiously with sodium bicarbonate or lime, collect residue for disposal
Evacuation Procedures: Remove unprotected personnel, restrict access
Decontamination: Do not wash down with water; use dry neutralizing agents

Handling and Storage

Handling: Use only in well-ventilated chemical fume hoods, open containers carefully, avoid contact with skin, eyes, and clothing, never add water or allow contact with moisture
Hygiene Requirements: Wash hands thoroughly after handling, remove contaminated clothing
Storage Conditions: Store in tightly closed containers made of compatible materials (glass or certain plastics), in a cool, dry, and well-ventilated area, away from moisture, bases, strong oxidizing agents, and incompatible materials
Segregation: Keep away from acids, alkalis, water-reactive materials, flammable substances
Container Precautions: Make sure containers are labeled properly, do not reuse empty containers

Exposure Controls and Personal Protection

Occupational Exposure Limits: ACGIH TLV: 1 ppm ceiling (hydrogen chloride byproduct); OSHA PEL: Not established for thionyl chloride specifically
Engineering Controls: Work in chemical fume hoods, provide local exhaust, use closed systems wherever possible
Personal Protection: Use acid-resistant gloves (butyl rubber, neoprene), full-face shield, chemical splash goggles, flame-resistant lab coat, chemical suit for large quantities
Respiratory Protection: For low-level exposure, use NIOSH-approved half or full-face respirators with acid gas cartridges; for high concentrations, use self-contained breathing apparatus
Other Protective Equipment: Safety shower and eyewash station nearby, chemical-resistant footwear
Environmental Controls: Follow strict spill containment and ventilation procedures, use proper waste systems

Physical and Chemical Properties

Appearance: Clear to pale yellow, fuming liquid
Odor: Pungent, choking
pH: Not applicable (reacts with water)
Melting Point: -104.5°C
Boiling Point: 79°C
Flash Point: Not flammable
Evaporation Rate: Not reported
Vapor Pressure: 127 mm Hg at 25°C
Vapor Density: 4.6 (air = 1)
Solubility: Reacts violently with water
Density: 1.638 g/cm³ at 20°C
Partition Coefficient: Not available
Viscosity: 0.54 mPa·s at 20°C
Autoignition Temperature: Not applicable

Stability and Reactivity

Chemical Stability: Stable under recommended storage conditions, decomposes on contact with water and moisture
Reactivity: Reacts exothermically with water, alcohols, amines, bases, oxidizing or reducing agents, and organic materials
Hazardous Reactions: Violent reaction with water, forms corrosive and toxic gases
Conditions to Avoid: Humidity, heat, open flames, any ignition sources, incompatible substances
Incompatible Materials: Water, alcohols, ammonia, strong bases, organic compounds, reducing agents
Hazardous Decomposition Products: Hydrogen chloride, sulfur dioxide, possible phosgene and chlorine gas

Toxicological Information

Acute Toxicity: LD₅₀ (oral, rat): 140 mg/kg; LC₅₀ (inhalation, rat): 45 ppm (1 hour)
Skin Corrosion/Irritation: Causes severe chemical burns, blistering, necrosis
Eye Damage/Irritation: Rapidly causes severe burns, can lead to permanent eye damage or blindness
Respiratory Sensitization: Severe pulmonary irritant, can cause chemical pneumonitis, edema
Chronic Effects: Prolonged exposure may damage respiratory tract, skin, and eyes irreversible; chronic cough, bronchitis cases documented
Possible Carcinogenicity: Not classified by IARC, NTP, or OSHA
Other Information: No evidence of mutagenicity or reproductive toxicity in available research

Ecological Information

Environmental Impact: Dangerous for aquatic life in acute exposures, acidifies water rapidly, low bioaccumulation potential
Persistence and Degradability: Hydrolyzes quickly in water to hydrochloric and sulfurous acids
Mobility in Soil: Highly mobile, will volatilize and react with water
Other Adverse Effects: Contributes to acidification of soil and water bodies, may damage infrastructure and disrupt ecosystems near spill sites
Regulation Relevance: Requires strict spill control and reporting in most countries

Disposal Considerations

Waste Treatment Methods: Neutralize cautiously with sodium bicarbonate or calcium hydroxide in a controlled fume hood, dilute and treat resulting solution as hazardous
Disposal of Packaging: Triple rinse with suitable neutralizing agent, dispose in chemical waste in accordance with national and local regulations
Special Precautions: Do not dump into sewers, surface water, or soil
Incineration: Only in properly equipped chemical incinerators with gas scrubbing
Consultation: Contact approved waste disposal contractors familiar with toxic and corrosive chemicals

Transport Information

UN Number: 1836
UN Proper Shipping Name: Thionyl chloride
Transport Hazard Class: 8 (Corrosive), 6.1 (Toxic)
Packing Group: I (high danger)
Labels Required: Corrosive, Toxic
Environmental Hazards: Marked as marine pollutant for water transport
Special Transport Precautions: Secure upright, separated from incompatible substances, government-mandated declarations required
Regulatory References: ADR/RID, IMDG Code, IATA

Regulatory Information

OSHA: Regulated as a highly hazardous chemical
EPA: Listed under CERCLA (RQ: 100 pounds), subject to SARA Title III, Section 302 and 313 reporting
EU REACH: Registered substance, strict supply chain requirements
Canada WHMIS: Class E, D1A, D2A (very toxic, corrosive)
Other Regulatory Details: Subject to export notification with some authorities, strict workplace control required
Label Elements: Danger, corrosive, toxic, environmental hazard
Restriction Notes: International transport and storage under regulatory oversight, compliance with local, regional, and international law required at all stages