Material Safety Data Sheet for Sec-Butyl Mercaptan

Identification

Product Name: Sec-Butyl Mercaptan
Chemical Name: 2-Butanethiol
CAS Number: 513-53-1
EC Number: 208-157-7
Synonyms: sec-Butanethiol, 1-Methyl-1-propanethiol
Recommended Use: Chemical intermediate, odorant for gases
Supplier: Details provided by manufacturer or distributor upon request
Emergency Phone: Refer to local and international poison centers or company emergency contacts

Hazard Identification

Classification: Flammable liquid (Category 3), Acute toxicity (Category 3, oral), Skin irritation (Category 2), Eye irritation (Category 2A), Aquatic acute (Category 2)
Label Elements: Signal word: Danger, Pictograms: Flame, Skull and Crossbones, Exclamation Mark, Environmental hazard symbol
Hazard Statements: Flammable liquid and vapor; toxic if swallowed; causes skin irritation; causes serious eye irritation; toxic to aquatic life
Precautionary Statements: Keep away from sparks, open flames, hot surfaces; avoid breathing vapors; wash hands thoroughly after handling; wear protective gloves and eye protection; avoid release to the environment
Other Hazards: Generates irritating or toxic gases upon combustion; vapor forms explosive mixtures with air; strong, unpleasant odor even at low concentrations

Composition / Information on Ingredients

Chemical Identity: Sec-Butyl Mercaptan
Concentration: 98-100%
Impurities/Additives: Typical samples contain trace sulfur compounds
Molecular Formula: C4H10S
Other Ingredients: No significant nonhazardous ingredients present
RTECS Number: EK5600000

First Aid Measures

Inhalation: Move affected person to fresh air; keep at rest in comfortable position for breathing; seek immediate medical attention if symptoms (such as dizziness, coughing, shortness of breath) occur
Skin Contact: Remove contaminated clothing and thoroughly wash affected area under running water using mild soap; seek medical advice if irritation or redness develops
Eye Contact: Rinse cautiously with water for 15 minutes, lifting upper and lower eyelids; remove contact lenses if present and easy to do; seek medical attention promptly
Ingestion: Rinse mouth thoroughly; do not induce vomiting; never provide anything by mouth to an unconscious individual; seek immediate medical help
Most Important Symptoms: Severe irritation of mucous membranes, headache, nausea, central nervous system depression, potential respiratory distress
Immediate/Emergency Treatment: Doctors should treat symptomatically; provide supportive care as appropriate

Fire-Fighting Measures

Suitable Extinguishing Media: Use water spray, dry chemical, alcohol-resistant foam, or carbon dioxide
Unsuitable Extinguishing Media: Avoid direct water jet; may spread fire or cause violent frothing
Specific Hazards: Burns with highly irritating, suffocating, and toxic fumes, including oxides of sulfur and carbon monoxide
Protective Equipment: Firefighters need full protective gear and self-contained breathing apparatus
Special Fire-Fighting Methods: Cool surrounding tanks and containers with water spray; contain contaminated water; prevent runoff into drains and water systems
Explosion Hazard: Mixtures with air can ignite easily and explode in confined areas; vapor heavier than air and travels far to source of ignition

Accidental Release Measures

Personal Precautions: Evacuate unnecessary personnel from area; ventilate enclosed spaces; use proper personal protection (gloves, goggles, respirator)
Environmental Precautions: Prevent spill from reaching water bodies, drains, soil around facility; notify authorities if contamination occurs
Methods for Cleanup: Absorb on inert, non-combustible material (like sand, earth), then scoop into chemical waste containers; avoid creating dust or vapor clouds; wash spill site with water after pickup
Decontamination: Neutralize with dilute bleach if possible; consult with experts before attempting chemical neutralization
Waste Disposal: Place collected material in sealed containers for appropriate disposal (see Disposal Considerations)

Handling and Storage

Handling: Work only in well-ventilated or exhaust-ventilated areas; keep containers closed when not in use; avoid all sources of ignition; avoid direct contact with skin, eyes, clothing; wash hands after handling
Storage Conditions: Store in flammable storage area in tightly sealed containers; keep away from heat, sparks, open flames; segregate from oxidizers, acids, and foodstuffs
Special Requirements: Ground and bond containers during transfer to prevent static discharge; ensure labeling is legible and up to date; regularly inspect containers for leaks

Exposure Controls and Personal Protection

Occupational Exposure Limits: No OSHA PEL; ACGIH TLV: 0.5 ppm (TWA, skin); also recommended ceiling values in some jurisdictions
Engineering Controls: Local exhaust ventilation, process enclosures, safety showers and eyewash stations
Personal Protection: Use NIOSH-approved chemical cartridge respirators (organic vapor type); wear butyl rubber or nitrile gloves, chemical splash goggles, flame-resistant lab coats or chemical suits
Hygiene Measures: Remove contaminated clothing immediately and launder before reuse; avoid eating, drinking, or smoking in work areas; wash thoroughly after work

Physical and Chemical Properties

Appearance: Clear, colorless to pale yellow liquid
Odor: Very strong, foul (similar to skunk or decayed cabbage)
Odor Threshold: Detectable at less than 0.1 ppm
pH: Not applicable (non-aqueous)
Melting Point: -117°C
Boiling Point: 98-99°C
Flash Point: 22°C (closed cup)
Evaporation Rate: Moderate to fast (compared to n-butyl acetate)
Flammability: Highly flammable
Vapor Pressure: ~67 mmHg (20°C)
Vapor Density: 2.9 (air = 1)
Relative Density: 0.828 (water = 1)
Solubility: Slight (in water); miscible with alcohols, ethers, most organic solvents
Partition Coefficient: log Kow 2.28
Autoignition Temperature: 310°C
Decomposition Temperature: Decomposes on heating to release toxic gases
Viscosity: Low (mobile liquid)

Stability and Reactivity

Chemical Stability: Remains stable in sealed containers under normal temperatures and pressures for storage
Reactive Conditions: Vigorous reactions possible with strong oxidizers, strong acids, alkali metals, and halogens; susceptible to air oxidation producing disulfides
Hazardous Polymerization: Has not been reported
Decomposition Products: Sulfur oxides, carbon oxides, hydrogen sulfide (incomplete combustion or degradation)
Other Concerns: May corrode some metals over time; avoided exposure of storage areas to sunlight and moisture

Toxicological Information

Acute Toxicity: Oral LD50 (rat): 178 mg/kg; inhalation LC50 (rat): not precisely quantified, but low; strong evidence for toxicity by all routes
Skin Irritation: Moderately irritating; repeated contact causes redness, dryness, burns
Eye Irritation: Vapor and liquid pain, redness, tearing, possible permanent injury
Chronic Effects: Prolonged exposure brings risks of liver, kidney, nervous system damage; not listed as carcinogenic
Sensitization: Not a proven sensitizer, but local irritation can trigger allergic responses in some individuals
Inhalation Hazards: Headache, dizziness, confusion, nausea, risk of unconsciousness at high concentrations
Target Organs: Central nervous system, mucous membranes, eyes, skin
Additional Information: Intense odor usually warns users before dangerous exposures occur

Ecological Information

Ecotoxicity: Harmful to aquatic organisms; may cause ongoing damage to aquatic environments at low concentrations
Persistence and Degradability: Biodegradable by soil and water microbes, but can persist if large amounts enter environment
Mobility: Volatile, can travel by air; migration to groundwater unlikely in significant amounts
Bioaccumulation: Not expected, due to rapid breakdown and low log Kow
Other Effects: Rapid oxygen depletion in water, risk of fish kills; foul odor can affect quality of life and disrupt wildlife behavior

Disposal Considerations

Waste Disposal Methods: Send material, residues, and contaminated items to licensed chemical disposal or incineration facility
Container Disposal: Empty containers can contain vapor or trace liquid; triple-rinse, deface labels, and puncture before sending to recycling or hazardous waste
Precautions: Do not allow disposal in municipal waste, sewers, or natural bodies of water; consult local, regional, and national authorities for compliant practices
Special Instructions: Follow regulations for hazardous waste; keep chain-of-custody records for larger quantities

Transport Information

UN Number: UN2347
Proper Shipping Name: Sec-Butyl Mercaptan
Transport Hazard Class: 3 (Flammable Liquids)
Packing Group: II
Hazard Identification Number: 33
Labels: Flammable Liquid, Toxic Substance
Environmental Hazards: Marine pollutant; notify authorities if accidental release occurs in transit
Additional Transport Details: Emergency Response Guidebook No. 131; transport in compliance with IMDG, IATA, ADR rules for dangerous goods; restrict air shipment except by authorized packaging

Regulatory Information

OSHA: Classified hazardous under OSHA 29 CFR 1910.1200
SARA Title III: Listed on Section 313 (<1%) as "toxic chemical"
TSCA: Included in US EPA Toxic Substances Control Act inventory
REACH Status: Pre-registered in European Union; subject to registration for use/import in quantities over one ton/year
Canadian WHMIS Classification: B2 (Flammable Liquids), D1B (Toxic), D2B (Irritant)
California Proposition 65: Not currently listed
Other International Inventories: Found on Australia AICS, Japan ENCS, Korea ECL, Philippines PICCS, China IECSC
Restriction Details: Use in strictly controlled, well-ventilated systems; restrictions apply based on jurisdictional laws governing occupational, environmental, and public exposures