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Chemical name: 2-Toluenethiol
Common names: o-Toluenethiol, 2-Methylbenzenethiol
CAS number: 137-07-5
Molecular formula: C7H8S
Physical appearance: Clear to pale yellow liquid, strong pungent odor resembling rotten eggs.
Notable use: Research and development, intermediate for chemical synthesis, rarely appears in mainstream industry outside of specialized labs.
Acute health risks: Harmful if inhaled, swallowed, or absorbed through the skin; exposure causes burning eyes, coughing, nausea, and headache.
Chronic exposure: Extended or repeated contact can cause dermatitis, respiratory complications, and sensitization of skin.
Fire and explosion risk: Highly flammable; releases toxic sulfur-containing fumes under fire conditions.
Environmental risk: Very toxic to aquatic life, persistent in the environment with risk of bioaccumulation.
GHS classification: Flammable liquid, acute toxicity (oral, dermal, inhalation), serious eye and skin irritant, aquatic acute hazard.
2-Toluenethiol: Typically encountered in pure or near-pure concentrations during laboratory or industrial use.
Specific impurities: Minor traces of toluene or other isomeric thiols possible depending on synthesis method.
Functional group: Contains both aromatic hydrocarbon and thiol functional groups, responsible for chemical reactivity and strong odor.
Skin contact: Remove contaminated clothing, immediately wash skin with large amounts of water and non-abrasive soap; persistent exposure linked to burns or severe irritation.
Eye contact: Flush eyes with water for at least 15 minutes, hold eyelids open; seek medical help immediately, as thiols can cause lasting damage.
Inhalation: Move individual to fresh air, monitor for respiratory distress; administer oxygen if breathing becomes difficult.
Ingestion: Rinse mouth with water only if individual is fully conscious, do not induce vomiting; thiol toxicity needs urgent medical care.
Suitable extinguishing media: Dry powder, carbon dioxide, alcohol-resistant foam.
Specific hazards: Vapors form explosive mixtures with air, low flash point, produces hydrogen sulfide and various oxides of sulfur and carbon on combustion.
Protective equipment: Full protective gear, self-contained breathing apparatus, as toxic and corrosive gases may fill confined space rapidly.
Personal precautions: Evacuate area, don chemical splash goggles and impervious gloves; thiol vapors linger close to ground and may spread from the source.
Containment methods: Prevent further spillage, ventilate enclosed spaces—thiols produce odors perceptible at extremely low concentrations.
Cleanup guidance: Absorb with inert dry material, place in chemical waste container, avoid using tools that may spark; thoroughly decontaminate area with water and detergent.
Safe handling guidance: Handle inside a chemical fume hood, never outside controlled environment, protect against static discharge.
Storage recommendations: Store below room temperature, in tightly sealed containers, away from oxidizing agents and ignition sources.
Incompatibilities: Avoid contact with strong bases, oxidizing substances, acids; reaction with metal surfaces accelerates thiol degradation and increases release of noxious gases.
Engineering controls: Bench-scale chemical work must include local exhaust or properly ventilated fume hood; ventilation needs routine inspection.
Personal protective equipment: Splash-proof goggles, chemical-resistant gloves, flame-retardant laboratory coat.
Respiratory hazards: Wear a NIOSH-approved respirator for organic vapors or supplied air for prolonged work;
Hygiene best practices: Remove contaminated clothing, wash hands and forearms immediately after handling, avoid eating or drinking in the work area.
Appearance: Clear, colorless to pale yellow liquid
Odor: Strong, rotten egg or skunk-like smell due to thiol group
Boiling point: Around 168°C
Melting point: Estimated near -30°C
Flash point: Low, around 48°C (closed cup)
Solubility: Poorly soluble in water, mixes well with common organic solvents such as ethanol or ether
Vapor pressure: Relatively high for a liquid of its size, contributes to strong odor spreading
Stability: Stores reasonably well in inert atmosphere and tightly closed system away from light and heat; open air and metal catalysts speed decomposition.
Reactive risks: Intense reactivity with oxidizers, can generate dangerous exothermic reactions; reacts slowly with oxygen over time, producing disulfides or sulfonic acids.
Hazardous decomposition: Burning or high-temperature breakdown produces hydrogen sulfide, sulfur dioxide, and toluene.
Acute effects: Inhalation causes headaches, nausea, eye and nasal irritation, potential pulmonary edema at high doses; skin contact produces intense burning or itching.
Chronic effects: Prolonged exposure may cause disruption in liver and kidney function; thiols sometimes sensitize skin, touching off allergic reactions on subsequent exposures.
LD50 data: Animal testing points to low LD50 (meaning chemical proves acutely toxic at small doses), so scrupulous safety work remains necessary.
Aquatic toxicity: Exhibits marked toxicity for aquatic organisms; even low concentrations can significantly disrupt freshwater or marine environments.
Persistence: Thiol compounds linger in sediment and soil, raising risks for food chain contamination.
Mobility: Volatile, with strong odor acting as a warning but insufficient to prevent unintentional environmental release.
Destruction methods: Incinerate in a chemical incinerator equipped with afterburners and scrubbers; landfill or drain disposal remains unacceptable for thiols, given risk for odor nuisance and environmental damage.
Precautionary disposal: Always segregate thiol waste, label containers clearly, transfer to licensed hazardous waste handlers. Never combine with common laboratory solvents, which could create dangerous mixtures.
Regulatory status: Transport of even small amounts triggers hazardous goods controls, with strict packaging and containment requirements.
Labeling: Requires flammable and toxic labels, handling under temperature control recommended for bulk transit.
Vehicle guidance: Operators must prevent leaks and mitigate fire risk through temperature monitoring and proper ventilation.
Compliance obligations: Subject to local and international hazardous substances laws, including storage, handling, labeling, and reporting accidental releases.
Workplace guidance: OSHA and similar agencies flag thiols as occupational hazards, mandating clear training and regular health monitoring for workers.
