tert-Butyl mercaptan

Heavy skunk odor

Strong offensive odor

0.8 (NFPA, 2010) - Less dense than water; will float

0.79426 at 25 °C/4 °C

Relative density (water = 1): 0.80

Mobile liquid

COLORLESS LIQUID

Insoluble (NFPA, 2010)

Slightly sol in water; very sol in alcohol, ether, liquid hydrogen sulfide

Very soluble in acetone; soluble in carbon tetrachloride

less than -20 °F (NFPA, 2010)

<-20 °F (<-29 °C) (closed cup)

-26 °C c.c.

149-153 °F at 760 mmHg (NFPA, 2010)

63.7-64.2 °C

64 °C

The substance decomposes on burning producing toxic gases including sulfur oxides.

When heated to decomposition or on contact with acid or acid fumes it emits highly toxic fumes of /sulfur oxides/.

-32 °F (ICSC, 2024)

-0.5 °C

Heat of fusion at melting point = 2.0782X10+7 J/kmol

0 °C

3.1 (NFPA, 2010) - Heavier than air; will sink (Relative to Air)

3.1 (Air= 1)

Relative vapor density (air = 1): 3.1

142.5 mmHg at 68 °F (ICSC, 2024)

181.0 [mmHg]

181 mm Hg at 25 °C /Extrapolated/

Vapor pressure, kPa at 20 °C: 19.0

Danger

H225 (35.5%): Highly Flammable liquid and vapor [Danger Flammable liquids]；H304 (64.5%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]；H317 (91.8%): May cause an allergic skin reaction [Warning Sensitization, Skin]；H319 (65%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]；H411 (27.2%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P210, P233, P240, P241, P242, P243, P261, P264+P265, P272, P273, P280, P301+P316, P302+P352, P303+P361+P353, P305+P351+P338, P321, P331, P333+P317, P337+P317, P362+P364, P370+P378, P391, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 691 reports by companies from 9 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.；Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

Chemical: 2-Propanethiol, 2-methyl-

Commission Regulation (EC) No 1565/2000 (Repealed by Com. Implementing Reg. (EU) No 872/2012)

2-Propanethiol, 2-methyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 2-Propanethiol, 2-methyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 23-12-2022 https://echa.europa.eu/registration-dossier/-/registered-dossier/2129

2-Propanethiol, 2-methyl-: HSNO Approval: HSR001102 Approved with controls

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:；HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids will float on water. (ERG, 2024)

Highly flammable. Vapour/air mixtures are explosive.

Dangerous, when exposed to heat or flame.

In general, mercaptans are flammable substances.

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:；May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas. Runoff from fire control or dilution water may cause environmental contamination. (ERG, 2024)

An eye and respiratory tract irritant; Inhalation of high concentrations can cause CNS depression; [ICSC] May cause mild skin and eye irritation, based on animal studies; Inhalation of high concentrations can cause CNS depression; [CHEMINFO] An irritant; May cause serious eye injury; [MSDSonline] See THIOLS.

Thiols, like TERT-BUTYL MERCAPTAN, can react with strong reducing agents, like alkali metals, nitrides, and hydrides, to form flammable hydrogen gas and strongly basic metal thiolates. Many of these compounds may liberate hydrogen sulfide upon decomposition or reaction with an acid. They are oxidized readily in the presence of oxidants. They may also react with isocyanates, similarly to alcohols.

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:；CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient.；SMALL FIRE: Dry chemical, CO2, water spray or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam.；LARGE FIRE: Water spray, fog or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam. Avoid aiming straight or solid streams directly onto the product. If it can be done safely, move undamaged containers away from the area around the fire.；FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

Use foam, carbon dioxide, powder. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth.

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:；Refer to the "General First Aid" section. Specific First Aid: Wash skin with soap and water. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. (ERG, 2024)

Alcohol foam, dry chemical, mist, fog.

If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped or safely confined. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, dry chemical or carbon dioxide. /Butyl mercaptan/

Fireproof. Separated from strong oxidants, strong bases, strong acids, metals, strong reducing agents.

...Materials which are toxic as stored or which can decompose into toxic components...should be stored in a cool, well ventilated place, out of the direct rays of the sun, away from areas of high fire hazard, and should be periodically inspected. Incompatible materials should be isolated...

Evacuate danger area! Remove all ignition sources. Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent and remove to safe place. Do NOT wash away into sewer. Carefully collect remainder, then remove to safe place.

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:；ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor-suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean, non-sparking tools to collect absorbed material.；LARGE SPILL: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor, but may not prevent ignition in closed spaces. (ERG, 2024)

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Evacuate danger area! Personal protection: filter respirator for organic gases and vapours adapted to the airborne concentration of the substance. Remove all ignition sources. Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations. Do NOT wash away into sewer.

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.

Ventilation control: generally process from which mercaptan vapor is liable to be evolved should as far as practicable be enclosed, and exhaust ventilation should be provided to prevent vapors from diffusing into atmosphere of workroom. /mercaptans/

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to disperse vapors and dilute standing pools of liquid. /Butyl mercaptan/

For more Preventive Measures (Complete) data for T-BUTYL MERCAPTAN (8 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 49(SRC), determined from a structure estimation method(2), indicates that t-butyl mercaptan is expected to have very high mobility in soil(SRC). Volatilization of t-butyl mercaptan from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 6.1X10-3 atm-cu m/mole(SRC), using a fragment constant estimation method(3). t-Butyl mercaptan is expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 181 mm Hg(4). Biodegradation data were not available(SRC, 2005).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 49(SRC), determined from a structure estimation method(2), indicates that t-butyl mercaptan is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 6.1X10-3 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 3 hours and 4 days, respectively(SRC). According to a classification scheme(5), an estimated BCF of 9(SRC), from an estimated log Kow of 2.1(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation data were not available(SRC, 2005).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), t-butyl mercaptan, which has an extrapolated vapor pressure of 181 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase t-butyl mercaptan is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 12 hours(SRC), calculated from its rate constant of 3.31X10-11 cu cm/molecule-sec at 25 °C(3). t-Butyl mercaptan does not absorb light at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight.

Cough. Dizziness. Headache. Nausea. Drowsiness.

Redness.

Nausea. Vomiting.

Using a structure estimation method based on molecular connectivity indices(1), the Koc of t-butyl mercaptan can be estimated to be 49(SRC). According to a classification scheme(2), this estimated Koc value suggests that t-butyl mercaptan is expected to have very high mobility in soil. Natural gas containing 0.5 lb of t-butyl mercaptan per million cubic feet was passed through a bed of pulverized, dry, raw montmorillonite clay and then measured for loss of odorant. Within 100 standard cubic feet, over 85% of the average influent concentration of t-butyl mercaptan was present in the effluent(3).

T-butyl mercaptan (CAS # 75-66-1) was evaluated for subchronic inhalation toxicity. The test substance was administered to rats (15/sex/group, strain not reported) at concentrations of 0 ppm, 9 ppm, 97 ppm, or 196 ppm for 6 hours/day, 5 days/week for 13 weeks. At 9 ppm, histopathology indicated inflammatory lesions in the lungs. At 97 ppm, minimal to mild interstitial fibrosis was indicated. At 196 ppm, interstitial fibrosis in the lungs of males and females, and nephrosis in male rats only was indicated.

/SIGNS AND SYMPTOMS/ /t-Butyl mercaptan/ is irritating to the eyes and the respiratory tract. Exposure at high levels may result in lowering of consciousness.

/SIGNS AND SYMPTOMS/ Strong, offensive smell of mercaptans can cause headache and nausea. High concentrations of their vapors in atmosphere can produce unconsciousness with cyanosis, a sense of coldness at the extremities and quickning of pulse ... Pulmonary edema /is also observed. /Mercaptans/

/SIGNS AND SYMPTOMS/ /T-butyl mercaptan may cause/ cough, dizziness, headache, nausea, drowsiness /by inhalation/.

An estimated BCF of 9 was calculated for t-butyl mercaptan(SRC), using an estimated log Kow of 2.1(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Henry's Law constant for t-butyl mercaptan is estimated as 6.1X10-3 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that t-butyl mercaptan is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 3 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 4 days(SRC). t-Butyl mercaptan's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). t-Butyl mercaptan is expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 181 mm Hg(3).

Chemical: 2-Propanethiol, 2-methyl-

Commission Regulation (EC) No 1565/2000 (Repealed by Com. Implementing Reg. (EU) No 872/2012)

2-Propanethiol, 2-methyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 2-Propanethiol, 2-methyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 23-12-2022 https://echa.europa.eu/registration-dossier/-/registered-dossier/2129

2-Propanethiol, 2-methyl-: HSNO Approval: HSR001102 Approved with controls

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Enzyme system responsible for conversion of endogenous toxic mercaptans in nontoxic thioether products via methylation is located in endoplasmic reticulum. Methylation of thiols studied was minimal in kidneys and brain, high activity seen in lungs. /Mercaptans/

Simple aliphatic and aromatic thiols undergo S-methylation in mammals to produce the corresponding methyl thioether or sulfide. Methylation is catalysed by thiopurine methyltransferase in the cytoplasm and thiol methyltransferase in microsomes, and both reactions require S-adenosyl-l-methionine as a methyl group donor. Thiopurine methyltransferase is present in human liver, kidney, and erythrocytes; preferential substrates for this enzyme include aromatic and heterocyclic thiols. S-Methylation of aliphatic thiols is catalysed by microsomal thiol methyltransferase, and the resulting methyl thioether (sulfide) metabolite would undergo S-oxidation to give the methyl sulfoxide and methyl sulfone analogues as urinary products. Thiols may react with glutathione and other endogenous thiol substances to form mixed disulfides. Both microsomal and cytoplasmic thioltransferasess have been reported to catalyse the formation of mixed disulfides. The resulting mixed disulfides can undergo reduction back to thiols, oxidative desulfuration, or oxidation to a sulfonic acid via the intermediate thiosulfinate and sulfinic acids. The principal form in the circulation would probably be a mixed disulfide formed with albumin. /Simple thiols/

Used as an odorant for natural gas, a chemical intermediate, and a bacterial nutrient; [HSDB]

Odorant, intermediate, bacterial nutrient

t-Butyl mercaptan is used primarily as an odorant at <30 ppm for natural gas so that leaks can be readily detected.

2023: 10,000,000 - <25,000,000 lb；2022: 10,000,000 - <25,000,000 lb；2021: 10,000,000 - <25,000,000 lb；2020: 10,000,000 - <25,000,000 lb

2-Propanethiol, 2-methyl- is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

(1972) PROBABLY GREATER THAN 4.54X10+5 GRAMS

(1975) PROBABLY GREATER THAN 4.54X10+5 GRAMS

Prepared from tert-butyl iodide, ZnS and alcohol.

t-Butyl mercaptan is manufactured by the reaction of isobutylene and hydrogen sulfide in the presence of acid catalysts.

All Other Basic Organic Chemical Manufacturing；Pesticide, Fertilizer, and Other Agricultural Chemical Manufacturing；Utilities

2-Propanethiol, 2-methyl-: ACTIVE

Thiols can be prepared by a variety of methods. The most-utilized of these synthetic methods for tertiary and secondary thiols is acid-catalyzed synthesis; for normal and secondary thiols, the most-utilized methods are free-radical-initiated, alcohol substitution, or halide substitution; for mercaptoalcohols, the most-utilized method is oxirane addition; and for mercaptoacids and mercaptonitriles, the most-utilized methods are Michael-type additions. /Thiols/