Ethanethiol Chemical Properties
- Melting point:-148 °C
- Boiling point:35 °C(lit.)
- Density 0.839 g/mL at 25 °C(lit.)
- vapor density 2.1 (vs air)
- vapor pressure 8.51 psi ( 20 °C)
- refractive index n
- FEMA 4258 | ETHANETHIOL
- Flash point:1 °F
- storage temp. 2-8°C
- solubility 6.8g/l
- pka10.6(at 25℃)
- form Liquid
- color Colorless
- OdorStrong chunk; offensive garlic.
- OdorEthanethiol has a strongly disagreeable odor that humans can detect in minute concentrations. The threshold for human detection is as low as one part in 2.8 billion parts of air. Its odor resembles that of leeks, onions or cooked cabbage, but is quite distinct. Ethanethiol is intentionally added to butane and propane (see: LPG) to impart an easily noticed smell to these normally odorless fuels that pose the threat of fire, explosion, and asphyxiation.
- Odor Threshold0.0000087ppm
- explosive limit2.8-18%(V)
- Water Solubility Soluble in alcohol, ether, waterMiscible with alcohol, petroleum naphtha, acetone, dilute alkali and ether. Slightly miscible with water.
- Merck 14,3726
- JECFA Number1659
- BRN 773638
- Henry's Law Constant3.57(x 10-3 atm?m3/mol) at 25 °C (Przyjazny et al., 1983)
- Exposure limitsTLV-TWA 0.5 ppm (～1.3 mg/m3 ) (ACGIH and MSHA); ceiling 10 ppm (OSHA); IDLH 2500 ppm (NIOSH).
- Stability:Stable. Extremely flammable - note low flash point. Incompatible with oxidizing agents, strong acids. May form explosive mixtures with air.
- CAS DataBase Reference75-08-1(CAS DataBase Reference)
- NIST Chemistry ReferenceEthanethiol(75-08-1)
- EPA Substance Registry SystemEthyl mercaptan (75-08-1)
- Hazard Codes F,Xn,N,F+
- Risk Statements 11-20-50/53-51/53-12-20/22
- Safety Statements 16-25-60-61
- RIDADR UN 2363 3/PG 1
- WGK Germany 3
- RTECS KI9625000
- F 13
- Autoignition Temperature570 °F
- TSCA Yes
- HS Code 2930 90 98
- HazardClass 3
- PackingGroup I
- Hazardous Substances Data75-08-1(Hazardous Substances Data)
- ToxicityLD50 orally in Rabbit: 682 mg/kg
Ethanethiol Usage And Synthesis
- DescriptionEthane thiol, commonly known as ethyl mercaptan, is a colorless gas or clear liquid with a distinct odor. It is an organosulfur compound with the formula CH3CH2SH. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. Its structure parallels that of ethanol, but with S instead of O. The odor of EtSH is infamous. Ethanethiol is more volatile than ethanol due to a diminished ability to engage in hydrogen bonding. Ethanethiol is toxic. It occurs naturally as a minor component of petroleum, and may be added to other wise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful.
- Chemical Propertiescolourless liquid with a penetrating,
- Chemical PropertiesEthyl mercaptan is a yellowish liquid (or a colorless gas above the BP). Strong, sharp odor of garlic or skunklike odor.
- Chemical PropertiesColorless to yellow liquid; fruity, sulfur aroma.
- Physical propertiesColorless liquid with a strong, disagreeable, skunk-like or rotten egg odor. Extremely flammable liquid or gas. An experimentally determined odor threshold concentration of 1 ppbv was reported by Leonardos et al. (1969). Katz and Talbert (1930) reported experimental detection odor threshold concentrations in the range 0.66–7.6 μg/m3 (0.26 to 3.0 ppbv).
- UsesLPG odorant, adhesive, stabilizer, chemical intermediate.
- UsesEthanethiol is used as an intermediate inthe manufacture of insecticides, plastics, andantioxidants; and as an additive to natural gasto give odor. It occurs in illuminating gas andin petroleum distillates.
- PreparationEthanethiol is prepared by the reaction of ethylene with hydrogen sulfide over a catalyst. The various producers utilize different catalysts in this process. It is also be prepared commercially by the reaction of ethanol with hydrogen sulfide gas over an acidic solid catalyst, such as alumina.
Ethanethiol was originally reported by Zeiss in 1834 . Zeise treated calcium ethyl sulfate with a suspension of barium sulfide saturated with hydrogen sulfide. He is credited with naming the C2H5S- group as mercaptum.
Ethanethiol can also be prepared by a halide displacement reaction, where ethyl halide is reacted with aqueous sodium bisulfide. This conversion was demonstrated as early as 1840 by Henri Victor Regnault.
- Production MethodsEthyl mercaptan is prepared by distilling ethyl potassium sulfate with potassium hydrogen sulfide. Additional mercaptans can be prepared in a similar manner with the corresponding proper ingredients.
- ReactionsEthane thiol is a valued reagent in organic synthesis. In the presence of sodium hydroxide, it gives the powerful nucleophile SEt-. The salt can be generated quantitatively by reaction with sodium hydride.
Ethane thiol can be oxidized to ethyl sulfonic acid, using bleach and related strong aqueous oxidants. Weaker oxidants, such as ferric oxide give the disulfide, diethyl disulfide :
2 EtSH + H2O2 → EtS-SEt + 2 H2O
Like other thiols, it behaves comparably to hydrogen sulfide. For example, it binds, concomitant with deprotonation to "soft" transition metal cations, such as Hg2+, Cu+, and Ni2+ to give polymeric thiolato complexes, Hg(SEt)2, CuSEt, and Ni(SEt)2, respectively.
- Aroma threshold valuesHigh strength odor, sulfurous fruity type; recommend smelling in a 0.01% solution or less.
- General DescriptionA clear colorless low-boiling liquid (boiling point 97°F) with an overpowering, garlic-like/skunk-like odor. Flash point -55°F. Less dense than water and very slightly soluble in water. Vapors are heavier than air. Vapors may irritate nose and throat. May be toxic if swallowed, by inhalation or by contact. Added to natural gas as an odorant. Used as a stabilizer for adhesives.
- Air & Water ReactionsHighly flammable. A very dangerous fire hazard. Very slightly soluble in water.
- Reactivity ProfileEthanethiol reacts violently with calcium hypochlorite, May react vigorously with other oxidizing reagents. On contact with strong acids or when heated to decomposition Ethanethiol emits highly toxic fumes of sulfur oxides [Sax, 9th ed., 1996, p. 1575].
- HazardToxic by ingestion and inhalation. Flammable, dangerous fire risk.
- Health HazardInhalation of vapor causes muscular weakness, convulsions, respiratory paralysis. High concentrations may cause pulmonary irritation. Liquid irritates eyes and skin. Ingestion causes nausea and irritation of mouth and stomach.
- Health HazardThe inhalation toxicity of ethanethiol islower than that of methanethiol. Intraperitoneal administration in rats at sublethaldoses caused deep sedation, followed bylethargy, restlessness, lack of muscular coordination, and skeletal muscle paralysis.Higher doses produced cyanosis, kidney andliver damage, respiratory depression, coma,and death. The intraperitoneal LD50 value inrats was 450 mg/kg (ACGIH 1986).Ethanethiol is metabolized to inorganicsulfate and ethyl methyl sulfone, and excreted. The oral LD50 value in rats is 680 mg/kg.In humans, repeated exposures to itsvapors at about 5 ppm concentration canproduce irritation of the nose and throat,headache, fatigue, and nausea.
- Chemical ReactivityReactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
- Safety ProfileModerately toxic by ingestion, inhalation, and intraperitoneal routes. A skin and eye irritant. Inhalation causes central nervous system effects in humans. A very dangerous fire hazard when exposed to heat or flame; can react vigorously with oxidizing materials. A moderate explosion hazard when exposed to spark or flame. Violent reaction with Ca(OCl)2. Will react with water or steam to produce toxic and flammable vapors. To fight fire, use CO2, dry chemical. When heated to decomposition or on contact with acid or acid fumes it emits hghly toxic fumes of SOx. See also MERCAPTANS.
- Potential ExposureThis material is used as a warning odorant for liquefied petroleum gases. It is used as an intermediate in the manufacture of many pesticides and other organic chemicals
- Environmental FateBiological. Ethyl mercaptan did not degrade in anaerobic sediments and sludges nor in
anaerobic freshwater conditions (van Leerdam et al., 2006).
Photolytic. A second-order rate constant of 1.21 x 10-12 cm3/molecule?sec was reported for the reaction of ethyl mercaptan and NO3 radicals in the atmosphere at 297 K (Atkinson, 1991).
Chemical/Physical. In the presence of nitric oxide, ethyl mercaptan reacted with OH radicals forming ethyl thionitrite. The rate constant for this reaction is 2.7 x 10-11 at 20 °C (MacLeod et al., 1984).
- ShippingUN2363 Ethyl mercaptan, Hazard Class: 3; Labels: 3-Flammable liquid
- Purification MethodsDissolve the thiol in aqueous 20% NaOH, extract it with a small amount of *benzene and then steam distil until clear. After cooling, the alkaline solution is acidified slightly with 15% H2SO4 and the thiol is distilled off, dried with CaSO4, CaCl2 or 4A molecular sieves, and fractionally distilled under nitrogen [Ellis & Reid J Am Chem Soc 54 1674 1932]. It has a foul odour. [Beilstein 1 IV 1390.]
- IncompatibilitiesMay form explosive mixture with air. Slowly forms peroxides. This material is a weak acid. Reacts with oxidizers, causing fire and explosion hazard. Reacts with strong acids evolving toxic and flammable hydrogen sulfide. May accumulate static electrical charges, and may cause ignition of its vapors. Attacks some forms of plastics, coatings and rubber. Aldehydes are frequently involved in self-condensation or polymerization reactions. These reactions are exothermic; they are often catalyzed by acid. Aldehydes are readily oxidized to give carboxylic acids. Flammable and/or toxic gases are generated by the combination of aldehydes with azo, diazo compounds, dithiocarbamates, nitrides, and strong reducing agents. Aldehydes can react with air to give first peroxo acids, and ultimately carboxylic acids. These autoxidation reactions are activated by light, catalyzed by salts of transition metals, and are autocatalytic (catalyzed by the products of the reaction). The addition of stabilizers (antioxidants) to shipments of aldehydes retards autoxidation
- Waste DisposalIncineration (1093℃) followed by scrubbing with a caustic solution
Ethanethiol Preparation Products And Raw materials
- Preparation ProductsMolinatePhorateSethoxydim2,3,4,5-Tetrahydro-5-methyl-1H-pyrido[4,3-b]indol-1-one5-(2-ETHYLTHIO PROPYL)-1,3-CYCLOHEXANEDIONE1-NAPHTHALENETHIOL2-Naphthalenethiol5,6-DIHYDRO-4-(2-METHYL-2-PHENYLHYDRAZINO)-2-1H-PYRIDINONE2,4-Piperadinedione6-ETHYLMERCAPTOPURINE3-AMINO-PROPIONIC ACID ETHYL ESTERDIPROPETRYNEradicaneEthyl 2-hydroxyethyl sulfide2-(ETHYLTHIO)NICOTINIC ACIDS,S'-Diethyldithiomalonate6-HYDROXYMELATONINEthanethioic acid S-ethyl esterethyl ethanethioate
- Raw materialsEtanolSULFURIC ACIDThiocarbamideBromoethane2-ChloroethanolHYDROGEN SULFIDESodium hydrosulfideSodium tungstate dihydrateTungstic acidEthylsulphuric acid
- MERCAPTANS METHYL MERCAPTAN POTASSIUM 1,2-NAPHTHOQUINONE-4-SULFONIC ACID ACID FUCHSIN CALCIUM SALT REACTIVE BLACK 5 1,2-NAPHTHOQUINONE-4-SULFONIC ACID SODIUM SALT Cyclohexyl mercaptan Benzyl thiocyanate D-Cystine METHYL (METHYLSULFINYL)ACETATE,80% TECH. Ethylthiocyanate 4-(ETHYLTHIO)BENZOIC ACID DI-N-BUTYL SULFOXIDE 4-CHLOROPHENYL 2-CHLORO-1,1,2-TRIFLUOROETHYL SULFONE 3-CHLOROPROPYL THIOACETATE 2-Chloroethyl ethyl sulfide METHYL (PHENYLSULFINYL)ACETATE CYCLOPENTANETHIOL
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