Methantiol ( methyl mercaptan ) CH 3 SH - the simplest representative of the homologous series of thiols , a colorless poisonous gas with a strong disgusting odor, at low concentrations resembling the smell of rotten cabbage.
| Methantiol | |
|---|---|
 | |
 | |
| Are common | |
| Systematic name | methanethiol |
| Traditional names | methyl mercaptan |
| Chem. formula | CH 4 S |
| Rat formula | CH 3 SH |
| Physical properties | |
| condition | Gas |
| Molar mass | 48.21 g / mol |
| Density | |
| Ionization energy | |
| Thermal properties | |
| T. melt. | -123 ° C |
| T. bale. | 5.9 ° C |
| T. aux. | |
| Etc. blast | |
| Steam pressure | |
| Chemical properties | |
| pK a | ~ 10.4 |
| Solubility in water | 2% |
| Solubility in | ethanol , diethyl ether |
| Classification | |
| Reg. CAS number | 74-93-1 |
| PubChem | |
| Reg. EINECS number | |
| Smiles | |
| Inchi | |
| RTECS | |
| Chebi | 16007 |
| ChemSpider | |
| Security | |
| MPC | 0.006 [1] |
| LD 50 | LD50: 60; 67 mg / kg |
| Toxicity | Highly toxic |
| R phrases | R12 , R23 , R50 / 53 |
| S-phrases | S16 , S25 , S33 S60 , S61 |
| GHS icons |     |
| NFPA 704 |  four four one |
Content
Properties
It is sparingly soluble in water, soluble in ethanol and diethyl ether . Highly flammable. At high concentrations, it negatively affects the central nervous system. The threshold for a person smelling methanethiol at a volume concentration of 1 part per million [3] .
Being in nature
Methantiol is formed during various decomposition processes of organosulfur compounds , primarily in the decay of proteins , which include sulfur-containing amino acids . It is also found in the feces and intestinal gases of humans and animals, being, along with skatol, the cause of their unpleasant odor .
Synthesis
In industry, methanethiol is synthesized from methanol and hydrogen sulfide using thorium dioxide deposited on alumina in an amount of 5-12%, or cobalt - thorium dioxide, at a temperature of 316-468 ° C as a catalyst .
Application
Methantiol is used in the production of the methionine amino acid used as a feed additive from acrolein. .
In the first stage, 3-methylthiopropionic aldehyde is synthesized by the addition of methanethiol to acrolein :
which is further used as a carbonyl component in Strecker synthesis :
Methantiol is used in the synthesis of pesticides and fungicides .
Methantiol is also used as an odorizing additive to natural gas used in everyday life for people to detect accidental leakages of natural household gas by smell [4] .
Danger
Methantiol is toxic, belongs to the 2nd hazard class. The maximum one-time MPC for the atmospheric air of populated areas is 0.006 mg / m 3 [5] .
See also
- Ethantiol
Notes
- ↑ GN 2.1.6.2326-08 Maximum allowable concentrations (MPC) of pollutants in the atmospheric air of populated areas. Supplement No. 4 to GN 2.1.6.1338-03
- ↑ 1 2 3 4 5 http://www.cdc.gov/niosh/npg/npgd0425.html
- ↑ Devos, M; F. Patte, J. Rouault, P. Lafort, LJ Van Gemert (1990). Standardized Human Olfactory Thresholds. Oxford: IRL Press. p. 101. ISBN 0-19-963146-8
- ↑ Schlager N., Weisblatt J., Newton DE Methyl Mercaptan - Chemical Compounds. - Thomson Gale. - 2006. - vol. 2 - pp 455-457.
- ↑ Maximum allowable concentrations (MPC) of pollutants in the atmospheric air of populated areas. Supplement 4 to GN 2.1.6.1338-03. (inaccessible link) . Date of treatment July 24, 2017. Archived May 21, 2015.