Names | |
---|---|
Preferred IUPAC name
2-Methylpropane-2-thiol | |
Other names
t-BuSH
2-Methylpropane-2-thiol 2-Methyl-2-propanethiol tert-Butyl mercaptan | |
Identifiers | |
3D model (
JSmol)
|
|
Abbreviations | TBM |
ChemSpider | |
ECHA InfoCard | 100.000.810 |
PubChem
CID
|
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
C4H10S | |
Molar mass | 90.18 g·mol−1 |
Appearance | Colorless liquid |
Density | 0.8 g/mL |
Melting point | −0.50 °C (31.10 °F; 272.65 K) |
Boiling point | 62 to 65 °C (144 to 149 °F; 335 to 338 K) |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
tert-Butylthiol, also known as tert-butyl mercaptan (TBM), and abbreciated t-BuSH, is an organosulfur compound with the formula (CH3)3CSH. This thiol is used as an odorant for natural gas,[ citation needed] which is otherwise odorless. It may also have been used as a flavoring agent. [1]
It was first prepared in 1890 by Leonard Dobbin [2] by the reaction of zinc sulfide and t-butyl chloride.
The compound was later prepared by the reaction of the Grignard reagent, t-BuMgCl, with sulfur to give the corresponding thiolate, followed by hydrolysis. [3] This preparation is shown below:
It is made industrially by the reaction of isobutylene with hydrogen sulfide over a clay (silica alumina) catalyst. [4]
tert-Butylthiol is deprotonated by lithium hydride in an aprotic solvent such as hexamethylphosphoramide (HMPA). The resulting lithium thiolate salt has been used as demethylating reagent. For example, treatment with 7-methylguanosine gives guanosine. Other N-methylated nucleosides in tRNA are not demethylated by this reagent. [5]
tert-Butylthiol reacts with thallium(I) ethoxide to give the thallium thiolate: [6]
This thallium thiolate can be used to convert acyl chlorides to the thioester:
tert-BuSLi reacts with MoCl4 with to give the tetra thiolate complex: [7]
tert-Butylthiol is the main ingredient in many gas odorant blends.[ citation needed] It is always utilized as a blend of other compounds, typically dimethyl sulfide, methyl ethyl sulfide, tetrahydrothiophene or other mercaptans such as isopropyl mercaptan, sec-butyl mercaptan and/or n-butyl mercaptan, due to its rather high melting point of −0.5 °C (31.1 °F). These blends are used only with natural gas and not propane, as the boiling points of these blends and propane are quite different. Because propane is delivered as a liquid and vaporizes to gas when it is delivered to the appliance, the vapor liquid equilibrium would substantially reduce the amount of odorant blend in the vapor.
tert-Butylthiol had been listed on the European Food Safety Authority (FL-no: 12.174) as a flavor additive. There is no indication of what flavor(s) it may have been used in. It has been removed from this list. [8]
tert-butylthiol as a very minor component of cooked potatoes. [9]
The Threshold limit value (TLV) is 0.5 ppm. tert-butylthiol has an odor threshold of <0.33 ppb. [10]
Names | |
---|---|
Preferred IUPAC name
2-Methylpropane-2-thiol | |
Other names
t-BuSH
2-Methylpropane-2-thiol 2-Methyl-2-propanethiol tert-Butyl mercaptan | |
Identifiers | |
3D model (
JSmol)
|
|
Abbreviations | TBM |
ChemSpider | |
ECHA InfoCard | 100.000.810 |
PubChem
CID
|
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
C4H10S | |
Molar mass | 90.18 g·mol−1 |
Appearance | Colorless liquid |
Density | 0.8 g/mL |
Melting point | −0.50 °C (31.10 °F; 272.65 K) |
Boiling point | 62 to 65 °C (144 to 149 °F; 335 to 338 K) |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
tert-Butylthiol, also known as tert-butyl mercaptan (TBM), and abbreciated t-BuSH, is an organosulfur compound with the formula (CH3)3CSH. This thiol is used as an odorant for natural gas,[ citation needed] which is otherwise odorless. It may also have been used as a flavoring agent. [1]
It was first prepared in 1890 by Leonard Dobbin [2] by the reaction of zinc sulfide and t-butyl chloride.
The compound was later prepared by the reaction of the Grignard reagent, t-BuMgCl, with sulfur to give the corresponding thiolate, followed by hydrolysis. [3] This preparation is shown below:
It is made industrially by the reaction of isobutylene with hydrogen sulfide over a clay (silica alumina) catalyst. [4]
tert-Butylthiol is deprotonated by lithium hydride in an aprotic solvent such as hexamethylphosphoramide (HMPA). The resulting lithium thiolate salt has been used as demethylating reagent. For example, treatment with 7-methylguanosine gives guanosine. Other N-methylated nucleosides in tRNA are not demethylated by this reagent. [5]
tert-Butylthiol reacts with thallium(I) ethoxide to give the thallium thiolate: [6]
This thallium thiolate can be used to convert acyl chlorides to the thioester:
tert-BuSLi reacts with MoCl4 with to give the tetra thiolate complex: [7]
tert-Butylthiol is the main ingredient in many gas odorant blends.[ citation needed] It is always utilized as a blend of other compounds, typically dimethyl sulfide, methyl ethyl sulfide, tetrahydrothiophene or other mercaptans such as isopropyl mercaptan, sec-butyl mercaptan and/or n-butyl mercaptan, due to its rather high melting point of −0.5 °C (31.1 °F). These blends are used only with natural gas and not propane, as the boiling points of these blends and propane are quite different. Because propane is delivered as a liquid and vaporizes to gas when it is delivered to the appliance, the vapor liquid equilibrium would substantially reduce the amount of odorant blend in the vapor.
tert-Butylthiol had been listed on the European Food Safety Authority (FL-no: 12.174) as a flavor additive. There is no indication of what flavor(s) it may have been used in. It has been removed from this list. [8]
tert-butylthiol as a very minor component of cooked potatoes. [9]
The Threshold limit value (TLV) is 0.5 ppm. tert-butylthiol has an odor threshold of <0.33 ppb. [10]