Tetrahydrothiophene

Structural formula
General
Surname	Tetrahydrothiophene
other names	THT Tetramethylene sulfide Thiolane
Molecular formula	C 4 H 8 S
Brief description	colorless liquid with an unpleasant odor
External identifiers / databases
CAS number 110-01-0 EC number 203-728-9 ECHA InfoCard 100.003.391 PubChem 1127 ChemSpider 1095 Wikidata Q412118
properties
Molar mass	88.17 g mol −1
Physical state	liquid
density	1.00 g cm −3
Melting point	−96 ° C
boiling point	121 ° C
Vapor pressure	19 h Pa (20 ° C)
solubility	very heavy in water (403 mg l −1 at 25 ° C) good in ethanol , diethyl ether , benzene and acetone
Refractive index	1.5045
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 225-302 + 312 + 332-315-319-412 P: 210-273-302 + 352-305 + 351 + 338-403 + 235
MAK	DFG / Switzerland: 50 ml m −3 or 180 mg m −3
Toxicological data	1750 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Tetrahydrothiophene (THT) is a saturated sulfur heterocycle .

Extraction and presentation

Tetrahydrothiophene can be obtained from tetrahydrofuran and hydrogen sulfide .

properties

Tetrahydrothiophene is a colorless liquid and can already be smelled at a concentration of 0.001  ppm (reminiscent of rotten eggs, garlic, coal gas).

• Viscosity : 1.042 cp (at 20 ° C)
• Sulfur content : 36.2% (mass fraction)
• Flash point 13 ° C
• lower explosion limit (LEL): 1.1 vol% (air at 20 ° C, 1013 hPa)
• Upper explosion limit (UEL): 12.3% by volume (air at 20 ° C, 1013 hPa)
• Ignition temperature 200 ° C

use

THT is used as an odorant (odor = odor; odorant) in natural gas . Since natural gas is almost odorless, the regional gas suppliers vaccinate natural gas in their gas pressure regulating systems / gas pressure regulating and measuring systems with a concentration of around 20 mg · m ⁻³ in order to give early warning of any leaky pipe installation. In addition to its unmistakable smell, THT is chemically stable. THT leaked from leaky underground lines is poorly absorbed by the ground. As a result of pipeline defects, the smell can also come to the surface. When burned with natural gas, however, it burns odorless.

safety instructions

As a released liquid, THT evaporates very quickly and can form highly flammable vapors when mixed with air, because the lower explosion limit is 1.1% by volume, the ignition temperature is 200 ° C, the flash point is 13 ° C. THT is comparable to gasoline in terms of fire and explosion risk. THT vapors are heavier than air and are irritating to the eyes, respiratory tract and skin. In liquid form, it is also absorbed through the skin. The LD ₅₀ value (oral, rat) is 1750 mg kg ⁻¹ .

Individual evidence

1. ↑ ^{a b c} Entry on tetrahydrothiophene. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
2. ↑ ^{a b c d e f g h i j k l m} Entry on tetrahydrothiophene in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
3. ↑ Entry on Tetrahydrothiophene in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values , accessed on November 2, 2015.
5. ↑ Tetrahydrothiophene data sheet from Sigma-Aldrich , accessed on January 17, 2011 ( PDF ).
6. ↑ IA Sharipova, Kh. M. Nasyrov, A. Kh. Sharipov, and MF Mazitov, "Synthesis of Tetrahydrothiophene from Tetrahydrofuran and Hydrogen Sulfide", Russian J. Org. Chem. 36 (1), 105 (2000).