What Is Thiole?
Thiole, also known as thiophene, is a pentacyclic heterocyclic compound with sulfur in the ring. Derived from the prefix “thio” for sulfur and “phene” for benzene, thiole is found in small amounts in tar and coal gas. Industrially, it is synthesized through a dehydrogenative ring-closing reaction of butane and sulfur at high temperatures.
Uses of Thiole
Thiole is used as a solvent and as a raw material for dyes, plastics, medical and agricultural chemicals. Oligothiole and their functional derivatives are used in high-tech applications like OLEDs, organic field-effect transistors, and organic solar cells. Polythiole, with many interconnected thioles, is used as a conductive polymer. Fused thiole is a high-performance semiconductor material essential for electronic devices such as high-mobility transistors, organic thin-film solar cells, and OLEDs.
Properties of Thiole
Thiole shares similar physical properties and chemical reactivity with benzene, emitting a similar odor. It is a colorless liquid with a melting point of -36.4°F (-38°C) and a boiling point of 183°F (84°C), mixing well with benzene, ether, and ethanol, but insoluble in water. Thiole is thermally stable and does not decompose even when heated to 1562°F (850°C).
Structure of Thiole
Thiole is a sulfur-containing heterocyclic compound with the chemical formula C4H4S. It resembles furan, with the oxygen atom replaced by sulfur. It has a molecular weight of 84.14 and a specific gravity of 1.051 g/mL. When acting as a substituent in compound naming, thiole rings are referred to as thienyl groups.
Other Information on Thiole
1. Synthesis of Thiole
Thiole can be synthesized by reacting carbon disulfide (CS2) with furan or methylfuran using a catalyst. In the laboratory, it’s produced by reacting sodium succinate with disulfide pentasulfide (P2S5) or carbon dioxide with disulfide trisulfide (P2S3).
2. Qualitative Reaction of Thiole
The indophenine reaction is used to identify small amounts of thiole, resulting in the formation of a blue dye. Thiole can also be identified through methods like gas chromatography.
3. Reaction Selectivity of Thiole
Thiole undergoes electrophilic substitution reactions selectively at the 2-position. When treated with a strong base like lithium alkyl, thiole forms a proton-drawn thienyl anion. However, due to its aromatic nature, addition reactions to double bonds are unlikely.
4. Thiole Applications
Thiole and its polymers, polythiole, are used in pharmaceuticals, agrochemicals, and dyes, and as targets for research in organometallics and organic semiconductors due to their conductive properties.