Thiophene C4H4S CAS:110-02-1

Thiophene is a five-membered heterocyclic compound containing one sulfur atom. It exists in small amounts in crude benzene obtained from coal tar and is a colorless liquid with a similar aromatic odor to benzene. Its boiling point is 84℃, it is insoluble in water, and can dissolve in ethanol, ether, acetone, benzene, carbon tetrachloride, heptane, pyridine, 1,4-dioxane, etc. Thiophene is flammable. It has strong heat resistance and does not decompose even when heated to 850℃. It does not polymerize, decompose or be oxidized under strong acid conditions. It has moderate toxicity. The five atoms on the thiophene ring are all sp2 hybridized and lie in the same plane. The unshared pair of electrons of the sulfur atom occupies the p orbital and overlaps with the p orbitals of the four carbon atoms, forming a closed conjugated system of five atoms with six electrons. Therefore, it has aromaticity. Thiophene is more prone to electrophilic substitution reactions than benzene, and the substitution mainly occurs at the α-position (2-position or 5-position). The important derivative of thiophene is biotin. It can undergo sulfonation reaction with concentrated sulfuric acid at room temperature to produce 2-thiophene sulfonic acid, which is soluble in sulfuric acid. Therefore, this method is commonly used to remove thiophene from crude benzene.