This substance, which had its preferred name changed by the IUPAC in 2013 to oxolane, is a heterocyclic compound classified as a cyclic ether. Colorless, water-miscible, organic, and possessing a low-viscosity in liquid form, oxolane is a precursor to various polymers and a versatile solvent. The most common method of manufacture industrially is the acid-catalyzed dehydration of 1,4-butanediol, which is not dissimilar to the synthesis of diethyl ether from ethanol. When combined with strong acids, oxolane is easily converted into a linear polymer referred to as poly(tetramethylene ether)glycol (PTMEG), also called polytetramethylene oxide (PTMO). PTMEG/PTMO is used to create elastomeric polyurethane fibers such as Spandex. The solvent applications for THF are implemented primarily when working with PVC and varnishes. As an aprotic solvent with a dielectric constant of 7.6, it is ideal for dissolving a wide variety of both nonpolar and polar chemical compounds, and since it is water-miscible it can form solid clathrate hydrate structures with water even at low temperatures.