Butane-1,4-diol, not to be confused with 1,3 butanediol, is a primary alcohol, and an organic compound, with the formula HOCH2CH2CH2CH2OH. It is a colorless viscous liquid. It is one of four stable isomers of butanediol. Synthesis In industrial chemical synthesis, acetylene reacts with two equivalents of formaldehyde to form butyne-1,4-diol. Hydrogenation of butyne-1,4-diol gives butane-1,4-diol. It is also made on an industrial scale from maleic anhydride in the Davy process, which is first converted to the methyl maleate ester, then hydrogenated. Other routes are from butadiene, allyl acetate and succinic acid. A biological route to BD has been commercialized that uses a genetically modified organism. The biosynthesis proceeds via 4-hydroxybutyrate. Industrial use Butane-1,4-diol is used industrially as a solvent and in the manufacture of some types of plastics, elastic fibers and polyurethanes. In organic chemistry, 1,4-butanediol is used for the synthesis of γ-butyrolactone (GBL). In the presence of phosphoric acid and high temperature, it dehydrates to the important solvent tetrahydrofuran. At about 200 °C in the presence of soluble ruthenium catalysts, the diol undergoes dehydrogenation to form butyrolactone. It is used to synthesize 1,4-Butanediol diglycidyl ether which is then used as a reactive diluent for epoxy resins. World production of butane-1,4-diol was claimed to be about one million metric tons per year and market price is about 2,000 (€ 1,600) per ton (2005). In 2013, worldwide production was claimed to be billions of lbs (consistent with approximately one million metric tons). Almost half of it is dehydrated to tetrahydrofuran to make fibers such as Spandex. The largest producer is BASF. Use as a recreational drug Butane-1,4-diol is also used as a recreational drug known by some users as "One Comma Four", "Liquid Fantasy", "One Four Bee" or "One Four B-D-O". A few Federal Courts have stated that 1,4-butanediol exerts effects similar to gamma-hydroxybutyrate (GHB), which is a metabolic product of 1,4-butanediol. But other Federal courts have ruled that it is not. Pharmacokinetics Butane-1,4-diol is rapidly converted into gamma-hydroxybutyric acid by the enzymes alcohol dehydrogenase and aldehyde dehydrogenase, and differing levels of these enzymes may account for differences in effects and side effects between users. While co-administration of ethanol and GHB already poses serious risks, co-administration of ethanol with 1,4-butanediol will interact considerably and has many other potential risks. This is because the same enzymes that are responsible for metabolizing alcohol also metabolize 1,4-butanediol so there is a strong chance of