2 Butanol Information
2-Butanol, or sec-butanol, is an organic compound with formula C H3CH(OH)CH2CH3. This secondary alcohol is a flammable, colorless liquid that is soluble in 12 parts water and completely miscible with polar organic solvents such as ethers and other alcohols. It is produced on a large scale, primarily as a precursor to the industrial solvent methyl ethyl ketone. 2-Butanol is chiral and thus can be obtained as either of two stereoisomers designated as (R)-(−)-2-butanol and (S)-(+)-2-butanol. It is normally found as an equal mixture of the two stereoisomers — a racemic mixture.
| (R)-(−)-2-butanol | (S)-(+)-2-butanol |
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Manufacture and applications
2-Butanol is manufactured industrially by the hydration of 1-butene or 2-butene:
Sulfuric acid is used as a catalyst for this conversion.[3]
Although some 2-butanol is used as a solvent, it is mainly converted to butanone ("MEK"), which is an important industrial solvent and found in many domestic cleaning agents and paint removers. Volatile esters of 2-butanol have pleasant aromas and are used in small amounts as perfumes or in artificial flavors.
Solubility
The solubility of sec-butanol is incorrect in most sources, including some of the most well-known references such as the Merck Index, the CRC Handbook of Chemistry and Physics, and Lange's Handbook of Chemistry. Even the International Programme on Chemical Safety lists the wrong solubility. This widespread error originated because of Beilstein's Handbuch der Organischen Chemie (Handbook of Organic Chemistry). This work cites a false solubility of 12.5 g/100 ml water. Many other sources used this solubility, which has snowballed into a widespread error in the industrial world. The correct data (35.0 g/100 ml at 20°C, 29 g/100 ml at 25°C, and 22 g/100 ml at 30°C) was first published in 1886 by Alexejew and then similar data was reported by other scientists including Dolgolenko and Dryer in 1907 and 1913, respectively. As petty of an error as this may seem, teachers and students have been frustrated by the error for years.[2]
Safety
Several explosions have been reported[4] during the conventional distillation of 2-butanol, apparently due to the buildup of peroxides with the boiling point higher than that of pure alcohol (and therefore concentrating in the still pot during distillation). As alcohols, unlike ethers, are not widely known to be capable of forming peroxide impurities, the danger is likely to be overlooked.
References
- ^ "2-butanol - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=6568. Retrieved 12 October 2011.
- ^ a b Alger, Donald B. (November 1991). "The water solubility of 2-butanol: A widespread error". Journal of Chemical Education (USA: ACS Publications) 68 (11): 939. doi:10.1021/ed068p939.1. http://pubs.acs.org/doi/abs/10.1021/ed068p939.1. Retrieved 12 October 2011.
- ^ Hahn, Heinz-Dieter; Dämbkes, Georg; Rupprich, Norbert (2005), "Butanols", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH .
- ^ Doyle, R. R. (1986). "2-Butanol safety warning". Journal of Chemical Education 63 (2): 186. doi:10.1021/ed063p186.2. , and references cited therein.
External links
- International Chemical Safety Card 0112
- NIOSH Pocket Guide to Chemical Hazards 0077
- IPCS Environmental Health Criteria 65: Butanols: four isomers
- IPCS Health and Safety Guide 4: 2-Butanol
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Categories:
- Alcohols
- Alcohol solvents
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