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Skeletal formula of 2-butanol
IUPAC name
Other names

sec-Butyl alcohol, 2-Butanol

2-Butyl alcohol
3D model (JSmol)

1718764 (R)
1718763 (S)

ECHA InfoCard 100.001.053
EC Number 201-158-5

396584 (R)
25655 (S)

MeSH 2-butanol
RTECS number EO1750000
UN number 1120
Molar mass 74.12 g·mol−1
Density 0.808 g cm−3
Melting point −115 °C; −175 °F; 158 K
Boiling point 98 to 100 °C; 208 to 212 °F; 371 to 373 K
290 g/kg[2]
log P 0.683
Vapor pressure 1.67 kPa (at 20 °C)
-57.683·10−6 cm3/mol
1.3978 (at 20 °C)
197.1 J K−1 mol−1
213.1 J K−1 mol−1
−343.3–−342.1 kJ mol−1
−2.6611–−2.6601 MJ mol−1
Safety data sheet inchem.org
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word WARNING
H226, H319, H335, H336
P261, P305+351+338
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasoline Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 22 to 27 °C (72 to 81 °F; 295 to 300 K)
405 °C (761 °F; 678 K)
Explosive limits 1.7–9.8%
Lethal dose or concentration (LD, LC):
16,000 ppm (rat, 4 hr)
10,670 ppm (mouse, 3.75 hr)
16,000 ppm (mouse, 2.67 hr)[3]
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 150 ppm (450 mg/m3)[3]
REL (Recommended)
TWA 100 ppm (305 mg/m3) ST 150 ppm (455 mg/m3)[3]
IDLH (Immediate danger)
2000 ppm[3]
Related compounds
Related butanols
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

2-Butanol, or sec-butanol, is an organic compound with formula CH3CH(OH)CH2CH3. This secondary alcohol is a flammable, colorless liquid that is soluble in 3 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-butan-2-ol 2D skeletal.png
S-butan-2-ol 2D skeletal.png

Manufacture and applications[edit]

2-Butanol is manufactured industrially by the hydration of 1-butene or 2-butene:


Sulfuric acid is used as a catalyst for this conversion.[4]

In the lab it can be prepared via Grignard reaction by reacting ethylmagnesium bromide with acetaldehyde in dried diethyl ether or tetrahydrofuran.

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.


The solubility of 2-butanol is incorrect in most sources,[2] 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 g 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 g at 20 °C, 29 g/100 g at 25 °C, and 22 g/100 g at 30 °C) were first published in 1886 by Alexejew and then similar data was reported by other scientists including Dolgolenko and Dryer in 1907 and 1913, respectively.


Several explosions have been reported[5] 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.


  1. ^ "2-butanol - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. Retrieved 12 October 2011. 
  2. ^ 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. Retrieved 12 October 2011. 
  3. ^ a b c d "NIOSH Pocket Guide to Chemical Hazards #0077". National Institute for Occupational Safety and Health (NIOSH). 
  4. ^ Hahn, Heinz-Dieter; Dämbkes, Georg; Rupprich, Norbert (2005), "Butanols", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH .
  5. ^ 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[edit]