2-Butanol

2-Butanol
Names
IUPAC name
Butan-2-ol[1]
Other names
sec-Butanol

sec-Butyl alcohol, 2-Butanol

2-Butyl alcohol
Identifiers
78-92-2 YesY
14898-79-4 (R) YesY
4221-99-2 (S) YesY
773649

1718764 (R)
1718763 (S)

ChEBI CHEBI:35687 YesY
ChEMBL ChEMBL45462 YesY
ChemSpider 6320 YesY
76392 (R) YesY
392543 (S) YesY
DrugBank DB02606 YesY
EC Number 201-158-5
1686

396584 (R)
25655 (S)

Jmol interactive 3D Image
MeSH 2-butanol
PubChem 6568
84682 (R)
444683 (S)
RTECS number EO1750000
UN number 1120
Properties
C4H10O
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/L[2]
log P 0.683
Vapor pressure 1.67 kPa (at 20 °C)
1.3978 (at 20 °C)
Thermochemistry
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
Hazards
Safety data sheet inchem.org
GHS pictograms
GHS signal word WARNING
H226, H319, H335, H336
P261, P305+351+338
Xi
R-phrases R10, R36/37, R67
S-phrases (S2), S7/9, S13, S24/25, S26, S46
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
3
1
0
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):
TWA 150 ppm (450 mg/m3)[3]
TWA 100 ppm (305 mg/m3) ST 150 ppm (455 mg/m3)[3]
2000 ppm[3]
Related compounds
Related butanols
 n-Butanol
Isobutanol
tert-Butanol
Related compounds
 Butanone
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)-(−)-2-butanol
(S)-(+)-2-butanol

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.[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.

Solubility

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 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.

Safety

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.

References

  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. 1 2 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. 1 2 3 4 "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

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