2-Butanol

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Template:Short description <templatestyles src="Chembox/styles.css"/>

Template:Chembox image cellTemplate:Chembox AllOtherNamesTemplate:Chembox headerbarTemplate:Chembox IndexlistTemplate:Chembox JmolTemplate:Chembox ChEMBLTemplate:Chembox ECHATemplate:Chembox E numberTemplate:Chembox IUPHAR ligandTemplate:Chembox UNIITemplate:Chembox CompToxTemplate:Chembox headerbarTemplate:Chembox SolubilityInWaterTemplate:Chembox headerbarTemplate:Chembox headerbarTemplate:Chembox GHS (set)Template:Chembox Lethal amounts (set)Template:Chembox setHeaderTemplate:Chembox setDatarowTemplate:Chembox setDatarowTemplate:Chembox setDatarowTemplate:Chembox SDSTemplate:Chembox headerbarTemplate:Chembox Datapage checkTemplate:Chembox Footer
2-Butanol
Template:Longitem Template:Unbulleted list
Template:Longitem 773649

1718764 (R)
1718763 (S)

ChEBI Template:Unbulleted list
ChemSpider Template:Unbulleted list
DrugBank Template:Unbulleted list
EC Number Template:Unbulleted list
Template:Longitem 1686

396584 (R)
25655 (S)

KEGG Template:Unbulleted list
MeSH 2-butanol
Template:Longitem Template:Unbulleted list
RTECS number Template:Unbulleted list
UN number 1120
Script error: No such module "collapsible list".
Script error: No such module "collapsible list".
Template:Longitem Template:Chembox Elements/molecular formula
Molar mass Template:Chem molar mass
Density 0.808 g cm−3
Melting point Template:Chembox CalcTemperatures
Boiling point Template:Chembox CalcTemperatures
log P 0.683
Vapor pressure 1.67 kPa (at 20 °C)
Acidity (pKa) 17.6 [4]
Template:Longitem Script error: No such module "val".
Template:Longitem 1.3978 (at 20 °C)
Template:Longitem 197.1 J K−1 mol−1
Template:Longitem 213.1 J K−1 mol−1
Template:Longitem −343.3 to −342.1 kJ mol−1
Template:Longitem −2.6611 to −2.6601 MJ mol−1
NFPA 704 (fire diamond) Template:NFPA 704 diamond
Flash point Template:Chembox CalcTemperatures
Template:Longitem Template:Chembox CalcTemperatures
Explosive limits 1.7–9.8%
Template:Longitem n-Butanol
Isobutanol
tert-Butanol
Template:Longitem Butanone

Template:Chembox Footer/trackingScript error: No such module "TemplatePar".Template:Short description

Butan-2-ol, or sec-butanol, is an organic compound with formula CH3CH(OH)CH2CH3. Its structural isomers are 1-butanol, isobutanol, and tert-butanol. 2-Butanol is chiral and thus can be obtained as either of two stereoisomers designated as (R)-(−)-butan-2-ol and (S)-(+)-butan-2-ol. It is normally encountered as a 1:1 mixture of the two stereoisomers — a racemic mixture.

This secondary alcohol is a flammable, colorless liquid that is soluble in three parts water and completely miscible with organic solvents. It is produced on a large scale, primarily as a precursor to the industrial solvent methyl ethyl ketone.

File:R-butan-2-ol 2D skeletal.svg File:S-butan-2-ol 2D skeletal.svg
File:R-Butan-2-ol-3D-balls.png File:S-Butan-2-ol-3D-balls.png
(R)-(−)-2-butanol (S)-(+)-2-butanol

Manufacture and applications

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

File:But-2-ene-hydration-2D-skeletal.svg

Sulfuric acid is used as a catalyst for this conversion.[6]

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

Although some butan-2-ol is used as a solute, it is mainly converted to butanone (methyl ethyl ketone, MEK), an important industrial solvent and found in many domestic cleaning agents and paint removers. Though most paint removers have ceased using MEK in their products due to health concerns and new laws. Volatile esters of butan-2-ol have pleasant aromas and are used in small amounts as perfumes or in artificial flavors.[6]

Solubility

The listed solubility of butan-2-ol is often incorrect,[3] 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.[3]

Precautions

Like other butanols, butan-2-ol has low acute toxicity. The LD50 is 4400 mg/kg (rat, oral).[6]

Several explosions have been reported[7][8][9] 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. 2-Butanol is in Class B Peroxide Forming Chemicals[10]

References

<templatestyles src="Reflist/styles.css" />

  1. ↑ Script error: No such module "citation/CS1".
  2. ↑ Script error: No such module "citation/CS1".
  3. ↑ a b c Script error: No such module "Citation/CS1".
  4. ↑ Serjeant, E.P., Dempsey B.; Ionisation Constants of Organic Acids in Aqueous Solution. International Union of Pure and Applied Chemistry (IUPAC). IUPAC Chemical Data Series No. 23, 1979. New York, New York: Pergamon Press, Inc., p. 989
  5. ↑ a b c d Script error: No such module "citation/CS1".
  6. ↑ a b c Template:Ullmann.
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ Script error: No such module "Citation/CS1".
  9. ↑ Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".

Script error: No such module "Check for unknown parameters".

External links

Script error: No such module "navbox".

Template:Authority control

Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=2-Butanol&oldid=1264855"