Isobutanol

Isobutanol

Names
IUPAC name 2-methylpropan-1-ol
Other names Isobutyl alcohol, IBA, 2-methyl-1-propanol, 2-methylpropyl alcohol, Isopropylcarbinol
Identifiers
CAS Number	78-83-1 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:46645 Y
ChEMBL	ChEMBL269630 Y
ChemSpider	6312 Y
ECHA InfoCard	100.001.044
EC Number	201-148-0
KEGG	C14710 Y
PubChem	6560
RTECS number	NP9625000
UNII	56F9Z98TEM Y
InChI InChI=1S/C4H10O/c1-4(2)3-5/h4-5H,3H2,1-2H3 Y Key: ZXEKIIBDNHEJCQ-UHFFFAOYSA-N Y InChI=1/C4H10O/c1-4(2)3-5/h4-5H,3H2,1-2H3
SMILES CC(C)CO
Properties
Chemical formula	C4H10O
Molar mass	74.122 g/mol
Appearance	Colorless liquid
Odor	sweet, musty
Density	0.802 g/cm3, liquid
Melting point	−108 °C (−162 °F; 165 K)
Boiling point	107.89 °C (226.20 °F; 381.04 K)
Solubility in water	8.7 mL/100 mL
log P	0.8
Vapor pressure	9 mmHg (20°C)
Refractive index (nD)	1.3959
Viscosity	3.95 cP at 20 °C
Hazards
Safety data sheet	ICSC 0113
EU classification (DSD)	Irritant (Xi)
R-phrases	R10 R37/38 R41, R67
S-phrases	(S2) S7/9 S13 S26 S37/39 S46
NFPA 704	3 1 0
Flash point	28 °C (82 °F; 301 K)
Autoignition temperature	415 °C (779 °F; 688 K)
Explosive limits	1.7–10.9%
Lethal dose or concentration (LD, LC):
LDLo (lowest published)	3750 mg/kg (rabbit, oral) 2460 mg/kg (rat, oral)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 100 ppm (300 mg/m3)
REL (Recommended)	TWA 50 ppm (150 mg/m3)
IDLH (Immediate danger)	1600 ppm
Related compounds
Related butanols	n-Butanol sec-Butanol tert-Butanol
Related compounds	Isobutyraldehyde Isobutyric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Isobutanol (IUPAC nomenclature: 2-methylpropan-1-ol) is an organic compound with the formula (CH₃)₂CHCH₂OH (sometimes represented as i-BuOH). This colorless, flammable liquid with a characteristic smell is mainly used as a solvent. Its isomers, the other butanols, include n-butanol, 2-butanol, and tert-butanol, all of which are important industrially.

Isobutanol is produced by the carbonylation of propylene. Two methods are practiced industrially, hydroformylation is more common and generates a mixture of isobutyraldehydes, which are hydrogenated to the alcohols and then separated. Reppe carbonylation is also practiced.

Higher-chain alcohols have energy densities close to gasoline, are not as volatile or corrosive as ethanol, and do not readily absorb water. Furthermore, branched-chain alcohols, such as isobutanol, have higher-octane numbers, resulting in less knocking in engines. Although produced naturally during the fermentation of saccharides and may also be a byproduct of the decay process of organic matter, Isobutanol or C5 alcohols have never been produced from a renewable source with yields high enough to make them viable as a gasoline substitute before the 2008 Nature article that produced over 20g/L isobutanol from glucose in E.coli.

To modify an organism to produce these compounds usually results in toxicity in the cell. This difficulty was bypassed by leveraging the native metabolic networks in E. coli but altered its intracellular chemistry using genetic engineering to produce these alcohols. Key pathways in E. coli were modified to produce several higher-chain alcohols from glucose, including isobutanol, 1-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-phenylethanol. This strategy exploits the E. coli host's highly active amino acid biosynthetic pathway by shifting part of it to alcohol production. It is proposed that these unusual alcohols can be produced as efficiently as the biosynthesis of ethanol.