Methyl isobutyl ketone

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Methyl isobutyl ketone
Skeletal formula of methyl isobutyl ketone
Ball-and-stick model of the methyl isobutyl ketone molecule
Names
IUPAC name
4-Methyl-2-pentanone
Other names
Isopropylacetone, Hexone, Isobutyl methyl ketone, 4-Methylpentan-2-one, 4-methyl-2-pentanone, 2-methyl-4-pentanone, 2-methylpropyl methyl ketone, 4-methyl-2-oxopentane, MIK, isobutylmethyl ketone, MIBK, isohexanone
Identifiers
108-10-1 N
ChemSpider 7621 N
EC number 203-550-1
Jmol-3D images Image
KEGG C19263 YesY
PubChem 7909
RTECS number SA9275000
Properties
C6H12O
Molar mass 100.16 g/mol
Appearance colorless liquid
Odor pleasant[1]
Density 0.802 g/mL, liquid
Melting point −84.7 °C (−120.5 °F; 188.5 K)
Boiling point 117 to 118 °C (243 to 244 °F; 390 to 391 K)
1.91 g/100 mL (20 °C)
Vapor pressure 16 mmHg (20 °C)[1]
1.3958
Viscosity 0.58 cP at 20.0 °C
Structure
2.8 D
Hazards
EU classification Flammable (F)
Harmful (Xn)
R-phrases R11, R20, R36/37, R66
S-phrases (S2), S9, S16, S29
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 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity (yellow): no hazard code Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 14 °C (57 °F; 287 K)
449 °C (840 °F; 722 K)
Explosive limits 1.2%-8.0% (93 °C)[1]
US health exposure limits (NIOSH):
TWA 100 ppm (410 mg/m3)[1]
TWA 50 ppm (205 mg/m3) ST 75 ppm (300 mg/m3)[1]
500 ppm[1]
Related compounds
Related ketones
Methyl isopropyl ketone
2-Pentanone
Diisobutyl ketone
Related compounds
2-Methylpentan-4-ol
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

Methyl isobutyl ketone (MIBK) is the organic compound with the formula (CH3)2CHCH2C(O)CH3. This colourless liquid, a ketone, is widely used as a solvent.

Production[edit]

Methyl isobutyl ketone is manufactured from acetone via a three-step process. Firstly acetone undergoes an aldol condensation to give diacetone alcohol, which readily dehydrates to give mesityl oxide. Mesityl oxide can then be hydrogenated to give MIBK:

Synthesis of MIBK from acetone

Modern processes combine these three steps into one.[2]

Several million kilograms are produced annually.[3]

Uses[edit]

MIBK is used as a solvent for nitrocellulose, lacquers, and certain polymers and resins.[3]

Precursor to 6PPD[edit]

Another major use is as a precursor to N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylene diamine (6PPD), an antiozonant used in tires. 6PPD is prepared by reductive coupling of MIBK with 4-aminodiphenylamine.[4]

Solvent and niche applications[edit]

Unlike the other common ketone solvents, acetone and MEK, MIBK has quite low solubility in water, making it useful for liquid-liquid extraction. It has a similar polarity to ethyl acetate, but greater stability towards aqueous acid and base. It can be used to extract gold, silver and other precious metals from cyanide solutions, such as those found at gold mines, to determine the levels of those dissolved metals. Diisobutyl ketone (DIBK), a related lipophilic ketone, is also used for this purpose. Methyl isobutyl ketone is also used as a denaturing agent for denatured alcohol. When mixed with water or isopropyl alcohol MIBK serves as a developer for PMMA electron beam lithography resist. MIBK is used as a solvent for CS in the preparation of the CS spray used currently by British police forces.[5]

References[edit]

  1. ^ a b c d e f "NIOSH Pocket Guide to Chemical Hazards #0326". National Institute for Occupational Safety and Health (NIOSH). 
  2. ^ [1], Uhde Technology Profile: MIBK
  3. ^ a b Stylianos Sifniades, Alan B. Levy, "Acetone" in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.
  4. ^ Hans-Wilhelm Engels et al., "Rubber, 4. Chemicals and Additives" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a23_365.pub2
  5. ^ Peter J Gray; Stark, MM; Gray, P. J; Jones, G R. N (2000). "Is CS spray dangerous? : CS is a particulate spray, not a gas" (Response to editorial). BMJ 321 (7252): 26. doi:10.1136/bmj.321.7252.46. PMC 1127688. PMID 10939811. 

External links[edit]