Methyl isobutyl ketone
|Methyl isobutyl ketone|
|Jmol-3D images||Image 1|
|Molar mass||100.16 g/mol|
|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|
|Solubility in water||1.91 g/100 mL (20 °C)|
|Refractive index (nD)||1.3958|
|Viscosity||0.58 cP at 20.0 °C|
|Dipole moment||2.8 D|
|EU classification||Flammable (F)
|R-phrases||R11, R20, R36/37, R66|
|S-phrases||(S2), S9, S16, S29|
|Flash point||14 °C; 57 °F; 287 K|
|Autoignition temperature||449 °C; 840 °F; 722 K|
|Related ketones||Methyl isopropyl ketone
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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:
Modern processes combine these three steps into one.
Several million kilograms are produced annually.
Precursor to 6PPD
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.
Solvent and niche applications
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.
- , Uhde Technology Profile: MIBK
- Stylianos Sifniades, Alan B. Levy, “Acetone” in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.
- 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.