4-Methyl-2-pentanol
[CAS 108-11-2]

Identification

• Classification: Organic raw materials >> Alcohols, phenols, phenolic compounds and derivatives >> Acyclic alcohol
• Name: 4-Methyl-2-pentanol
• Synonyms: Isobutyl methyl carbinol; Methyl isobutyl carbinol
• Molecular Formula: C₆H₁₄O
• Molecular Weight: 102.18
• CAS Registry Number: 108-11-2 (72847-31-5)
• EC Number: 203-551-7
• SMILES: CC(C)CC(C)O

Properties

• Density: 0.8±0.1 g/cm³ Calc.^*, 0.802 g/mL (Expl.)
• Melting point: -90 °C (Expl.)
• Boiling point: 133.5±8.0 °C 760 mmHg (Calc.)^*, 132 °C (Expl.)
• Flash point: 41.1 °C (Calc.)^*, 41 °C (Expl.)
• Solubility: water: 2.0 g/100g (Expl.)
• Index of refraction: 1.412 (Calc.)^*, 1.41 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS07 WarningGHS02
• Risk Statements: H226-H335
• Safety Statements: P210-P233-P240-P241-P242-P243-P261-P271-P280-P303+P361+P353-P304+P340-P319-P370+P378-P403+P233-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	3	H226
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H332

• Transport Information: UN 2053

chemBlink Chemical Story

4-Methyl-2-pentanol, CAS 108-11-2, is a branched six-carbon alcohol widely known as methyl isobutyl carbinol, or MIBC. PubChem records the formula C6H14O and describes it as a clear, colorless liquid. Its moderate water solubility, volatility and interfacial behavior have made it useful both as an industrial solvent and, especially, as a frother in mineral flotation.

Froth flotation separates mineral particles by exploiting differences in surface wettability. Air is dispersed through a mineral slurry, hydrophobic particles attach to bubbles, and a froth carries selected material toward the surface. A frother does not usually supply the main mineral selectivity; instead, it helps control bubble formation, froth texture and persistence. MIBC became a standard reference frother because it can produce a relatively mobile froth that is strong enough for separation without becoming excessively persistent.

The molecular structure explains part of this behavior. Its hydroxyl group provides affinity for the aqueous interface, while the branched hydrocarbon portion prefers the less polar environment near air or hydrophobic surfaces. MIBC therefore concentrates at interfaces and modifies bubble coalescence and froth properties. Outside mineral processing, 4-methyl-2-pentanol has also been used as a solvent or chemical intermediate.

MIBC is flammable and its vapors require appropriate industrial controls. Its chemical story is a reminder that an important reagent does not always work by reacting with the target material. In flotation, a small alcohol can influence an entire separation process mainly by organizing itself at gas-liquid interfaces and changing the behavior of bubbles.

References:
1. PubChem, 4-Methyl-2-pentanol, CID 7910, CAS 108-11-2.
2. Fuerstenau MC, Jameson GJ, Yoon RH, eds. Froth Flotation: A Century of Innovation. SME, 2007.
3. Wills BA, Finch JA. Wills' Mineral Processing Technology. 8th ed. Elsevier, 2016.

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