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4-Methylpentan-2-ol, commonly known as methyl isobutyl carbinol (MIBC), is a colorless organic compound with the chemical formula C6H14O. 4-Methylpentan-2-ol is used as a ore flotation foamer in the mining sector and as a solvent in various industries
CAS Number: 108-11-2
EC / EINECS Number: 203-551-7
UN/NA Number: UN 2053 (Methyl isobutyl carbinol)
PubChem CID: 7910
ChemSpider ID: 7622
RTECS Number: SA7350000
Molecular Weight: 102.177 g/mol
CHEMICAL NAME
Common Name / IUPAC Name: 4-Methylpentan-2-ol
IUPAC Nomenclature: 4-methylpentan-2-ol
Preferred IUPAC Name: 4-Methylpentan-2-ol
Synonyms:Methyl Isobutyl Carbinol (MIBC),Isobutyl Methyl Carbinol, 4-Methyl-2-pentanol,Methyl amyl alcohol, 1,3-Dimethylbutanol, 2-Pentanol, 4-methyl-, Isobutylmethylcarbinol
4-METHYLPENTAN-2-OL (IUPAC name: 4-methylpentan-2-ol) or methyl isobutyl carbinol (MIBC) is an organic chemical compound used primarily as a frother in mineral flotation and in the production of lubricant oil additives such as zinc dithiophosphate.
4-METHYLPENTAN-2-OL is also used as a solvent, in organic synthesis, and in the manufacture of brake fluid and as a precursor to some plasticizers.
4-METHYLPENTAN-2-OL is an acetone derivative in liquid state, with limited solubility in water but generally miscible with most organic solvents.
4-Methylpentan-2-ol is a secondary branched-chain aliphatic alcohol.
Carbon Chain: A 5-carbon pentane chain.
Functional Group: A hydroxyl group (-OH) attached to C-2 (making it a secondary alcohol).
Substituent: A methyl group (-CH3) attached to C-4.
Stereochemistry: Contains one chiral center at Carbon-2 (C-2), existing as a racemic mixture of (R)- and (S)-enantiomers in commercial preparations:
(2R)-4-methylpentan-2-ol
(2S)-4-methylpentan-2-ol
Usage Areas
Mineral Flotation: Foaming agent in the process of enriching metal ores (such as copper, zinc, lead).
Solvent: Solvent for paints, resins, waxes, oils and nitrocellulose.
Organic Synthesis: Intermediate raw material in the production of plasticizers and other chemical derivatives.
Primary Applications
1. Mineral Flotation Frother: Widely used as a frothing agent in the mining industry for copper, lead, zinc, and molybdenum ore flotation.
2. Industrial Solvent: Serves as a medium-boiling solvent for cellulose nitrate, ethylcellulose, lacquers, vinyl resins, and protective coatings.
3. Chemical Intermediate: Used in synthesizing lube oil additives (such as zinc dithiophosphates) and extractions of rare earth minerals.
PHYSICAL & CHEMICAL PROPERTIES
Physical State: Clear, colorless liquid
Odor: Mild, pleasant alcohol-like / hydrocarbon-like odor
Melting / Freezing Point: -90 °C (-130 °F; 183 K)
Boiling Point: 131.6 °C (268.9 °F; 404.8 K)
Density: 0.8075 g/cm³ at 20 °C (Water = 1.0)
Vapor Pressure:
- 0.7 kPa (5.25 mmHg) at 20 °C
- 0.93 kPa at 25 °C
Relative Vapor Density (Air = 1): 3.53
Solubility in Water: Moderately soluble (approx. 15–20 g/L at 20 °C)
Solubility in Organic Solvents: Fully miscible with ethanol, diethyl ether, acetone, benzene, chloroform, and most common organic solvents.
Partition Coefficient (Log Pow): 1.43–1.57 (indicates low potential for bioaccumulation)
Flash Point: 41 °C (105.8 °F) - Closed Cup (Combustible Liquid)
Auto-ignition Temperature: 305 °C (581 °F)
Explosive / Flammability Limits in Air:
- Lower Explosive Limit (LEL): 1.0% by volume
- Upper Explosive Limit (UEL): 5.5% by volume
Refractive Index (n20/D): 1.411
Dynamic Viscosity: 4.1 mPa·s at 20 °C
Surface Tension: 22.8 mN/m at 20 °C
Chemical Formula: C6H14O
Empirical Formula: C6H14O
InChI Key: Catalogs/Standard: IWVSSGLTYWKWEY-UHFFFAOYSA-N
InChI String: InChI=1S/C6H14O/c1-5(2)4-6(3)7/h5-7H,4H2,1-3H3
INDUSTRIAL PREPARATION & SYNTHESIS
Commercial production of 4-methylpentan-2-ol typically follows a multi-step catalytic process starting from acetone:
1. Aldol Condensation:
Two molecules of acetone undergo aldol condensation in the presence of a base (e.g., sodium hydroxide) to yield diacetone alcohol.
2 CH3COCH3 ---> CH3COCH2C(OH)(CH3)2
2. Dehydration:
Diacetone alcohol is dehydrated using an acid catalyst to form Mesityl Oxide (an alpha,beta-unsaturated ketone).
CH3COCH2C(OH)(CH3)2 ---> CH3COCH=C(CH3)2 + H2O
3. Catalytic Hydrogenation:
Mesityl Oxide undergoes complete selective catalytic hydrogenation over metals such as nickel, copper, or palladium to convert both the double bond and the carbonyl group into alcohol functional groups.
CH3COCH=C(CH3)2 + 2 H2 ---> CH3CH(OH)CH2CH(CH3)2 (4-Methylpentan-2-ol)
APPLICATIONS & USES
MIBC (4-Methylpentan-2-ol) is a high-volume industrial chemical with diverse industrial applications:
Froth Flotation Frother (Primary Industrial Application):
Extensively used in the mining and mineral processing industry as a frothing agent (frother).
Highly effective in the flotation separation of sulfide ores such as copper, lead, zinc, and molybdenum, as well as coal processing.
Creates stable, manageable foam/froth bubbles that allow hydrophobic mineral particles to adhere and rise to the surface.
Industrial Solvent:
Dissolves nitrocellulose, ethyl cellulose, acrylic resins, vinyl resins, natural gums, and alkyd resins.
Used as a solvent in surface coatings, lacquers, paints, enamels, and varnishes.
Serves as a medium-boiling solvent that aids flow, leveling, and blush-resistance in surface coatings.
Chemical Intermediate:
Used in the manufacture of lubricating oil additives, particularly zinc dithiophosphates (ZDDP), which act as anti-wear and anti-corrosion agents in engine oils.
Used in the synthesis of xanthate flotation collectors.
Used as an intermediate in organic chemical synthesis (esters, plasticizers, surfactants).
Formulations & Other Uses:
Component in hydraulic fluid formulations.
Extractor solvent for essential oils, pharmaceuticals, and organic acids.
Additive in dry cleaning soaps and industrial degreasers.
7. SAFETY, TOXICOLOGY & HANDLING
GHS Classification:
Flammable Liquids (Category 3)
Specific Target Organ Toxicity - Single Exposure (Category 3, Respiratory Irritation)
Serious Eye Damage / Eye Irritation (Category 2A)
GHS Hazard Statements:
H226: Flammable liquid and vapor.
H319: Causes serious eye irritation.
H335: May cause respiratory irritation.
GHS Precautionary Statements:
P210: Keep away from heat, hot surfaces, sparks, open flames, and other ignition sources. No smoking.
P261: Avoid breathing dust/fume/gas/mist/vapors/spray.
P280: Wear protective gloves/eye protection/face protection.
P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing.
Occupational Exposure Limits (OEL):
OSHA PEL: 25 ppm (100 mg/m³) TWA [Skin designation]
NIOSH REL: 25 ppm (100 mg/m³) TWA, STEL 40 ppm (160 mg/m³) [Skin]
ACGIH TLV: 20 ppm TWA, 40 ppm STEL
Health Hazards & Symptoms:
Inhalation: Irritation of nose and throat, headache, dizziness, drowsiness, central nervous system depression.
Eye Contact: Moderate to severe eye irritation, redness, watering.
Skin Contact: Prolonged or repeated exposure can cause defatting of skin, dryness, cracking, and mild irritation. Absorption through intact skin is possible.
Ingestion: Harmful if swallowed. May cause gastrointestinal discomfort, nausea, vomiting, and aspiration toxicity risks.
Storage & Transport:
Store in tightly closed containers in a cool, dry, well-ventilated area away from heat, sparks, and open flames.
Incompatible Materials: Strong oxidizing agents, strong acids, strong bases, alkali metals, halogens, isocyanates.
