| HS Code | 902710 |
| Chemical Formula | C4H10O |
| Iupac Name | 2-methylpropan-1-ol |
| Molecular Weight | 74.12 g/mol |
| Cas Number | 78-83-1 |
| Appearance | Colorless liquid |
| Odor | Characteristic alcohol odor |
| Density | 0.802 g/cm3 at 20°C |
| Melting Point | -108.1 °C |
| Boiling Point | 107.7 °C |
| Flash Point | 28 °C (closed cup) |
| Solubility In Water | 8.7 g/100 mL at 20°C |
| Vapor Pressure | 9 mmHg at 20°C |
| Refractive Index | 1.3959 at 20°C |
As an accredited Isobutyl Alcohol factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Isobutyl Alcohol, 500 mL, packaged in a sealed glass bottle with secure cap and full hazard labeling. |
| Container Loading (20′ FCL) | Isobutyl Alcohol loaded in a 20′ FCL as UN-approved drums/IBCs, securely stowed, labeled Class 3 flammable, with proper ventilation. |
| Shipping | Isobutyl Alcohol (UN 1212, Class 3, Packing Group III) is a flammable liquid requiring proper hazardous materials shipping. Transport in approved drums, IBCs, or tank containers away from ignition sources. Ensure segregation from oxidizing agents, proper labeling, and documentation. Use grounded equipment and adequate ventilation to prevent vapor accumulation. |
| Storage | Store Isobutyl Alcohol in tightly sealed containers in a cool, dry, well-ventilated area, away from heat, sparks, open flames, and strong oxidizers. Use explosion-proof equipment and grounded containers to prevent static buildup. Keep the storage area clearly labeled, spill-controlled, and accessible to emergency response supplies. |
| Shelf Life | Shelf life is typically 3 years when stored tightly sealed, away from heat, sparks, and incompatible oxidizing materials. |
Esterification of isobutyl alcohol with glacial acetic acid is conducted in jacketed glass-lined reactors at 110–120°C. The catalyst charge is sulfuric acid at 0.2–0.5 wt% of total reaction mass or a sulfonic acid resin in fixed-bed continuous service. The equilibrium is shifted by removal of water as a heterogeneous toluene or cyclohexane azeotrope. Crude isobutyl acetate is neutralized with sodium carbonate solution, washed with water, dried with anhydrous sodium sulfate, and vacuum distilled. Finished ester for high-solids industrial coatings is controlled to ≥99.0 wt% purity, ≤0.05 wt% water, and ≤0.01 wt% acidity as acetic acid. In coil coating and container coating solvent blends, isobutyl acetate is incorporated at 10–25 wt% of total solvent. The ester shortens tack-free time relative to n-butyl acetate while maintaining flow in high-solids systems subject to EU Solvent Emissions Directive 2010/75/EU and 40 CFR Part 59. Production-scale electrostatic spray lines record orange peel when ambient humidity exceeds 70% and isobutyl acetate exceeds 20 wt% of the solvent blend. At lower addition levels, vertical sag resistance improves but flow-out may become insufficient on large flat panels. End products include high-solids polyester coil coatings, container enamels, and aerosol industrial paints.
| Feedstock parameter | Method | Typical acceptance range |
|---|---|---|
| Acidity, as acetic acid | ASTM D1613-06(2021) | ≤0.005 wt% |
| Water content | ASTM D1364-02(2012) | ≤0.1 wt% |
| Color, platinum-cobalt | ASTM D1209-05(2019) | ≤10 Pt-Co |
| Non-volatile matter | ASTM D1353-13(2021) | ≤0.005 g/100 mL |
| Distillation range | ASTM D1078-11(2019) | Initial ≥106°C, dry point ≤109°C |
Potassium isobutyl xanthate is synthesized by reacting isobutyl alcohol with potassium hydroxide and carbon disulfide. The molar ratio of potassium hydroxide to isobutyl alcohol is maintained between 1.00 and 1.05; carbon disulfide is fed at 1.00–1.05 mol per mol alcohol to maintain a slight excess. The reaction is exothermic and requires brine cooling to keep the mass below 35°C. Above 40°C the xanthate undergoes thermal decomposition to isobutyl alcohol, carbon disulfide, and potassium carbonate. This side reaction consumes yield and generates volatile sulfur species. Carbon disulfide addition is spread over 2–4 h while maintaining pH above 10.5. The reactor is a glass-lined or stainless vessel with a nitrogen-purged condenser, carbon disulfide day tank, and caustic scrubber on the vent. Final product is dried under vacuum at 45–55°C to moisture ≤2.0 wt%. In copper, lead, and zinc sulfide flotation circuits, the collector is dosed at 20–150 g/t of dry ore depending on pulp potential and liberation. Batch-to-batch variation in free caustic above 0.5 wt% can shift pulp pH and depress molybdenum recovery in copper-moly separation. Published data for specific pulp potential thresholds in this configuration is limited; plant trials are required. End products are mineral concentrates from sulfide flotation plants, especially copper, lead, zinc, and precious metal by-product circuits.
For radiation-curable pressure-sensitive adhesives and flexographic inks, isobutyl alcohol is esterified with acrylic acid at 80–110°C under 40–70 kPa vacuum. Toluene or cyclohexane is used as azeotroping solvent. The charge contains 100–300 ppm monomethyl ether hydroquinone (MEHQ) and a hydroquinone co-inhibitor to prevent radical polymerization. Air sparging is maintained because dissolved oxygen is required for MEHQ activation. Crude isobutyl acrylate is washed with dilute caustic, water, and brine, then vacuum distilled. Finished monomer is controlled to ≥99.5 wt% purity, ≤0.1 wt% water, and ≤0.005 wt% acidity. For bulk storage, MEHQ is adjusted to 10–20 ppm. In adhesive compounding, isobutyl acrylate modifies peel, tack, and surface wetting on corona-treated polyethylene and oriented polypropylene label facestocks. The branching of the ester side chain alters copolymer glass transition temperature relative to n-butyl acrylate. Formulators adjust alkyl chain branching to tune shear resistance. At addition levels of 15–30 wt% in UV-curable flexographic ink vehicles, viscosity is measured under ISO 2884-1 at 23°C and 100 s⁻¹. End products include pressure-sensitive label adhesives, UV flexo inks, acrylic polymer emulsions, and concrete cure-and-seal coatings.
Diisobutyl phthalate is produced from phthalic anhydride and isobutyl alcohol in a two-stage esterification using titanium or tin organometallic catalysts at 180–220°C. The final stage is run under vacuum to strip excess alcohol and water of reaction. The crude ester is neutralized with sodium carbonate, deodorized by vacuum steam stripping, and filtered through activated carbon. Finished DIBP is controlled to ≥99.5 wt% ester content, ≤0.1 wt% water, and ≤0.05 mg KOH/g acid value. In flexible PVC compounding, DIBP is incorporated at 20–60 phr for industrial profiles and cable sheathing. It lowers melt viscosity and permits lower barrel zone temperatures on twin-screw extruders. Fume generation increases at die temperatures above 190°C. Regulatory status under Regulation (EC) No 1907/2006 Annex XVII Entry 51 restricts DIBP in toys and childcare articles at concentrations above 0.1% by weight individually or combined with DEHP, DBP, and BBP. The substance is also included in the REACH candidate list as a substance of very high concern. Industrial PVC compounds, rubber sealing strips, and technical textiles remain within current permitted use areas. Exporters to the European Union must document end-use and avoid downstream dispersion into consumer childcare articles. Published data for specific migration rates in industrial flooring systems are limited; food-contact uses require case-by-case migration testing under harmonized EU methods.
In nitrocellulose wood lacquer systems, isobutyl alcohol functions as a medium-evaporating latent solvent. It does not dissolve nitrocellulose by itself but extends the true solvent blend of esters and ketones. Typical addition ranges from 5–15 wt% of the total solvent package. The alcohol increases hydrogen bonding with absorbed water and extends solvent release. This prevents micro-void formation and surface blush when coating lines operate above 70% relative humidity. The boiling point is 107.8°C and closed-cup flash point is 28°C. On air-assisted airless wood finishing lines, spray viscosity is adjusted to 25–35 s with a ISO 2431 4 mm flow cup at 20°C. Furniture manufacturers in tropical humidity replace n-butanol with isobutyl alcohol at equal weight to improve overspray dissolution without lifting preceding nitrocellulose coats. The addition is not unlimited. Solvent blends containing more than 30 wt% aromatic hydrocarbons can develop resin precipitation when isobutyl alcohol exceeds 20 wt%. The precipitated resin phase clogs edge-coating nozzles and produces visible particles in sealer coats. Non-volatile content is checked by ASTM D1644. End products include nitrocellulose sanding sealers, pre-catalyzed wood lacquers, gravure printing inks, and clear coats for wood furniture.
Catalytic amination converts isobutyl alcohol to monoisobutylamine over cobalt- or nickel-promoted alumina catalysts at 150–200°C and 1.0–5.0 MPa hydrogen partial pressure. The ammonia-to-alcohol molar ratio is maintained between 8:1 and 20:1 to suppress secondary and tertiary amine formation. The reactor effluent is separated by pressure distillation into ammonia, water, unreacted alcohol, monoisobutylamine, diisobutylamine, and triisobutylamine. Published single-pass conversion data for this specific catalyst configuration are limited. Commercial units rely on continuous distillative recycling of unreacted alcohol. Monoisobutylamine is then converted to dithiocarbamate vulcanization accelerators, including zinc diisobutyldithiocarbamate. In rubber compounding, the accelerator is added at 0.5–1.5 phr with sulfur and zinc oxide. Cure characteristics are measured on a moving die rheometer under ISO 6502. Overdosing above 2.0 phr shortens scorch time and may cause bloom on EPDM extrusion profiles. End products include EPDM automotive weatherstrips, natural rubber industrial mats, and NBR sealing elements.
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Isobutyl alcohol, systematic name 2-methylpropan-1-ol, CAS 78-83-1, is a branched primary alcohol with empirical formula C4H10O and molar mass 74.12 g/mol. Industrial material is produced predominantly by rhodium- or cobalt-catalysed hydroformylation of propylene to isobutyraldehyde, followed by catalytic hydrogenation over a copper/zinc oxide or nickel catalyst at elevated pressure. The commercial product is supplied under several designations: standard ester-grade material with purity ≥99.5 wt%, low-water urethane-grade material with water ≤0.03 wt%, and intermediate industrial-grade material for solvent blending. At 20 °C the density is 0.802–0.804 g/mL, the normal boiling point is 107.9 °C, and the closed-cup flash point is 28 °C. These properties place the solvent between methyl isobutyl ketone and n-butanol in evaporation rate while retaining primary alcohol reactivity toward carboxylic acids, isocyanates, and methylol intermediates.
Two commercial grades are differentiated by water, acidity, and colour after shipment. Ester-grade isobutanol is used where the alcohol is consumed by chemical reaction; urethane-grade material is filtered and dried for moisture-sensitive polyurethane and amino-crosslinker applications. The following values are typical specification windows accepted in bulk tank-truck deliveries; individual supplier certificates of analysis may list tighter internal release limits.
| Property | Test method | Ester-grade value | Urethane-grade value |
|---|---|---|---|
| Purity | ASTM D1719 | ≥99.5 wt% | ≥99.5 wt% |
| Water | ASTM D1364 | ≤0.10 wt% | ≤0.03 wt% |
| Acidity as acetic acid | ASTM D1613 | ≤0.005 wt% | ≤0.003 wt% |
| Colour, Pt-Co/APHA | ASTM D1209 | ≤10 | ≤10 |
| Distillation range at 101.3 kPa | ASTM D1078 | 107.0–108.0 °C | 107.0–108.0 °C |
| Nonvolatile matter | ASTM D1353 | ≤0.005 g/100 mL | ≤0.005 g/100 mL |
| Refractive index n20/D | ASTM D1218 | 1.395–1.397 | 1.395–1.397 |
| Aldehydes and ketones as isobutyraldehyde | GC-FID area% | ≤0.05 wt% | ≤0.02 wt% |
The water limit is operationally critical for urethane-grade product because water reacts with isocyanate groups, releasing carbon dioxide and increasing viscosity during prepolymer manufacture. A batch receiving water above 0.03 wt% is therefore rejected or rerouted to ester production where the water is removed during initial distillation.
In continuous esterification trains for isobutyl acetate and isobutyl acrylate, the producer typically charges the alcohol in molar excess relative to the carboxylic acid. The reaction is equilibrium-limited; process designs using 316L stainless-steel reactive distillation columns equipped with structured packing and a decanter for azeotropic water removal shift conversion beyond conventional batch limits. Overhead temperature is controlled to return organic phase to the column while removing water; bottom temperature is maintained in the 110–120 °C range when acetic acid is the acyl donor. A strong-acid catalyst such as p-toluenesulfonic acid or methanesulfonic acid is used at low loading, and residual acidity after neutralisation with sodium carbonate or dilute sodium hydroxide is monitored by ASTM D1613. For isobutyl acrylate, the inhibitor 4-methoxyphenol is introduced at 10–15 ppm relative to monomer to prevent radical polymerisation during vacuum stripping. Published data for exact tray-by-tray kinetic parameters in commercial mixed-butanol esterification columns is limited; however, process licensors commonly specify a reflux ratio and organic-phase recycle set point that reduces residual carboxylic acid below 0.02 wt% before final distillation.
Isobutanol differs from n-butanol in boiling point, freezing point, solvent-release profile, and the hydrolytic stability of ester derivatives. In melamine-formaldehyde and urea-formaldehyde crosslinkers, both alcohols are used to etherify methylol groups, but isobutanol produces a resin with a lower solution viscosity at equivalent solids because the branched alkyl group disrupts intermolecular hydrogen bonding. When 10 wt% of n-butanol is replaced by isobutanol in a hexamethoxymethylmelamine/alkyd bake enamel, cone-and-plate viscosity at 25 °C commonly decreases by several percent; the exact reduction is formulation-dependent and is established by ASTM D2196 in the end-use formula. The lower boiling point of isobutanol at 107.9 °C compared with 117.7 °C for n-butanol increases the rate of solvent release during the early bake zone, which can create solvent-popping defects if the film skins before residual solvent escapes. The formulation window therefore shifts; users replace only a portion of n-butanol, or adjust coalescing-solvent content to maintain ASTM D2369 VOC compliance and avoid defects in film builds above 50 µm dry film thickness.
Across the four butanol isomers, the structural position of the hydroxyl group controls both reactivity and storage behaviour. Isobutanol is a primary alcohol and esterifies cleanly; 2-butanol is secondary and forms esters more slowly; tert-butanol is tertiary and, under acid catalysis, undergoes dehydration to isobutylene rather than clean esterification. This makes isobutanol a direct substitute for n-butanol in many ester syntheses, whereas sec-butanol and tert-butanol are not interchangeable without changing reactor design and product distribution.
| Property | Isobutyl alcohol | n-Butanol | 2-Butanol | tert-Butanol |
|---|---|---|---|---|
| Hydroxyl class | Primary | Primary | Secondary | Tertiary |
| Normal boiling point at 101.3 kPa | 107.9 °C | 117.7 °C | 99.5 °C | 82.4 °C |
| Freezing point | −108 °C | −90 °C | −115 °C | 25.6 °C |
| Closed-cup flash point | 28 °C | 35 °C | 24 °C | 11 °C |
| Acid-catalysed esterification behaviour | Clean primary esterification | Clean primary esterification | Slower secondary ester formation | Dehydration to isobutylene dominates |
| Representative downstream use | Ester solvent, amino resin intermediate | Plasticiser alcohol, solvent | Methyl ethyl ketone precursor, paint remover | Anti-knock additive, reagent |
Derivative formation highlights the practical consequences of branching. Isobutyl acetate boils at 118 °C versus 126 °C for n-butyl acetate; diisobutyl phthalate has lower plasticising efficiency than dibutyl phthalate and is restricted under REACH Annex XVII entry 51 in certain plasticised articles. Because the branched primary alcohol retains primary hydroxyl reactivity, it esterifies under conditions closer to n-butanol than to 2-butanol; this is the principal reason isobutanol is used as a direct replacement when logistics favour oxo-derived branched feedstock.
In high-solids polyester/melamine coil coating lines, the letdown solvent package is sometimes adjusted from n-butanol to isobutanol to reduce low-shear viscosity while maintaining primary alcohol functionality needed for transetherification during cure. Typical industrial coil coating lines apply the film with roll coaters at line speeds of 60–120 m/min and peak metal temperature of 210–232 °C. Under these conditions, isobutanol leaves the film earlier than n-butanol, which shortens leveling time and can increase solvent-popping risk in films above 50 µm dry film thickness when the solvent package is not reformulated. Published data for this specific coil-coating substitution is limited; actual defect thresholds vary with polyester molecular weight, melamine grade, and peak metal temperature. Equipment optimisation therefore requires trial coatings on a roll coater with line speed and peak metal temperature logged against ASTM D2369 VOC content and ASTM D3359 cross-cut adhesion.
Storage and handling boundaries are established by flammability and water pickup. Bulk tanks should be blanketed with nitrogen, grounded, and fitted with flame arresters; the closed-cup flash point is 28 °C and the flammable concentration range is 1.7–10.6 vol% in air at 25 °C. If the alcohol is stored in humid coastal sites with open vents, water content can rise above the urethane-grade limit of 0.03 wt% within one humid season; closed-loop transfer with dry air or nitrogen gas is therefore required for moisture-sensitive applications. Isobutanol is incompatible with strong oxidisers, strong acids at elevated temperature, and alkali metals. Transfer piping is commonly constructed of carbon steel or 316L stainless steel; copper and copper alloys are avoided in continuous service because trace oxidation products may form coloured residues.
