+8615371019725
| HS Code | 642614 |
| Product Name | Isobutanol (IBA) |
| Iupac Name | 2-Methylpropan-1-ol |
| Synonyms | Isobutyl alcohol; 2-methyl-1-propanol; isobutanol |
| Cas Number | 78-83-1 |
| Ec Number | 201-148-0 |
| Molecular Formula | C4H10O |
| Molecular Weight | 74.12 g/mol |
| Appearance | Colorless liquid |
| Odor | Mild alcohol-like |
| Density | 0.802 g/cm3 at 20 °C |
| Melting Point | -108 °C |
| Boiling Point | 107.9 °C |
| Flash Point | 28 °C (closed cup) |
| Autoignition Temperature | 415 °C |
| Explosive Limits | 1.7–10.9 vol% in air |
| Vapor Pressure | 10.5 mmHg at 20 °C |
| Solubility | Soluble in water (approx. 8.5 g/100 mL at 25 °C); miscible with most organic solvents |
| Refractive Index | 1.3959 at 20 °C |
| Viscosity | 3.95 mPa·s at 20 °C |
| Logp | 0.76 |
| Un Number | UN 1212 |
| Hazard Class | 3 (Flammable liquid) |
| Packing Group | III |
| Ph | Neutral (approx. 7) |
As an accredited Isobutanol IBA factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Isobutanol (IBA) packaged in 200 L steel drums, DOT-approved with secure bung closures, UN marking, and clear flammable liquid hazard labels. |
| Container Loading (20′ FCL) | Isobutanol IBA loaded in 20′ FCL: 80 x 200L drums, net 12,800 kg, hazardous Class 3, UN1212, Packing Group III. |
| Shipping | Isobutanol (IBA), UN1212, is a Class 3 flammable liquid, Packing Group III. Ship in approved steel drums, tank trucks, or ISO tanks, properly labeled and documented. Keep away from heat, sparks, and oxidizers; ensure ventilation, grounding, and compliance with DOT/IMDG/IATA regulations. Use UN-approved packaging and emergency response information. |
| Storage | Store isobutanol (IBA) in a cool, dry, well-ventilated area away from heat, sparks, open flames, and strong oxidizers. Keep containers tightly closed, properly labeled, and grounded to prevent static ignition. Use approved flammable-liquid storage cabinets or dedicated solvent stores. Protect from direct sunlight and incompatible materials. Ensure spill containment and adequate ventilation. Store at ambient temperature, segregated from acids, bases, and reactive compounds. |
| Shelf Life | Isobutanol (IBA) is stable; shelf life about 24 months if stored sealed, cool, dry, well-ventilated, away from heat and ignition sources. |
In coil coating topcoat systems formulated around saturated polyester resins crosslinked with partially alkylated melamine-formaldehyde resins, isobutanol performs two distinct functions: as a co-solvent controlling evaporation during reverse roller application and as a blocking/etherifying alcohol in the aminoplast resin phase. The solvent blend is engineered to maintain a relative evaporation rate that allows leveling without sag on a moving strip that reaches peak metal temperatures between 216 °C and 249 °C within 30–45 s oven dwell time. Addition rates for isobutanol in the total liquid coating typically occupy 2.0–6.0 wt%, with the upper boundary constrained by viscosity depression and the lower boundary dictated by aminoplast compatibility and flow. Compliance for this segment is evaluated under ASTM D5402-19 for MEK double-rub solvent resistance, ASTM D3363 for pencil hardness, EN 13523-1 for coil coating test conditioning, and Directive 2004/42/EC Annex IIA for decorative and vehicle refinish VOC limits. Production-scale application occurs on a continuous coil line where chromate or chrome-free pretreatment is followed by primer and topcoat application via reverse roller coater; isobutanol-containing topcoats are cured in multi-zone air-flotation ovens with the first zone held at 120–160 °C to promote solvent flash without blistering. Finished product types include polyester/melamine prepainted steel and aluminium for architectural cladding, garage door panels, appliance wrappers, and lighting reflectors. Process limitations must be noted: residual isobutanol in the cured film beyond 0.5 wt% measured by headspace GC can lower glass transition temperature and increase susceptibility to dirt pickup on uncoated coil stored at ambient temperatures above 35 °C.
In the synthesis of partially isobutylated melamine-formaldehyde crosslinkers, isobutanol serves as the etherifying alcohol that caps methylol groups and reduces the number of free hydroxymethyl sites available for self-condensation. The reaction sequence begins with methylolation of melamine using aqueous formalin at pH 8.0–9.0 and 60–80 °C, followed by acid-catalyzed etherification at pH 2.5–4.5 and reflux at 90–105 °C. The molar feed ratio of isobutanol to combined formaldehyde is maintained at 1.1:1 to 1.4:1, and water removal is controlled to push the equilibrium toward alkoxy substitution; final solids are measured by ISO 3251:2019 at 125 °C for 1 h, VOC content by ISO 11890-2:2020, and free formaldehyde by sulfite titration. Production equipment includes glass-lined or stainless steel reactors with packed column reflux, Dean-Stark water removal, and vacuum distillation to strip excess isobutanol to below 0.3 wt% in the finished resin. Downstream, the resin is blended into acid-catalyzed baking enamels at 15–30 wt% of total binder solids and cured at 130–160 °C for 20–30 min. Finished product types include coil primer and enamel crosslinkers, general industrial baking enamels for metal furniture, automotive parts, and drum coatings. The principal limitation is water tolerance: over-alkoxylation with isobutanol increases hydrophobicity but reduces crosslink density, so the molar substitution ratio must be controlled within the specified window or cure response and MEK resistance decline.
Solventborne nitrocellulose clear and pigmented lacquers for wood finishing incorporate isobutanol as a latent oxygenated diluent rather than as an active nitrocellulose solvent, with the ester and ketone phase carrying solvency while isobutanol moderates evaporation and reduces blushing in high-humidity spray booths. The formulation addition range is commonly 5.0–12.0 wt% of the total solvent blend, with the lowest level tied to viscosity reduction and the upper limit set by compatibility and odour. Compliance is verified through ASTM D1200-10(2018) Ford cup viscosity measurement, ASTM D3359-17 cross-cut adhesion on sealed wood substrates, ASTM D1640 drying time evaluation, and Directive 2004/42/EC Annex IIA category limits for wood coating VOC. In production, RS ½-sec nitrocellulose is pre-wetted with isobutanol to prevent electrostatic agglomeration, then dispersed under high-speed dissolver at peripheral tip speeds of 15–25 m/s with alkyd or maleic resin, plasticizer, and matting agents. The lacquer is applied by air-assisted airless spray at 18–25 s Ford #4 viscosity; the flash-off interval between coats is extended by 3–5 min when relative humidity exceeds 70% to prevent moisture blush. Finished product types include solid wood office furniture, kitchen cabinet doors, acoustic guitar bodies, and high-gloss piano black undercoats. Preserved at 20–25 °C in closed containers, the formulation remains stable; however, when isobutanol exceeds 12 wt%, film hardness development slows because residual solvent plasticizes the dried film for up to 72 h.
In solventborne flexographic and gravure ink systems printed on surface-treated polyester, BOPP, and aluminium foil, isobutanol is introduced during letdown as a retarding co-solvent to prevent premature skin formation in shallow anilox cells and to adjust the evaporation gradient for high-speed CI flexo presses running at 150–300 m/min. The addition level in finished ink is typically 1.0–5.0 wt%, with the upper limit controlled by odour and retained solvent specifications measured by headspace GC according to ISO 11890-2:2020 or equivalent. Compliance for indirect food contact laminates follows 21 CFR 175.300 resinous and polymeric coating requirements, the EuPIA Guideline on Printing Inks Applied to the Non-Food Contact Surface of Food Packaging, and ISO 2836:2021 for light fastness of printed matter. Production begins with pigment dispersion in a polyurethane or nitrocellulose varnish on a bead mill, followed by letdown to 22–28 s Zahn #2 cup viscosity and press-side adjustment with a blend of isobutanol, ethyl acetate, and propyl acetate. Drying tunnel conditions are staged at 50–70 °C with air velocity above 10 m/s to drive residual solvent below 5 mg/m² before lamination. Finished product types include retort pouch outer webs, snack food laminates, confectionery wrappers, and shrink sleeve labels. A key process boundary is that isobutanol should not be used as the sole tail solvent in water-based ink wash-ups because its limited water miscibility and high interfacial tension produce roller stripping on ceramic anilox surfaces.
Polychloroprene-based contact adhesives formulated for postforming and high-pressure laminate bonding incorporate isobutanol as a tail solvent that extends open time and reduces stringing during roll coating of both substrates. The addition ratio is generally 4.0–12.0 wt% of the total solvent blend, replacing a portion of toluene or cyclohexane without collapsing adhesive viscosity; the exact dosage is adjusted by solids content and application method. Compliance is anchored to ASTM D903-98(2017) for peel resistance of adhesive bonds, EN 13986:2004+A1:2015 for wood-based panels in construction, and REACH Regulation (EC) No 1907/2006 for solvent phase compositional control. Manufacturing occurs in closed stainless steel mixers where polychloroprene rubber is masticated with magnesium oxide, zinc oxide, and para-tert-butylphenol formaldehyde resin, then cut back with a solvent sequence in which isobutanol is added after the aromatic solvent phase; high shear is avoided because polymer degradation increases gel content and reduces green strength. Application to high-pressure laminate and particleboard is performed by roller coater at 120–180 g/m² wet film weight; the open time at 23 °C and 55% RH is extended by 2–4 min relative to a non-alcohol blend, allowing lay-up of large table tops. Finished product types include office desktops, cabinetry, automotive interior laminates, and shoe sole attaching operations. The operational boundary is clear: isobutanol should not be combined with isocyanate-based hardeners in the same adhesive batch because the hydroxyl group consumes the crosslinker and causes premature viscosity rise, and moisture ingress above 0.15 wt% in the solvent blend reduces bond strength after ageing.
Isobutyl acrylate and isobutyl methacrylate monomer synthesis uses isobutanol as the esterifying alcohol in a continuous or batch esterification reactor charged with acrylic acid or methacrylic acid, an acid catalyst, and a polymerization inhibitor system. The feed molar ratio of isobutanol to acid is typically held at 1.1:1 to 1.5:1, with excess alcohol recovered by distillation and recycled; inhibitor content in the reactor is maintained at 15–50 ppm monomethyl ether hydroquinone relative to monomer, measured by ASTM D3125-15. The reaction is run at 95–115 °C under azeotropic water removal, with oxygen inhibition of the vapor phase and a reflux splitter controlling ester purity above 99.5 wt%. Compliance obligations include REACH registration and risk management for acrylate monomers, ASTM D4415 dimer content in acrylic acid feedstock, and ISO 9001:2015 batch release for monomer colour and acidity. Downstream polymerization of isobutyl acrylate into acrylic copolymers is conducted via solution or suspension polymerization in stainless steel reactors at 70–90 °C using peroxide or azo initiators; the glass transition of the resulting polymer is lower than n-butyl acrylate copolymers, which influences film flexibility and tack. Finished product types include automotive refinish acrylic topcoats, pressure-sensitive adhesives, UV-curable oligomers, and fabric coating binders. The primary process limitation is the oxygen sensitivity of isobutyl acrylate in storage; bulk monomer must be maintained with headspace oxygen at 6–21% by volume and MEHQ at the lower indicated level to avoid runaway polymerization at ambient temperatures above 30 °C.
Diisobutyl phthalate is manufactured by esterifying phthalic anhydride with excess isobutanol using a tetraalkyl titanate or sulfuric acid catalyst at 140–180 °C; the feedstock molar ratio of isobutanol to phthalic anhydride is maintained between 2.2:1 and 2.8:1, and the crude ester is neutralized, steam-stripped, and filtered to achieve a colour specification below 25 Hazen and acid value below 0.05 mg KOH/g. In flexible PVC compounding, DIBP is added at 30–60 phr depending on target Shore A hardness, where the lower range is used for calendered film and the upper range for plastisol coatings and slush molding. Compliance is governed by REACH Annex XVII entries 51 and 52, which restrict phthalates including DIBP in toys and childcare articles above 0.1 wt%, and by ASTM D3291-11(2022) for plasticizer compatibility under compression. The downstream production process involves dry blending suspension PVC resin, DIBP, stabilizer, and filler in a hot mixer at 80–110 °C, followed by cooling and either calendering at 150–170 °C or extrusion of profiles and hoses. Finished product types are restricted to industrial and building applications such as non-food floor tile, tarpaulin, garden hose, automotive underbody sealant, and wire harness sheathing; DIBP is not suitable for food contact articles, medical tubing, or children’s toys. A critical processing limitation is that DIBP has higher volatility and lower plasticizing efficiency than dioctyl phthalate, so it is not recommended for continuous outdoor profiles exposed to service temperatures above 60 °C, where migration and embrittlement data measured by loss on heating under ISO 176:2005 indicate significant plasticizer loss.
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Isobutanol IBA (CAS 78-83-1; 2-methyl-1-propanol) is supplied as a clear branched primary C4 alcohol for use as an oxygenated solvent and downstream intermediate. The product has molar mass 74.12 g/mol, normal boiling point 107.9 °C at 101.325 kPa, density 0.802 g/cm³ at 20 °C by ASTM D4052, and closed-cup flash point 28 °C by ASTM D56. Refined-grade sales specifications typically state purity ≥99.5 wt% by GC-FID, water ≤0.10 wt% by ASTM E203, acidity ≤0.005 wt% as acetic acid by ASTM D1613, APHA colour ≤10 by ASTM D1209, and atmospheric distillation range 106.5 °C–108.5 °C by ASTM D1078. Water solubility at 25 °C is approximately 8.5 g/100 g water, and the product must be protected from moisture ingress when used in moisture-sensitive isocyanate or esterification reactions.
The branched structure differentiates IBA from linear n-butanol: the normal boiling point is 107.9 °C compared with 117.7 °C for n-butanol, while the flash point is 28 °C compared with 35 °C. The property differences are not additive in all solvent formulations because activity coefficients in mixed resin systems deviate from Raoult’s law. For direct substitution, the formulation must be rebalanced by viscosity and evaporation-rate testing rather than by simple mass replacement.
Three commercial grades are commonly offered: technical, refined, and low-water ester/urethane grade. Technical grade has purity ≥99.0 wt%, water ≤0.20 wt%, and acidity ≤0.010 wt%. Refined grade has purity ≥99.5 wt%, water ≤0.10 wt%, and acidity ≤0.005 wt%. Low-water ester grade has purity ≥99.7 wt%, water ≤0.05 wt%, and acidity ≤0.003 wt%. Carbonyl content as isobutyraldehyde is controlled to ≤0.05 wt% in the refined and low-water grades because residual aldehyde causes colour formation in amino-crosslinked baking enamels. The relevant batch certificate methods are GC-FID for purity, ASTM E203 for water, ASTM D1613 for acidity, ASTM D1209 for colour, and ASTM D1078 for distillation range. Non-volatile residue is typically ≤0.005 wt% by gravimetric evaporation at 105 °C.
Standard packaging comprises 200 L epoxy-phenolic lined steel drums, 1000 L intermediate bulk containers, and bulk road tankers of 20–25 t. The low-water version is ordered by sales specification rather than by a separate model number. Bulk shipments are inerted with nitrogen during loading, and the headspace oxygen target is ≤5 vol%.
Production-scale storage at paint and resin plants uses stainless steel 304 or 316 vessels of 20–50 m³, with internal dip pipes, conservation vents, and desiccant vent dryers. In a coil-coating line drawing IBA from a 25 m³ ambient tank under 2–5 kPa nitrogen overpressure, delivered water content is observed to vary between 0.03 wt% and 0.06 wt% per batch. Failure of the desiccant dryer raises water to 0.12 wt% within 14 days, which exceeds the low-water ester grade limit. Transfer pumps with magnetically coupled seals and flameproof motors are specified under ATEX 2014/34/EU because the flash point is 28 °C; drummed product stored outdoors should be reblanketed with dry nitrogen after each withdrawal.
IBA is produced by hydroformylation of propylene to isobutyraldehyde, followed by catalytic hydrogenation to the alcohol and multi-column refining. The crude alcohol stream contains hydrogenation intermediates, water, light aldehydes, and heavy oxo residues. Low-boiling isobutyraldehyde is removed as lights; the alcohol product cut is taken at 106–109 °C at atmospheric pressure, while heavy ends are withdrawn at >110 °C. The boiling point gap between IBA (107.9 °C) and n-butanol (117.7 °C) permits conventional separation, but sec-butanol (99.5 °C) may remain in the lights cut if present. Atmospheric drying is limited by the water azeotrope; simple distillation cannot economically reduce water below the low-water grade limit, so final drying uses molecular-sieve adsorption or pervaporation. In a 70-theoretical-stage divided-wall column, the product side draw is monitored by on-line density and mid-infrared hydroxyl analysis; deviations above 0.10 wt% water automatically divert the side draw to the wet-alcohol drum.
Upstream of the final column, a coalescer and a guard bed of 3A molecular sieve protect the ester-grade water specification. The product loop is maintained at 30–40 °C to avoid colour formation during extended hold-up. Published data for the specific hydrogenation catalyst cycle length is generally less available than distillation operating data, but the production bottleneck is typically the dryer capacity rather than the alcohol column when low-water grade is run continuously.
In high-solids nitrocellulose and alkyd baking enamels, IBA is added as a latent solvent to reduce spray viscosity while retaining solvent release. A reverse-roll coil-coating line running at 35 m/min requires a flow time of 60–80 s in an ISO 2431 cup with 4 mm orifice at 20 °C. Replacement of n-butanol with IBA at a 1:1 mass ratio lowers measured flow time by 8–15 s without changing non-volatile content above 55 wt%. Volatile organic content measured by ASTM D2369 remains in the 250–350 g/L range depending on co-solvent load. Solvent popping resistance is maintained when the thinner package is adjusted to compensate for the higher evaporation rate of IBA relative to n-butanol.
Esterification of IBA with acetic acid, acrylic acid, or dibasic acids is carried out in glass-lined or 316L batch reactors with azeotropic water removal. A typical acid-catalysed charge uses 0.3–1.0 wt% p-toluenesulfonic acid relative to total charge. In the 90–110 °C range, equilibrium conversion to isobutyl acetate is approached within 2–4 h; water removal via reflux decanter shifts the equilibrium. The main side product is diisobutyl ether from acid-catalysed dehydration. Ether formation becomes measurable above 120 °C or when acid concentration exceeds 1.0 wt%. A 10 m³ batch esterification line with two-stage vacuum distillation yields crude isobutyl acetate having ester content 98.5–99.0 wt%, residual alcohol ≤0.1 wt%, and acidity ≤0.01 wt% as acetic acid. For isobutyl acrylate, polymerisation inhibitor is maintained at 15–25 ppm phenothiazine or hydroquinone monomethyl ether, and the vacuum stripper is operated below 100 °C to reduce thermal dimer formation.
The water of reaction is removed by azeotropic distillation; the overhead condensate splits in a decanter with an alcohol-rich organic phase and an aqueous phase. The aqueous phase is stripped before discharge to meet site biological treatment limits. The decanter organic layer is refluxed to the reactor, and its IBA content reduces raw-material loss. Excess water in the alcohol feed increases reboiler duty and extends batch time; low-water grade feed reduces decanter fouling and phase-separation upsets.
The choice between IBA and linear n-butanol is controlled by viscosity, boiling point, and the volatility of the derived ester. Table 1 compares the butanol isomers and the corresponding acetate ester boiling points.
| Property | n-Butanol | Isobutanol IBA | sec-Butanol | tert-Butanol |
|---|---|---|---|---|
| CAS registry number | 71-36-3 | 78-83-1 | 78-92-2 | 75-65-0 |
| Molar mass | 74.12 g/mol | 74.12 g/mol | 74.12 g/mol | 74.12 g/mol |
| Normal boiling point at 101.325 kPa | 117.7 °C | 107.9 °C | 99.5 °C | 82.4 °C |
| Density at 20 °C | 0.810 g/cm³ | 0.802 g/cm³ | 0.806 g/cm³ | 0.786 g/cm³ |
| Closed-cup flash point | 35 °C | 28 °C | 24 °C | 11 °C |
| Hydroxyl type | primary linear | primary branched | secondary | tertiary |
| Water solubility at 25 °C | 7.7 g/100 g | 8.5 g/100 g | 12.5 g/100 g | miscible |
| Corresponding acetate ester boiling point | 126 °C | 118 °C | 112 °C | 98 °C |
IBA offers a primary hydroxyl group for esterification, which avoids the slower secondary hydroxyl kinetics of sec-butanol and the dehydration tendency of tert-butanol. However, the branched chain reduces solvent power for high-molecular-weight cellulosic resins compared with n-butanol; formulation adjustments are evaluated by Brookfield viscosity at 25 °C under ASTM D2196. Compared with methyl isobutyl ketone, IBA has higher water tolerance but lower active solvency; replacement in nitrocellulose lacquers requires maintaining true solvent content above 20 wt% and may require additional ester solvent to prevent blushing.
In continuous acrylic acid esterification, replacement of n-butanol with IBA lowers reactor boiling point but narrows the boiling gap between alcohol and water. The IBA–water azeotrope is condensed and decanted; the alcohol-rich organic layer is refluxed to the reactor, while the aqueous layer is sent to stripping. A 40-theoretical-stage distillation column with structured packing yields isobutyl acrylate having ester content 99.5 wt%, residual acrylic acid ≤0.01 wt%, and residual alcohol ≤0.1 wt% after caustic water wash and vacuum topping. The lower boiling point of IBA reduces reboiler steam load, but increases uncondensed organic vapour in the decanter vent; vent condensers operated at -10 °C are required to maintain atmospheric emissions below local thresholds. The change from n-butanol to IBA is not a straight drop-in on existing n-butyl acrylate decanters because the IBA–water phase separation time is longer; weir height and hold-up volume must be increased by approximately 15–20% to prevent aqueous carry-over into the dehydration column.
In two-component polyurethane topcoats, the primary hydroxyl of IBA is reactive toward free isocyanate crosslinkers; therefore IBA is not used in the reactive pot mix. It may be used in the pre-evaporation diluent stage if the flash-off tunnel reaches substrate temperatures of 50–70 °C for at least 5 min before the crosslinker is applied in a separate pass. The limitation is specific to free isocyanate systems and does not apply to blocked isocyanate baking enamels where deblocking occurs above 140 °C.
When used as an extractant for oxygenated solutes from aqueous streams, IBA shows higher water solubility than n-butanol and lower water solubility than sec-butanol, allowing intermediate polarity tuning. In a pulsed liquid–liquid extraction column of 150 mm diameter operating at 1.5 Hz, the distribution coefficient for light oxygenates is lower than n-butanol but the aqueous raffinate contains more dissolved alcohol; published data for this specific column configuration is limited. For process design, the mutual solubility data and binary interaction parameters must be measured by gas chromatography according to ASTM E1510.
Recovery of IBA from mixed solvent streams is constrained by the water azeotrope and the flash point. In a 500 L glass-lined batch recovery still operated at 20–30 kPa, the head temperature shifts to 70–80 °C, reducing ignition risk below the atmospheric flash point. A reflux ratio of 3:1 produces a first cut that is the aqueous alcohol azeotrope; the decanted alcohol-rich phase is recycled. Recovered IBA from a mixed stream containing methoxypropyl acetate, xylene, and IBA is taken in the 106–109 °C cut at atmospheric pressure, while xylene remains in the sump. Achievement of 99.0 wt% recovered purity requires redistillation over molecular sieves. Vacuum operation is preferred because the closed-cup flash point of the overhead stream is 28 °C; nitrogen blanketing and flameproof pumps are applied.
Flammability classification under GHS is Flam. Liq. 3, H226; the product is also classified as Acute Tox. 4, H302; Skin Irrit. 2, H315; Eye Dam. 1, H318; and STOT SE 3, H335. Storage and handling must comply with ATEX 2014/34/EU and NFPA 30. For food-contact coating solvent applications, migration limits are evaluated under 21 CFR 175.300 and 21 CFR 175.105 where applicable. Equipment should avoid long residence times above 120 °C in the presence of strong acids, as dehydration to butenes and ether formation become significant.
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