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Butoxypropan-1-ol is an alpha-isomer-rich mixture of propylene glycol n-butyl ether isomers used primarily as an industrial solvent and coupling agent.
Butoxypropan-1-ol combines strong organic solvency with partial water solubility, controlled evaporation, low surface tension, and low viscosity.
Butoxypropan-1-ol is established in cleaning products, coatings, printing inks, adhesives, agricultural formulations, textiles, and chemical synthesis.
CHEMICAL IDENTITY AND COMMON NAMES
The industrial name Butoxypropan-1-ol is commonly associated with propylene glycol butyl ether under CAS 29387-86-8.
This registry identity represents an isomeric composition rather than one isolated positional isomer.
The commercial composition contains predominantly 1-butoxypropan-2-ol, CAS 5131-66-8, together with a smaller quantity of 2-butoxypropan-1-ol, CAS 15821-83-7.
Modern production processes normally generate more than 95% of the secondary-alcohol alpha isomer.
CAS 29387-86-8 should be distinguished from CAS 5131-66-8, which identifies the isolated or separately registered major alpha isomer.
Both identities are encountered commercially under the general names propylene glycol n-butyl ether and PnB.
Synonyms and Common Names: Butoxypropan-1-ol, Butoxypropanol, Butoxy-1-propanol, Propylene glycol butyl ether, Propylene glycol n-butyl ether, Propylene glycol monobutyl ether, Propylene glycol mono-n-butyl ether, Propylene glycol butoxy ether, Propylene glycol butyl ether mixed isomers, Butyl propylene glycol ether, Monopropylene glycol n-butyl ether, PGBE, PGnBE, PnB, 1,2-Propanediol monobutyl ether, 1,2-Propanediol mono-n-butyl ether, 1,2-Propylene glycol monobutyl ether, 1,2-Propylene glycol 1-monobutyl ether, Propanediol butyl ether, Propanol 1(or 2)-butoxy-, 1-Butoxypropan-2-ol, 1-Butoxy-2-propanol, 3-Butoxypropan-2-ol, 1-Butoxy-2-hydroxypropane, 2-Hydroxy-3-butoxypropane, n-Butoxypropanol, alpha-Propylene glycol mono-n-butyl ether
TECHNICAL IDENTIFICATION
CAS Number: 29387-86-8
EC / EINECS Number: 249-598-7
Molecular Formula: C7H16O2
Molar Mass: 132.20 g/mol
Registry Name: Propanol, 1(or 2)-butoxy-
Chemical Family: P-series glycol ethers
Major Component: 1-Butoxypropan-2-ol, CAS 5131-66-8
Minor Component: 2-Butoxypropan-1-ol, CAS 15821-83-7
PHYSICAL AND CHEMICAL PROPERTIES
Appearance: Clear, colourless liquid
Odour: Mild, characteristic ether-like odour
Boiling Range: Approximately 165–175 °C at 1013 hPa
Freezing Point: Below -80 °C
Density: Approximately 0.88 g/cm³ at 20 °C
Specific Gravity: Approximately 0.878 at 25 °C
Flash Point: Approximately 63–69 °C, closed cup
Autoignition Temperature: Approximately 260 °C
Lower Flammability Limit: Approximately 1.1% by volume in air
Upper Flammability Limit: Approximately 8.4–9.0% by volume in air
Vapour Pressure: Approximately 1.1 hPa at 20 °C
Relative Vapour Density: Approximately 4.6, with air equal to 1
Water Solubility: Approximately 52–55 g/L at 20–25 °C
Water Solubility in Butoxypropan-1-ol: Approximately 15.5% by weight at 25 °C
Log Pow: Approximately 1.2 at 20 °C
Dynamic Viscosity: Approximately 2.8–3.1 mPa·s at 25 °C
Kinematic Viscosity: Approximately 3.85 mm²/s at 20 °C
Surface Tension: Approximately 27.5 mN/m at 25 °C
Evaporation Rate: Approximately 0.093, with n-butyl acetate equal to 1
Refractive Index: Approximately 1.416–1.420 at 20–25 °C
Specific Heat Capacity: Approximately 1.98 J/g·°C at 25 °C
Heat of Vaporisation: Approximately 320 J/g at the normal boiling point
Solubility in Organic Media: Miscible with most common organic solvents
FUNCTIONAL CHARACTERISTICS
The molecular structure contains a hydrophilic hydroxyl group, an ether linkage, and a hydrophobic n-butyl group.
This combination gives Butoxypropan-1-ol an effective balance between water compatibility and oil, grease, resin, and polymer solvency.
The n-butyl group provides affinity for hydrophobic soils and coating resins.
The hydroxyl and ether groups support hydrogen bonding, coupling, and controlled compatibility with aqueous formulation components.
Low surface tension improves substrate wetting, soil penetration, levelling, and spreading.
Partial water solubility enables Butoxypropan-1-ol to connect aqueous phases with hydrophobic ingredients that would otherwise separate.
The controlled evaporation rate provides sufficient working time for cleaning, coating flow, coalescence, and ink transfer while limiting prolonged solvent retention.
Butoxypropan-1-ol evaporates more rapidly than higher propylene glycol butyl ethers such as dipropylene glycol n-butyl ether.
PRODUCTION AND COMMERCIAL FORM
Butoxypropan-1-ol is produced through catalytic ring opening of propylene oxide with n-butanol.
Reaction at the less substituted carbon of propylene oxide preferentially produces the secondary-alcohol alpha isomer.
The reaction mixture is distilled to recover unreacted butanol and separate Butoxypropan-1-ol from water, light components, dipropylene glycol butyl ether, and heavier glycol ethers.
Final purification controls colour, odour, acidity, water, boiling range, and non-volatile residue.
Commercial material is supplied principally as a high-purity technical solvent containing more than 95% alpha isomer and a controlled minor-isomer fraction.
High-purity grades commonly target total glycol ether assay of at least 99%.
APPLICATIONS AND INDUSTRIES
Industrial and institutional cleaning
Butoxypropan-1-ol functions as a solvent and coupling agent in heavy-duty cleaners, degreasers, glass cleaners, all-purpose cleaners, metal cleaners, and hard-surface cleaning products.
Strong affinity for grease, oil, soap deposits, adhesive residue, and organic soil improves removal from metal, glass, ceramic, and polymer surfaces.
Butoxypropan-1-ol lowers aqueous surface tension and promotes wetting of contaminated surfaces.
Partial water solubility enables concentrated cleaning formulations to incorporate hydrophobic solvents, fragrances, and soil-removal ingredients.
Butoxypropan-1-ol is also used in paint, coating, adhesive, and ink removers.
Controlled evaporation supports effective contact time while reducing the residue associated with slower glycol ethers.
Paints and coatings
Butoxypropan-1-ol serves as an active solvent, coupling solvent, flow aid, and coalescing agent in industrial, architectural, automotive, maintenance, and water-reducible coatings.
The balanced structure supports compatibility between water, coating resins, pigments, and formulation additives.
Butoxypropan-1-ol promotes wetting, levelling, film continuity, gloss development, and controlled drying.
In waterborne latex systems, the solvent assists polymer-particle deformation and can reduce the minimum film-forming temperature.
Butoxypropan-1-ol also supports water-reducible aerosol coatings and solvent-borne formulations requiring strong resin solvency with moderate evaporation.
Solvent loading is balanced against drying time, film hardness, blocking resistance, and residual odour.
Printing inks and graphic arts
Butoxypropan-1-ol is used as a solvent and evaporation-control component in printing inks and related graphic formulations.
The solvent dissolves or couples dyes, resins, binders, and additives while supporting ink transfer and substrate wetting.
Butoxypropan-1-ol provides a useful drying profile for formulations that require more open time than highly volatile alcohols.
Low surface tension assists uniform print coverage on paper, polymer films, and coated substrates.
Adhesives and sealants
Butoxypropan-1-ol functions as a solvent, viscosity modifier, and coupling agent in selected adhesive and sealant systems.
The glycol ether assists resin dissolution, substrate wetting, application uniformity, and controlled solvent release.
Butoxypropan-1-ol is also used in adhesive removers and surface-preparation products.
Its affinity for organic residues helps soften adhesive films before mechanical removal or rinsing.
Agricultural formulations
Butoxypropan-1-ol is used as an inert carrier and coupling solvent in water-based pesticide, herbicide, and other agricultural formulations.
The solvent helps incorporate hydrophobic active ingredients and formulation auxiliaries into aqueous concentrates and spray systems.
Butoxypropan-1-ol improves wetting and distribution on plant and soil surfaces.
Grade selection for agricultural use emphasizes water, acidity, colour, odour, residue, and regulatory documentation.
Textile and leather processing
Butoxypropan-1-ol serves as a solvent and coupling agent for dyes, resins, oils, and processing auxiliaries used in textile and leather operations.
Partial water compatibility supports uniform incorporation of hydrophobic ingredients into aqueous treatment baths.
The solvent’s wetting and penetration properties assist printing, dye application, cleaning, and surface-finishing processes.
Controlled evaporation supports drying without the extended retention associated with heavier glycol ethers.
Chemical synthesis and intermediates
Butoxypropan-1-ol is used as a reaction solvent and chemical intermediate.
The available hydroxyl group permits esterification and other transformations used to manufacture glycol ether derivatives, specialty solvents, epoxide-related products, and plasticizer intermediates.
The combination of ether and alcohol functionality also supports use as a processing solvent for resins, polymers, surfactants, and specialty organic products.
Low viscosity facilitates charging, mixing, pumping, and product recovery.
Personal-care and specialty formulations
Butoxypropan-1-ol is used in regulated personal-care formulations as a solvent, fragrance carrier, and humectant-related ingredient.
Personal-care grades require tightly controlled identity, purity, odour, colour, residual reactants, and documentation.
GRADE SELECTION AND PRODUCT SUITABILITY
Technical solvent grade is suitable for general cleaning, coatings, inks, adhesives, textile processing, and chemical manufacturing.
Important control parameters include assay, isomer composition, water, acidity, colour, distillation range, and non-volatile residue.
Coatings and ink grades emphasize resin solvency, controlled evaporation, low water content, colour, odour, and consistent boiling behaviour.
The water specification is particularly important in moisture-sensitive binders and curing systems.
Cleaning-formulation grades emphasize coupling performance, aqueous phase stability, odour, colour, and compatibility with surfactants and alkaline builders.
Low non-volatile residue is important for glass, metal, and low-streak surface cleaners.
Agricultural and personal-care grades require application-specific purity, impurity control, traceability, and regulatory documentation.
Residual propylene oxide, n-butanol, acidity, water, and heavier glycol ethers are important selection parameters.
FORMULATION AND PROCESS CONSIDERATIONS
Butoxypropan-1-ol can be premixed with hydrophobic actives, resins, fragrances, or other solvents before incorporation into an aqueous phase.
Surfactants and hydrotropes can be used to extend formulation clarity beyond the solvent’s direct water-solubility limit.
Addition temperature, pH, electrolyte concentration, and surfactant structure affect coupling and phase stability.
Finished formulations should be evaluated for clarity, cloud point, viscosity, separation resistance, and freeze-thaw performance.
In waterborne coatings, Butoxypropan-1-ol is commonly incorporated during pigment grinding, binder dilution, or final let-down.
The selected addition point influences resin compatibility, pigment wetting, viscosity, foam, and coalescence.
Cleaning formulations often combine Butoxypropan-1-ol with water, surfactants, alkaline builders, chelating agents, and complementary solvents.
The balance between solvency and evaporation determines soil-removal time, rinsability, streaking, and worker exposure.
Butoxypropan-1-ol can absorb water during exposure to humid air.
Closed transfer and storage protect moisture-sensitive applications and preserve specification consistency.
Extended contact with oxygen can promote peroxide formation, particularly during solvent recovery, concentration, or distillation.
Stored or recycled material intended for evaporation or distillation should include peroxide monitoring as part of process control.
QUALITY, SPECIFICATIONS AND DOCUMENTATION
Assay: Gas chromatography
Isomer Composition: Alpha- and beta-isomer distribution
Appearance: Clear and free from suspended matter
Colour: APHA or platinum-cobalt colour
Water Content: Karl Fischer analysis
Acidity: Reported as acetic acid or acid number
Distillation Range: Initial boiling point, dry point, and distillation recovery
Density: Measured at a stated temperature
Refractive Index: Measured at a stated temperature
Residual n-Butanol: Gas chromatography
Residual Propylene Oxide: Trace-level analysis
Heavy Glycol Ethers: Dipropylene glycol butyl ether and higher homologues
Non-Volatile Residue: Gravimetric residue after evaporation
Peroxide Content: Important for aged, recovered, or redistilled solvent
Odour: Mild and characteristic, without abnormal contamination
Coalescing Performance: Film formation, drying, and minimum film-forming temperature
Coupling Performance: Aqueous clarity, cloud point, and phase stability
A Certificate of Analysis records the lot-specific quality parameters.
The Technical Data Sheet describes solvent performance and physical properties.
The Safety Data Sheet provides classification, exposure controls, firefighting information, storage requirements, and transport status.
SAFETY AND REGULATORY CONSIDERATIONS
Signal Word: Warning
Skin Irritation: Category 2
Eye Irritation: Category 2
H315: Causes skin irritation
H319: Causes serious eye irritation
Butoxypropan-1-ol is a combustible liquid that can generate ignitable vapour-air mixtures when heated.
Vapours are heavier than air and can travel along floors or through confined spaces toward an ignition source.
High vapour or aerosol concentrations can cause headache, dizziness, drowsiness, and respiratory discomfort.
Repeated skin exposure can remove natural oils and aggravate irritation.
Butoxypropan-1-ol exhibits low acute oral, dermal, and inhalation toxicity.
The alpha-isomer-rich commercial material is not classified for reproductive toxicity, mutagenicity, carcinogenicity, or skin sensitisation.
Butoxypropan-1-ol is readily biodegradable and has low bioaccumulation potential.
Uncontrolled discharge should nevertheless be prevented because large solvent releases can disturb wastewater treatment and reduce dissolved oxygen in receiving water.
FIRST AID
Inhalation: Move the affected person to fresh air and keep the person at rest in a position comfortable for breathing.
Inhalation: Obtain medical attention if dizziness, drowsiness, respiratory discomfort, or other symptoms occur.
Skin Contact: Remove contaminated clothing and wash the affected skin thoroughly with soap and lukewarm water for at least 15 minutes.
Eye Contact: Rinse cautiously with clean water for at least 15 minutes while holding the eyelids open.
Eye Contact: Remove contact lenses when easy to do and obtain medical attention if irritation persists.
Ingestion: Rinse the mouth and do not induce vomiting.
Ingestion: Obtain medical attention after ingestion of a significant quantity.
Note to Physicians: Treat symptomatically and monitor respiratory and central nervous system effects.
HANDLING AND STORAGE
Use effective general ventilation or local exhaust where vapour, mist, or aerosol can be generated.
Avoid breathing vapours and prevent repeated skin or eye contact.
Wear chemical splash goggles, compatible chemical-resistant gloves, and protective clothing.
Neoprene and other solvent-resistant glove materials are used after selection for the required contact time and working conditions.
Keep away from flames, hot surfaces, sparks, welding operations, and other ignition sources.
Use grounded and bonded transfer equipment and non-sparking tools.
Store in tightly closed, properly vented containers in a cool, dry, well-ventilated area.
Protect from strong oxidizing agents, strong acids, prolonged air exposure, and moisture uptake.
Properly lined steel and stainless steel are suitable storage materials.
Copper, unlined mild steel, and incompatible plastics or elastomers can cause discolouration, permeation, swelling, or loss of mechanical integrity.
Nitrogen blanketing is used for warm bulk storage and transfer conditions that approach the solvent’s flash point.
Empty containers retain combustible vapour and require the same ignition controls as filled containers.
FIRE AND SPILL RESPONSE
Use dry chemical powder, carbon dioxide, regular foam, water spray, or water fog for fire control.
Do not use a direct solid water stream because it can spread burning liquid.
Firefighters should use protective clothing and self-contained breathing equipment.
Thermal decomposition can generate carbon monoxide, carbon dioxide, and irritating organic vapours.
Eliminate ignition sources, ventilate the area, and keep unnecessary personnel away from a spill.
Contain the liquid with dry sand, earth, or another non-combustible absorbent and collect it using non-sparking equipment.
Prevent entry into drains, basements, confined spaces, soil, surface water, and groundwater.
PACKAGING AND PROCUREMENT CONSIDERATIONS
Butoxypropan-1-ol is commonly supplied in lined steel drums, intermediate bulk containers, and bulk or tank-container quantities.
Packaging should protect the solvent from moisture, contamination, air exchange, and excessive heat.
Transport classification is determined by the measured closed-cup flash point of the supplied grade.
Material with a flash point at or below 60 °C is transported as UN 3271, Ethers, n.o.s., Class 3, Packing Group III.
Material with a flash point above 60 °C falls outside Class 3 under standard ADR, IMDG, and IATA criteria.
Procurement planning should define the required CAS identity, alpha-isomer content, total assay, water, colour, acidity, distillation range, residual butanol, heavy glycol ethers, non-volatile residue, packaging, and intended application.
For Butoxypropan-1-ol grade selection, specifications, formulation requirements, documentation, packaging, and supply planning, contact Ataman Kimya.
+90 216 577 10 10
info@atamankimya.com
