OXYBISPROPANEDIOL

Oxybispropanediol is a versatile polyhydric alcohol composed of two propylene glycol units joined by an ether linkage, forming a flexible, highly polar molecule with excellent solvency and moisture-retention properties.
Oxybispropanediol serves as a reactive diol in polyurethane, polyester, and alkyd resin synthesis, where it enhances elasticity, hydrolytic stability, and processability, while also functioning as a humectant in cosmetics and personal-care formulations.
Oxybispropanediol's high thermal stability, low volatility, and broad compatibility with water, alcohols, glycols, and organic solvents make oxybispropanediol valuable in coatings, adhesives, heat-transfer fluids, plasticizers, and other industrial systems.

CAS Number: 25265-71-8
EC Number: 246-770-3
Molecular Formula: C6H14O3
Molecular Weight: 134.17 g/mol

Synonyms: Propanediol, oxybis-, monohexadecyl ether, 75278-97-6, DTXSID90996741, 3-[3-(Hexadecyloxy)-3-hydroxypropoxy]propane-1,1-diol, 21872-45-7, 1,2-Propanediol, 3,3'-[oxybis[(2-hydroxy-3,1-propanediyl)oxy]]bis-, UNII-YX76MGM96B, YX76MGM96B, SCHEMBL10329835, DTXSID00432362, EINECS 310-131-8, 1,3-Propanediol, 2,2′-(oxybis(methylene))bis(2-ethyl-, 1,3-Propanediol, 2,2′-[oxybis(methylene)]bis[2-ethyl-, 2,2′-(Oxybis(methylene))bis(2-ethylpropane-1,3-diol), 2,2′-(oxydimethanediyl)bis(2-ethylpropane-1,3-diol), 2,2′-(Oxydimethylen)bis(2-ethyl-1,3-propandiol), 2,2′-(Oxydiméthylène)bis(2-éthyl-1,3-propanediol), 2,2′-[Oxybis(methylene)]bis(2-ethyl-1,3-propanediol), 2,2′-[Oxybis(methylene)]bis(2-ethylpropane-1,3-diol), 2,2′-Oxybis(methylene)bis(2-ethyl-1,3-propanediol), 23235-61-2, 245-509-0, DI(TRIMETHYLOLPROPANE), ditrimethylolpropane, MFCD00192117, 2,2′-[oxybis(methylene)]bis[2-ethylpropane-1,3-diol], 2-(2,2-dimethylolbutoxymethyl)-2-ethyl-propane-1,3-diol, 2-[2,2-bis(hydroxymethyl)butoxymethyl]-2-ethyl-propane-1,3-diol, 2-[2,2-bis(hydroxymethyl)butoxymethyl]-2-ethylpropane-1,3-diol, 2-ethyl-2-{[2-ethyl-3-hydroxy-2-(hydroxymethyl)propoxy]methyl}propane-1,3-diol, 98%, DI -TRIMETHYLOLPROPANE, Di(trimethylol propane), di-trimethylolpropane, EINECS 245-509-0

Oxybispropanediol is a versatile polyhydric alcohol composed of two propylene glycol units joined by an ether linkage, forming a flexible, highly polar molecule with excellent solvency and moisture-retention properties. 
Oxybispropanediol appears as a clear to slightly yellow, low-odor, viscous liquid with a high boiling point and low vapor pressure, offering strong compatibility with water, alcohols, glycols, and many organic solvents.

Owing to its two primary hydroxyl groups, oxybispropanediol serves as a reactive diol in polyurethane, polyester, and alkyd resin synthesis, where it enhances elasticity, hydrolytic stability, and processability.
Oxybispropanediol's humectant character makes it valuable in cosmetics and personal care formulations, while its thermal stability and low volatility support its use in heat-transfer fluids, hydraulic fluids, plasticizers, and solvent systems.
Overall, oxybispropanediol is widely appreciated for its safety profile, formulation flexibility, and ability to improve the performance of both industrial and consumer products.

Oxybispropanediol is a multifunctional polyhydric alcohol distinguished by its ether-linked dual propanol units and two reactive primary hydroxyl groups.
This unique molecular structure gives the material a combination of high polarity, strong hydrogen-bonding capability, and enhanced flexibility, making it highly effective as both a chemical intermediate and a performance-enhancing additive.

In its typical commercial form, oxybispropanediol is a clear to faintly yellow, mildly odorous, viscous liquid with low vapor pressure, high thermal stability, and excellent hygroscopicity, allowing it to retain moisture and remain stable during prolonged processing.
Oxybispropanediol dissolves readily in water, alcohols, glycols, and many organic media, which significantly broadens its use across polymer, coating, cosmetic, and specialty chemical industries.

In polymer chemistry, oxybispropanediol functions as an important reactive diol monomer, participating in the formation of polyurethanes, alkyd resins, polyester polyols, acrylic systems, and radiation-curable oligomers.
The ether bridge incorporated within Oxybispropanediol's backbone imparts softness, elasticity, improved low-temperature flexibility, and greater hydrolytic resistance to the resulting polymers.

These attributes make Oxybispropanediol valuable in applications ranging from flexible foams and elastomers to adhesives, sealants, and coatings requiring durability under variable environmental conditions.
As a solvent and plasticizer, oxybispropanediol contributes to enhanced film formation, reduced brittleness, smooth flow, and improved pigment dispersion in paints, inks, and waterborne formulations, while its low volatility ensures slow, even evaporation.

In the personal care and cosmetic sector, Oxybispropanediol's low toxicity profile, humectant nature, and emollient behavior make it a key component in skin creams, lotions, cleansers, and hair conditioning systems, where it enhances moisture retention, improves spreadability, and stabilizes emulsions.
Beyond these uses, oxybispropanediol acts as a valuable intermediate in synthesizing esters, surfactants, specialty lubricants, hydraulic fluids, and heat-transfer fluids, benefiting from its high boiling point and oxidative stability.
Across all these applications, Oxybispropanediol is prized for its formulation versatility, safety, chemical reactivity, and ability to improve performance characteristics, making oxybispropanediol a widely used and highly adaptable material in both industrial and consumer product technologies.

Market Overview of Oxybispropanediol:
The global market for oxybispropanediol, positioned within the broader class of specialty diols and multifunctional polyhydric alcohols, is experiencing steady growth driven by rising demand for advanced polymers, high-performance coatings, and modern personal-care formulations.
Although smaller in scale compared with commodity glycols, oxybispropanediol benefits from its unique performance profile—including strong solvency, low volatility, humectancy, and enhanced polymer flexibility—which makes it valuable in polyurethane systems, water-based coatings, adhesives, and cosmetic formulations.

Market expansion is particularly strong in the Asia–Pacific region, where rapid industrialization and increasing production of high-value polymers and personal-care products boost consumption.
In mature markets such as Europe and North America, growth is supported by regulatory shifts toward low-VOC materials and the continuous development of specialty intermediates.

Despite competition from lower-cost diols, oxybispropanediol maintains a solid niche due to its superior compatibility and functionality.
Overall, the market outlook remains positive, with ongoing opportunities in high-performance, low-VOC, and formulation-critical applications.

Uses of Oxybispropanediol:
Oxybispropanediol is used across a wide range of industrial and consumer applications due to its dual hydroxyl functionality, strong solvency, low volatility, and excellent compatibility with both hydrophilic and hydrophobic systems.
In polymer chemistry, Oxybispropanediol serves as a reactive diol in the production of polyurethanes, polyester polyols, alkyd resins, and acrylic systems, where its ether linkage imparts improved flexibility, hydrolytic stability, and low-temperature performance to the final materials.

In coatings, inks, and adhesives, Oxybispropanediol acts as an efficient solvent and coalescent, enhancing film formation, flow, leveling, and pigment dispersion, particularly in low-VOC and waterborne formulations.
In personal care and cosmetic products, oxybispropanediol functions as a humectant, emollient, and solvent that improves moisture retention, enhances skin feel, stabilizes emulsions, and supports uniform distribution of active ingredients.

Oxybispropanediol also serves as an intermediate for manufacturing esters, surfactants, and specialty chemical additives used in lubricants, cleaners, and heat-transfer fluids.
Thanks to its high boiling point and low vapor pressure, Oxybispropanediol is incorporated into hydraulic and thermal fluids where long-term thermal stability is required.
Overall, oxybispropanediol’s versatility makes it an essential ingredient in polymers, coatings, cosmetics, specialty fluids, and chemical synthesis.

Applications of Oxybispropanediol:
Oxybispropanediol finds application across multiple industrial sectors because of its diol functionality, strong solvency, and excellent compatibility with diverse formulation systems.
In polymer manufacturing, Oxybispropanediol is widely used as a reactive monomer for producing polyurethanes, polyester polyols, alkyd resins, and acrylic oligomers, where it enhances flexibility, hydrolytic resistance, and low-temperature durability. 

In the coatings, inks, and adhesives industry, Oxybispropanediol serves as a coalescent, plasticizer, and high-boiling solvent that improves film formation, flow, leveling, and pigment dispersion, especially in water-based, low-VOC systems.
The personal care and cosmetics sector employs oxybispropanediol as a humectant, emollient, and solvent in creams, lotions, cleansers, and hair-care products, benefiting from its moisture-retention capacity and gentle sensory profile.

In specialty chemicals, Oxybispropanediol acts as an intermediate for producing esters, surfactants, plasticizers, lubricants, and functional additives.
Additionally, Oxybispropanediol's high boiling point and thermal stability make it useful in heat-transfer fluids, hydraulic fluids, and industrial cleaners where low volatility and long service life are required.
Because of this versatility, oxybispropanediol is utilized in chemical synthesis, formulation chemistry, and high-performance material systems across various industries.

Benefits of Oxybispropanediol:
Oxybispropanediol offers a wide range of benefits that make it valuable in polymer systems, coatings, cosmetics, and specialty chemical formulations.
Oxybispropanediol's dual primary hydroxyl groups provide strong reactivity in polyurethane and polyester synthesis, enabling improved flexibility, toughness, and hydrolytic stability in the resulting polymers.

The presence of an ether linkage contributes additional molecular softness and enhances low-temperature performance, while also reducing brittleness compared with more rigid diols.
As a high-boiling, low-volatility solvent, Oxybispropanediol promotes uniform film formation, better flow and leveling, and reduced evaporation losses in coatings, inks, and adhesives, supporting compliance with low-VOC standards.

Oxybispropanediol’s excellent solvency and miscibility with water, glycols, alcohols, and many organics make it highly versatile in both aqueous and solvent-borne systems.
In personal-care applications, Oxybispropanediol functions as a humectant and emollient, improving moisture retention, skin feel, and formulation stability without causing irritation.

Oxybispropanediol's thermal and oxidative stability enables long service life in heat-transfer and hydraulic fluids, while its low odor, low toxicity, and non-corrosive nature support safer handling and user-friendly formulations.
Altogether, these benefits make oxybispropanediol a high-performance, multipurpose ingredient across numerous industrial and consumer product sectors.

Production of Oxybispropanediol:
Oxybispropanediol is typically produced through a series of controlled chemical reactions involving propylene oxide and water or alcohol initiators, generating a mixture of ether-linked propanol units with primary hydroxyl groups at both ends.
The most common industrial route begins with the hydrolysis and oligomerization of propylene oxide, a process catalyzed under carefully regulated temperature and pressure conditions.

During this reaction, propylene oxide undergoes ring-opening, forming propylene glycol, which then reacts further through etherification to produce higher oligomers; when two propanol units link via an oxygen bridge, oxybispropanediol is formed.
This controlled ether bond formation gives the molecule Oxybispropanediol's characteristic flexibility and solvent properties.

The reaction mixture is then purified through fractional distillation, vacuum stripping, or thin-film evaporation to isolate the desired diol from other glycols and by-products.
Additional steps such as neutralization, filtration, dehydration, and stabilization ensure that the final product meets industrial purity requirements.
Overall, the production process is designed to balance reactivity, selectivity, and thermal control to yield a stable, high-purity multifunctional diol suitable for use in polymers, coatings, personal care products, and specialty chemicals.

Synthesis of Oxybispropanediol:
Oxybispropanediol is synthesized through a controlled ether-forming reaction involving propylene oxide and propylene glycol, producing a diol in which two propanol units are linked through an oxygen bridge.
The synthesis begins with the ring-opening polymerization of propylene oxide, typically catalyzed by alkaline catalysts such as potassium hydroxide.

In this step, propylene oxide reacts with an initiator—most commonly propylene glycol—forming a growing chain of propylene glycol oligomers.
When the reaction conditions are optimized to favor dimer formation rather than long-chain oligomers, the system promotes the coupling of two hydroxypropyl groups through nucleophilic substitution, resulting in the formation of oxybispropanediol (bis(2-hydroxypropyl) ether).

The key synthetic step is the etherification reaction, where the hydroxyl group of one propylene glycol molecule attacks the epoxide ring of propylene oxide, forming an ether linkage and yielding a diol with two primary hydroxyl groups.
Reaction temperature (typically 100–160 °C), catalyst concentration, and feed ratios must be carefully controlled to maximize selectivity toward the desired diol while minimizing the formation of higher oligomers or cyclic by-products.

Once the reaction is complete, the crude mixture is subjected to neutralization, vacuum stripping, and fractional distillation to remove residual catalyst, unreacted materials, water, and higher-molecular-weight oligomers.
Additional purification steps, such as dehydration, filtration, and polishing, produce a high-purity, stable oxybispropanediol suitable for applications in polymer synthesis, coatings, cosmetics, and specialty chemicals.

History of Oxybispropanediol:
The history of oxybispropanediol is closely tied to the development of propylene oxide chemistry and the expansion of polyether polyol technology during the mid-20th century.
Oxybispropanediol's origins can be traced to early research in the 1940s–1950s, when chemical manufacturers began exploring the ring-opening polymerization of propylene oxide to produce propylene glycol, polyether glycols, and ether-linked oligomers with improved flexibility and thermal stability.

During this period, chemists discovered that under controlled alkaline catalysis, propylene oxide not only formed simple glycols but also underwent etherification reactions, producing dimeric and oligomeric structures—one of which was oxybispropanediol.
As polyurethane chemistry rapidly expanded in the 1950s–1970s, driven by the booming automotive, construction, and consumer goods industries, intermediates like oxybispropanediol became important tools for modifying polymer properties such as softness, elasticity, and hydrolytic resistance.

By the late 20th century, advances in catalyst design and process control allowed producers to fine-tune selectivity for specific oligomers, enabling more consistent and higher-purity production of oxygen-bridged diols.
During this time, oxybispropanediol gained broader adoption not only in polyurethanes and resins but also in coatings, personal-care formulations, and specialty fluids, benefiting from its low volatility, excellent solvency, and favorable safety profile.

As environmental and regulatory pressures increased in the early 21st century—especially around VOC reduction and safer cosmetic ingredients—the material’s performance advantages aligned well with emerging market needs, reinforcing its status as a specialty diol with high formulation versatility.
Today, oxybispropanediol remains a staple intermediate in modern polymer chemistry and formulation science, valued for both its historical chemical reliability and its ongoing relevance in advanced, low-VOC, and high-performance products.

Stability and Reactivity of Oxybispropanediol:
Oxybispropanediol is considered chemically stable under normal ambient temperatures and recommended storage conditions.
Oxybispropanediol does not polymerize spontaneously and maintains stability in the presence of air and light.
Oxybispropanediol shows low volatility and resists oxidative degradation.

Conditions to avoid:
Excessive heat (above process limits)
Strongly acidic or strongly basic environments at elevated temperature
Prolonged exposure to high moisture during storage

Incompatible materials:
Strong oxidizing agents (may cause exothermic reactions)
Strong acids or bases (may increase degradation or promote unwanted side reactions)
Reactive metal surfaces at very high temperature

Hazardous decomposition products:
At high temperatures: carbon monoxide (CO), carbon dioxide (CO₂), and trace aldehydes
Thermal breakdown may release irritant organic vapors

Handling and Storage of Oxybispropanediol:

Handling:
Use with adequate ventilation to prevent aerosol or mist formation.
Avoid contact with eyes and prolonged skin exposure.

Do not breathe mist or heated vapor.
Wear appropriate protective equipment when transferring large quantities.
Prevent spills—product is viscous and may create slipping hazards on floors.

Storage:
Store in tightly closed containers made of compatible materials (stainless steel, HDPE).
Keep in a cool, dry, well-ventilated area away from direct sunlight and heat sources.

Protect from moisture and contamination.
Store between 5–30 °C for optimal stability.
Keep separate from oxidizers, acids, and alkalis.

First Aid Measures of Oxybispropanediol:

Inhalation:
Move the person to fresh air.
Keep at rest and monitor breathing.
If symptoms such as coughing or throat irritation persist, seek medical attention.

Skin Contact:
Wash gently with plenty of water and mild soap.
Remove contaminated clothing.
Seek medical advice if redness or irritation develops.

Eye Contact:
Rinse cautiously with clean water for at least 15 minutes while holding eyelids apart.
Remove contact lenses if present and easy to do.
Seek medical attention if irritation persists.

Ingestion:
Rinse mouth with water.
Do not induce vomiting unless instructed by medical personnel.

Drink water if the person is fully conscious.
Seek medical attention if large amounts were swallowed or if symptoms occur.

Firefighting Measures of Oxybispropanediol:

Suitable extinguishing media:
Water spray (fog), dry chemical, foam, or CO₂
Use water spray to cool containers exposed to fire

Specific hazards:
Product is combustible at high temperatures
Burning may produce CO, CO₂, and irritating organic vapors
Heated containers may rupture if pressure builds

Protective equipment for firefighters:

Self-contained breathing apparatus (SCBA):
Full firefighting protective clothing
Avoid breathing fumes or combustion gases

Accidental Release Measures of Oxybispropanediol:

Personal precautions:
Wear gloves, eye protection, and protective clothing.
Ensure adequate ventilation.
Avoid skin/eye contact and inhalation of mists.

Environmental precautions:
Prevent entry into drains, surface water, or soil.
Contain spill to avoid environmental contamination.

Methods for clean-up:
Stop the leak if safe to do so.
Absorb with inert materials (sand, vermiculite, universal absorbent).

Collect into containers for disposal.
Clean contaminated surfaces with water and detergent; avoid solvents.
Dispose of waste according to local regulations.

Exposure Controls / Personal Protective Equipment of Oxybispropanediol:

Engineering controls:
Use in well-ventilated areas or with local exhaust ventilation.
Keep airborne concentrations of mist as low as reasonably achievable.
Closed transfer systems recommended for industrial handling.

Personal Protective Equipment:

Eye/Face Protection:
Safety glasses with side shields or chemical splash goggles.

Skin Protection:
Chemical-resistant gloves (e.g., nitrile, neoprene).
Long sleeves or lab coat for routine handling.
Additional protective clothing for large-scale transfer.

Respiratory Protection:
Not typically necessary under normal use.
Use an approved respirator if mists, aerosols, or heated vapors exceed safe levels.

Hygiene Measures:
Wash hands thoroughly after handling.
Remove contaminated clothing and wash before reuse.
Do not eat, drink, or smoke while handling the product.

Identifiers of Oxybispropanediol:
CAS Number: 25265-71-8
EC Number: 246-770-3
Molecular Formula: C₆H₁₄O₃
Molecular Weight: 134.17 g/mol
Chemical Structure: HO–CH₂–CH(CH₃)–O–CH₂–CH(CH₃)–OH
HS Code: Typically classified under 2905.59
INCI Name: Dipropylene Glycol (INCI nomenclature includes all isomeric forms)
REACH Status: Registered as part of dipropylene glycol category substances

CAS: 25265-71-8
EC: 246-770-3
Molecular Formula: C₆H₁₄O₃
Molecular Weight: 134.17 g/mol
IUPAC Name: 2,2′-Oxydi(1-propanol)
INCI: Dipropylene Glycol
SMILES: CC(O)COCC(C)O
UN Number: Not regulated
HS Code: 2905.59

Molecular formula: C12H26O5
Average mass: 250.335
Monoisotopic mass: 250.178024
ChemSpider ID: 81280

Properties of Oxybispropanediol:
Appearance: Colorless to slightly yellow viscous liquid
Odor: Mild, low odor
Molecular Weight: 134.17 g/mol
Boiling Point: > 200 °C
Melting Point: < –50 °C (typically remains liquid)
Flash Point: > 120 °C (High, low flammability)
Density (20 °C): ~1.01–1.03 g/cm³
Viscosity (25 °C): High, ~75–90 mPa·s
Refractive Index (20 °C): ~1.436–1.439
Solubility: Completely miscible with water, alcohols, glycols, many organics
Vapor Pressure: Very low
Partition Coefficient (log P): Low (hydrophilic)
pH (10% solution): Neutral to slightly acidic
Stability: Stable under normal conditions; hygroscopic
Decomposition: Produces CO, CO₂, and organic vapors at high temperature

Molecular Weight: 314.33 g/mol
XLogP3-AA: -4.1
Hydrogen Bond Donor Count: 6
Hydrogen Bond Acceptor Count: 9
Rotatable Bond Count: 14
Exact Mass: 314.15768240 Da
Monoisotopic Mass: 314.15768240 Da
Topological Polar Surface Area: 149 Ų
Heavy Atom Count: 21
Complexity: 207
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 4
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes

Specifications of Oxybispropanediol:
Purity: ≥ 98% (typical for high-grade dimer fraction)
Appearance: Clear to slightly yellow liquid
Color (APHA): ≤ 30
Water Content (Karl Fischer): ≤ 0.2%
Acidity (as acetic acid): ≤ 0.01%
Hydroxyl Value: 790–830 mg KOH/g
Density (20 °C): 1.01–1.03 g/cm³
Viscosity (25 °C): 75–90 mPa·s
Refractive Index (20 °C): 1.436–1.439
Boiling Range: > 200 °C
Flash Point (Cleveland Open Cup): ≥ 120 °C
Odor: Mild, low odor
Solubility: Fully miscible with water and many organics
Residual Propylene Glycol: ≤ 1%
Residue on Evaporation: ≤ 0.01%