Picture a water-based paint whose formula looks flawless on paper, yet when it is applied in cool weather the film never fully forms, the surface chalks and cracks. Or picture an industrial degreaser that is crystal clear in the drum but splits into two phases the moment it meets oil on the shop floor. Both problems usually share one root cause: a glycol-ether solvent that was chosen wrongly or left out entirely. This is exactly where butyl glycol earns its place.
What Is Butyl Glycol?
Butyl glycol, known chemically as 2-butoxyethanol or ethylene glycol monobutyl ether (EGBE), with CAS number 111-76-2, is a clear, colorless liquid with a mild ether odor. Its molecule carries both an ether group and an alcohol (hydroxyl) group; one end loves water, the other end loves the oil/organic phase. This dual character is what makes butyl glycol fully miscible with both water and a wide range of organic solvents — one of the most valuable properties a solvent can offer.
On the market you may see it labeled "butyl glycol," "butyl cellosolve," "EGBE" or "2-butoxyethanol"; all of these point to the same substance, CAS 111-76-2. The "glycol ether" designation matters: this family consists of an alkyl group (here, butyl) bonded to a glycol backbone through an ether linkage, and it is known for producing slow-evaporating, powerful solvents.
Three core properties make butyl glycol so widely used across industry: full miscibility with both water and organics, slow, controlled evaporation, and the power to dissolve a broad range of resins and soils. Thanks to this trio, a single raw material can form a film in a water-based paint, bind oil in a cleaner, and adjust flow in an ink. We covered the general logic of solvent selection in our guide on solvent selection for paints and coatings; this article focuses specifically on the role of butyl glycol.
Key Physical and Chemical Properties
We have gathered the parameters that formulators and buyers reach for most often into a single table:
| Property | Typical Value | Note |
|---|---|---|
| CAS No | 111-76-2 | Single, fixed identity |
| Chemical name | 2-Butoxyethanol (ethylene glycol monobutyl ether) | Abbreviated "EGBE" |
| Molecular formula | C₆H₁₄O₂ | — |
| Molecular weight | ~118.17 g/mol | — |
| Appearance | Clear, colorless liquid | Mild ether odor |
| Density (20 °C) | ~0.90 g/cm³ | Lighter than water |
| Boiling point | ~168–171 °C | High; evaporates slowly |
| Freezing point | ~ -75 °C | Very low |
| Flash point | ~62 °C (closed cup) | Flammable liquid; keep away from ignition |
| Vapor pressure (20 °C) | ~0.1 kPa | Low; low volatility |
| Water solubility | Fully miscible | Miscible with organics too |
| Evaporation rate (BuAc=1) | ~0.07 | Very slow |
These values are for typical commercial butyl glycol; for the actual values of the batch you receive, always confirm against the COA (Certificate of Analysis). In particular, water content and color (APHA) are the first items to check, because they directly affect how the solvent behaves in the formulation.
The Defining Trait of Butyl Glycol: Slow Evaporation
Solvent power is not the only parameter that decides whether a solvent is "good"; how fast it evaporates is often more decisive. Fast-evaporating solvents leave the surface wet only briefly, while slow-evaporating ones stay in the system longer, giving flow, leveling and film formation the time they need.
Compared with n-butyl acetate — the industry reference at an evaporation rate of 1.0 — butyl glycol evaporates very slowly. That makes it well suited for use as a tail solvent: even after the fast solvents in the system have flashed off, butyl glycol remains in place and helps the film close properly.
The table below ranks common solvents by relative evaporation rate (n-butyl acetate = 1.0 reference). This is the most practical way to visualize which solvent in your formula will "go first" and which will "stay behind":
| Solvent | Relative Evaporation Rate (BuAc=1) | Character |
|---|---|---|
| Acetone | ~5.6–7.7 | Very fast |
| Ethyl acetate | ~4.1 | Fast |
| Isopropyl alcohol (IPA) | ~1.5–2.1 | Medium-fast |
| Butyl acetate (reference) | 1.0 | Medium |
| Butyl glycol (EGBE) | ~0.07 | Very slow |
| Butyl di glycol (DEGBE) | ~0.004 | Extremely slow |
The message from the table is clear: when butyl glycol is used in the same formula as fast solvents (acetone, ethyl/butyl acetate), it plays a balancing role. For anyone curious about the volatility profile of those fast solvents, our comparison of ethyl acetate and butyl acetate is a good complement; there we detailed where the fast-evaporating acetates are preferred — the opposite end of the spectrum from butyl glycol.
Full Miscibility With Water and Organics: The "Bridge" Solvent
Butyl glycol's second superpower is that it is fully miscible with both water and organic solvents. The hydroxyl group at one end of the molecule loves water; the butyl-ether portion at the other end loves the oil/organic phase. This amphiphilic structure turns butyl glycol into a coupling ("bridge") solvent that holds two otherwise incompatible phases together.
What does that mean in practice? When you need to dissolve and keep homogeneous an organic component (oil, resin, active ingredient) that is not water-soluble inside a water-based formula, butyl glycol sits between the two phases and unites the system into a single, stable phase. It prevents phase separation, haze and sedimentation. This is precisely why it appears so frequently in cleaning chemicals and water-based paints.
Butyl Glycol Applications
Butyl glycol is a versatile solvent that is not confined to a single sector. The same molecule builds a film in a water-based paint, strips oil in an industrial cleaner, and tunes flow in an ink. Let us look at its uses alongside their application requirements.
Coalescing (Film-Forming) Solvent in Water-Based Paints
In water-based (latex/acrylic) paints the most critical moment is when the water evaporates and the polymer particles must fuse together into a continuous film. This event is called coalescence, and at room temperature most polymers cannot achieve it fully on their own. This is where a coalescing solvent comes in.
Butyl glycol (and its slower sibling, butyl di glycol) temporarily softens the surface of the polymer particles as the water evaporates; once the particles are soft enough, pressure and surface tension fuse them together into a crack-free, continuous film. Once the film has formed, the coalescing solvent slowly evaporates and leaves the system, leaving behind a hard, durable coating.
Why butyl glycol is preferred here:
- Slow evaporation: It stays in the system for the time film formation requires.
- Polymer-softening power: It plasticizes the particle surface effectively.
- Low-temperature workability: It helps the film close properly even in cool conditions (it lowers the minimum film-forming temperature).
The cost of the wrong coalescent is a film that chalks, cracks and fails to adhere in the field. The right coalescent delivers a smooth, durable coating even at low temperatures. Striking that balance means thinking about the solvent system as a whole; we gathered the full framework in our guide on solvent selection for paints and coatings.
Coupling Solvent in Cleaners and Degreasers
Butyl glycol is one of the "unsung heroes" of the cleaning sector. It is found in most glass cleaners, all-purpose surface cleaners, industrial degreasers and floor cleaners. Its role is twofold:
- Dissolving oil and soil: It effectively dissolves organic oils, greases and soot/carbon residues.
- Building a water-oil bridge: In a water-based formula it keeps the dissolved oil homogeneous, prevents phase separation and haze, and keeps the product clear and stable.
Its typical role in glass cleaners follows directly from this: butyl glycol strips the oily film from the surface, and because it evaporates slowly it gives the wipe-down enough time to clean without leaving streaks or marks. In industrial degreasers it dissolves stubborn oil on metal surfaces while keeping the formula as a single phase. We covered what each raw material does in cleaning and detergent formulations in our overview of cleaning and detergent chemicals; butyl glycol is the classic answer to the coupling-solvent need in those formulas.
Brake Fluids and Hydraulic Fluids
Thanks to their high boiling points and water miscibility, butyl glycol and its derivatives are used as components in some brake fluid and hydraulic fluid formulations. The high boiling point helps reduce the risk of vapor lock when the system heats up. These applications are subject to strict specifications; the grade and impurity profile to be used must always be determined according to the formula.
Inks, Printing and Industrial Solvent
In printing inks butyl glycol works as a solvent that adjusts the balance between flow and drying; its slow evaporation delays premature drying at the print head, ensuring smooth transfer. It is also used as a solvent/humectant in wood-coating varnishes, leather finishing, textile printing pastes and various industrial formulations. Its broad solvency and water miscibility make it a "flexible" component across many different recipes.
Butyl Glycol vs Butyl Di Glycol: Which One, When?
Butyl glycol's closest relative is butyl di glycol (diethylene glycol monobutyl ether, DEGBE, CAS 112-34-5). Both are glycol-ether solvents and do similar jobs; however, butyl di glycol has one additional glycol unit in the molecule, and this markedly changes its evaporation and boiling behavior.
| Criterion | Butyl Glycol (EGBE) | Butyl Di Glycol (DEGBE) |
|---|---|---|
| CAS No | 111-76-2 | 112-34-5 |
| Chemical name | Ethylene glycol monobutyl ether | Diethylene glycol monobutyl ether |
| Boiling point | ~168–171 °C | ~230–231 °C |
| Evaporation rate (BuAc=1) | ~0.07 (very slow) | ~0.004 (extremely slow) |
| Residence time in film | Long | Much longer |
| Typical role | Balanced coalescing / coupling solvent | Heavy-duty coalescent, low-temp film |
| Water miscibility | Full | Full |
The practical rule is this: butyl glycol offers a balanced evaporation profile and is preferred when the solvent is meant to leave the system within a defined time. Butyl di glycol stays in the film much longer; it comes into play especially when you need to improve low-temperature film formation, extend open time, or want an extremely slow tail solvent. Most formulators use the two together in different ratios to fine-tune the evaporation profile.
The question to ask when choosing is simple: "When do I want the solvent to leave the film?" If you want it to leave early, you lean toward butyl glycol; if you want it to leave as late as possible, you lean toward butyl di glycol. We supply both products in a range of packaging options; you can browse the full portfolio in our glycols and derivatives product category.
Purity, Grade and Documentation
Butyl glycol is generally supplied in technical/industrial grade, typically at >= 99% purity. Even though every batch looks like the same clear liquid, there are critical parameters that can vary from batch to batch and directly affect performance in the formulation:
- Purity (>= 99%): The main-component ratio; low purity brings solvency and reproducibility problems.
- Water content: High water disrupts both the solvency balance and the behavior in water-sensitive formulas.
- Color (APHA): A clear/colorless appearance; yellowing is a sign of impurity or degradation.
- Acidity and impurity profile: Important in reactive systems and sensitive coatings.
None of these values can be verified by eye; the distinction is always made with the COA + MSDS pair. Request a batch-specific COA that matches the lot number of the delivered batch; a generic catalog certificate does not represent the product in your hands. The logic of labeling and hazard classification can be assessed together with the safety topics in our cleaning and detergent chemicals article.
Storage, Packaging and Handling
Butyl glycol is a flammable liquid, and because it can be absorbed through the skin, correct storage and handling conditions matter. Points to watch in the field:
- Packaging: Usually offered as HDPE/steel jerrycans, ~185–200 kg drums, ~1000 L IBC (tote), or bulk tanker options.
- Storage: In a cool, dry, well-ventilated area, away from heat and spark sources, in closed containers. Because of its flash point (~62 °C), flammable-liquid storage rules apply.
- Compatibility: Keep away from strong oxidizers; suitable materials are generally steel and appropriate polymer packaging.
- Personal protection: Because of skin absorption and eye/respiratory irritation, suitable gloves, goggles and ventilation are essential; follow the exposure limits on the current MSDS.
Packaging choice is not just a logistics decision — it is a cost and quality decision. For regular, high-volume consumption, IBC and bulk lower the unit cost; for fluctuating, project-based consumption, smaller jerrycans/drums provide both flexibility and reduced degradation risk in opened packaging. Defining your consumption rhythm up front prevents most surprises when choosing the right packaging type.
Common Mistakes
Knowing in advance the mistakes that have been repeated for years on the butyl glycol side saves both money and time:
- Ignoring evaporation rate: Looking at solvency but forgetting volatility is the most common error. If fast and slow solvents are not balanced in the same formula, the film closes either too early or too late.
- Confusing butyl glycol with butyl di glycol: The names are similar, the behaviors are not. Choosing the wrong one ruins low-temperature performance or drying time.
- Settling for a generic-type COA: A catalog certificate does not represent the batch in your hands; request a batch-specific COA with the lot number printed on it.
- Not tracking water content: In water-sensitive formulas, high water content leads to phase separation and loss of performance.
- Underestimating flammability and exposure: Because of skin absorption and the flash point, storage, ventilation and personal protection must not be neglected.
Most of these mistakes can be prevented by asking the right questions before ordering and checking the documentation on delivery.
Choosing the Right Butyl Glycol: A Decision Guide
For a purchasing decision, answering the following questions in order is enough to eliminate most mistakes:
- What is the application? A water-based paint coalescent, a cleaner coupling solvent, or an ink/coating? The application determines the required evaporation profile.
- When do you want the solvent to flash off? If it should leave early, lean toward butyl glycol; if it should leave as late as possible, lean toward butyl di glycol.
- What purity and water content are required? Specify the values on the COA according to your formula's tolerance.
- What packaging and volume? Base the jerrycan/drum/IBC/bulk choice on annual consumption and consumption rhythm.
When choosing a supplier, documentation transparency, batch traceability and technical support are decisive. As Yüksek Kimya, we supply glycol-ether solvents — led by butyl glycol and butyl di glycol — in a range of packaging options for a broad spectrum of applications, from automotive to textile, from packaging to paint-coating and cleaning. For export buyers in particular, batch-consistent COA documentation and reliable packaging for international shipment are part of what we plan into every order. You can review the full portfolio in our glycols and derivatives product category.
Request a Quote and Sample
The price of butyl glycol varies with purity, packaging type, order quantity and current raw-material/exchange-rate conditions. For this reason we work with a project-specific quotation model rather than fixed online pricing.
To move forward with the right product at the right price, send us your application, estimated quantity and packaging preference, and we will present a current price quote together with the relevant MSDS and COA documents. We are also ready to support your sample requests. For quotes and any questions, reach us through our contact page; our team will be glad to help you determine the most suitable solvent for your application — butyl glycol, butyl di glycol, or a combination of the two.
Related reading
Frequently Asked Questions
What is butyl glycol and what is its chemical name?
Butyl glycol, chemically 2-butoxyethanol or ethylene glycol monobutyl ether (EGBE), CAS number 111-76-2, is a clear, colorless glycol-ether solvent with a mild ether odor. Its full miscibility with both water and most organic solvents, combined with a very slow evaporation rate, makes it indispensable in paint, cleaning and coating formulations.
What does butyl glycol do in water-based paints?
In water-based (latex) paints butyl glycol acts as a coalescing (film-forming) solvent. As the water evaporates it temporarily softens the polymer particles so they fuse together into a continuous, crack-free film, then it slowly evaporates and leaves the film behind. It improves film formation at low application temperatures by lowering the minimum film-forming temperature.
What is the difference between butyl glycol and butyl di glycol?
Both are glycol-ether solvents, but butyl di glycol (diethylene glycol monobutyl ether, CAS 112-34-5) has a higher boiling point and a much slower evaporation rate. Butyl glycol offers a more balanced evaporation profile, while butyl di glycol stays in the film longer and is preferred where extended open time or low-temperature film formation is required.
What should I check when buying butyl glycol?
Verify purity (typically >= 99%), water content and color (APHA) against a batch-specific COA, and request a current MSDS. Choose packaging (jerrycan, drum, IBC or bulk tanker) based on your consumption volume. Because butyl glycol is flammable and can be absorbed through the skin, plan storage and handling conditions from the outset.