What Is 2-Butoxyethanol (CAS 111-76-2)?
2-Butoxyethanol, also called ethylene glycol monobutyl ether or butyl glycol, is an organic solvent with the molecular formula C6H14O2 and CAS number 111-76-2. It is a colourless liquid with a mild ether odour, and its structure CH3CH2CH2CH2-O-CH2CH2-OH makes it an ether-alcohol, which is why it dissolves both in water and in most common organic solvents. Commercial material is normally supplied at 99% purity in 180 kg drums, and the main Harmonised System code under which it is traded is 2909.43.
Is 2-Butoxyethanol a Surfactant?
Strictly speaking, no. A surfactant is a molecule with a clear split between a long hydrophobic tail and a hydrophilic head group that migrates to an interface and forms micelles above a critical concentration. 2-Butoxyethanol has only a short four-carbon tail and no charged head group, so it does not behave as a classic surfactant and has no meaningful critical micelle concentration. What it does have is surface-active character: it lowers surface tension and, more importantly, it is an effective coupling solvent, able to bring a hydrophobic resin and water into one stable phase. This coupling and wetting behaviour is why the material is often described loosely as a surfactant, and why it is formulated alongside genuine surfactants in so many cleaning products.
Properties and Typical Specifications
| Parameter | Typical value |
|---|---|
| CAS number | 111-76-2 |
| Molecular formula | C6H14O2 |
| Molar mass | 118.17 g/mol |
| Appearance | Colourless liquid, mild ether odour |
| Purity | 99% minimum |
| Density at 20 °C | About 0.90 g/cm³ |
| Boiling point | About 171 °C |
| Flash point | About 61 °C closed cup |
| Solubility | Miscible with water and with most organic solvents |
| Harmonised System code | 2909.43 |
| Transport classification | UN 2810, Class 6.1, packing group III |
Main Industrial Uses
Coatings and inks are the largest outlet. As a coupling solvent and coalescing aid, 2-butoxyethanol helps resins, pigments and additives dissolve evenly in water-based and solvent-based systems, improves flow and film formation, and supports adhesion and drying speed. In cleaning products it cuts grease and oily soil, which is why it appears in hard-surface cleaners, industrial degreasers, metal-cleaning baths and vehicle-cleaning formulations. Electronic manufacturing uses it for circuit-board and component cleaning and as a carrier in printing and coating processes. Other established applications include oilfield and workover fluids, where it acts as an oil-water coupling solvent and helps prevent wax and gas-hydrate related problems, and specialty formulations such as agricultural adjuvants and, in some regions under restriction, personal-care solvents.
Handling, Storage and Compliance
2-Butoxyethanol is harmful if inhaled and irritating to the eyes and skin, and it can be absorbed through the skin, so exposure should be controlled by local exhaust ventilation, closed transfer where possible, and suitable chemical-resistant gloves, goggles and work clothing. Store it in tightly closed, correctly labelled containers in a cool, dry, well-ventilated area away from oxidising agents and ignition sources, and keep spills out of drains and soil. Although the flash point of about 61 °C means the material is not classified as a flammable liquid for transport, it is still combustible and any large spill of hot product can release ignitable vapour. Check local chemical-control and cosmetic-ingredient rules before use in consumer products.
Frequently Asked Questions
Q: Is 2-butoxyethanol a surfactant?
Not in the strict sense. It is a glycol ether and a strong coupling solvent with surface-active behaviour, but it lacks the long tail and head group structure of a true surfactant and forms no micelles.
Q: What is the CAS number of 2-butoxyethanol?
The CAS number is 111-76-2 and the molecular formula is C6H14O2.
Q: Is 2-butoxyethanol soluble in water?
Yes. It is fully miscible with water and with most organic solvents, which is the basis of its use as a coupling solvent.
Q: What is 2-butoxyethanol used for?
Coatings and inks, water-based and solvent-based cleaners, degreasers, electronic component cleaning, oilfield and workover fluids, and other specialty formulations.
Q: Is 2-butoxyethanol flammable?
It has a closed-cup flash point of about 61 °C, so it is combustible rather than a transport-classified flammable liquid, but it will still burn and should be kept away from ignition sources.
Q: What is the UN number for 2-butoxyethanol?
It is shipped under UN 2810, Class 6.1, packing group III.