Propylene glycol mono-n-butyl ether, known by its chemical formula C7H16O2, brings together versatility and performance in one compound. The structure features a propylene glycol backbone, with a single n-butyl group replacing one of the hydrogen atoms. As a clear liquid with a slight characteristic odor, it usually appears at room temperature in liquid form but may form crystals under certain conditions. I have seen packaging range from drums to smaller containers, emphasizing its importance in industrial and laboratory environments.
This substance carries a molecular weight of about 132.2 g/mol. Breaking it down, one propylene glycol unit links with a single n-butyl ether group, forming a stable ether bridge. The ether bond increases the molecule’s resilience against hydrolysis, which means water-based systems won’t break it down quickly. The structure's balance between hydrophobic and hydrophilic regions plays a key role in its effectiveness as a solvent and coupling agent.
Propylene glycol mono-n-butyl ether has a density near 0.88 g/cm³ at 20°C, showing it’s slightly lighter than water. In my experience handling this chemical, the boiling point lands around 171°C, which keeps its loss due to evaporation under control in most open-system uses. With low viscosity and high miscibility, it blends easily with many organic solvents and some water. One of the stand-out qualities is its mild odor—less pungent than similar glycols—making it easier to work with in closed spaces. It rarely comes in flakes, powder, pearls, or solid form since its melting point sits well below most storage and shipping temperatures, keeping it safely liquid.
Most commercial deliveries present propylene glycol mono-n-butyl ether as a colorless to pale yellow liquid, shipped in metal drums or plastic totes. Some companies may offer concentrated solutions if you need a particular dilution, but I have almost never seen it as a powder or solid unless frozen in special lab settings. In day-to-day industrial work, its consistent liquid form simplifies measurement and transfer.
The main use cases lean heavy into its solvent power. I’ve watched paint and coating manufacturers use this ether as a coalescent, helping polymer particles blend during film formation. In cleaning products, its balance of hydrophilic and lipophilic properties lifts oily soils without being harsh on surfaces. Printer ink formulators take advantage of its quick evaporation and compatibility with pigments. These properties come straight from its molecular traits—good solvency, manageable volatility, and gentle odor.
The molecular formula C7H16O2 gives a clear picture of its elemental makeup: seven carbons, sixteen hydrogens, and two oxygens. Chemically, it sits among glycol ethers—a family recognized for balancing water- and oil-friendly features. Propylene glycol mono-n-butyl ether’s straight-chain butyl ether link distinguishes it from other glycol ethers. This subtle difference changes how it dissolves greases or mixes with other raw materials, so choosing it over similar chemicals really does impact the result.
On the shipping or customs side, the Harmonized System (HS) Code for propylene glycol mono-n-butyl ether usually falls under 290949. This code covers a range of glycol ethers. As a result, imports and exports require proper documentation, especially with ever-tightening safety regulations. From my experience assisting with cross-border shipments, clarity in documentation cuts delays and prevents costly detentions at ports.
Direct exposure to propylene glycol mono-n-butyl ether calls for caution. Although less toxic than older solvents, it can irritate skin, eyes, and the respiratory tract if mishandled. Chronic exposure at high levels may affect liver or kidney function, so working with certified chemical-grade gloves and goggles never feels optional. Ventilation matters, especially since inhaling vapor over extended shifts can lead to headaches or dizziness based on data from workplace safety authorities. Even with moderate acute toxicity, spills need prompt cleanup and proper containment to prevent fire hazards—flash points sit above 60°C but not high enough to ignore risks. Correct labeling and safety data documentation make a real difference on a busy shop floor, especially for new team members.
The production of propylene glycol mono-n-butyl ether usually begins with propylene oxide and n-butanol, both derived from petrochemical sources. Their supply relies on stable fossil fuel markets—a reality that businesses and governments are wrestling with as they chase more sustainable sourcing. The lifecycle impact of this ether depends on both how it’s manufactured and how much escapes into the air or water after use. Some research points to degradation in the environment, but large spills can have short-term toxicity in aquatic systems. From my experience, strict containment and recycling practices—plus responsible procurement—lower both workplace risks and environmental footprint.
Building safer workplaces starts with proper ventilation and protective equipment. Closed systems, like automated filling and mixing units, cut down direct exposure and vapor release. I have seen effective results from regular staff training sessions, focusing on proper transfer and storage, which directly lowers incidents. Moving toward alternatives—such as bio-based solvents—offers another long-term solution, though very few options match the exact performance profile and price point of propylene glycol mono-n-butyl ether right now. Where possible, using only as much as necessary and recovering leftover solvents for recycling eases both financial and environmental cost.
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