1-Butyl-3-Ethylimidazolium Chloride shows up on many lab supply lists, and I keep running into this compound in research projects focused on ionic liquids. It falls into the imidazolium class, a group of chemicals often used for their ability to act as solvents far outside the range of water or the average organic liquid. Chemically, you see a positively charged imidazolium ring, with a butyl and an ethyl group attached at adjacent positions, paired with a simple chloride anion. This structure explains its strong ionic nature and solid physical presence at room temperature. People working with it call it by its short name, [C4C2Im]Cl, reflecting its straight-up formula: C9H17ClN2.
Talking physical characteristics, this compound comes as a solid at standard temperature, but it can take other forms, including flakes, powders, small pearls, or sometimes larger crystals that don’t crumble easily. The density hangs around 1.1 g/cm³, which seems ordinary, but in practice this value helps when you need to prepare a consistent solution or calculate amounts for a reaction scale-up. The crystalline solid shows no strong odor, and unlike classic inorganic salts, it doesn’t soak up water from the air too badly, which means less hassle for storage. With these kinds of ionic liquids, the low melting point is a major selling point, as many stay liquid even below room heat. Still, in this case, the chloride version holds onto its solid state unless you melt it above 60°C, depending on crystal purity and sample prep.
Given its strong polarity, this material dissolves salts not just in water, but also in some organic solvents that most salts steer clear of. In electrochemistry, researchers use it as a supporting electrolyte. I have seen it help out as a reaction medium for organic transformations that can’t run in water—for instance, pushing difficult substitution and rearrangement reactions toward completion. The ionic nature almost always leads to super-low vapor pressure, so danger from inhalation drops way down—still, gloves and glasses stay non-negotiable since direct contact irritates skin and eyes. Combining this with its low flammability, you might see it described as a “safe” chemical under typical handling, yet every MSDS flags it as hazardous if used without basic lab discipline.
1-Butyl-3-Ethylimidazolium Chloride tends to ship in jars or plastic bags, labeled by weight (from 100 grams to kilograms), and often marked with the HS Code 2921.19.9000 for customs. Lab grade means the batch gets checked for purity by NMR or HPLC, keeping chloride at the right level and ruling out unwanted side products from manufacturing. Color stays nearly white, but real-world batches sometimes have a faint yellow tint, depending on storage. Suppliers report molecular weight right at 204.7 g/mol. Most production lines use high-purity 1-butylimidazole and ethyl chloride, reacting under controlled conditions to build the final salt, followed by repeated wash cycles and vacuum drying.
Direct experience working with ionic liquids shows their hazards compare well to many traditional organic solvents. Still, with this imidazolium chloride, the usual lab CAUTION sign stays up. Touching the powder without gloves gets harsh on my skin, and handling the solid too much ends up making a real mess—little pearls and flakes stick to gloved hands and plastic spatulas alike. The MSDS rates this compound as harmful by ingestion and contact, and I always make sure to work under a hood if grinding or dissolving larger quantities just so stray powder doesn’t hang in the air. Unlike many raw materials, this salt does not build up much static or present strong fire hazards. Disposal requirements demand transfer to licensed waste facilities, not the sink. Water treatment plants struggle with these ionic liquids, so treating waste at source remains the only real option until new destruction technologies get tested.
Ingredient-wise, the route goes back to simple, cost-effective starting points. 1-Butylimidazole, a base chemical for a lot of imidazolium salts, meets up with ethyl chloride in an alkylation step, with precautions for moisture and atmospheric CO2. This synthetic path keeps the molecular structure tidy: two nitrogen atoms spaced apart by a five-atom aromatic ring, a butyl chain for oil-loving properties, an ethyl for balance, topped with a chloride counterion. The blend of hydrocarbon chains and ionic centers lets the salt dissolve a wide series of other raw materials—catalysts, metals, and even certain plastics that most solvents shun. Every lab set up for next-generation catalysis, high-efficiency extractions, battery innovations, or lubricants research keeps this on their shelves.
Risks get a lot of attention with any synthetic chemical. 1-Butyl-3-Ethylimidazolium Chloride, like the broader class of ionic liquids, avoids most problems linked to flammable solvents, but doesn’t get a free pass. Extended exposure—especially through cuts or open skin—brings on irritation and sometimes rash, so lab routines never skip a skin barrier. Airborne dust risk stays low, but anyone handling large quantities prefers powderless forms, like compact pearls or pre-made aqueous solutions, to dodge particulate exposure. Push toward greener chemistry always asks: How can this compound end its life without hurting the environment? Researchers have been hunting for fully degradable ionic liquids, and some now manufacture variants with built-in breakdown points—molecular switches that snap apart under light or heat.
With every new paper on energy storage, electrosynthesis, or solvent-free chemistry, the demand for specialized ionic liquids grows. 1-Butyl-3-Ethylimidazolium Chloride remains a top pick because of its blending of safety, performance, and cost. Families of researchers and chemical engineers choose it over classic solvents not just from tradition but because it lets them reach reaction outcomes without epic spills or fire drills. This focus feels personal—small improvements in safety and reduction in toxic emissions affect all of us, whether it’s in a sprawling industrial facility or a two-person academic lab. As policymakers and businesses push for better chemical handling and lower emissions, materials like this keep the momentum going, driving progress that extends beyond the confines of the lab bench.
