1-Hexyl-3-Methylimidazolium Hydrogensulfate stands out as an ionic liquid, yet at room temperature, it can appear as a viscous liquid, a crystalline solid, or even as flakes or pearls depending on its storage and handling. The chemical structure features a six-carbon hexyl chain attached to a methylimidazolium ring, paired with a hydrogensulfate anion. This pairing produces not just unique chemical reactivity but also interesting physical characteristics, allowing the compound to find a place in several industries. You see this material used in labs for catalysis, extractions, and as a solvent, mostly because of its stability in both acidic and basic environments.
Chemically, this compound carries the formula C10H21N2O4S. The molecular structure isn’t just for textbook learning. Having spent time working with similar ionic liquids, it’s hard not to notice the role the long alkyl chain plays in solubility and phase behavior. The imidazolium core brings strong ionic character, and the hydrogensulfate anion expands acidity and reactivity. The whole assembly allows for advantages like low volatility and negligible flammability, important in chemical processing where safety concerns matter every day.
The density typically runs near 1.18 g/cm³ at 25°C, sometimes higher or lower with minor impurities or water uptake. In terms of form, you find it as clear to pale yellow liquid, crystalline solid, or pearlescent flakes. The melting point usually sits between 30°C and 40°C, but in high-purity samples, the solidification happens sooner. Some batches can seem syrupy or even resemble powdered glass, depending on processing. The material absorbs atmospheric moisture fairly quickly, which can shift its density and even physical state. Touching the compound, you’d notice it feels slippery, even oily. That’s part of why operators take care around open containers in the lab, because droplets can land on benches and equipment where they hang on. Some suppliers package it in indexed liter bottles or foil-sealed pouches to prevent contact with air and moisture, a practice I’ve seen firsthand in chemical storerooms.
From a trade and import perspective, the HS Code used internationally is 2933.39, covering heterocyclic compounds. Manufacturers list purity from 98% or higher, which matters if trace metals or water interfere with catalyst work or synthetic steps downstream. Typical specifications include chloride, iron, and water contents, along with color and physical form. Working in a process environment, I’ve known teams to request datasheets outlining melting point, density, spectral data, and particle size, since these impact material handling and reactivity. The compound performs differently in powder, pearl, or flakes form, so stockroom managers keep an eye on matching inventory items to project needs.
This ionic liquid often comes from reaction of 1-methylimidazole with 1-chlorohexane, followed by neutralization with sulfuric acid. Sourcing reliable raw materials minimizes batch-to-batch variation, and I’ve seen process chemists rely on trusted suppliers for precisely that reason. The resulting compound plays a role in organic synthesis, electrochemical studies, and metal processing because it supports ion transport, works at temperature extremes, and stands up to chemical attack. Peers in research labs have used it as a safer replacement for volatile organic solvents, since its vapor pressure is very low, which reduces inhalation hazard in open bench work. In pilot plants, process engineers need to consider all phases of the material — liquid, powder, or crystals — since transfer, mixing, and cleanup go smoother with a consistent product form.
On the safety front, though this ionic liquid avoids the explosive, flammable risks of some organic chemicals, it brings its own concerns. Prolonged skin contact can trigger irritation. Eye exposure has led to redness and discomfort, based on industry incident reports, and so I always recommend gloves and goggles around it. Inhaling dust or vapor isn’t common in well-run labs because of its low volatility, but spills on hot surfaces can launch odors which need proper ventilation. Toxicological studies point toward the potential for aquatic harm, pressing for tight controls on disposal. Large-scale handlers need absorbent pads and spill kits nearby; seeing these protocols during audits shows just how seriously safety is taken — not as a box-checking exercise, but as part of daily work culture. Chemical hygiene plans treat accidental release, fire response, and medical exposure all as real possibilities, which builds trust with workers and local communities.
Over the years, regulations have grown stricter around ionic liquids, mostly because the full environmental footprint takes time to emerge. For this compound, effluent guidelines push for contained, closed-system usage. Many countries restrict open drain disposal and ask for neutralization steps if the chemical enters waste streams. Companies lean on internal testing and external certification, using ISO standards as proof of safe handling. Any new process using this material earns a close review of storage, transfer, and emergency response, based on the need to avoid groundwater contamination or long-term uptake by aquatic systems.
Safer industrial practices often start with product labeling, employee training, and engineering controls. Having worked on chemical safety projects, I’ve seen the benefits of integrating fume cupboards, splash-proof packaging, and automated transfer lines. Substituting ionic liquids for hazardous solvents helps with compliance and air quality, but only if the entire lifecycle — from raw material to waste — is considered. Some operations have moved toward closed-loop recycling and on-site purification of used ionic liquids, which not only keeps costs under control but also boosts their environmental reputation. At the regulatory level, clearer guidelines would help producers and users make better risk assessments about the broader impacts. Product development teams who understand and respect the specifics of this compound’s properties — from density to molecular weight to handling risk — can help craft a safer, cleaner, more innovative chemical industry.
