Tetrabutyl-Ammonium Bis(Fluorosulfonyl)Imide belongs to a growing set of synthetic salts used in modern electrochemical applications and pharmaceutical research. Chemists turn to this material for its predictable interaction with lithium and sodium ions, especially in battery technologies that demand particular structural and ionic features. The compound’s chemical formula, C16H36F2N2O4S2, gives it a complex structure, with tetrabutylammonium as a bulky cation paired with a bis(fluorosulfonyl)imide anion that anchors its unique solubility and reactivity profile. For me, the thing that stands out is how this salt manages to stay stable at elevated temperatures and demonstrates a wide electrochemical window once dissolved in the right solvents.
Looking at the properties, this salt generally appears as a solid at room temperature, often showing up as white to off-white flakes, powder, or crystalline pearls. As someone who’s had to measure density in the lab, I’ve found its density typically hovers around 1.1 to 1.2 g/cm3, making it fairly easy to measure out without worrying about it clumping or absorbing moisture instantly. Under lab lights, the crystals reflect a mild luster – a cue to its purity and stable molecular build. At the molecular level, the symmetric tetrahedral arrangement of the tetrabutylammonium cation gives stability, while the bis(fluorosulfonyl)imide anion’s delocalized charge allows high solubility in polar solvents like acetonitrile and dimethyl carbonate. In the flask, this salt doesn’t lump together quickly, which saves plenty of time during prep work or scale-up.
Tetrabutyl-Ammonium Bis(Fluorosulfonyl)Imide falls under several regulatory codes for trade, but most chemical suppliers list it with an HS Code around 2921.19—a category reserved for quaternary ammonium salts and derivatives. Come customs time, that detail matters because improper labeling can delay shipments or spike costs. Most suppliers offer specifications such as purity exceeding 98%, with trace moisture below 0.5%, and particle size options ranging from sub-millimeter flakes to fine powders, based on the application. In my experience, higher purity means fewer side reactions in sensitive R&D processes, which translates directly to reliability when scaling up for pilot batches.
You get this salt in different shapes and sizes—solid as tight crystals, milled powder, compact pearls, or even as a thick solution if a supplier blends it for rapid mixing. The form matters because handling and solubility shift based on the size and surface area. Powder spills easily, so for me, using flakes or pearls cuts down on air contamination and makes it less likely that static will send it flying around the fume hood. In larger production, the material can arrive in sealed liter bottles or lined drums designed to keep moisture out, since contact with water changes the chemical makeup and ruins the product. Some users dissolve it on-site, creating custom concentrations for specific electronic or laboratory uses, and the process can run consistently thanks to its predictable solubility curve.
Safety matters every step of the way, and with Tetrabutyl-Ammonium Bis(Fluorosulfonyl)Imide, gloves and goggles turn into non-negotiable basics. The bis(fluorosulfonyl)imide anion gives this salt corrosive potential, and exposure to skin or eyes leads to painful irritation and possible burns. Scientific sources point out that dust inhalation may trigger respiratory response, and like many organofluorine compounds, reaction with water or acids can produce harmful gases. I try to weigh and transfer this material inside a well-ventilated fume hood for that reason. Good supply partners offer SDS documents outlining risks, along with waste disposal advice to prevent environmental release. Accidents strain both the team and the bottom line, so proper storage in airtight containers, away from heat and incompatible substances, becomes routine.
Producing Tetrabutyl-Ammonium Bis(Fluorosulfonyl)Imide begins with high-purity tetrabutylammonium and freshly made bis(fluorosulfonyl)imide acid or related intermediates. Tight quality control over these raw materials sets the stage for reliable batches, and reputable suppliers publish origin data plus analytical certificates with every shipment. During synthesis, the combination reaction occurs under dry atmospheres using inert gases like nitrogen, since contact with air or moisture wrecks purity and reduces shelf life. Material scientists monitor for trace metals, sulfur content, and halide contaminants as well, because even parts-per-million levels can change battery or electrolysis results downstream. Evaluating these inputs has taught me that small tweaks in precursor sourcing can send ripple effects across entire product lines.
Tetrabutyl-Ammonium Bis(Fluorosulfonyl)Imide often ends up in cutting-edge energy storage systems, high-performance electrochemical devices, and select pharmaceutical syntheses where stable, non-nucleophilic anions make a critical difference. Battery engineers value how the fluorosulfonyl imide structure enables long cycle life and high voltages without promoting secondary reactions. Chemists working on catalytic systems rely on this salt to separate organic layers or create clean reaction environments, since the non-coordinating anion and lipophilic cation pair well with both hydrophobic and hydrophilic solvents. Performance in application depends directly on the form chosen, handling methods, and supply chain transparency, and users must vet quality over mere price.
Delving deeper into the chemistry, the molecular weight stands near 422 g/mol, which affects dosing calculations for both analytical and synthetic work. The salt resists hydrolysis under neutral to dry conditions yet reacts swiftly with bases or nucleophiles, limiting some types of side reactions and making it easy to recover from non-aqueous solutions. In solid state, you see a tightly organized ionic lattice, but dissolution quickly scatters the cation and anion, unlocking fast transport and minimizing viscosity buildup. This performance data features in technical datasheets, and researchers lean on it for predicting compatibility with new materials or electrolytes being tested.
Handling always circles back to storage choices, especially for moisture-sensitive compounds like this ammonium salt. Shelf stability can stretch for years when kept cool, dry, and sealed away from direct sunlight and reactive chemicals. My experience storing this material in desiccators or vacuum-sealed packaging has shown that simple prevention routines work best—opening containers only for brief transfers, clearly labeling hazard ratings, and tracking lot numbers in shared lab logs. Companies with ISO certification or equivalent quality management systems often outperform those with spotty tracking, a detail that resonates during audits or customer reviews.
In practice, safe use requires following chemical hygiene plans and periodically rechecking stock dates, especially where old powder can harden or clump, cutting accuracy in weight. Used solutions and excess bulk must go through licensed chemical waste streams, as improper dumping causes regulatory headaches and public health concerns due to persistent fluorinated byproducts. I’ve watched improper disposal threaten both sewer systems and company certifications, so we keep spill kits, clear signage, and regular training as standard. Working safely with Tetrabutyl-Ammonium Bis(Fluorosulfonyl)Imide calls for experience, preparation, and a firm respect for the chemistry behind the name.
