Tetramethylammonium Hydrogen Sulfate, often found under the chemical formula (CH3)4NHSO4, stands as a well-recognized quaternary ammonium compound. This material often appears in labs and across the chemical industry as a reliable source of both hydrogen sulfate ions and the tetramethylammonium cation. Combining the known reactivity of quaternary ammonium salts with strong acidic sulfate properties, Tetramethylammonium Hydrogen Sulfate shows up in many specialized chemical syntheses, electrochemical processing, and analytical applications where the functional performance of the sulfate group needs to be paired with high solubility or phase transfer characteristics. Proper handling and a good understanding of the material’s structure help drive safer and more efficient use, especially in industries where exact results and reliability matter.
The compound typically presents as a solid with well-defined crystalline features. Depending on manufacturing methods or conditions, it may appear either as flakes, fine powder, large granules such as pearls, or compact crystals. Each physical form offers traits that suit particular storage, measurement, or usage procedures. Some processes benefit from the high surface area of the powder or small crystals, providing efficient dissolution rates in solution. Others rely on the stability and ease of handling found in denser flakes or pearls. Though not commonly encountered as a liquid, Tetramethylammonium Hydrogen Sulfate dissolves easily in water, creating a transparent solution over a wide range of concentrations. The prepared solutions, measured in liters, support processes that need tight colligative properties and predictable acid dissociation.
With a molecular formula of C4H13NO4S and a molecular weight (molar mass) close to 171.22 g/mol, this compound blends a positively charged tetramethylammonium ion and the hydrogen sulfate anion. Its ionic character drives high solubility, particularly in polar solvents like water or some alcohols. The solid salt does not smell, does not appear volatile under normal conditions, and keeps its structure in tightly sealed containers. In the crystal lattice, bulky methyl groups provide extra stability while allowing for efficient ion pairing, which proves important in both catalytic roles and ion exchange tasks.
Activated raw material purity matters, as impurities in Tetramethylammonium Hydrogen Sulfate sometimes alter outcomes in analytical or synthetic settings. Industry-grade product usually falls within a minimum purity threshold above 98%. Proper storage at room temperature maintains the white to off-white crystalline solid. The density sits near 1.23 g/cm³ at ambient conditions, offering good shelf-life and minimal caking as long as packaging remains dry and sealed. It melts at higher temperatures, typically above 100°C, and decomposes if subjected to sustained high heat. Those working with aqueous solutions observe high conductivity and strong acidic behavior, stemming from the fully dissociated hydrogen sulfate moiety.
International trade identifies Tetramethylammonium Hydrogen Sulfate through the Harmonized System (HS) Code 2923.90.9090, which falls under quaternary ammonium salts and their derivatives. Customs authorities and safety professionals rely on accurate classification to comply with shipping, storage, and import/export regulations. The product ships in drums, polymer-laminated sacks, or sealable containers to avoid moisture uptake and contamination.
Safety deserves constant attention. Workers coming in contact with this chemical must wear proper eye protection, gloves, and laboratory coats. Though not acutely toxic under ordinary handling, Tetramethylammonium Hydrogen Sulfate can cause irritation to skin, eyes, and upper respiratory tract. Accidental ingestion or inappropriate mixing with other chemicals, especially strong bases, risks the release of potentially harmful fumes and byproducts. Facilities using Tetramethylammonium Hydrogen Sulfate benefit from efficient ventilation, accessible eyewash stations, and established spill containment protocols. Emergency information from the Safety Data Sheet (SDS) lays out first aid measures and fire-fighting guidance, considering that the compound does not support combustion, but breakdown can produce toxic nitrogen oxides and sulfur oxides. Disposal should never flow to drains or the environment but follow chemical waste guidelines and authorized treatment pathways to prevent harm to aquatic and groundwater systems.
In industry, this compound works well as a phase-transfer catalyst in organic synthesis, easing movement of reactants between water and organic layers for increased reaction yields. Chemical researchers use the product for controlled precipitation, pH calibration, and as an electrolyte ingredient for electroplating or battery studies. Its strong acid component helps labs standardize alkali content in titration, and the stable, non-volatile ammonium structure keeps it manageable in automated, high-throughput workflows. The electrical conductivity, paired with consistent ionic strength, provides a useful platform for detailed analytical methods such as ion chromatography and capillary electrophoresis. In some routes, high-purity product supports pharmaceutical intermediate production, pushing the boundaries of what chemists can accomplish with selective methylation and sulfonation steps.
Reliable suppliers draw on consistent raw material streams, using certified methylamines and top-grade sulfuric acid to keep batch variability minimal. Each lot sees rigorous inspections—testing for heavy metals, organic residues, and water content to secure compliance with REACH, RoHS, and other regulatory frameworks that promote human and environmental safety. Robust internal audits, traceability records, and periodic inspections all work to keep handling and quality on track. By tightening up each step, right from the earliest feedstock selection, producers invest not only in safety and customer satisfaction but also in a reduced footprint for downstream environmental impact.
Tetramethylammonium Hydrogen Sulfate stores best in cool, dry, airtight conditions, away from strong oxidizers and incompatible chemicals. The crystalline or powdered product fills vessels made of chemically inert plastics or powder-coated metals. Moisture control keeps the material from caking, hydrolyzing, or forming clumps that jeopardize weighing accuracy. Bulk buyers often look for weather-proof drums or lined bags capable of withstanding cargo vibrations and long voyages. Secure labeling—listing UN numbers, hazard pictograms, lot details, and expiry—helps downstream handlers track and record each supply event from warehouse to workstation, minimizing mix-ups and exposure risks.
Detailed understanding of the structure, solubility, density, and acidity underpins every safe and effective use of Tetramethylammonium Hydrogen Sulfate, whether in a teaching lab or a manufacturing plant. Properties like density, crystal habit, and phase stability inform vital decisions—such as dosing, reactivity, and shelf-life—which all contribute to efficiency and cost savings in the field. With demand rising for science-driven manufacturing and greener processes, chemical users need reliable property data to model reactions, cut waste, and improve supply chains. Scientists, engineers, and regulatory managers alike depend on transparency at each link in the chain to unlock the full benefit of this versatile, but potentially hazardous, chemical tool.
