4-Aminophenol appears as a slightly off-white to grayish solid at room temperature. Chemists and material suppliers know it as an important raw material with the molecular formula C6H7NO, boiling down to a benzene ring attached to both an amine group and a hydroxyl group at opposite ends. The chemical balance in this molecule creates distinctive properties that drive its usefulness across multiple industries. Many laboratories receive it in a few physical formats. Some get it as fine powder. Others handle white to grayish flakes or even crystalline clusters. It dissolves fairly well in hot water, sparking a clear solution as it goes. Most users report a faint odor not unlike phenol itself—a familiar sign in labs stocked with organic intermediates.
The melting point usually sits near 187°C with a boiling point over 285°C, which gives it solid stability under regular lab and production conditions. Pouring a small batch on a scale results in a density of about 1.293 g/cm3, so a liter of loose flakes runs heavier than you might expect. As a raw material, purity becomes essential. Most buyers look for a minimum product content upwards of 99%. It resists oxidizing in dry storage but reacts fairly quickly if exposed to air and moisture. These reactions show up as darkening of the chemical, hinting at unwanted side products forming. Much of the global shipment heads out under HS Code 292229, pegging it as an organic compound with both amino and hydroxyl functions.
The structure of 4-Aminophenol combines a benzene ring, a staple of aromatic chemistry, with a para-positioned amino group (–NH2) opposite a hydroxyl group (–OH). This setup not only guides its reactivity but gives it some unique solubility features—fair in cold water, much better in hot. Many see the benefit in manufacturing dyes, photographic developers, and pharmaceuticals, especially acetaminophen (paracetamol). I remember years back, watching operators handle it in bulk, always wearing gloves and eye protection since dust exposure can be rough over time. The powder drifts easily, clinging to plastics and stainless steel, making cleanup important to avoid contamination of other batches.
Warehouses stock it as either flakes or microcrystalline powder. Both forms pour smoothly and fit well in drum or bag packaging. Customers often ask for particle size, moisture content, and iron impurities because these numbers affect the final product's outcome in their lines. Typical industrial specs include an assay (by titration) not lower than 99%, moisture below 0.5%, and iron under 0.001%. For those working in solution prep, 4-Aminophenol dissolves at roughly 14 g per 100 ml of water at 25°C, becoming nearly twice as soluble in boiling water. This jump in solubility is handy for those making concentrated developer baths or intermediates for API synthesis.
Like many aromatic amines, 4-Aminophenol carries real safety flags. Prolonged contact with skin can cause irritation; inhaled dust leads to coughing or shortness of breath, especially in closed spaces with poor air filtration. The acute toxicity isn’t high compared to some amines, but chronic exposure creates risks to health and safety staff should never overlook. The chemical can oxidize into quinone-type products or nitrophenol derivatives. These side products darken storage containers and taint production runs, showing the importance of good seals and climate control. Always keep fire extinguishers nearby, since dust can become combustible under the right conditions. Local laws regulate shipping and waste of large amounts, especially for export and import under the correct HS Code. In case of spillage, containment with non-reactive absorbents and sealed bags is the way forward, followed by chemical waste pickup aligned with environmental rules.
4-Aminophenol serves as one of the key starting materials for drugs, especially for making acetaminophen, a global pain reliever. The route from aminophenol to finished tablet relies on clean, impurity-free starting stock, shaped by batches that match strict molecular and physical standards. In the photo-developer world, it acts as a reducing agent, turning silver salts into distinct black-and-white images—technology that still powers some scientific and medical devices. Textile dye makers and pesticide formulators choose it for its reactive positions: neither fully electron-rich nor poor, lending itself to coupling and substitution. Having seen production up close, I know that consistency in density, purity, and moisture shapes quality and regulatory compliance.
Many regulatory agencies set exposure thresholds for aromatic amines given their possible toxic breakdown in plants or through worker contact. In the workplace, robust ventilation, regular personal protective equipment use, and careful inventory management cut the risk to staff and product alike. Remote monitoring of air quality within large storage rooms, along with automated cleaning cycles, flush out dust accumulations that tend to be both a fire and lung hazard. From the viewpoint of transportation safety, double-sealed packaging, clear labels with the correct HS Code, and rigid adherence to international shipping norms ensure fewer accidents and shipment errors. Chemical producers looking to minimize risk often reformulate batch sizes, shifting from one-tonne super-sacks to smaller, easily handled containers—trading off efficiency for better control and less exposure risk during unloading and blending.
Working with chemical intermediates over the years, I’ve realized the difference good documentation and honest supplier relationships make. 4-Aminophenol stands out as a raw material where improper handling leaves a lasting mark on finished goods. Even a fractional rise in iron or water content upsets dye purity or developer performance. Inspections, both visual and by lab analytics, must be ongoing, not just at acceptance but after each storage cycle. Some manufacturers use silica desiccants and nitrogen blanketing to stop the slow creep of humidity that drives unwanted reactions. Chemical buyers need to choose sources who lay out all material specifics, down to trace levels, to guarantee every kilogram lines up with the needs of the end product. Regular training, real-time monitoring, and investment in both people and technology help keep hazards in check while making sure every batch lives up to tough expectations set by users and regulators worldwide.
