Sodium 4-hydroxybenzene sulfonate dihydrate emerged from the rise of organic chemistry in the late 1800s, a time when chemists began exploring ways to turn aromatic compounds into functional industrial chemicals. Long before computer-modeled synthesis, the only way to figure out new molecules was in a glass flask, observing color shifts and precipitates. In dye production, especially, researchers noticed how sulfonation not only made compounds water-soluble but allowed deep, reliable color binding. It proved its worth on a commercial scale during the rapid expansion of European dye houses. Sodium 4-hydroxybenzene sulfonate became a dependable workhorse, bridging benzenes’ hydrophobic nature and the needs of a world learning to mass-produce textiles and specialty chemicals.
This compound, often shortened to sodium phenol sulfonate, appears in industries where the balance of hydrophilic and aromatic units is crucial. The addition of sulfonate groups creates something more manageable and less volatile than simple phenols, allowing for easier storage and dosing. It’s rarely a star ingredient, but it steps in everywhere—dye intermediates, stabilizer blends, even certain electroplating baths. Its practicality comes from a track record of reliability, straightforward handling, and predictable chemistry that scales well from the bench to the warehouse.
Sodium 4-hydroxybenzene sulfonate dihydrate forms colorless or very pale crystalline powder with steady flow. Like many aromatic sulfonates, it shows significant solubility in water but little tendency to dissolve in non-polar solvents. The hydration keeps dust at bay in large-scale mixing, a welcome feature for anyone working with tons rather than grams. Chemically, its phenolic function remains mildly acidic, making it a good partner for coupling reactions, or for driving sulfonate chemistry in aqueous media. Structure-wise, the sodium cation anchors the sulfonate for easy dissolution and less static—something you notice on days when air is dry and powdery ingredients otherwise stick everywhere.
Industry standards require a clear breakdown, listing purity—often better than 98%—moisture content, and sodium content. Responsible vendors supply batch-level analysis. It's not enough to trust a label; every container should deliver a certificate of analysis, allowing users to audit supplier quality. Labeling includes precise storage instructions: keep dry, avoid strong oxidizers nearby, and minimize prolonged exposure to air to avoid caking. Any changes from batch to batch need highlighting, as even minor impurity swings can impact color or reactivity in end-use applications, especially where downstream processes demand consistency.
Most commercial production starts from phenol, which reacts with concentrated sulfuric acid to introduce the sulfonate group. The process demands careful temperature control—too cool, and the reaction lags; too hot, and unwanted byproducts gum up purification. Once the reaction has run its course, neutralization with sodium hydroxide yields the sodium salt form. Some processes recruit a crystallization or filtration step, where achieving high yield without purity loss calls for good chemistry know-how and experience. Newer industrial setups apply recycling techniques to drive down cost and waste, reclaiming excess reactants where possible and reducing the sulfate burden in effluents, a real concern for both regulatory and environmental performance.
This compound stands out for its versatility in industrial reactions. As an intermediate, it undergoes diazotization, coupling with aromatic amines or further sulfonation. The phenolic OH lends itself to etherification, esterification, and oxidation—reaction types valuable in creating specialty dyes, optical brighteners, and stabilizers. It takes seasoned chemists to tune the process and avoid over-sulfonation or unwanted side-reactions—problems that not only waste raw materials but risk unwanted color formation in the final application. Years in the lab have shown me the difference that careful solvent choice and reaction monitoring make; even a small variation in water content or pH can nudge the outcome one way or another.
In catalogs, it runs under names like sodium p-hydroxybenzenesulfonate, sodium p-phenolsulfonate, or simply sodium phenol sulfonate. English translations of German or French trade names sometimes pop up, a holdover from the days when much of the chemical industry literature ran through European houses. Practitioners check the full chemical name, molecular formula (C6H5NaO4S·2H2O), and CAS number to avoid costly mix-ups with other sulfonates—something that can plague even seasoned procurement officers if due diligence slips.
Handling sodium 4-hydroxybenzene sulfonate dihydrate means respecting basic hygiene and PPE—dust mask, goggles, gloves. The material isn’t known for severe toxicity, but repeated skin or eye contact raises irritant concerns. Facilities choosing to take up this compound in bulk should invest in dust extraction systems, clear spill protocols, and training for batch operators. Material Safety Data Sheets urge attention to good housekeeping and careful storage. Regulatory agencies track its use, so ongoing staff education around labeling changes, Global Harmonized System codes, and emergency response is not optional.
Dye manufacturing leans heavily on this material, especially in synthesizing azo and sulfur dyes. Its chemical behavior determines brightness and washfastness in finished textiles. Beyond dyes, sodium 4-hydroxybenzene sulfonate shows value in water treatment, functioning as a dispersing agent, preventing scale, and helping stabilize metal plating solutions. It finds its way into photographic developers, rubber compounding, and as a standard in analytical chemistry labs. Each of these uses profits from its stability, solubility, and controllable reactivity, especially in demanding industrial workflows where downtime translates to immediate cost. My own years in a lab setting taught me that swapping in a lesser sulfonate almost always raises complications—whether incomplete reaction, residue, or inconsistent end product.
Intensive R&D, especially from the late 20th century forward, sought to unlock better ways to integrate phenolic sulfonates into large-molecule structures. Improving functional dye classes, creating safer photochemicals, and developing greener surfactant systems all brought innovation. Variables like reaction temperature, time, and catalyst selection got scrutinized to ensure both efficiency and minimal waste. Green chemistry principles continue to reshape how production manages byproducts and energy use. On the application front, researchers look to embed these molecules into novel polymers, electronics, and even as charge-balancing agents in electrochemical sensors. Advanced chromatography and spectroscopy techniques let chemists map purity and molecular structure more accurately than ever before, helping manufacturers build more efficient processes.
Longstanding safety data, especially from industrial epidemiology studies, point to moderate irritant effects. Acute toxicity remains low, but animal tests and accidental exposure have shown repeated, high-dose contact should be prevented to avoid chronic symptoms. Environmental fate studies show high solubility makes it mobile in water; UV resistance means little natural breakdown. This calls for tight controls in effluent streams, as persistent organics can accumulate. Hazard assessments by bodies like ECHA and EPA inform permissible exposure limits and waste management standards. Proper worker training, air monitoring, and use of scrubbing systems limit risk. Toxicology labs regularly re-examine these materials as regulations change, using animal-free testing and in vitro methods where possible, underscoring the mix of ethical science and practical oversight.
The drive toward sustainable chemistry will push sodium 4-hydroxybenzene sulfonate producers to lower energy input, reduce waste, and tighten emissions. Researchers in large companies and universities study ways to engineer the molecule for better performance in electronics, coatings, and high-value polymers. As textile and pharmaceutical industries shift to water-based processes, the need for stable sulfonates with minimal side effects will only grow. Technology like real-time spectroscopic monitoring could improve response to process variation, resulting in fewer off-spec batches. Green chemistry, regulatory pressure, and rapidly shifting application needs blend to keep innovation alive, while the dependable old molecule carries its decades-long tradition forward into new territory.
Sodium 4-hydroxybenzene sulfoate dihydrate usually doesn’t turn heads outside chemistry circles, but it deserves a closer look. I’ve mixed and measured more bench chemicals than I can count, and some like this one stand out for how often you find them behind the scenes in big industries. The compound’s specialty comes from its structure, combining the aromatic ring of phenol with sulfonate and sodium, making it water-soluble and reactive in particular settings. Scientists and engineers don’t pick it by accident; they want its sulfonating power and stability in water-based systems.
My first introduction to this chemical happened in a textile dyeing lab. The staff relied on this ingredient to synthesize dyes, notably azo dyes, which color fabrics and even food products. The sulfonate group helps keep the dye molecules dissolved and evenly spread in water, so colors come out bright and consistent. For anyone with a chemistry set and some experience staining cloth, this makes all the difference between faded, patchy shirts and vibrant, uniform results. The global market for synthetics like these is huge—textiles, leathers, printing inks—all draw on such stable dye intermediates. The European Food Safety Authority has even looked at dye byproducts for food safety, reflecting how this chemistry reaches far beyond textiles.
Medicine cabinets around the world lean on this compound, though it rarely shows up in the ingredients list. Many times, chemists start with sodium 4-hydroxybenzene sulfoate when building antibiotics and sulfa drugs. It gives manufacturers a solid, reproducible starting point for their syntheses—something I’ve learned provides huge benefits for quality control in pharma. Leading pharmaceutical journals discuss the role of these aromatic intermediates in safe drug formulation, citing improvement in stability or easier purification. These use cases stress the value of traceability and documented sourcing, issues underlined by both FDA and WHO guidelines.
Not every application involves large marketplaces. In analytical labs, sodium 4-hydroxybenzene sulfoate serves as a reagent for producing standards, like in water testing or other analytical chemistry methods. Research papers mention it when describing methods for detecting trace metals or validating chromatography systems. Over the years, I’ve learned that labs tend to choose reliable chemicals like this to reduce background noise in measurements, which directly impacts public health data accuracy.
Another surprising space: photography. Black-and-white photo development has relied on sulfonate additives to improve contrast development and reduce blemishes. Old-school hobbyists and industrial imaging teams alike value this chemical for its ability to boost image clarity without causing unpredictable reactions.
Like many industrial chemicals, the story doesn’t end at the factory or lab bench. Manufacturing, transporting, and disposing of sodium 4-hydroxybenzene sulfoate carry environmental and safety risks. This is no trivial detail. Case studies from the European Chemicals Agency (ECHA) show the importance of managing spills and keeping wastewater treatment standards high. I’ve seen too many sites cut corners in labeling and hazard communication, only to pay for it with contaminated water or unnecessary exposure. Regulatory agencies continue to push for more transparent documentation and responsible use. As a chemist, I value these checks: clear hazard summaries, traceable supply chains, honest risk assessments. It’s not just red tape—it’s about stewarding resources well and protecting people.
Sodium 4-hydroxybenzene sulfonate dihydrate comes with the formula C6H5NaO4S·2H2O. The heart of this compound sits in its aromatic ring, with a sulfonate group and a hydroxyl snuggled onto the benzene ring. You’ll spot the sulfonate group at the fourth carbon, opposite the hydroxy group—setting up a structure that pushes the boundaries of both water solubility and chemical versatility. Two water molecules bond with each unit, shifting physical properties and fine-tuning the way this compound interacts in solution.
Growing up in neighborhoods dotted with textile mills, I saw chemistry weave into daily life. Many forget just how chemicals like this shape industries, from dyes to cleaning agents. Sulfonated aromatic compounds, including sodium 4-hydroxybenzene sulfonate dihydrate, play serious roles in textile coloring and water treatment. The presence of sodium boosts its solubility, keeping everything free flowing and dissolvable, whether it’s synthesizing reactive dyes or helping move pollutants out of water.
Looking at numbers from the Integrated Pollution Prevention and Control (IPPC) Bureau, textile finishing remains a top water consumer, dumping thousands of tons of dye effluent every year. Getting the right chemicals into the process helps make cleanup more efficient and sustainable. That’s where water-loving molecules such as this one turn out indispensable.
No synthetic journey, small-scale hobby or factory-level, escapes debates about chemical handling. This compound deserves respect, both for its sodium content and the sulfonate group. Solid gloves, good ventilation, and careful storage avoid most trouble. Toxicology databases say sodium 4-hydroxybenzene sulfonate shows low acute toxicity; drift from spills gets handled with proper containment. From my college lab years, no mishap stirs up anxiety faster than sulfur-based compounds hitting wet floors.
Sourcing always traces back to reliable suppliers. The American Chemical Society maintains clear lists to cross-check certifications or purity levels. Trace contaminants mess up results—so quality assurance matters.
Beneath its long name, sodium 4-hydroxybenzene sulfonate dihydrate enables greener chemistries. Green chemistry circles explore how renewable feedstocks and closed water cycles could replace more hazardous routes. Europe’s REACH regulations put the squeeze on persistent, harmful chemicals, steering more demand to water-soluble, less toxic options such as this one.
Switching over to these alternatives can trim industrial waste and offer downstream benefits far beyond the lab bench. Investment in recycling, worker training, and innovative product design will map out cleaner, safer futures for communities neighboring chemical plants.
Better labeling and safer packaging drop accident rates in handling and transportation. Sharing real-world feedback between researchers and manufacturers tightens each step, from raw material imports to finished formulations. Policymakers can incentivize best-in-class chemistry—those that deliver function but keep environmental impact in check.
Everyone—scientists, regulators, community members—has a stake in these choices. Real reform comes through clearer communication, steady investment, and honest risk reporting. That approach honors both the power and the limits of chemistry, keeping people and the planet safe while shaping progress.
Anyone who’s ever worked with chemicals knows there’s no room for shortcuts. Whether you’re a chemistry teacher, a research assistant, or a hobbyist chasing a new project, the name of a substance can spark a mix of bravado and anxiety. Sodium 4-hydroxybenzene sulfoate dihydrate doesn’t look scary on paper. In the bottle, it’s just a powder, not unlike many others that end up in glass vials on science shelves. But personal experience and available toxicology data keep reminding me that the “safe” label never means “ignore the risks.”
This substance pops up in dye synthesis, pharmaceutical research, and analytical reagents. Manufacturers assign it a safety data sheet for a reason: accidental exposure happens, even when folks don’t mean it. The data points out that swallowing it brings some toxicity. Spill it on your skin or splash it in your eyes, and irritation can follow. The risk of inhaling the dust is real, causing coughing or respiratory discomfort for some people, especially when ventilation is lacking.
No chemical gets a pass just because it hasn’t triggered a national scandal. Just because science hasn’t recorded massive health issues from small exposures doesn’t mean no risks sneak in. Several years spent in research labs taught me to treat every white powder with healthy respect, even if colleagues brush it off as “not particularly hazardous.” Minor accidents—such as leaning across a bench too quickly and ending up with itchy hands—prove that complacency will always cost you.
Lab professionals train for a reason. They don gloves and splash goggles for reasons that go far beyond following the rules. Chemical safety relies on more than reading the fine print. Experience—like wiping up a careless spill—teaches faster than a handbook. Sodium 4-hydroxybenzene sulfoate dihydrate will irritate skin and eyes. Regular gloves keep you out of trouble, and fume hoods or open windows make a difference. Respirators usually stay in the cabinet, but local rules may call for one during larger tasks. Eyes unprotected in a lab full of glass? That always sounds like a recipe for regret.
Maintaining good ventilation in the workspace helps. I once worked with a team where ignorance of simple lab ventilation led to several trips to the nurse. Now, I open windows or turn on blowers without thinking twice. Chemical hygiene means immediate cleanup, careful labeling, and knowing emergency procedures. Most folks forget that hand-washing saves more skin than any fancy coating on gloves.
Reliable safety practices come from experience and training—never from copy-pasting digits off safety sheets. The ECHA (European Chemicals Agency) catalogues risks and offers precautions, focusing on what science and accidents have revealed. And science keeps learning. Universities, schools, and companies have a duty to keep those who mix, pour, and measure safer than the textbooks alone suggest. In the end, people—not policy—prevent the real accidents.
Leaving chemicals in the open, skipping gloves, or pretending experience trumps basic rules—none of these old habits belong in a modern lab. No one enjoys chemical exposure, no one brags about injuries, and everyone counts on colleagues who care enough to watch out for the basics. For sodium 4-hydroxybenzene sulfoate dihydrate, as with most chemicals, smart habits beat bravado every time.
Anytime people handle specialty chemicals like Sodium 4-Hydroxybenzene Sulfoate (dihydrate), the first thing that comes to mind is safety. Risks sneak up on anyone who lets their guard down. This compound pulls in moisture from the air, so leaving a bag open on the shelf turns powder to sludge in no time. I’ve seen this happen in labs and small production rooms where someone underestimated just how quickly air can ruin an entire batch. Decent storage spans more than tossing a container onto a warehouse shelf.
From years working around bench chemistry, I’ve learned plastic containers with tight lids make life easier. This compound doesn’t play nice with cardboard sacks or leaky bottles. A high-density polyethylene drum or jar keeps humidity from creeping in, especially if workers close everything right after each use. I’ve done spot checks in cramped academic labs—where an extra hour left open meant chunks forming in what used to be a free-flowing salt. That’s a headache for anyone measuring out quantities later.
Humidity and heat speed up breakdown. Sodium 4-Hydroxybenzene Sulfoate (dihydrate) handles room temperature just fine, but things can go sideways in summer or in tropical warehouses. If the place feels muggy, crystals clump and lose precision in dosing or mixing. Sunlight does no good either. I always push for storage rooms to stay out of direct sunlight, ideally at a constant temp, and with dehumidifiers running when possible. These steps helped me cut down on product loss, keep inventory accurate, and avoid expensive disposal costs.
In shared research spaces, I’ve run into containers labeled in smeared marker or nothing at all. A proper label showing full chemical name, hazard info, and opening date makes sharing safer. Accidental swaps can lead to ruined experiments or dangerous reactions. Clear, durable labels and a chemical logbook keep these mix-ups from happening. That’s saved more than one graduate student’s project.
Some folks pack all their solids onto one rack. Big mistake, if you want to avoid chemical surprises. Sodium 4-Hydroxybenzene Sulfoate (dihydrate) mixes best with itself, not with acids, bases, or other active agents stored nearby. Spills and fumes happen, so a shelf dedicated just to compatible compounds cuts risks. OSHA and other regulations point out the importance of not letting incompatible chemical families cozy up. I’ve witnessed a minor acid leak destroy packs of sensitive salts, leading to both financial and safety headaches.
Most labs and small plants have rules. What keeps everyone honest isn’t just rules; it’s habits and a sense of duty to coworkers. The most trustworthy setups I’ve seen involve regular, simple training—reminding people why they seal up the jar, sweep up spills, and keep chemicals in their zone. Quick walk-arounds two or three times a week prevented accidents on my watch.
If space is tight, small investment in airtight secondary bins or a dedicated cabinet offers big returns in longevity and consistency. Dataloggers help track room conditions, alerting the team before humidity spikes. Old hands pairing up with newer staff to check on storage areas helps everyone learn and stay sharp on the basics. These small, steady improvements beat big, expensive fixes down the line.
In the end, storing Sodium 4-Hydroxybenzene Sulfoate (dihydrate) safely comes down to a mix of common sense, respect for the material, and consistency in daily habits. It’s not about high-tech solutions, but about people caring enough to pay attention.
Sodium 4-hydroxybenzene sulfonate dihydrate holds a spot in labs, manufacturers’ inventories, and even high school chemistry classrooms. It appears as a white or off-white crystalline powder that almost looks like sugar but doesn’t dissolve in your coffee cup the same way. This chemical finds use in everything from dyes to pharmaceuticals, and anyone who has spilled some knows it clumps just a little in the air, especially with a bit of humidity.
The powder form is one of the features that make it easy to handle—scooping, measuring, transferring all go smoother compared to sticky or oily chemicals. In my time working with powdered reagents, the minute grit and how it settles on a spoon or creases along the fold of a weigh boat gives clues about its crystallinity and moisture content. Sodium 4-hydroxybenzene sulfonate dihydrate comes as fine, free-flowing crystals, not granules or lumps.
This compound dissolves quickly in water, leaving behind a clear solution. If you’ve ever made a solution for calibration or a reaction, you’ll notice the powder sinks and vanishes without residue. Solubility simplifies cleanup and guarantees even distribution, an advantage in both industrial and research settings. Unlike some stubborn powders, every last bit gets taken up by water, which points to a solid job by the chemists who synthesize and purify it.
You won’t catch much of a scent when handling the powder. A quick sniff above the container comes back clean, so you don’t deal with nauseating or harsh fumes. White color with a slight cream hue helps spot any contamination or degradation by eye. I’ve always valued that—clear color means less guesswork when storing and using chemicals.
Dihydrate means there’s water locked into every molecule, but it doesn’t mean it soaks up gallons of humidity from the air. Still, given enough time in a humid storeroom, clumping can show up. Keeping containers firmly sealed and stored in a dry cabinet slows down that process. Anyone who’s worked in a basic lab knows the struggle with powders that cake together, and while this compound doesn’t do it as badly as others, a little care always pays off.
Sodium 4-hydroxybenzene sulfonate dihydrate melts in the 100–106°C range, where dihydrate water gets released, and the powder turns into a syrup. Heating beyond that, as you might do for drying or decomposing, gives off further signs—water vapor first, some browning with more heat. In my experience, a slow, even temperature rise avoids splattering and surprises, especially if the sample sits in a delicate glass dish.
The lack of irritating dust or strong odor makes handling safer, but using gloves and a dust mask stays good practice. Eye protection remains essential. Curiosity gets the better of folks sometimes, but long sleeves and care reduce the chances of an unexpected rash or spill.
These physical characteristics define how you store, transfer, and use this compound. If a chemical clumps or refuses to dissolve, wasted time follows, and experiments run off track. Good handling and care in the lab protect both people and the reliability of every test or product made with this stuff. Sticking to dry storage, quick resealing, and gentle handling keeps the material ready for action without a hassle.
| Names | |
| Preferred IUPAC name | sodium 4-hydroxybenzenesulfonate dihydrate |
| Other names |
Sodium p-hydroxybenzenesulfonate Sodium 4-hydroxybenzenesulfonate Sodium parahydroxybenzenesulfonate 4-Hydroxybenzenesulfonic acid sodium salt dihydrate Sodium sulphoxyquin Sodium PHBS dihydrate |
| Pronunciation | /ˈsəʊdiəm fɔːr haɪˈdrɒksiˌbɛnˈziːn ˈsʌl.foʊ.eɪt daɪˈhaɪdreɪt/ |
| Identifiers | |
| CAS Number | 15708-41-5 |
| Beilstein Reference | 120914 |
| ChEBI | CHEBI:91237 |
| ChEMBL | CHEMBL2103838 |
| ChemSpider | 159482 |
| DrugBank | DB14057 |
| ECHA InfoCard | 03f8be8f-1c2a-45bd-9e7a-ab82b1f34570 |
| EC Number | 240-112-0 |
| Gmelin Reference | 71633 |
| KEGG | C01761 |
| MeSH | D015547 |
| PubChem CID | 159217 |
| RTECS number | DJ7876000 |
| UNII | 46Q15P2S47 |
| UN number | UN3077 |
| Properties | |
| Chemical formula | C6H5NaO5S·2H2O |
| Molar mass | 282.21 g/mol |
| Appearance | White crystalline powder |
| Odor | Odorless |
| Density | 1.425 g/cm3 |
| Solubility in water | Soluble in water |
| log P | -3.4 |
| Acidity (pKa) | 10.3 |
| Basicity (pKb) | 7.18 |
| Magnetic susceptibility (χ) | -51.0e-6 cm³/mol |
| Refractive index (nD) | 1.540 |
| Dipole moment | 7.35 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 239.0 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -1124.92 kJ/mol |
| Pharmacology | |
| ATC code | A16AX31 |
| Hazards | |
| Main hazards | Harmful if swallowed. Causes serious eye irritation. Causes skin irritation. |
| GHS labelling | GHS07, GHS09 |
| Pictograms | GHS07 |
| Signal word | Warning |
| Hazard statements | H319: Causes serious eye irritation. |
| Precautionary statements | Precautionary statements: P261, P280, P305+P351+P338, P337+P313 |
| NFPA 704 (fire diamond) | 1-0-0 |
| Flash point | > 174.8°C |
| LD50 (median dose) | LD50 (median dose): >2000 mg/kg (Rat) |
| PEL (Permissible) | PEL: Not established |
| REL (Recommended) | 0.05∼0.5% |
| Related compounds | |
| Related compounds |
Sodium benzenesulfonate Sodium p-toluenesulfonate 4-Hydroxybenzenesulfonic acid 4-Hydroxybenzoic acid Potassium 4-hydroxybenzenesulfonate |
