P-Xylenesulfonic acid appeared in chemical literature during the rise of sulfonation chemistry in the twentieth century. Early patents focused on introducing the sulfonic acid group to aromatic hydrocarbons, as manufacturers needed stronger acids for dye intermediate production and polymer chemistry. This compound filled a niche in making surfactants and helped shape detergent chemistry. Labs in Europe and North America invested time figuring out how to improve yield, minimize byproducts, and recycle spent acids. Synthetic methods grew more efficient with each decade, and engineers handled larger batches as commercial demand increased. Across industries, the acid became common as companies searched for sharper methods to introduce sulfonic groups on benzene rings. By the mid-to-late 1900s, books and handbooks listed it as a robust option for chemical modification workhorses.
Commercial p-xylenesulfonic acid shows up as a white to slightly beige powder or, less often, as a semi-crystalline solid. Bulk buyers prefer high assay and low water to cut down waste. The powder dissolves in water quickly, freeing the sulfonic acid group for its key role as a strong acid and catalyst. In specialty chemicals and intermediate production, this compound fits well because it handles temperature swings during manufacturing, unlike some weaker acids which decompose or trigger nasty side reactions.
This compound falls under aromatic sulfonic acids, with a molecular weight around 186 g/mol. Typical samples show melting points close to 110°C, but water uptake can knock that down. Handling reveals a non-volatile, non-flammable substance, but watch for its corrosive bite. Strong solubility comes from the powerful sulfonic acid group, which grabs onto water, alcohols, and some polar solvents. Heat doesn’t make it burn, but temperatures above its melting point and overexposure do lead to darkening and degradation. It does not emit funny smells or fumes under standard lab conditions but reacts vigorously with strong bases and mild oxidants. Its stability makes it a trustworthy acid for both routine bench chemistry and larger industrial operations.
Factories selling p-xylenesulfonic acid grade their product by purity, residual xylenes, moisture, and heavy metals. Certificates of analysis lay out batch data for these markers. Labels warn of the corrosive risk, wearing gloves and splash goggles while handling. Safety Data Sheets flag its environmental hazards and hazardous waste considerations. Workers in storage and shipping look for sealed, moisture-proof bags or drums, always marked with hazard pictograms and transport codes. Regular training and record-keeping prevent mix-ups and trace back any shipment in case of a recall. These steps trace their roots from international chemical safety agreements as much as plant-level responsibility.
Most plant chemists prepare p-xylenesulfonic acid by sulfonating p-xylene with sulfuric acid or oleum. Heating the mixture between 70°C and 120°C gives sulfonation in the para position. Side products, like ortho-xylenesulfonic acid or multi-sulfonated xylenes, require fractional crystallization or filtration to purify the final product. Some prefer a two-step method, isolating the sodium salt by neutralization, then converting it to free acid by acidification. Manufacturers sometimes recycle sulfuric acid from the mother liquor, reducing sampling costs and environmental impact. Water removal and drying present hurdles, as the final acid absorbs water from air, sometimes degrading its shelf life or lumping in storage.
The robust sulfonic group on p-xylenesulfonic acid opens up many reaction options. Neutralization with alkali bases like sodium hydroxide forms the sodium salt, often used for water treatment or dye manufacturing. Organic chemists use it as a strong acid catalyst in esterification and dehydration reactions, especially when they want to avoid mineral acids that cause charring or side-products. In some labs, it works to do further substitutions on the benzene ring under controlled conditions. Under oxidative conditions, xylenesulfonic acids can convert into more complex sulfur-containing aromatic sulfonates important in surfactant research. The acid also takes part in trans-sulfonation reactions, trading sulfonic groups among aromatic rings to fine-tune surfactant properties.
Trade and scientific literature use several names for this acid: para-xylenesulfonic acid, 4-xylenesulfonic acid, and p-toluenesulfonic acid’s dimethyl homolog, depending on context or naming traditions. Some suppliers use abbreviations, such as PXS acid or PXSA, which echo global trends in lab shorthand. Each name ties back to the parent xylene structure, with ‘para’ or ‘4-’ indicating the position of the sulfonic acid group relative to the methyls on the benzene ring. Listings in specialty chemical catalogs or procurement databases let users cross-check synonyms and avoid order mistakes.
Operational safety draws on years of industrial experience. This acid causes severe burns on contact with skin and eyes, so workers put on chemical-resistant gloves, face shields, and proper coveralls before opening bags. Its dust irritates the nose, meaning engineers fit extraction hoods and fine particle masks in filling rooms. Extended exposure to mist or dust raises concerns for airway inflammation, demanding proper ventilation and routine health checks. Companies report all incidents, including minor spills, and run regular drills for containment and disposal. Neutralization with dilute sodium carbonate or calcium hydroxide provides a straightforward way to handle disposal, but all waste routes need careful control to avoid water contamination. Manufacturers reaching into food or cosmetic ingredient supply chains test and certify for ultra-low heavy metals, dioxins, and persistent organic pollutants. Training new staff centers on safe stowage, reading hazard labels, and speedy response to splashes or leaks, driven as much by company pride as regulatory pressure.
Industrial chemistry leans on p-xylenesulfonic acid in a surprising range of applications. The detergent industry uses its sodium salt as a starting material for anionic surfactants. Dyes and pigments, which demand tight control on molecular structure, benefit from it as a sulfonation agent and intermediate. In polymerization tasks, this acid serves as a catalyst to drive esterification, polyester, and alkyd resin reactions. Laboratories that study aromatic substitution count on it for introducing sulfonate groups in aromatic rings, creating new chemical libraries for drug and material screening. Wastewater treatment outfits sometimes use xylenesulfonates to bind up heavy metals. Paper and pulp mills apply the acid for modifying lignin and improving pulp yield. Even in electroplating, its ability to form stable complexes comes in handy, leading to smoother metal deposits and longer bath life.
R&D labs view p-xylenesulfonic acid as both a building block and a probe for mechanism studies. Synthetic organic chemists use it to explore new catalysts for green chemistry, looking to replace strong mineral acids with solid or recyclable acid catalysts inspired by the sulfonic group. Material scientists create modified polymers by post-sulfonation of aromatic backbones, seeking membranes and resins that withstand heat and acids. Analytical chemists test its ability to act as a counterion in chromatography and separations. Drug discovery teams employ the compound to build libraries of sulfonated aromatics, testing for enzyme inhibition, antibacterial and anti-inflammatory properties. Academic groups network with industry in search of easier, cleaner sulfonation processes and scale-up routes that reduce hazardous waste. The structure makes it a recurring benchmark for comparing new sulfonation methods in journals and technical conferences.
Toxicology reports show this acid does not rate as highly acutely toxic, but it remains corrosive after skin or eye exposure. Inhalation of high dust concentrations can irritate or burn mucous membranes. Chronic studies in rodents do not suggest significant long-term systemic toxicity, but repeated exposure causes local tissue damage. Environmental monitoring flags risks of aquatic toxicity if large spills hit waterways, since the sulfonic group increases bioavailability for some aquatic organisms. Labs involved in safety evaluation run OECD-standard tests on biodegradability, aquatic toxicity, and soil mobility. Some researchers track breakdown products in advanced water treatment systems, keeping tabs on ecological impact. Most safety advice boils down to barrier protection during handling, local containment where breakdown is slow, and quick neutralization of spills.
Looking ahead, the field expects more use of p-xylenesulfonic acid analogs in eco-friendly catalytic applications, particularly where recyclable and low-waste acids can replace mineral acids. Demand for new surfactants—especially those that break down safely—fuels ongoing research, where this compound serves as a crucial intermediate. Cleaner, less energy-intensive production methods hold promise, as industries push for zero-waste and circular chemical loops. Electrochemistry and energy storage projects look at sulfonated aromatics for conductive polymers and salt exchange membranes. Regulatory bodies want tighter controls on byproducts and lower exposure thresholds for all aromatic sulfonates, which steers R&D into new purification technologies and life-cycle assessments. Sharing data and standardizing testing across borders will help the industry keep pace with green chemistry expectations, stretching the basic chemistry roots of p-xylenesulfonic acid into new, unexpected territories.
P-Xylenesulfonic acid brings more than a mouthful of syllables—it's a specialty chemical. This compound works in all sorts of chemical settings because it’s strong and reliable as a sulfonating agent. Laboratories and factories both rely on it for its ability to transfer sulfonic groups into other molecules. Anyone who’s ever witnessed a batch chemical process will recognize the need for efficient reactions and minimal waste. That’s what makes this acid pop on the shelf for chemists and manufacturers alike.
You’ll find p-xylenesulfonic acid participating in sulfonation reactions, which show up everywhere from plastics to specialty dyes. In the dye industry, this acid turns molecules more water-soluble so they bond better with fabrics. Clothing colors stick longer and keep brightness through more laundry cycles. Plastic manufacturers handle this acid to make high-performance materials you find in electronics, bottles, and even your kitchenware. Its role isn’t flashy, but without it, many products would fall short in quality or performance.
P-Xylenesulfonic acid steps up as a catalyst too. Catalysts speed up chemical reactions and, in industrial settings, time really does mean money. This acid’s strong ability to donate protons lets it push forward a range of organic transformations. That’s especially important for pharmaceuticals. In my college lab days, synthesis often slowed to a crawl without the right acidic catalyst. With p-xylenesulfonic acid in the mix, conversions picked up, leading to better yields and purer final products. The same holds true at scale in pharmaceutical plants, where each percentage point gained in efficiency equals lower costs and fewer resources wasted.
This compound doesn’t stay locked up in labs or factories. It shows up in water treatment, helping to break down stubborn organic pollutants. By using p-xylenesulfonic acid, treatment plants reduce tough-to-remove substances far faster. The ability to knock out these pollutants means cleaner drinking water communities count on. Public health experts point to sulfonic acids like this as useful tools in the ongoing fight against contamination, especially as regulations get tougher and detection equipment grows more sensitive.
Handling p-xylenesulfonic acid comes with real safety challenges. Like many strong acids, it’s corrosive. It needs secure handling and proper gear to avoid burns or contamination. Sustainable manufacturers focus on reducing byproducts and keeping emissions low. The global chemical industry has moved toward greener chemistry principals. I’ve seen newer factory lines where engineers design processes to keep acids like this one contained and reused as much as possible. Recycling minimizes harm and keeps regulatory authorities from knocking on the door.
Demand for products built to last means chemical processes aren’t fading anytime soon. Still, the push toward safer and more efficient systems grows stronger each year. Chemists design new routes to achieve the same results with less waste, leaning on the reliability of classic acids but keeping an eye on their environmental footprint. P-xylenesulfonic acid stands as a reminder that one compound, used thoughtfully, can help bridge present-day industry with a cleaner, safer future.
P-xylenesulfonic acid, with the chemical formula C8H10O3S, stands out in organic chemistry circles. Its structure borrows from the aromatic hydrocarbon p-xylene, but with a sulfonic acid group attached. I’ve seen folks brush past the importance of knowing these formulas, especially once you move past undergraduate labs, but it pays to get familiar with what such a formula tells you.
To break it down, p-xylene forms the backbone with two methyl groups on opposite sides of a benzene ring. Sulfonation switches the game: introduce a sulfonic acid group, and the molecule’s chemical behavior takes a sharp turn. This formula does more than check a box—it reflects a new set of properties and potential risks.
Consider quality control, chemical safety, and research. In my lab years, I learned that a wrong assumption about a chemical’s structure could trigger headaches—equipment corrosion, unexpected reactions, or safety threats. With C8H10O3S, you understand the acid’s strength, solubility, and reactivity. That has ripple effects whether you’re working in an industrial setting, an academic lab, or teaching students chemistry fundamentals.
Process safety links directly with molecular structure. Mishandling sulfonic acids can lead to burns or environmental contamination. Mistakes pile up when details like the formula get overlooked. If you’re mixing, storing, or disposing of it, knowing the formula stops you from treating it like simple p-xylene or confusing it with another sulfonic acid. Those aren’t just theoretical risks—I’ve seen companies swallow financial hits after warehouse fires or contaminated wastewater slipped through due to basic chemical misunderstandings.
P-xylenesulfonic acid finds use as a catalyst, often in organic synthesis, including making pharmaceuticals, dyes, and resins. Its acidity comes from that sulfonic group. Lab experiments get predictable only with correct, detailed knowledge of the molecules involved. The formula lets chemists calculate exact quantities, measure pH, or anticipate by-products. It’s not enough to know a “sulfonic acid” is involved—each sulfonic acid has its own quirks. C8H10O3S signals more than a label; it’s a set of instructions and warnings rolled into one.
On another note, environmental health regulations get stricter every year—a trend I’ve watched accelerate. Trace amounts of industrial chemicals keep showing up in groundwater. Accurate recordkeeping and identification can’t happen without the right formula. Authorities tracking pollutants or accidental spills need unambiguous data to inform cleanup and safeguard public health. The wrong chemical formula on a shipping manifest or regulatory document leads to confusion, fines, and sometimes lawsuits.
A straightforward move is training: chemistry education has to stay current, reaching beyond rote memorization. I’ve seen seasoned technicians struggle with new chemicals because they learned a shortcut a decade ago that no longer fits the updated regulations. Good reference materials help too. Digital databases with reliable chemical structures cut down mistakes. Yet, it’s the culture in workplaces that seals the deal—places that encourage asking for clarification, sharing accurate data, and double-checking formulas create safer spaces for everyone.
Getting specific with chemical formulas like that of p-xylenesulfonic acid isn’t about pedantic detail—it’s about keeping science, industry, and the public safe and informed. In chemistry, precision builds trust from the lab bench all the way to the water table.
Some chemicals just demand respect. P-Xylenesulfonic acid definitely deserves its own set of rules. Anyone who’s spent time around labs or chemical plants knows a slip-up during storage can cause headaches, lost money, ruined equipment, or worse. P-Xylenesulfonic acid often comes into play in organic synthesis and dye production. It is a strong acid and as unassuming as it may look at first glance, it brings real risks if stored with a casual attitude.
P-Xylenesulfonic acid has a punch. It causes corrosion on contact—both to people and to the wrong storage vessels. Even just a little humidity can trigger reactions inside a poorly sealed drum. The acid lover in me sees this as an invitation to disaster. Vapors irritate the respiratory tract, and direct skin contact can cause burns. Even seasoned chemists get caught off guard sometimes, especially when busy hands get a bit careless.
The first thing any company or researcher should know: this acid reacts strongly with bases, strong oxidizers, and water. Store it with the wrong chemicals and you can get fires or toxic fumes in return. That’s not a risk worth taking for the sake of convenience.
For years, I have seen good intentions undone by cheap containers or storage shortcuts. Skip the overused shelves and opt for heavy-duty, corrosion-resistant containers—high-density polyethylene or glass work well here. Metal drums almost always end up pitted and leaky after a while, even with coatings. The container’s seal needs to be tight every time. Moisture sneaks in quickly in a humid warehouse, leading to dangerous clumping or leaks.
Always store p-xylenesulfonic acid away from sunlight and away from heat sources. Even a little bit of light can degrade some acids, and an overheated room speeds up unwanted reactions. Store in a well-ventilated, cool, dry space, with signs warning about the acid’s hazards. Some facilities mark separate sections just for corrosive acids. This step isn’t overkill—it’s a basic layer of defense.
Never line up acids next to bases. Someone will eventually mix them, usually after a long shift or a distraction. Separate chemicals by family and label shelves clearly. The best storerooms use spill containment trays. If a bottle tips or a cap leaks, a few milliliters stay put instead of soaking through cardboard or right onto someone’s shoes.
All storage rules fall flat if people ignore them. Ongoing staff training pays for itself. I remember one plant where repeated safety walkthroughs finally curbed a string of accidental exposures. Personal protective gear—acid-resistant gloves, goggles, proper aprons—should stay within reach, not across the corridor or under a pile of paperwork. Emergency eyewash and showers should not be optional, especially if large containers come into play in a facility.
Check storage regularly. A scheduled inspection routine catches cracked seals or loose lids before an accident forces a shutdown. Use a digital system if you track inventory—a spilled acid or missing drum causes more trouble if you notice only after months roll by. Leaning on guidelines from well-known safety organizations gives any chemical operation a backbone. OSHA, NIOSH, or local regulatory agencies teach with decades of incident data behind their advice.
Anyone working with strong acids learns respect—sometimes the hard way. Good storage practices sound like common sense, but chemical burns and equipment failures prove that reminders never go out of style.
Chemicals can either simplify your operations or send you running for your gloves and goggles. P-xylenesulfonic acid sits in this gray zone for many folks working with dyes, catalysts, and specialty resins. People hear the name, and alarms go off—big words can do that. But looking past the labels helps everyone keep things in perspective.
P-xylenesulfonic acid won’t vaporize into the air at room temperature, which means you’re not going to breathe it in just by being nearby. The trouble kicks in if skin or eyes get splashed; the acid is corrosive. It stings, causes redness, and can damage tissue with enough contact. Swallowing it or getting a good, deep lungful due to mishap could end up being dangerous, just like it would with many other concentrated acids in the workspace.
No one wants a toxic worksite, not even for high-value production. Lab data places p-xylenesulfonic acid in the irritant column, not quite as dangerous as the heavy hitters like sulfuric acid or hydrofluoric acid. That said, repeated exposure over time without protection can lead to chronic skin issues or damage to mucous membranes. Protective clothing does the trick—long sleeves, decent gloves, splash goggles. Workplaces that train their people well can keep accidents close to zero.
Larger spills or routine dumping spell trouble, not because p-xylenesulfonic acid poisons rivers instantly, but because it increases acidity and can upset the balance in local water systems. Aquatic life generally doesn’t appreciate sudden changes in pH. It doesn’t take much to neutralize the acid for waste streams—basic compounds like lime or soda ash get used all the time in chemical treatment plants. Still, any business working with the stuff should speak to local authorities about proper disposal. Stories of “gone down the drain” mishaps make regulators nervous for a reason.
According to the European Chemicals Agency and U.S. EPA, p-xylenesulfonic acid doesn’t rank among the top-tier toxic chemicals. Acute toxicity—the quick, high-impact harm—remains low compared to organophosphate pesticides or industrial solvents like benzene. The biggest hazard comes from people rushing, skipping safety checks, or using busted gear. Cutting down on accidents comes from well-worn habits: test equipment regularly, label bottles, keep eyewash stations clear, and take ten seconds before pouring something out of a drum.
Hazard depends on dose, route of exposure, and how well people actually follow protocols on the floor. I’ve seen more than one warehouse stay accident-free thanks to people knowing what “corrosive” means, not just what’s printed in a bulk chemical catalog. Communication works better than lectures, especially across shifts with changing crews. Clear labels and honest, straightforward training go further than fear-based messaging.
No chemical deserves blind trust, but not every acid should be painted as a monster. We all want products that work and environments where no one ends up hurt, either on the job or in the community nearby. Handling and disposal procedures matter more than the chemical’s name alone. Solid information—not rumor—keeps people from costly mistakes.
P-Xylenesulfonic acid appears in chemical literature more often than many people realize. Some folks remember it from their time in organic chemistry, while others come across it on a chemical supply list. For those new to this compound, p-xylenesulfonic acid combines a benzene ring with methyl groups in the para position and has a sulfonic acid group attached. Chemists care about its properties for catalysis, synthesis, and even environmental science.
The molecular weight often pops up during handling, transportation, and regulatory paperwork. It's not just a number; it can be the difference between a smooth reaction and one that needs rethinking. To get the value, sum the atomic weights of every atom in the molecule. P-xylene includes eight carbon atoms, ten hydrogen atoms, and for the sulfonic acid group, count a sulfur, three oxygens, and an extra hydrogen. The math: 8 x 12.01 (carbon) + 10 x 1.01 (hydrogen) + 32.07 (sulfur) + 3 x 16.00 (oxygen) + 1.01 (extra hydrogen), giving a total near 186.23 g/mol.
More than a trivia question in a textbook, having an exact molecular weight shapes lab work. Chemists develop calculations for molar ratios based on this figure. Suppose too much or too little gets into a reaction; yields slump, costs rise, and sometimes equipment gums up in the process. Reagents like p-xylenesulfonic acid bring acidity that can tip reactions either toward success or failure. I’ve seen shifts in product purity just from small miscalculations tied back to molar masses.
Big industries often scale up reactions that use this compound. A missed decimal point in molecular weight can cost thousands in wasted chemicals and lost batches. Safety data sheets and regulatory filings depend on this number, too. Shipping, storage, and waste handling rules rely on knowing the weight per mole. Even small specialty suppliers invest in up-to-date references for cases like this. Errors seep quickly from a piece of paper to a live process, and that can risk both safety and compliance.
Getting these figures right isn’t only about grabbing numbers from a chart. Typos and old references hang around in handouts and safety protocols. Some older textbooks round atomic weights or drop a decimal. Sometimes people copy formulas wrong, missing a hydrogen or swapping groups without noticing. Scientists double-check structures and calculate using reliable databases like PubChem, Sigma-Aldrich, or peer-reviewed journals.
To avoid problems, double-check calculations with two or more sources. Modern labs use software that shows the structure and calculates molecular weight on the fly. When I prepare a new reagent or review someone’s analysis, I use both printed handbooks and online databases. Training new lab staff includes going through molecular weight checks and error-spotting exercises.
P-xylenesulfonic acid gives a good lesson in paying attention to detail in chemistry. That 186.23 g/mol doesn’t just sit on a label—it shapes the outcome of experiments and ensures all the pieces come together the right way.
| Names | |
| Preferred IUPAC name | 4-methylbenzenesulfonic acid |
| Other names |
Benzenesulfonic acid, 1,4-dimethyl- p-Xylene-4-sulfonic acid 4-Methyl-1,3-benzenedisulfonic acid 4-Methylsulfonate xylene Sulfo-p-xylene acid |
| Pronunciation | /ˌpiːˈzaɪliːnsʌlˈfɒnɪk ˈæsɪd/ |
| Identifiers | |
| CAS Number | 104-79-4 |
| Beilstein Reference | 1760737 |
| ChEBI | CHEBI:52041 |
| ChEMBL | CHEMBL2057320 |
| ChemSpider | 160393 |
| DrugBank | DB03765 |
| ECHA InfoCard | 100.015.682 |
| EC Number | 214-373-8 |
| Gmelin Reference | 8989 |
| KEGG | C12027 |
| MeSH | D011692 |
| PubChem CID | 6927 |
| RTECS number | ZE9625000 |
| UNII | 2V5K6B617F |
| UN number | UN2582 |
| Properties | |
| Chemical formula | C8H10O3S |
| Molar mass | 186.22 g/mol |
| Appearance | White to light yellow crystal |
| Odor | Odorless |
| Density | 1.18 g/cm3 |
| Solubility in water | Very soluble |
| log P | -1.0 |
| Vapor pressure | <0.1 mm Hg (20°C) |
| Acidity (pKa) | -2.5 |
| Basicity (pKb) | 6.52 |
| Magnetic susceptibility (χ) | -69.5×10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.537 |
| Viscosity | 26 mPa·s (25 °C) |
| Dipole moment | 2.07 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 204.0 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -604.2 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -3542.7 kJ/mol |
| Pharmacology | |
| ATC code | C09XA53 |
| Hazards | |
| Main hazards | Causes severe skin burns and eye damage. |
| GHS labelling | GHS05, GHS07 |
| Pictograms | GHS05 |
| Signal word | Danger |
| Hazard statements | H314: Causes severe skin burns and eye damage. |
| Precautionary statements | Precautionary statements: "P260, P264, P280, P301+P330+P331, P303+P361+P353, P305+P351+P338, P310, P321, P363, P405, P501 |
| NFPA 704 (fire diamond) | 3-1-2-Acido |
| Flash point | 138 °C (280 °F; 411 K) |
| Lethal dose or concentration | LD50 (oral, rat): 1000 mg/kg |
| LD50 (median dose) | LD50 (median dose): Oral rat LD50 = 676 mg/kg |
| NIOSH | ZE2450000 |
| PEL (Permissible) | Not established |
| REL (Recommended) | REL (Recommended): 2.5 mg/m3 |
| Related compounds | |
| Related compounds |
Benzene sulfonic acid m-Xylenesulfonic acid o-Xylenesulfonic acid p-Xylene Toluene-4-sulfonic acid |
