People have tinkered with sulfonic acids since the late 1800s, often chasing new ways to tweak molecules for better results in industry and research. Ethanesulphonic acid, coming from a family that includes methane- and toluenesulphonic acid, started turning heads in the 20th century once chemists figured out its knack for acting as both a strong acid and a customer-friendly reagent. This discovery soon rolled into wide-ranging applications, from medicinal chemistry to newer types of industrial catalysts. Over time, as safety standards and regulations matured, producers refined batch purity and minimized by-products–responding to demands for reliable, high-quality reagents. The chemical’s rise often tracks the history of industrial chemistry itself, where folks learned hard lessons about handling, waste reduction, and environmental impact.
At its core, ethanesulphonic acid is an organosulfur compound with the formula C2H6SO3H. In simpler terms, you get a colorless liquid or sometimes a solid, depending on storage conditions. One feature makes it popular: you get strong acidity without catching some of the nasty side effects of mineral acids like sulfuric. It doesn’t corrode equipment quite as fast and slips easily into aqueous (water-based) systems. Ask anyone who works in synthesis or formulations, and you’ll hear how a consistent, high-purity stock means fewer production headaches and more predictable lab results.
On the bench, ethanesulphonic acid shows up as a sturdy liquid, though solid samples are possible under the right conditions. Its boiling point sits around 165°C with some decomposition, and it mixes cleanly with water at all ratios. This makes it a good pick for water-heavy processes. The acid strength is strong (pKa about -1.6 in water), so it can split or rearrange plenty of stubborn molecules. At the same time, its sulfur atom invites a slew of chemical reactions, opening the door for modifications. It doesn’t have a particularly sharp smell, which is a blessing compared to other sulfonic relatives.
Suppliers ship ethanesulphonic acid under a range of purity grades—often 98% or above—depending on who’s using it and where. Drums, jugs, or special containers keep the material stable and dry, with labeling that spells out hazard warnings (corrosive, eye and skin hazard), UN numbers, and conditions for safe shipping. Most bottles sport a batch number, expiration date, and selector charts that tie into compliance systems for tracking purity and regulatory checks. GHS-compliant pictograms stand out, as agencies have cracked down on sloppy labeling and data gaps after high-profile spills and exposure incidents.
Industry routes mostly stick to sulfonation of ethane by oleum or sulfur trioxide in a controlled setting. Unlike old-school processes, today’s setups focus on cleaner conversions with fewer side-products. Some labs prefer to start from ethyl alcohol or ethyl halides, pushing the reaction with concentrated sulfuric acid, then purifying with vacuum distillation. Big plants typically use continuous flow reactors, monitoring temperature, acidity, and by-products in real time to hit high yields. This gives them an edge—it’s about squeezing out the most acid from every batch, skipping multiple washes or reprocessing cycles.
With its strong acid punch and a sulfur center, ethanesulphonic acid steps up for all sorts of transformation jobs in synthesis. It acts as an acid catalyst in dehydration, esterification, and etherification reactions. Folks in medicinal chemistry lean on it when they want to bump up solubility or tweak drug candidates. Chemists use it to make ethanesulphonates, which show up in everything from detergents to drug salts. For more complicated work, the sulfonic group can act as a precursor for further substitution or condensation reactions, so it’s got value both as a raw material and a process tool.
You’ll hear it called various names—ethanesulfonic acid, ethylsulfonic acid, or 1-sulfonatoethane. Some catalogs simply mark it as ESA, mirroring industry shorthand. It’s also coded under CAS number 594-45-6. Companies sell it under branded names too, but the structure stays the same. When comparing sources, what matters is not the brand but the purity, water content, and absence of sulfur compound contaminants. Experienced chemists check the certificate of analysis, not just the price tag.
Touching ethanesulphonic acid without gloves or safety glasses usually ends badly; it eats through skin, burns eyes, and feels just as nasty inside as out. Spills need neutralization with basic solutions and thorough clean-up. Operators keep eye-wash stations and acid-neutralizing spills kits nearby—folks in the chemical industry have seen too many accidents to skip these details. Storage comes down to cool, dry rooms in acid-resistant containers, often lined with compatible materials like Teflon or glass. Workers need real training: how to handle, store, and dispose of it without cutting corners. In some countries, regulatory audits and certifications track every shipment from cradle to grave.
Outside basic research, ethanesulphonic acid shows up in drug manufacturing, as a catalyst in organic synthesis, and occasionally in electroplating baths. It’s valued for producing active pharmaceutical ingredients where strong, non-oxidizing acidity is a must. Pharma companies use it to make ethanesulphonate salts of drugs such as amiodarone, improving solubility and bioavailability. In industrial chemistry, reactors rely on it to drive selectivity or speed in monomer prep or polymerization. Water treatment and detergent industries explore it for sulfonation steps, though cost and safety can slow broader adoption.
Academic labs and chemical producers push for greener routes to make or recycle ethanesulphonic acid. Some are exploring biocatalytic or solvent-free approaches to lower the carbon footprint. Others focus on developing derivatives with reduced toxicity or new performance benefits. Universities also use it as a case study for teaching green chemistry and hazard management, showing students both its potential and pitfalls. Partnerships between companies and research centers sometimes focus on novel applications, like tuning battery electrolytes or targeting specialty polymers.
Toxicologists have tested ethanesulphonic acid in cell cultures and animal studies to get a handle on immediate and long-term risks. Results show it delivers corrosive damage at the point of contact but doesn’t build up in organs or linger in tissues the way some heavier sulfonates do. Regulatory agencies urge precautions, noting that inhalation should be avoided, and accidental spills demand swift action. The push for better personal protective equipment and updated workplace exposure limits started after documentation of chemical burns and respiratory irritation. The material’s strong acidity also calls for careful environmental management; direct dumping into waterways triggers alarms at environmental bureaus worldwide.
Looking forward, the fate of ethanesulphonic acid ties closely to industrial demand for high-strength acids that don’t bring along trace metals or oxidizers. As regulations tighten on pollution and exposure, demand is shifting towards cleaner, more sustainable production. Innovations in continuous processing, recycling, and safer alternatives could redefine how industries rely on it. Pharmaceutical and specialty chemical makers drive most of the market, but new research around battery technologies and renewable energy may expand demand. Public health concerns and sustainability trends keep producers on their toes, pushing for materials that work hard without leaving an environmental mess behind.
Ethanesulphonic acid pops up in a surprising number of labs. Some folks know it as ESA or ethanesulfonic acid. Its main reputation comes from its strong acid properties. In my experience working with chemists, what stands out is ESA’s reliability as a supporting acid for certain chemical reactions where cleaner results matter. There’s something about a strong acid that doesn’t bring extra stuff—unlike sulfuric acid, ESA rarely introduces sulfate contamination. That makes it an easy choice for reactions that can’t risk chemical clutter. Analysts in pharmaceuticals trust ESA when they need to calibrate their instruments for drugs because it offers a buffer that stays stable and consistent.
Pharmaceutical researchers often turn to ethanesulphonic acid during liquid chromatography. I recall sitting in with a friend from a drug testing lab who explained the nuisance of noisy data and unpredictable peaks. ESA brings order to the mix, acting as a buffer in HPLC (high-performance liquid chromatography). For biological samples where even a small shift in acidity can throw the entire test, ESA provides a reliable environment. It holds the pH right on target. That means new medicines get an honest screening and dangerous side effects show up in the data instead of hiding behind chemical noise.
Manufacturers favor ethanesulphonic acid in synthesizing specialty chemicals. Many processes demand acid catalysis, particularly in creating certain dyes, perfumes, and building blocks for bigger molecules. In these moments, ESA becomes the go-to rather than more aggressive or high-maintenance acids. It speeds up reactions without introducing unwanted byproducts. This keeps waste down and product purity on track. If you’ve ever smelled synthetic fragrances or seen brightly colored paints, there’s a fair chance ESA played a part somewhere along the chain.
Fuel cell developers, especially those pushing for cleaner urban transport, also rely on ethanesulphonic acid. Polymer electrolyte membrane fuel cells often incorporate sulfonic acids for safer operation and improved efficiency. ESA meets a need for non-volatile, thermally-stable acids, supporting proton movement across the fuel cell membrane. Teams aiming to replace gasoline engines look to ESA thanks to its reliability at high temperatures and lack of foul-smelling byproducts. For urban buses, forklifts, and backup generators, this means quieter power without extra environmental headaches.
Ethanesulphonic acid brings benefits but demands real respect in storage, handling, and disposal. Its corrosive nature means anyone working with it should take chemical burns seriously and invest in proper protective gear. Waste containing ESA needs careful neutralization—dumping it untreated risks soil and water safety. In practical lab discussions, I’ve seen teams set up strict oversight procedures and reinforce safety training in everyday practice, not as a side note. Companies that treat ESA with care and proper controls help keep people and the local environment out of harm’s way.
Researchers keep finding new possibilities for ESA, particularly in green chemistry and tech sectors. Demands for cleaner energy and less polluted manufacturing give ESA a new sense of relevance. By balancing process improvements with strong oversight, teams can harness its abilities without putting people or the environment in the crosshairs. Proper training, investment in monitoring, and greener disposal close the loop and keep usage responsible.
Ethanesulphonic acid plays an interesting role in organic chemistry, popping up in labs, industry, and even discussion forums for good reason. You find it labeled as a strong acid, tough enough to make its mark alongside more famous variants. The chemical formula for ethanesulphonic acid is C2H6O3S, which unpacks to two carbon atoms, six hydrogens, three oxygens, and a single sulfur atom.
The structure itself looks straightforward at first glance. You have an ethyl group—just two carbons linked in a chain. Tacked onto the tail sits a sulfonic acid group (-SO3H). It’s this strongly electronegative sulfonic group that gives the acid its punch. Drawing it out, you’ll chart an ethane backbone with a -SO3H group dangling where you’d usually find a hydrogen. In plain terms: CH3CH2SO3H. The real punch lies in that sulfonic acid group, one of the most powerfully acidic attachments you can pin to an organic molecule.
Walking into a lab, seeing rules and formulas taped to the wall, it’s easy to breeze past why structures matter. I learned this lesson the hard way, working through an organic synthesis project that needed a good catalyst. Ethanesulphonic acid, strong but not quite as harsh as sulfuric acid, stood out. The way it donates protons, thanks to its structure, lets it drive reactions without frying sensitive organic compounds.
The physical behavior of ethanesulphonic acid, traced right back to its structure, shapes its usefulness. It’s a colorless liquid, easy to handle, water-soluble, and resistant to oxidation. Unlike hydrochloric or sulfuric acid, you often find it in situations where you want strong acidity but don’t want complex byproducts. That’s a rare combination in acid chemistry.
This acid isn’t just a chemistry curiosity—it carries practical impact in everyday research and industrial setups. Pharmaceutical processes, especially, benefit from its direct, strong acid presence. Manufacturing uses also hinge on it for things like dye production and battery electrolytes.
From experience, I’ve seen ethanesulphonic acid solve practical problems, most especially as a non-volatile, manageable acid. Its lower volatility leads to less hazmat anxiety in the air, and that makes the workspace safer. Plus, it avoids the dense fumes you get with other acids, reducing corrosion worries on sensitive machines.
Handling can get tricky without gloves and eye protection. Though it’s less aggressive than some classics, those strong acid properties don’t play around. The need for responsible storage and neutralization after use remains non-negotiable. It won’t evaporate into thin air, so neutralizing it with a base before disposal is a step no one can skip.
Developers keep an eye on greener methods for producing and recovering ethanesulphonic acid. Waste reduction, recycling, and safe handling practices are more than just boxes to check—they protect staff and the surrounding environment. Embracing sealed systems, proper ventilation, and real-time acidity monitoring make workplaces both productive and safe.
Every claim about acids like ethanesulphonic acid rests on trustworthy data, peer-reviewed reports, and hands-on results. The benefits show up not only in textbooks but also in the real challenges faced during synthesis or industrial scaling. With the right respect for its properties and structure, this acid turns into a useful and manageable tool in the chemist’s toolbox.
Ethanesulphonic acid pops up in various manufacturing environments, especially in the making of chemicals, dyes, and pharmaceuticals. Its properties make it valuable, but sharing space with this acid in a lab or factory invites risks that can’t go ignored. My first real encounter involved a college research lab. Someone accidently spilled it onto a benchtop and, before we could grab a neutralizer, the acid started eating its way through the outer finish. That moment really highlighted the way strong acids do their damage.
A review of its Material Safety Data Sheet pulls back the curtain. Ethanesulphonic acid has a low pH, usually below 1, and it releases toxic fumes at higher concentrations. A splash on skin can lead to burns, blistering, and pain within seconds—no time to brush it off. Extended exposure even in diluted form sometimes causes deeper tissue injuries. Eyes are even more sensitive, sometimes facing permanent damage. This kind of reactivity earns it a red flag among lab techs and safety managers.
The molecule acts similar to sulfonic acids such as methanesulphonic acid and benzenesulphonic acid. Anyone pouring it out of a glass bottle should wear gloves, goggles, and splash protection. Breathing its vapors may feel like inhaling a lungful of vinegar fire, and chronic low-level exposure brings headaches and respiratory trouble, according to research from the National Institute for Occupational Safety and Health (NIOSH).
Most workplace accidents with strong acids share a theme: improper handling and poor training. Sometimes, damage stretches beyond people. Ethanesulphonic acid can chew through metal, varnish, and plastic that hasn’t been tested for acid resistance. If a spill seeps under a worn floor or drips into electrical equipment, repairs can eat up budgets.
Some folks underestimate the destructive nature of acids until they see tables etched with streaks or lab coats eaten away at the sleeves. My early chemistry work drove that point home. Even diluted versions call for respect. Long after that spill on the lab table, I found myself scrubbing my hands extra carefully after any work with similar substances.
In large-scale settings, proper training goes way beyond a single safety poster. Teams need regular drills, updated labeling, storage in acid-safe cabinets, and emergency showers in arm’s reach. Regulators like OSHA and European counterparts recognize these issues. Their rules force companies to map out not just safe handling but fast, effective response if things go sideways.
Real solutions rest on prevention and education. Control measures include acid-resistant gloves, goggles that seal tightly, and chemical fume hoods so nobody breathes fumes unnoticed. Secondary containment shields against accidental splashes, especially when dealing with larger volumes.
Companies can lower risk with clear training on what happens when acids meet water, metals, or organics. I’ve seen best results in labs and factories where workers pause, review their steps, and keep a spill kit at hand—no shortcuts, no guesswork. Real safety comes from a mindset of participation and respect for even small amounts of hazardous acids.
Ethanesulphonic acid delivers value in manufacturing and research, but ignoring its corrosive bite easily results in painful injuries and damaged property. Smart precautions pay off—often in ways that become stories for the next round of newcomers.
Ethanesulphonic acid, with its fierce acidity, commands respect from anyone working in a laboratory or industrial space. Plenty of strong acids line the chemical shelves, but ethanesulphonic acid stands out for its mix of strength and utility—used in pharmaceuticals, dye chemistry, and as a catalyst in organic synthesis. Over the years I’ve watched greenhorns and seasoned techs alike underestimate its potential hazards, so let’s get honest about what works on the ground.
Store ethanesulphonic acid like you mean it: dry, cool, and away from anything that could trigger a reaction. Humid rooms, ultraviolet light, and crowded shelves mean trouble. I recall one summer where a colleague stacked acids near an open window—vapors snaked out, metal fixtures pitted, and glassware fogged. Corrosive fumes traveled fast, and the mess took days to clean. Use chemical-resistant shelving, nothing wooden or chipped metal. Always label containers with the correct hazard symbols; more than once I’ve caught an old bottle with a faded label hiding at the back of a shelf, an accident waiting for curious hands.
Some folks skip gloves for “quick” tasks or think safety goggles are for newcomers. After seeing a friend spend days flushing her skin with water after a splash, no one in our group treats PPE like a suggestion. Nitrile gloves, a fitted lab coat, and sealed eye protection push the odds in your favor. Respirators come out if you’re anywhere close to making up solutions or decanting from a bulk container. Spills are less of an “if” than a “when,” and every hallway has a poster about the right neutralizer to use—with ethanesulphonic acid, sodium bicarbonate won’t let you down.
I worked on a process scale-up where instructions changed weekly. New team members were shadowing night shifts, and someone moved a drum without logging it. Next morning, no record matched the location—the barrel sat in a sunny delivery bay. Our team learned fast that every movement and every opening needed logging, a habit that stuck. Double-check transfer lines for leaks, confirm ventilated containment—especially if you’ve worked with less disciplined systems before. The worst accidents in my memory started with routine shortcuts.
Old, half-empty containers gather on shelves and attract beginners looking for easy material. In every shop I’ve worked, clear protocols for neutralization and collection stopped tragedies. Waste gets logged, labeled, and sent to the proper facility. On a smaller scale, even a high-school lab must treat remnants with care—good habits start early. Acid-resistant secondary containment trays save floors and budgets from damage each year. You spot the well-run places by how clean and organized their disposal areas stay.
People slip into bad habits without reminders. Regular review sessions, real stories about near-misses, and updates on regulations keep everyone paying attention. Chemists, techs, and custodial staff stay safer when everyone understands what’s on the shelf and how to respond in a hurry. New hires get buddy shifts with old hands, and every spill gets logged, however minor.
For all its power, ethanesulphonic acid works well with respect, training, and teamwork. I’ve learned more from watching good and bad examples than any manual could teach. The best operations leave little to chance and trust routines built on first-hand experience, not just printed policies.
Working in chemistry labs and manufacturing plants, I’ve seen how purity makes or breaks a project. Taking ethanesulphonic acid as an example, two grades show up again and again: the laboratory grade, commonly above 99%, and a lower technical or industrial grade, sometimes between 70% and 95%. The distinction looks small on paper, but the stakes are real. High-purity ethanesulphonic acid usually comes as a clear, colorless liquid or solid. Lower purity means trace metals, water, or even bits of organic by-products from upstream synthesis.
Anyone who has tried to pull off a sensitive reaction knows the pain that comes from overlooked contaminants. Even a fraction of a percent impurities forces cleaners, delays, or failed batches. I recall a synthesis where trace iron in a lower-purity batch skewed the color and yield, costing a whole day. Pharmaceutical companies demand 99% or better—there’s too much on the line. In organic chemistry, researchers use the high-purity variant where a single side-reaction risks ruining the result. In the electroplating industry, a lower-purity option saves cost for less-crucial needs. The trick lies in balancing price against contamination risk.
Data from reputable suppliers, such as Sigma-Aldrich or Merck, places “reagent-grade” ethanesulphonic acid at 99% minimum, occasionally spiking to 99.5%. Most standard production batches hit within that range, measured by gas chromatography or titration. Industrial markets, like textile treatment or cleaning fluids, tolerate grades starting around 70%, accepting some dissolved residue if it comes with a lower bill. In the United States and Europe, regulations may push for traceability, urging documentation of metal content and water percentage.
Cutting corners on purity rarely pays off if quality control matters. A factory manager once told me how a shipment of lower-quality acid jammed a reactor line due to precipitated solids. Even weeks later, cleanup headaches haunted the crew. In consumer-facing sectors, safety and quality demand the highest grades, with batch-to-batch consistency tracked. Food and pharmaceutical regulation, including oversight from the US FDA and Europe’s EMA, requires strict adherence not just to the stated purity percentage but trace element reporting as well.
Purity is not just about numbers on a label. Laboratory teams and purchasing managers need supplier transparency, including batch analysis reports, impurity sources, and water content. Running a small test batch saves headaches, especially when switching vendors. Technology upgrades such as better distillation and chromatographic purification will keep pushing purity standards higher. Environmental and workplace safety rules require accurate labeling: knowing what’s in the bottle cuts risk for workers and saves trouble with regulations.
My take is that knowing the required purity before buying unlocks smoother projects, safer processes, and time saved on troubleshooting. The old saying, “You get what you pay for,” rings true with reagents. By asking tough questions of suppliers, demanding documentation, and understanding end-use priorities, both labs and production lines set themselves up for success.
| Names | |
| Preferred IUPAC name | Ethane-1-sulfonic acid |
| Other names |
Ethanesulfonic acid Esilic acid 2-Sulfonoethane C2H6O3S |
| Pronunciation | /ˌɛθ.eɪn.sʌlˈfɒn.ɪk ˈæs.ɪd/ |
| Identifiers | |
| CAS Number | 126-96-5 |
| 3D model (JSmol) | `Ethanesulphonic Acid JSmol 3D model string`: ``` CCS(=O)(=O)O ``` |
| Beilstein Reference | 1430807 |
| ChEBI | CHEBI:28855 |
| ChEMBL | CHEBI:29031 |
| ChemSpider | 64507 |
| DrugBank | DB03128 |
| ECHA InfoCard | 07a6fde8-cc3c-482c-930f-30eebf24ad43 |
| EC Number | 200-545-1 |
| Gmelin Reference | Gmelin Reference: 91250 |
| KEGG | C01434 |
| MeSH | D017352 |
| PubChem CID | 8668 |
| RTECS number | KH2975000 |
| UNII | 26NT0U8497 |
| UN number | UN2689 |
| CompTox Dashboard (EPA) | 7H4M467378 |
| Properties | |
| Chemical formula | C2H6O3S |
| Molar mass | 110.17 g/mol |
| Appearance | Colorless liquid |
| Odor | Odorless |
| Density | 1.29 g/cm3 |
| Solubility in water | Very soluble |
| log P | -2.0 |
| Vapor pressure | 0.0133 hPa (20 °C) |
| Acidity (pKa) | 1.51 |
| Basicity (pKb) | -10.6 |
| Magnetic susceptibility (χ) | -48.2·10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.411 |
| Viscosity | 17 mPa·s (20 °C) |
| Dipole moment | 2.56 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 175.0 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -954.7 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -962.7 kJ/mol |
| Pharmacology | |
| ATC code | A16AX06 |
| Hazards | |
| Main hazards | Corrosive, causes severe skin burns and eye damage, harmful if swallowed or inhaled. |
| GHS labelling | GHS02, GHS05 |
| Pictograms | GHS05,GHS07 |
| Signal word | Danger |
| Hazard statements | H314: Causes severe skin burns and eye damage. |
| Precautionary statements | P280, P301+P330+P331, P303+P361+P353, P305+P351+P338, P310 |
| NFPA 704 (fire diamond) | 3-0-2-Ac |
| Flash point | 122 °C |
| Autoignition temperature | 590 °C |
| Lethal dose or concentration | LD50 oral rat 760 mg/kg |
| LD50 (median dose) | LD50 (median dose) of Ethanesulphonic Acid: 1,000 mg/kg (rat, oral) |
| NIOSH | KL6300000 |
| PEL (Permissible) | Not Established |
| REL (Recommended) | 50 mg/m³ |
| IDLH (Immediate danger) | IDLH: Not established |
| Related compounds | |
| Related compounds |
Methanesulfonic acid Propanesulfonic acid Benzenesulfonic acid Sulfuric acid Ethanesulfonate |
