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Methanesulfonic acid (MSA) hasn’t always gotten the attention of other, flashier chemicals, but its story traces back through a long chain of industrial and laboratory discovery. Early mention of similar sulfonic acids dots the chemical literature of the nineteenth century, though solid, commercial-scale routes to MSA only really took off in the twentieth. Chemists put effort toward finding strong acids that could replace more volatile or problematic materials like hydrochloric and sulfuric acid, and MSA stepped onto the scene with some distinctive advantages. Developed not just as a lab curiosity but as a practical, approachable acid, MSA saw adoption in both organic synthesis and electrochemical industries. Generations of researchers and engineers fine-tuned its production processes, adapting methods to fit the changing demands of electronics, pharmaceuticals, and specialty chemicals. If anything, the growth of methanesulfonic acid reflects a broader shift in industry—people kept hunting for chemicals that serve their function without dragging along a trunk of hazards and side effects.
As someone who’s unscrewed more than a few reagent bottles over the years, I can say that MSA hardly strikes an intimidating pose. Clear, nearly odorless, and with no drama upon opening, it belies some of its power as a strong acid. Laboratories stack it next to its sulfonic cousins, but it carves out its own reputation. It’s not flammable, doesn’t fume like sulfuric, and dissolves in water with surprising ease. Factories lean on it for metal finishing and pharmaceuticals value it for precision in synthesis—fewer byproducts, cleaner processes. If you scan recent market data, demand for MSA keeps nudging upward, as industries look to replace more hazardous acids piece by piece. Every academic chemist has probably glimpsed MSA’s formula, CH3SO3H, at least once during their coursework—it's a staple that persists and adapts without stealing the limelight.
Getting to know MSA means noticing practical details ahead of textbook definitions. Its strong acidity shows up as a willingness to protonate whatever comes near, even rivaling mineral acids in many tasks. Unlike sulfuric acid, methanesulfonic acid stays non-oxidizing, which keeps unwanted side reactions to a minimum. Its melting point, hanging around 20°C, means it can flow as a liquid at room temperature or solidify in a chilly room—something you actually see now and then in labs that still haven’t upgraded their climate control. That liquid physicality also makes it easy to measure, pour, and formulate into bath solutions for plating or cleaning. In solubility, it partners gladly with water and many organics, which lowers the barrier to blending and introducing it into multistep reactions. Its density and viscosity square up well within reach of typical chemical pumps, lowering the risk of blockages or handling accidents in process engineering setups.
Working hands-on with chemicals, you learn that the real world rarely matches the idealized diagrams in handbooks. MSA comes in various grades—reagent, technical, electronic—but the acid content sticks reliably close to 99 percent. Quality control folks sample lots using titration or gas chromatography for impurities like dimethyl sulfone or trace metals, since even a whiff of a contaminant can mess up a sensitive reaction or mar a circuit board finish. Labels on containers flag the hazard codes and mark the UN number, reflecting its classification as a corrosive but not a flammable or explosive. There’s less paperwork than for other strong acids, which isn’t an invitation to shortcut safety, but it does lighten the administrative load. In practice, product purity and consistency beat fancy certificates. If you’re using MSA in a pharmaceutical route or high-reliability electronics, routine batch testing just becomes part of life.
Many chemical innovations start with one question: how do we make this at scale, safely and cheaply? MSA’s main synthetic route runs through the oxidation of methyl mercaptan or dimethyl sulfide—both tricky chemicals in their own right. More recently, direct sulfonation of methane with oleum shot up in popularity due to its efficiency, but not everyone has the appetite for handling high-pressure reactors and concentrated sulfuric acid. Whichever route, process engineers focus on coaxing selectivity and yield to balance productivity against waste and byproduct removal. Modern facilities control reaction temperatures closely and use specialty catalysts to drive up efficiency, since waste disposal costs for sulfur-containing byproducts keep climbing. Every batch gets filtered and neutralized before bottling, reflecting hard-won lessons on keeping corrosive vapors inside pipes and off the production floor. In academic research, people sometimes fuss with boutique approaches using lesser-known sulfonation agents, but in reality, large-scale operations stick to proven methods because volumes and deadlines rule the day.
MSA stands out for its simplicity and stubborn reliability. As a sulfonic acid, its main trick is proton donation—that’s a big deal in organic chemistry. It can kick off esterification, help drive elimination reactions, or sit in as a catalyst in all sorts of syntheses. I’ve run reactions where using MSA over sulfuric meant less side product, easier separation, and friendlier workups. In electroplating, it sheds metal ions onto cathodes with fewer side reactions compared to harsher acids. And for those chasing greener credentials, MSA’s non-volatile nature and minimal fumes make it safer to work up and vent. The acid handles routine modifications—neutralization, salt formation, ester production—without drama. Its methyl group means it doesn’t entangle in polymer backbones like some aromatic sulfonics, so it’s less likely to leave residue or persistent byproducts downstream. Applied chemists and process engineers appreciate this predictability, which translates as lower maintenance and fewer surprises.
Over the years, MSA has collected a cast of alternative names, showing up as methylsulfonic acid, methane sulfonic acid, or abbreviated boldly as MSA. Academic journals and patents often toggle between these, occasionally adding an IUPAC twist. If you bounce between global suppliers, you’ll see local variations—sometimes written as methanesulfonate when referring to salts derived from the acid. Some technical documents throw in older names, a reminder of the shifting language of chemistry that confounds even seasoned professionals. In practice, anyone who’s ordered it for the bench soon learns to double-check product codes rather than argue over spelling, because nothing ruins a synthesis faster than a shipment of the wrong sulfonic acid.
No career in chemistry comes without a few splashes and spills, which teaches quick respect for proper safety routines. MSA’s rewards come with risks. Strong corrosiveness means you need sturdy gloves, goggles, and fume hoods on duty every time. Though less toxic by inhalation than some peers, MSA can chew through tissue or pit metal surfaces quickly. Facilities using MSA set up spill containment, special waste streams, and clearly marked storage to prevent cross-reactions. In pharmaceutical or food contexts, regulators have strict residue limits—a testament to how thorough toxicity assessments have grown over the decades. Training and safety culture matter more than the safety data sheet because at the end of the day, avoiding accidents depends on personal discipline. Incident records show that mistakes usually happen when people cut corners on PPE or ignore routine leak checks.
MSA’s greatest asset may be its versatility across industries. Metal finishers prize it for producing bright, even plating in electronics manufacture. As a reagent in organic synthesis, MSA steps in where harsher acids either fail or bring too much baggage, enabling the synthesis of pharmaceutical intermediates and fine chemicals with reliable yields. In laboratories, esterification and protecting group chemistry use MSA to achieve predictable outcomes with easy workups. Researchers studying batteries use it as a supporting electrolyte in some experimental setups, and it pops up in cleaning compounds where strong, non-volatile acids help strip away scale. Unlike some specialty reagents whose reach is narrow and technical, MSA finds a home wherever chemists need a reliable mix of strength, safety, and predictability. Each field values different aspects—clean reaction profiles, easy waste neutralization, regulatory compliance, or even price stability.
Research into new applications for MSA continues, especially as sustainability and green chemistry take center stage. Scientists examine its use as a catalyst in biomass conversion, hoping to generate useful chemicals from renewable feedstocks with minimal waste. Some published studies chart how MSA-based systems help solubilize tricky compounds for advanced materials research, especially when working beyond the boundaries of water solubility. Electrochemical engineers have tested methanesulfonic acid in rechargeable batteries, exploring its electrolyte stability and how it affects electrode life. Researchers are also probing greener synthetic routes to MSA itself, tapping renewable methane sources and optimizing reaction conditions. The quest for cleaner, less resource-intensive chemistry endows old standbys like MSA with renewed relevance, pushing the boundaries of what this forgotten acid can offer.
Despite its status as a heavy-duty acid, MSA fares reasonably well under modern toxicity screens. Acute toxicity remains low, with regulatory bodies generally rating it less hazardous than strong mineral acids for inhalation or long-term exposure, as long as concentrations stay within recommended limits. Both industry experience and animal studies show that direct contact with concentrated solutions burns tissue, but environmental persistence looks limited—MSA breaks down to simple inorganic salts without forming persistent organic pollutants. Wastewater treatment plants can usually neutralize residual MSA efficiently, though high loads can stress the system. Chronic exposure studies, especially in the workplace, remain under close review. Global harmonization of labeling and exposure limits proves challenging, but international hazard data give process managers solid grounds for risk decisions. Workplace air monitoring and regular health surveillance for exposed workers have kept major incidents rare, showing that practical risk management pays off.
Looking down the road, MSA promises to stay relevant as industries migrate away from legacy chemicals seen as environmental or safety risks. Rising demand for cleaner electronics and pharmaceuticals makes the search for “greener” acids more than a trend—it's a business necessity. Methanesulfonic acid’s low volatility and manageable toxicity position it as a candidate for substitution, especially in regulated environments. Chemists are driving innovations in surface finishing, electroplating, and organic synthesis, betting on MSA’s predictability and mild environmental footprint. The next wave of research angles toward renewable routes, improved catalyst supports, and pushing reaction efficiency ever higher. Stakeholders who invested early in MSA technology now watch with interest as policy and market pressures continue to shift. If practical, scalable green chemistry becomes the new normal, odds are methanesulfonic acid will play a part, quietly and reliably, as it always has.
Methanesulfonic Acid, usually called MSA, barely makes headlines outside of science circles, but it shapes more industries than most people realize. This colorless, strong acid pops up in workplaces ranging from electronics labs to car factories, all because of its unique properties.
If you have ever held a smartphone or even spare change, you have seen the surface-level magic of electroplating. MSA carries out a silent job behind the scenes in this field. Electroplaters value it because it provides efficient metal deposition without the health and environmental danger posed by conventional acids like hydrochloric or sulfuric. MSA’s low toxicity and biodegradability take the sting out of a very tough job, turning it into a safer space for workers and less risky for the planet.
In electronics, precise chemical reactions matter more than anything. MSA serves as a supporting character in the etching and cleaning of printed circuit boards (the green sheets inside every phone and computer). Its performance brings consistent results without the heavy corrosion or fumes that triggered headaches and complaints in other processes. By making the workplace less hazardous, it not only keeps workers healthy but also improves productivity.
Chemists often reach for MSA in the lab because it pushes reactions forward cleanly and predictably. Pharmaceutical companies use it while synthesizing molecules for common and life-saving drugs. Aspirin, antibiotics, and even some treatments for complicated diseases go through MSA-based processes along the way. Controlling the reaction environment saves money and time, pushing cures from whiteboards to pharmacy shelves faster.
In renewable energy and electric cars, MSA steps in as part of some battery chemistries. Its stability and conductivity help push ions around so efficiently that manufacturers redesign legacy batteries to incorporate it. Sourcing safer chemicals that do the job of older, pollution-heavy acids keeps companies in business and lets them meet tightening environmental standards without breaking the bank.
On the maintenance side, MSA offers powerful cleaning without the harsh legacy of traditional mineral acids. Cleaning systems, especially in breweries and dairies, use diluted MSA to strip away residue, clear pipes, and prep tanks in record time. It keeps up with the pace of modern food production and leaves behind less waste for wastewater plants to treat.
As regulations shift and the public grows more aware, industries switch from legacy acids to alternatives like MSA to protect employees and limit environmental fallout. Replacing nastier chemicals with MSA in a process can mean fewer days lost to injury, less money spent on protective gear, and a smaller cleanup bill after spills.
For companies on the front lines, small changes in a supply room can echo through entire organizations. MSA’s rise signals a slow, hopeful turn toward smarter, safer industry practices—proof that even the most technical substance can improve lives on and off the manufacturing floor.
Methanesulfonic acid, known by its chemical formula CH3SO3H, shows up everywhere from industrial cleaning to electroplating and organic synthesis. This strong acid comes with a punch: it wears a powerful corrosive badge, yet stays manageable compared to sulfuric acid or hydrochloric acid. Most labs handle methanesulfonic acid in its pure, undiluted liquid form, where it delivers a concentration close to 100%. In some cases, you’ll run across 70% or 85% solutions, but pure acid brings the most bang for the buck.
Concentration isn’t just a technical detail; it’s a safety concern and a practical one. Handling pure MSA feels different than working with standard mineral acids. It doesn’t fume like hydrochloric acid and it’s less volatile, which means spills stay put long enough to clean up safely. The acid’s high concentration gives it muscle for the toughest tasks–pickling metal, catalyzing chemical reactions, or stripping old paint. But nobody treats it lightly: skin burns, metal corrosion, poisonous fumes with the wrong combinations—those risks keep safety goggles glued to my face.
Think of MSA like a precision tool. In pharmaceuticals, it leaves fewer side reactions compared to mineral acids. Electronics manufacturers prefer it for cleaning circuit boards thanks to its non-volatile nature. Metal finishers rely on its steady punch: a strong acid that doesn’t bring along chloride ions to encourage rust. That’s something you can see first-hand if you spill it on any part of a steel wrench—MSA eats away confidently but leaves behind less of that flaky, orange corrosion you get with hydrochloric acid.
The chemical industry needs to balance practicality and responsibility. Methanesulfonic acid hits a sweet spot: easy biodegradability, minimal leftover mess after neutralizing, and a safer alternative to some old-school acids. A 2007 study showed MSA breaking down in wastewater treatment to harmless products, well below safety thresholds. That doesn’t excuse cutting corners on PPE or ventilation, because MSA will still burn skin and eyes and release toxic fumes mixed with bleach or other oxidizers.
I’ve seen safety teams debate storage. The secret sits in simple common sense: keep the bottle tightly closed, store away from oxidizers, and limit how much you keep on hand. Spills get cleaned with a liberal dose of sodium bicarbonate or soda ash, then tested to confirm neutralization before rinsing down the drain. These basics avoid most headaches. For larger-scale users, local wastewater guidelines need checking, but most authorities rank MSA as less problematic after neutralization–unlike acids that leave persistent residues.
Factories invested in handling systems tailored for aggressive acids do well with MSA. Stainless steel or plastic tanks, automated dilution systems, and local exhaust hoods cut down incidents. Training remains the cornerstone; folks on the ground deserve clear instructions and just-in-case gear nearby. In my work, I stand behind the idea that spending extra to train staff saves money and pain down the line.
Folks in smaller labs or repair shops benefit from premixed, lower-strength versions. Buying what you need in manageable quantities cuts the risk of accidents. Education matters, too. Simple posters on acid handling, first aid, and neutralization procedures worked better than any technical manual.
Methanesulfonic acid boils down to a simple truth: know its strengths, respect its risks, and keep safety front of mind. That approach rewards everyone—whether crafting pharmaceuticals, etching a printed circuit, or just cleaning glassware for the next experiment.
Methanesulfonic acid (MSA) shows up in batteries, electronics, and even cleaning products these days. It’s got a reputation for being strong and dependable in chemical jobs, but it’s no household vinegar. Anyone who’s ever worked in a lab knows sulfur-based acids pack a punch. One careless splash, a rush to get a job done, or skipping a step in routine can turn a typical workday into a sprint to the emergency shower.
MSA brings serious risks to people and the environment. Direct contact can cause burns, and breathing the vapors irritates the nose and lungs. Spills on metal surfaces can create slippery messes or even corrode tools and fixtures. Those relying on MSA for industrial cleaning or battery work need to remember: shortcuts rarely pay off in chemical safety.
Reliable safety gear makes all the difference. Chemical-resistant gloves—nitrile or neoprene—stay strong when acids get involved. Eye protection with tight-fitting goggles can spare you a trip to the ER if a drop splashes. A sturdy lab coat or acid-resistant apron keeps clothes and skin protected. Closed-toe shoes stop acid from ruining more than your day. Folks who forget their gear find out quickly why the rulebook exists.
Working with MSA in a cramped, poorly ventilated space raises the risk of breathing in vapors. My own experience in older labs taught me to look for working fume hoods and not settle for open windows. Chemical vapors love to linger, and nobody wants a cough lasting until the weekend. Floors and benches where you use acids should stay clean, dry, and clear of food or drinks—rust stains on stainless steel are a small warning sign compared to what accidents can bring.
MSA eats through reactive metals and some plastics. Store bottles in cabinets marked for corrosive chemicals, ideally below eye level. Tight lids and proper secondary containers mean less chance of overturns or leaks. Mixing MSA with other chemicals must follow the recipe, not guesswork. A tired worker who skips the label check risks dangerous reactions or poisonous gases.
New hires regret not paying attention during safety briefings about MSA. Clear instructions and hands-on practice set the right habits early. Supervisors who hold regular drills on spills and eyewash use keep response times sharp. People sharing workstations benefit from clear signage and up-to-date material safety data sheets. Forget paper-pushing—those safety docs help you know what to do when plans go sideways.
Accidents happen fast with MSA. Build muscle memory by rehearsing spill cleanup. Keep neutralizing agents like sodium bicarbonate close by, and have spill kits ready to go. If MSA finds skin or eyes, flush with water for at least 15 minutes and seek help. Reporting small spills matters, not just the big ones—today’s puddle might cause tomorrow’s accident if ignored.
People notice hazards before management does. Workers protected by a culture where they can report unsafe conditions or equipment without fear keep the whole team safer. Anyone using MSA should feel empowered to ask questions, speak up about faulty gear, and suggest safety tweaks. One voice can spot a missed risk and prevent a trip to the doctor or worse.
Anyone who’s stood in a storeroom with chemical drums knows a distinct sense of focus sets in. Methanesulfonic Acid (MSA) brings that presence. It’s strong, colorless, and holds usefulness from electroplating to pharma. It takes just one mistake with acids like MSA for a normal workday to go sideways. As someone who’s lost plenty of gloves and a good few boots to chemical mishaps over the years, every detail of safe storage matters to me—far beyond rulebooks.
Acids only forgive those who respect them. MSA comes packed in airtight, corrosion-resistant containers for a reason. Plastic high-density polyethylene (HDPE) containers hold up well, and sometimes stainless steel stands in. An ordinary steel drum won’t cut it since MSA eats at most metals with stubborn patience. Outside of the original packaging, transfer needs care. Using glass might sound safe, but even glass can pit and crack from repeated exposure. Containers must stay tightly closed, and old, compromised seals become accidents waiting to happen. Every time evaporation finds a gap, fumes can build up—and that puts your tools, storage, and even the air you breathe at risk.
MSA shows its reliability best below 30°C (86°F). Heat pushes up pressure and starts to test seals and container integrity. Refrigeration brings its own issues—below freezing, MSA can start to solidify. You don’t want to swap liquid danger for icy lumps you’ll have to re-liquify, either. Aim for a stable, dry place at room temperature, away from sources of heat. Dryness is everything: moisture creeping into a container can dilute or react, sometimes explosively, with strong acids like this.
Segregation in storage isn’t bureaucracy. If MSA sits by oxidizers, organic peroxides, cyanides, or bases, it can lead to fires, toxic gas buildup, or explosions. An example: one technician I knew kept sulfuric acid too near a sodium cyanide barrel—an unlabelled shelf shuffle later triggered a frightening gas leak during inventory. Separate acids from anything reactive using distinct shelves or even dedicated rooms. Ventilation within each area should sweep fumes upward and out, never allowing invisible risk to build in corners. Signage gives everyone fair warning of what’s at stake behind each door. Lock up dangerous chemicals, so only trained hands can access them: security doesn’t mean just hanging a padlock. It means clear record keeping for who moves, uses, or inspects each chemical.
Too many facilities stash chemical PPE in an “emergency cabinet” with good intentions, but those gloves or goggles gather dust until it’s too late. Anyone handling MSA should wear gear daily—chemical-resistant gloves, goggles, long sleeves, and sometimes a face shield. Face-to-face with corrosive splashes, there’s no replacement for preparedness. Emergency showers and eyewash stations make a difference; I’ve watched colleagues rush to use both and walk away with nothing worse than a bad day, not a trip to the burn unit. Spill kits loaded with neutralizers and absorbents belong nearby, not behind a locked door halfway down the hall.
Trust in safe storage grows from routines. Audit shelves, check inventory, test containers for integrity, and refresh training before it expires. Don’t leave old or leaking drums “for next time”—prompt disposal following local environmental and safety rules will always beat risky improvisation. Reporting near-misses or spills creates transparency, keeping everyone aware that chemical accidents often start with storage habits. You never want to explain an accident in hindsight, especially if a simple storage tweak could have saved trouble. Methanesulfonic Acid demands respect but rewards diligence, and lives and livelihoods depend on remembering that.
Methanesulfonic acid gets pitched as a “greener” acid, especially when compared to sulfuric or hydrochloric acids. It doesn’t give off toxic fumes at room temperature, and it mixes well with water. In industries, MSA, as it’s called, shows up in electroplating, pharmaceuticals, and cleaning agents. Manufacturers often claim MSA replaces nastier acids and helps cut down hazardous waste in some applications. On the surface, such benefits start to sound appealing.
I’ve spent years working with chemical supplies in lab settings, which means I keep a close eye on what goes down the drain. MSA’s low vapor pressure stands out right away; it isn’t likely to fill the air with choking smog or odor. That doesn’t mean you can pour it out freely, but it does mean the risk of an exposure incident drops compared to more volatile acids. Those who’ve handled hydrochloric or nitric acid know how quickly those can cause harm, even if handled carefully. So the safer air profile of MSA matters for workplaces and communities nearby.
This is where things get complicated. Chemists like to point out that MSA, as a simple organic molecule, breaks down in water over time. Studies, including research published in Chemosphere and other academic sources, have shown that certain microbes can digest MSA in controlled settings. In laboratory tests, MSA has a half-life measured in days to weeks, depending on microbial activity and the presence of oxygen. That's a plus over some other persistent industrial chemicals.
The story changes out in the wild. Not all water bodies teem with the right micro-organisms. Load up a stream with MSA, and breakdown slows way down if the natural conditions aren’t right. Urban and industrial wastewater treatments tend to have a good mix of bugs that handle MSA. Rural water systems or low-flow natural streams don’t always cope as easily. So environmental release can cause local imbalances, especially in places where runoff pools for long periods.
Switching from sulfuric acid to MSA may cut worker risk, and the new acid won’t create dangerous fogs or rapidly corrode metals. That’s a big upgrade for safety. Less corrosive fumes hanging around means lower wear on infrastructure as well. Wastewater containing MSA, though, can add up fast in plants that run high volumes. Like any industrial acid, careless handling brings about fish kills or vegetation damage if spills happen.
In my own facility, tests on effluent showed that treating both sulfuric acid and MSA needed similar neutralization steps before disposal. It’s never just a matter of “is it biodegradable” or not—the bigger question is if the local plant can process it before it hits lakes and rivers. And for remediation, biological treatment processes like activated sludge show promise in scrubbing MSA, but only if they're well-managed and properly maintained.
Focusing on safer chemical substitutes matters, no doubt about it. MSA offers some real wins over the nastier acids that dominated industry for decades. Still, no industrial acid flows into the world without some consequence. True environmental responsibility comes from more than just switching formulas. It demands upgraded treatment, solid spill response, and thorough worker training. For some companies, closed-loop recycling or targeted distillation of used acid can recycle MSA—cutting total demand and slashing loss to the environment.
Replacing hazardous chemicals will always draw headlines, but people handling MSA or managing projects with it should remember: a “green” label doesn’t justify cutting corners. Staying informed, supporting local monitoring, and pushing for better treatment tech makes a bigger difference than any easy marketing claim. MSA isn’t a silver bullet, but with care, it can play a smarter role in cleaner industry.
| Names | |
| Preferred IUPAC name | Methanesulfonic acid |
| Other names |
Methanesulfonic acid MSA Methanesulfonate Methanesulfonic acid solution Mesylic acid Sulfonic acid, methyl- Methylsulfonic acid Methanosulfonic acid |
| Pronunciation | /ˌmɛθ.eɪn.sʌlˈfɒn.ɪk ˈæs.ɪd/ |
| Identifiers | |
| CAS Number | 75-75-2 |
| Beilstein Reference | 505738 |
| ChEBI | CHEBI:40958 |
| ChEMBL | CHEMBL1233247 |
| ChemSpider | 54868 |
| DrugBank | DB11158 |
| ECHA InfoCard | 03bb3b5c-4cf2-4daa-9a3a-7d0a5903ee8d |
| EC Number | EC 200-898-6 |
| Gmelin Reference | 8347 |
| KEGG | C01438 |
| MeSH | D008767 |
| PubChem CID | 6137 |
| RTECS number | OA4900000 |
| UNII | TY8407688E |
| UN number | UN3265 |
| CompTox Dashboard (EPA) | DTXSID9020083 |
| Properties | |
| Chemical formula | CH4O3S |
| Molar mass | 96.10 g/mol |
| Appearance | Colorless to slightly yellow liquid |
| Odor | Odorless |
| Density | 1.48 g/cm³ |
| Solubility in water | Miscible |
| log P | -2.0 |
| Vapor pressure | 0.54 hPa (20 °C) |
| Acidity (pKa) | -1.9 |
| Basicity (pKb) | -2.0 |
| Magnetic susceptibility (χ) | -48.6e-6 cm³/mol |
| Refractive index (nD) | 1.430 |
| Viscosity | 8.6 cP (25 °C) |
| Dipole moment | 1.65 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 92.1 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -639.8 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -724.2 kJ·mol⁻¹ |
| Pharmacology | |
| ATC code | V03AB37 |
| Hazards | |
| Main hazards | Corrosive, causes severe skin burns and eye damage, harmful if swallowed or inhaled. |
| GHS labelling | GHS05, GHS07 |
| Pictograms | GHS05,GHS07 |
| Signal word | Danger |
| Hazard statements | H290, H314 |
| Precautionary statements | P280, P301+P330+P331, P303+P361+P353, P305+P351+P338, P310, P501 |
| NFPA 704 (fire diamond) | 3-0-2-Acid |
| Flash point | > 138°C |
| Autoignition temperature | 560 °C |
| Lethal dose or concentration | LD₅₀ (oral, rat): 2,000 mg/kg |
| LD50 (median dose) | LD50 (oral, rat): 1600 mg/kg |
| NIOSH | WSH7125000 |
| PEL (Permissible) | There is no specific OSHA PEL (Permissible Exposure Limit) established for Methanesulfonic Acid (MSA). |
| REL (Recommended) | REL (Recommended): 1 ppm (3 mg/m³) |
| IDLH (Immediate danger) | Not established |
| Related compounds | |
| Related compounds |
Sulfuric acid Methanesulfonyl chloride Methylsulfonylmethane (MSM) Methanesulfinic acid Benzenesulfonic acid |
