© 2026 Nanjing Finechem Holdings Co., Ltd,
All Right Reserved
Dichloromethane first caught serious attention in the 19th century. As industry started booming, the demand for versatile solvents grew. Chemists looking for reliable alternatives stumbled upon this chlorinated methane derivative, noting its strong dissolving abilities and volatile nature. Through the decades, manufacturers scaled up its production. It played a role in advances as diverse as paint stripping, pharmaceutical synthesis, and later, electronics. The legacy of dichloromethane holds a mirror to the industrial era’s ambition—an era that didn’t just accept risk but sometimes ran full tilt at it.
Dichloromethane, usually called DCM or methylene chloride, comes off as a clear, colorless liquid with a mild sweet scent. I remember opening a container in a college lab, the vapor slipping out in an almost invisible wave. That aroma is not random—it speaks to the substance’s volatility and its tendency to leave containers fast if you don’t cap them quickly. Chemists favor it for its strong solvency and easy evaporation. Laboratories and factories reach for the high-purity (≥99.8%) anhydrous grade when purity can’t be compromised, like in pharmaceutical preparations or synthetic protocol development. Some folks recognize dichloromethane by its chemical formula, CH2Cl2, but for most, it’s just the stuff that cuts through grease, paint, or resin with a speed that’s almost uncanny.
Dichloromethane sits in a sweet spot: boiling point near 40°C, heavy vapor density, and little taste for flames. Folks use its density (1.33 g/cm³ at 20°C) and non-flammability to their advantage, especially for delicate separations or where open flames present a risk. Its high vapor pressure makes it hazardous in confined spaces—a fact anyone who’s spent a day with solvents quickly learns. Its molecular structure carries two chlorine atoms bound to methane, helping it break bonds in organic matter and lending it that signature solvent kick. While it won’t catch fire easily, the vapor can knock you down and out with short exposure, a reminder that physical properties steer real-life risks.
Chemicals at this purity level carry a guarantee: less than 0.2% water, and most times, trace impurities clock below 50 parts per million. The technical sheets detail specific gravities, acidity levels, metals content, and optical clarity. Labels flash warnings: carcinogenic risk, acute toxicity, possible mutagenicity. They include proper identification numbers like CAS 75-09-2, UN codes, and regulatory phrases pulled from OSHA and European guidelines. Any supplier worth their salt offers certificates, lot tracing, and handling notes, because the devil never hides in the details—he spells them out in black and red on the drum.
Manufacturers mainly use chlorination of methane or methyl chloride. Industrial reactors push methane and chlorine gas through controlled ballets of temperature and pressure, steering the reaction to minimize creation of trichloromethane and other byproducts. Fractional distillation lets plant operators collect dichloromethane at its tidy boiling point. Emphasis lands on keeping water out of the final product, either by drying with molecular sieves or by distilling over calcium hydride. In the lab, small batches come together much the same way, scaled down to glassware, blowtorches, and close observation—simple chemistry with a sharp eye for yield and purity.
Dichloromethane acts mostly as a solvent, not a reactant. Still, under the right snap of energy or strong alkaline conditions, it breaks down into formaldehyde and hydrochloric acid. As a chlorinated compound, it can act as a chlorinating agent in some specialty syntheses, although greener options now turn heads. In reactions with strong bases or at high temps, you can tease out higher chlorinated methanes, but this path never caught on past the pilot plant stage due to cost and risk factors. Chemists often rely on DCM to dissolve tough organic substrates—and sometimes as the non-reactive layer in phase-transfer reactions.
Across industries and catalogs, names include methylene chloride, DCM, methane dichloride, and R-30. In some applications, it’s tagged as MC or methylene bichloride. In the paint industry, it might show up as just “stripper solvent,” and in pharma, by its full purity grade with a batch number close by. Each name reflects a perspective: the IUPAC purist, the mechanic, the pharmaceutical analyst. Synonyms matter less in a locked cabinet than in paperwork or safety data sheets, where correct labeling draws the line between compliance and chaos.
Lab safety officers pound home one rule: never trust the fumes. Regulatory standards from OSHA, NIOSH, and the EU set short exposure limits at low parts per million. Prolonged or repeated inhalation can trigger nervous system effects, sensory loss, or even death. Dichloromethane metabolizes to carbon monoxide in the liver, tying its toxicity back to suffocation risk. Storage protocols demand cool, ventilated rooms with chemical-rated containment. Splash goggles, nitrile gloves, and full-face shields cut personal risk during handling. For transport, it travels as a hazardous good, boxed, labeled, and tracked. Spills demand fast attention—absorb, ventilate, and keep sources of ignition away, since decomposition at high temperatures can spark phosgene.
Even as environmental scrutiny rises, dichloromethane powers through jobs in pharmaceuticals, paint removal, adhesives, metal cleaning, and extraction processes. Pharma researchers tap DCM for extracting delicate alkaloids or coupling tricky reactants. Electronic device makers lean on it to strip away stubborn resin or polymer layers. In the food industry, it plays a controversial role, making decaf coffee through caffeine extraction. Each field demands the same base properties: reach for DCM when nothing else works as smoothly or efficiently.
Recent years have brought efforts to tweak—or even bypass—DCM for cleaner, greener chemistries. Scientists explore replacements like ethyl acetate, even though nothing quite matches the volatility-solvency combo. Innovation focuses not only on substitutes but also on improving containment, recycling, and vapor capture. Analytical chemists push for methods that minimize waste or find new ways to recycle used DCM. There’s an unspoken challenge among synthetic chemists: unlock the next solvent system, one with all the upside and half the risk.
Human and animal studies draw a tough picture: dichloromethane can pass through skin, hit the bloodstream, and quickly metabolize into carbon monoxide and even formaldehyde. Research ties occupational exposure to possible liver and lung changes, along with neurotoxic effects. The International Agency for Research on Cancer classifies it as possibly carcinogenic to humans. Studies over decades show increased cancer risk in lab animals dosed chronically, and observational research now extends scrutiny into population studies. Toxicologists continue tracking its breakdown products—and keep adding to the call for strengthened handling and lower allowable emissions.
The coming years won’t banish dichloromethane overnight, but tighter regulation is certain. Demand in pharmaceuticals, laboratory synthesis, and specialty processing holds firm, but pressure mounts to find drop-in alternatives or retool old processes for safer chemicals. The chemical industry edges toward greener chemistry—both for compliance and to address consumer pressure. Improvements in vapor recovery, personal protection, and online monitoring now allow for safer handling. The hope remains that research will spotlight novel solvents that can step in where DCM once reigned, letting future generations look back on methylene chloride with respect but without regret.
Dichloromethane stands out on many lab benches, mostly because it dissolves a wide range of substances with ease. I remember my first organic chemistry project in university—the goal was to isolate caffeine from tea leaves. The first step involved mixing crushed leaves with this clear, sharp-smelling liquid. Within minutes, the solution separated the caffeine and left unwanted plant material behind. Chemists keep coming back to dichloromethane because of its knack for pulling out target compounds from complicated mixtures, especially in natural product isolation and pharmaceutical synthesis.
Chromatography depends on finding a solvent that won’t mess up the balance between the stationary and mobile phase. Dichloromethane has become a staple for thin-layer and column chromatography. Its volatility helps things move along faster, letting scientists collect pure fractions sooner and concentrate samples with minimal fuss. I watched colleagues run hundreds of TLC plates and columns—some had shelves stacked with solvent bottles, but DCM (as we called it) was always in heavy use.
Some reactions fall apart with water around. Dichloromethane, especially the ultra-pure anhydrous kind, keeps moisture-sensitive reactions going without disruption. Every chemist learns early about Grignard reagents and carbene transfers; these techniques rely on dry conditions to avoid unwanted side reactions. Using anhydrous dichloromethane gives better control. Results often improve enough to save hours of troubleshooting, plus fewer toxic byproducts show up in the waste stream.
Labs often prepare samples for GC-MS or HPLC by using dichloromethane extraction. This solvent draws out analytes cleanly from environmental, biological, or food matrices. I’ve spent countless hours testing environmental samples for pesticide contamination, and every method started by shaking the sample with DCM, separating the layers, and injecting the cleaned-up extract into an analytical instrument. This step boosts accuracy, translating directly to more trustworthy results.
Handling dichloromethane comes with responsibility. The risks—acute toxicity, possible carcinogenic effects, and vapor inhalation dangers—are real. I’ve seen colleagues work inside fume hoods, wearing splash goggles and thick gloves. Some switches are easy, like swapping to ethyl acetate for less hazardous steps. For must-use cases, good ventilation and waste capture help lower exposure and prevent environmental mishaps. Some universities enforce strict waste tracking, so every milliliter gets handled with care from start to finish.
Scientists are creative; new solvents are coming forward, aiming to do DCM’s job with less risk. Cyrene and ethyl lactate have started to show up in green chemistry circles. Sometimes these greener choices work, sometimes not, but the push is on. For now, dichloromethane remains in rotation wherever no substitute delivers the same purity or speed. Choosing wisely—using only as much as necessary, replacing it where possible, and following strong safety habits—keeps labs productive while protecting health and the planet.
Dichloromethane, also called methylene chloride, pops up in all sorts of places—paint strippers, lab solvents, the plastics world. Its strong ability to dissolve and break down potent materials makes it a staple in the chemical toolkit. Still, its danger stretches far past the label on the bottle. Long ago, working with strong solvents meant trusting them. These days, you can’t afford that. Mishandling dichloromethane means risking your health and everyone else’s in the room.
Exposure most often happens through breathing in the vapors. Unlike strong-smelling solvents, dichloromethane glides under the radar—most folks don’t notice until their head gets heavy, or worse. High vapor levels can knock someone out cold, even if they think a splash of fresh air will keep them safe. This solvent soaks in through skin, too, pulling health risks into the body another way. People sometimes learn the hard way: irritation to eyes and skin is only the start, while concentrated fumes slow breathing, fog the mind, or cause heart problems. Long-term risks like cancer come with continued, repeated use.
Staying safe means building a disciplined routine. A fume hood serves as the MVP—no shortcut gets around proper ventilation. If that gear isn’t on hand, there’s no sense gambling with fans or open windows. A laboratory or workshop without a dedicated extraction system puts everyone in the line of fire.
Personal protection matters. From experience, gloves made from nitrile or neoprene act as the front line—simple latex fails fast against strong solvents. Safety glasses guard the eyes from accidental splashes that can leave a burn or lasting damage. Some jobs call for a sturdy face shield and a lab coat, especially if you’re pouring bottles or handling open containers. One slip can cost you plenty.More folks should take the time to fit masks with organic vapor cartridges. Tossing on a random dust mask won’t block vapors from the lungs. Always check the filter type—mistakes here end up in a hospital visit, not just a bad day at work.
Dichloromethane demands proper storage. Stash it in labeled, chemical-safe containers, far from heat and open flames. Spills happen, so keep absorbent materials ready and never mop up barehanded. The garbage bin out back won’t cut it for leftovers or contaminated materials. Licensed hazardous waste professionals deal with these leftovers so nothing leaches into soil or groundwater. Ignoring this step creates headaches for the community years down the line.
No one’s too skilled for a safety walk-through. Refresher courses on handling dangerous chemicals, reading material safety data sheets, and using equipment keep the risks real in people’s minds. Even with decades under your belt, it’s easy to get comfortable, then get burned—literally. Clear labels, buddy checks, and a step-by-step routine work better than trusting luck or memory. Everyone involved owes it to themselves and their coworkers to keep everyone sharp and focused, every time.
Plenty of industries would swap dichloromethane for a “green” alternative if one worked just as well. In some tasks, no substitute works as quickly or as powerfully. Until that day comes, respect and careful handling serve as the only shield against harm. Speaking up about close calls and sharing tips from real-world experience helps others stay safe. Getting through a workday healthy means more than following rules—it means using your head, trusting your training, and building habits strong enough to keep both you and your team out of trouble.
Pure dichloromethane, or DCM, finds its way into labs and production floors as a valued solvent. This compound works for extractions, polymer processing, and all sorts of applications where purity calls the shots. Contaminants can skew results and spark safety issues. Over the years, I’ve seen the best science stumble over small storage slips. A decades-old bottle in a dusty storeroom tells its own story: a yellowed label, tracks of moisture, a telltale whoosh as the cap cracks open—a sure sign the purity didn’t survive the wait.
DCM evaporates easily. Even a loosely capped vessel lets it vanish. It also absorbs moisture straight from the air. That’s a one-two punch for purity loss. DCM feels like a clear liquid, but it’s surprisingly aggressive—seeping past soft seals, corroding metal, and dissolving plastics not designed for the job. Its affinity for moisture means high humidity spoils what started as a high-grade solvent.
Forget ordinary bottles. The best safeguard against contamination is an amber glass container with a ground-glass stopper or a PTFE-lined cap. Amber glass blocks stray light, reducing slow degradation. Ground-glass stoppers, if clean and dry, offer an airtight seal better than screw tops. If you have to use a screw cap, PTFE liners resist the solvent’s sneaky ways.
Moisture—keep it out. Every time the cap pops open, humid air can creep in. Some labs use a stream of dry nitrogen to blanket the liquid before sealing up. Desiccators, packed with silica gel, help draw out any stray water vapor from the storage air itself.
The cooler, the better. DCM lasts longer in a cold environment. Room temperature isn’t ideal. A dedicated flammable chemical fridge—certified and vented—can stop evaporation and slow any breakdown. I’ve kept DCM for over a year without purity loss just by shelving it low in a proper lab refrigerator and avoiding frequent opening. Direct sunlight or hot spots around equipment accelerate spoilage, so low light and steady temperature guard against unexpected reactions.
Label it like your experiment depends on it. Good practice means every bottle carries the concentration, the date it was opened, and any transfer history. A quick glance lets you pick the freshest batch or toss one that’s spent too long collecting dust. Mystery bottles from years past do more harm than good.
Handling hazardous chemicals takes more than following a checklist. In smaller labs, training can fall behind, or budget limits mean daily compromises. No high-end fridge? Shift the bottle to the lowest shelf in the coolest safe space, away from light and traffic, and keep transfers to a minimum. In larger sites, building a “first-in, first-out” system with regular checks and dated logs stops surprises in the storeroom.
Keep in mind, DCM sits on various hazard lists. Its vapors harm the nervous system and pose a threat to groundwater if spilled. Every mishandled bottle becomes a safety concern, not just an issue for lab results. From my side of the bench, good storage habits turn into a culture of caution—an attitude far more protective than any single guideline.
Maintaining the purity of dichloromethane isn’t just about ticking boxes. Small, practical shifts in how chemicals get stored—the right bottles, cool and dry shelves, careful labeling—pay off in reliable experiments and safe labs.
I’ve spent countless hours in labs where solvent bottles never gather dust. Among the most familiar is dichloromethane, sometimes called DCM or methylene chloride. With a purity of at least 99.8%, the anhydrous stuff slices through grease, resin, and plenty more. Its magic comes from its powerful polar nature. Anyone who’s handled this solvent learns fast—it’s not gentle with everything it touches.
Many folks reach for plastic wares out of habit. It’s light, cheap, and leftovers from one experiment find reuse in the next. Dichloromethane laughs at that plan. Polycarbonate, polystyrene, and polypropylene all risk damage. Even small exposures without immediate effect start a silent process: brittleness, cloudiness, even cracks. One story I remember—someone used a soft polypropylene beaker and wondered why it looked like battered old Tupperware by the afternoon. DCM will eat through most soft plastics in short order.
PTFE (commonly known as Teflon) does a lot better. There’s a reason you see it in high-end chemical-resistant gear. DCM just slides off; no swelling, no dissolving. Polyethylene holds up fairly well, but there's always a bit of risk. Silicone stoppers—these also manage to keep their shape. PVC and acrylic? Not so lucky. The clouding and warping show up before the experiment's done.
Lab glassware shrugs off dichloromethane. Even after years of use, well-made borosilicate glass doesn’t cloud or corrode. Same goes for metals like stainless steel. Ordinary soft metals—think aluminum—can fall prey to corrosion, especially long-term. I’ve scraped away mysterious white powder from aluminum foil that had only brief DCM contact. Stainless steel holds up far better, which justifies its frequent use in chemical filtration setups.
Rubber seals often stump beginners. Nitrile or Viton stays tough, but natural rubber will fall apart—losing elasticity, swelling, and eventually leaking. I’ve seen O-rings turn to mush if made of the wrong compound. For any parts holding pressure or acting as seals, getting compatibility right makes all the difference.
Stories shared across labs point to one lesson: solvent compatibility is a daily, practical concern, not just a line on a safety sheet. Anyone who has lost a precious sample to a leaky or crumbled container remembers the lesson long after. Rapid leaks also drive up costs and inflate disposal concerns, as spilled DCM vaporizes quickly, adding to air quality hazards.
Before any experiment, checking a compatibility chart beats risking an expensive spill or injury. Investing in glassware and proper seals pays off over time. Building a reliable lab kit doesn’t just protect from damage; it cuts down on waste, fires, and exposure risk. Anyone thinking of repurposing a leftover water bottle for solvent work is flirting with trouble. Laboratory-grade containers create a safer, more predictable environment.
Dichloromethane has serious uses and a temper to match. Old hands know its quirks—newcomers discover them, sometimes the hard way. Rely on glassware, select plastics with care, and pick seals that stand firm, and DCM does what you ask. Skimp on compatibility, and you risk more than your experiment’s results. The quality of science rests on a good handle of the tools and the materials—nowhere is that truer than with a tough solvent like dichloromethane.
Dichloromethane, often called DCM by folks in the lab, turns up in everything from extractions to cleaning glassware. With a purity topping 99.8% and anhydrous properties, many expect it to sit on a shelf almost indefinitely. That idea only works if you ignore how time, air, and the occasional careless cap job add up. People with experience handling volatile organics learn fast: shelf life isn't just a number on a label. It plays into lab safety, experimental results, and budget planning — sometimes all in the same day.
If stored tightly sealed, in a cool, dark spot away from moisture and direct sunlight, high-purity dichloromethane generally lasts about two years. That comes from manufacturers' recommendations and real-world lab experience. Some labs stretch it longer, but degradation risk rises. DCM doesn’t go sour overnight, but it does pick up small amounts of acid from interacting with air and light. The chemical slowly forms hydrogen chloride, which creates a build-up of corrosion or complications for anybody chasing high-precision results.
Glass bottles with secure caps, sitting in a flammables cabinet, help DCM last close to its expected shelf life. Small amounts of water can slip in every time the bottle opens, even if only a second or two passes. Even though it says 'anhydrous' on the label, that water content creeps up over months, especially with older seals or bottles opened in humid air.
Dichloromethane breaks down to several nastier compounds, including phosgene in the presence of oxygen and light. It takes a while, but nobody wants to gamble with long-term health or accidental exposures. I’ve seen labs discard DCM every 18 months whether or not the sticker says it expires later. Older bottles start raising eyebrows once the inside cap or rim shows rust or the liquid gives off a faint, sharp odor different from its usual sweet smell.
Older DCM also tends to lose its edge in extraction protocols. Solvent drag, loss of yield, and increased residue often point to a bottle that's outstayed its welcome. Strict labs test for acidity or water pickup before signing off on bottling or critical syntheses. Many skip the hassle and write off anything questionable, since a failed experiment costs more than a wasted liter of solvent.
Tougher storage habits stretch out the useful life of DCM. Pour what’s needed into a smaller container to avoid repeated openings. Use amber bottles to cut out light exposure where possible. Keep detailed logs of opening dates and batch numbers. Nobody wants a midnight panic during an urgent reaction because a solvent failed unexpectedly.
Labs also rotate stock aggressively. New DCM bottles go to the back, older bottles right in front. Purging expired or doubtful material protects both people and data. Waste programs deal with the rest, following government guidelines. At the end of the day, treating DCM as perishable rather than immortal reflects respect for safety, reliable science, and the people doing the daily grind with these chemicals.
| Names | |
| Preferred IUPAC name | Dichloromethane |
| Other names |
Methylene chloride DCM Dichloromethane |
| Pronunciation | /daɪˌklɔːrəˈmiːθeɪn/ |
| Identifiers | |
| CAS Number | 75-09-2 |
| 3D model (JSmol) | `ClCCl` |
| Beilstein Reference | 1209226 |
| ChEBI | CHEBI:15767 |
| ChEMBL | CHEMBL134 |
| ChemSpider | 5790 |
| DrugBank | DB00844 |
| ECHA InfoCard | 03b4e7fc-7efd-4300-be6c-e5c1e4d44ca5 |
| EC Number | 200-838-9 |
| Gmelin Reference | 140214 |
| KEGG | C01426 |
| MeSH | D002683 |
| PubChem CID | 6344 |
| RTECS number | PA8050000 |
| UNII | F847N2Q362 |
| UN number | UN1593 |
| Properties | |
| Chemical formula | CH2Cl2 |
| Molar mass | 84.93 g/mol |
| Appearance | Colorless liquid |
| Odor | Sweet, chloroform-like |
| Density | 1.325 g/mL at 25 °C (lit.) |
| Solubility in water | 20 g/L (20 °C) |
| log P | 1.25 |
| Vapor pressure | 47.4 kPa (20 °C) |
| Acidity (pKa) | ~NA~ |
| Basicity (pKb) | 13.76 |
| Magnetic susceptibility (χ) | −10.2 × 10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.424 |
| Viscosity | 0.413 mPa·s (20 °C) |
| Dipole moment | 1.60 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 88.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -95.6 kJ·mol⁻¹ |
| Std enthalpy of combustion (ΔcH⦵298) | -686.0 kJ/mol |
| Pharmacology | |
| ATC code | D08AX |
| Hazards | |
| Main hazards | Harmful if swallowed, in contact with skin or if inhaled. Suspected of causing cancer. Causes skin irritation and serious eye irritation. May cause respiratory irritation. |
| GHS labelling | GHS02, GHS07, GHS08 |
| Pictograms | GHS02, GHS07 |
| Signal word | Warning |
| Hazard statements | H302 + H332: Harmful if swallowed or if inhaled. H315: Causes skin irritation. H319: Causes serious eye irritation. H351: Suspected of causing cancer. |
| Precautionary statements | P261, P271, P280, P301+P310, P304+P340, P308+P313, P403+P233 |
| NFPA 704 (fire diamond) | 2-1-0 |
| Autoignition temperature | 605 °C |
| Explosive limits | 13–22% (V) |
| Lethal dose or concentration | LD₅₀ Oral - Rat - 1,600 mg/kg |
| LD50 (median dose) | LD50 (oral, rat): 1600 mg/kg |
| NIOSH | NIOSH: PA8050000 |
| PEL (Permissible) | PEL (Permissible Exposure Limit) of Dichloromethane (Anhydrous ≥99.8%): 25 ppm (TWA) |
| REL (Recommended) | 20 ppm |
| IDLH (Immediate danger) | IDLH: 2,000 ppm |
| Related compounds | |
| Related compounds |
Chloroform Chloromethane Carbon tetrachloride Methanol Ethylene dichloride Tetrahydrofuran Acetonitrile |
