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Diethyl Maleate, also known as DEM, has been a regular player in the world of industrial and laboratory chemistry since the early 20th century. Anyone who has thumbed through an old organic chemistry textbook will recognize its structural simplicity: essentially, DEM forms by adding ethanol across the double bond of maleic acid. In early studies, chemists gravitated to DEM thanks to its straightforward synthesis and the way it opened the door for all kinds of esterification and Michael addition reactions. It's a bridge compound. In the postwar boom, as the chemical sector ramped up mass synthesis of everything from medicines to polymers, DEM earned its way onto production lines as a feedstock, especially in the push for new plasticizers, solvents, and additives.
Pour some DEM out and you'll notice it forms a clear, colorless liquid, easy to spot on the shelf amid syrups and oils. The fruity smell might catch you off guard if you're not expecting it. Its melting point sits well below freezing, and it boils just above water's threshold, so open-air handling usually ends with evaporation. DEM doesn't dissolve in water, preferring to float on top or mix with most common organic solvents. Its double bond begs for chemical attention, making it reactive in all the right ways for practical synthesis.
The bottle's label usually proclaims at least 99% purity, which matters when small impurities can make a mess of a reaction. It's a molecule with two ethyl groups stuck on the ends–not much room for ambiguity. You see the chemical formula, C8H12O4, and you know what you’re getting. Regulations expect you to check for residues of maleic acid or diethyl fumarate, but in well-prepared DEM, these show up in trace amounts, often below detection. Packaging doesn't feel flashy—usually glass or steel containers sealed tightly to hold back air and moisture, as exposure can lead to slow breakdown or hydrolysis.
Most commercial producers stick with a reliable method: acid-catalyzed esterification of maleic acid using ethanol. Add a touch of sulfuric acid to hurry things along, and distill off water to tip the reaction forward. Some plants use maleic anhydride instead, saving a step and boosting yields, but the dance stays the same—heat, react, then clean it up by washing and drying. It doesn't spark headlines, but getting a pure batch without leftover acid or unreacted alcohol turns out to be the hardest part if you care about quality downstream.
Anyone who’s mixed up DEM with amines remembers how quickly it forms Michael adducts, finding use in everything from pesticide manufacture to pharmaceutical intermediates. In the lab, that double bond gets attacked by nucleophiles or used to block other reactive sites. DEM also steps in for controlled cross-coupling work or to snatch up free radicals in stabilization jobs. Sometimes, chemists change the ethyl groups for other alcohols, morphing DEM into a new family member with slightly tuned properties, chasing better solubility or lower boiling points depending on what the process demands.
Nobody likes stumbling over chemical tongue-twisters, so DEM earned a few aliases. Diethyl cis-butenedioate shows up in technical literature, and old safety sheets toss around names like diethyl (Z)-butenedioate or 2-butenedioic acid diethyl ester. Whether you see it in English or German or French catalogs, the core is the same, but each translation tips its hat to the same functional backbone in the molecule.
Stuffing DEM into your daily routine without paying attention can spell trouble, especially if you’re sloppy about ventilation. Its fumes can irritate skin and lungs, and long hours in a poorly ventilated storeroom drive that home fast. Spilled DEM spreads quickly: you’d rather catch it on an absorbent pad than let it creep across the floor. Wearing gloves and goggles isn't negotiable in any plant or proper lab. Fire safety drills always include a nod to DEM, given its flash point and low boiling point combination. Proper handling boils down to routine care: label, store cool and dry, and keep it out of hands untrained in organic work. Waste streams need care because the molecule lingers and breaks down slowly, especially if it slips into waterways.
Walk through an industrial park and you'll find DEM as a building block in agricultural chemicals, sometimes as a stabilizer for plastics, and other times as a touchstone for specialty solvents. Paint and coatings manufacturers slip it into formulations to tweak flexibility and weather resistance, while a handful of pharmaceutical companies use it as a starting block for custom intermediates. Researchers still discover new transformations for DEM–in green chemistry, for example, they're using it to carry out reactions that dodge more dangerous reagents or create less waste, which news outlets have started to celebrate.
Take a stroll through recent research papers, and you catch a persistent effort to find safer or more effective alternatives to older, more hazardous chemicals. DEM stands out as a substrate for new catalyst research, especially in the hunt for metal-free synthesis, or in finding selective ways to introduce carbon-carbon bonds without expensive metals. Bio-based routes to DEM also inch forward, with teams exploring ways to reengineer fermentation processes for cheaper and greener starting materials. Even the biomedical field gives DEM occasional love for designing better-targeted drug molecules, thanks to that reliable double bond.
Toxicologists don’t call DEM benign. Take in enough fumes or spill some over your skin, and you’ll find it triggers irritation and, at high doses, more severe effects. Animal studies showed that sustained high exposure can stress organs, hinting at the need for tight workplace controls. Chronic effects haven’t matched the threat level of more notorious esters, but regulators in Europe and North America keep close tabs, especially with its move into areas touching food packaging or cosmetics. Waste handling and disposal rules try to close loopholes since water contamination can push mutagenic byproducts into broader environments. Anything being considered for large-scale use ends up back under the microscope with each regulatory change.
Futures for DEM don’t stick with the status quo. As the world puts more pressure on green chemistry, DEM might find itself as a stepping stone to bio-derived polymers that cut out petroleum feedstocks. Plastics, coatings, adhesives–all old haunts for DEM–look set for a shakeup as sustainability standards ramp up. Researchers keep hunting for ways to minimize residual toxicity, or to engineer chemical processes that lock away byproducts. DEM's role in Michael additions and as an intermediate gives it a technical edge, provided its lifecycle fits with emerging environmental guidelines. It wouldn't surprise anyone if in a few years, this chemical, long stashed in lab drawers and industrial bulk tanks, becomes a talking point not just for technical people, but for everyone interested in the chemicals that shape daily life.
Diethyl Maleate, or DEM, doesn’t spark recognition like aspirin or caffeine, but its reach spans chemical and pharmaceutical industries. This colorless liquid, with a mild, fruity smell, takes on jobs that keep products working right. In my early career as a lab technician, we relied on DEM for more than a few projects—sometimes as a reagent, sometimes as a stabilizer. I learned quickly that even a small amount can shift a whole process.
One of DEM’s key roles happens in pharmaceutical manufacturing. Many drugs—especially those designed to stick around in the bloodstream longer—contain molecules that need to be shielded or altered for better absorption. DEM acts as a masking agent by binding to active groups on other molecules, making those drugs safer or easier to absorb. In real-world terms, that means some medications are more predictable and less likely to hurt the liver or kidneys. The process isn’t glamorous, but for people using painkillers, anti-cancer agents, or antivirals, DEM has made those pills more effective.
Chemists lean on DEM for making other chemicals. It often steps in to trap or “scavenge” substances like thiols that can cause unwanted side reactions. I remember one organic synthesis that screeched to a halt because impurities built up; adding DEM solved the issue right away. This makes DEM a “clean-up crew” for complicated reactions, keeping things running smoothly. The work it does behind the curtain supports not just pharmaceuticals but also flavors, scents, and specialized polymers.
DEM plays a quiet part in plastics, adhesives, and coatings. It reacts with other compounds to create polymers with certain strengths or flexibility. Admittedly, most people buying new shoes or sporting equipment never hear about DEM, but the comfort and durability of certain products owe something to the way DEM shapes those materials at the molecular level. The compound helps manufacturers customize plastic films and coatings so they stretch, resist tears, or stick just right.
Handling DEM brings up important questions about workplace safety. Skin and eye contact cause irritation, and inhalation can be harmful. My experience working with DEM taught me to stay cautious and respect the rules—always using gloves and goggles. This matters because lower-volume specialty chemicals sometimes escape notice when policies focus on bulk chemicals. Well-trained workers and strict labeling help prevent accidents, which keeps the environment and employees safe. Researchers tracking worker exposure haven’t flagged DEM as a big risk in consumer products, but keeping a close watch makes sense.
One thing I’d like to see is more transparency in supply chains for compounds like DEM. Tracking sourcing and handling, making data public, and keeping stakeholder feedback open build trust. When companies put out clear safety data and encourage customers to ask questions, it’s easier to respond to concerns. Governments can help by funding independent studies on long-term health and environmental effects. DEM, while vital, fits in a category where a little more sunlight would benefit everyone involved.
Diethyl maleate gives off a slightly fruity smell and looks like a colorless liquid. Its chemical formula is C8H12O4. Most folks working in a lab setting will recognize it as a dialkyl ester made by reacting maleic acid with ethanol. Someone who works in an industry making pharmaceuticals, cosmetics, or even plastics will likely bump into this compound sooner or later.
Every molecule of diethyl maleate holds a backbone of maleic acid. Replace the two carboxylic acid hydrogens with ethyl groups and you have it: (CHCOOC2H5)2. Its official IUPAC name reads as "diethyl (Z)-but-2-enedioate". The core structure shows a double bond between the two central carbons. This double bond keeps both ester groups on the same side, giving diethyl maleate its "cis" or "Z" configuration.
Chemically drawn, the structure looks like this:
I worked in a polymer science lab for a few years and noticed how often my team would grab diethyl maleate off the shelf. Our synthesis work needed efficient “Michael acceptors” — molecules that react smoothly with nucleophiles like amines and thiols. Diethyl maleate fits the bill because those two electron-withdrawing ester groups pull electrons out of the double bond, making the whole molecule more reactive. Chemists use it to add soft, flexible properties to plastic resins, or as a base for making medicines that fight off certain toxins in the body.
Factually, research has proven diethyl maleate interacts with glutathione in living systems. This has use in studying how cells handle oxidative stress. Another corner of the world, companies developing insecticides or paints check out its structure for making safer, biodegradable coatings. The long experience of practical and medical chemists with this molecule makes it clear: good understanding of the chemical formula and 3D structure lets developers tailor performance, reduce hazards, and increase effectiveness at the bench or the production floor.
Handling diethyl maleate calls for common sense and reliable data. Eye and skin contact can irritate, as documented in workplace safety sheets from the CDC and NIOSH. My time in the lab showed that even well-ventilated rooms benefit from proper gloves and goggles. Storing the bottle away from strong acids and bases stops unwanted reactions, and the structure helps explain why: the electron-rich sites can interact with aggressive chemicals very quickly.
Better success in using diethyl maleate comes from paying attention to its chemical behavior. Research backed by peer-reviewed studies recommends using it in closed systems or under fume hoods. Also, environmental regulations guide its disposal due to slight aquatic toxicity. Relying on knowledge about its formula—those eight carbons, twelve hydrogens, and four oxygens—pays off when aiming to avoid accidents and produce cleaner products.
Diethyl Maleate isn’t a household name, but anyone working in a lab or small-scale chemical plant likely recognizes it. This colorless liquid sees plenty of use in chemical synthesis, pharmaceuticals, and agriculture. Like plenty of organic solvents, it promises both utility and hidden hazards. I’ve handled similar chemicals in academic and industry settings, and certain lessons always stick.
Let’s talk storage. Diethyl Maleate doesn’t demand fancy technology for containment, but standard lab glass bottles with tight-fitting screw caps work best. I always choose glass or coated metal for storing volatiles like this because plastics sometimes soften or crack. No researcher enjoys mopping up a spill or running into surprise vapors due to a cheap cap. Resist the urge to stick it in the sunlight or near heat: a simple cabinet, away from ignition sources, keeps most issues at bay. Temperatures around room level (about 20-25°C) feel like obvious choices, but it’s easy to forget when the air-conditioning hiccups during a hot summer. Humidity control matters, too. Moisture can creep in and change the nature of the chemical.
Labeling looks like a formality, but any seasoned technician knows the dangers of mystery bottles. Always write the name, date, and any hazard info right on the bottle. I’ve seen folks lose weeks of work because of bad labels—one mix-up in the fridge made a mess I’d rather forget.
Direct skin contact brings irritation, sometimes even a rash. Those latex or nitrile gloves sitting in every chemical lab are there for a reason. I remember a classmate who once skipped gloves for “just a second.” He regretted that when the stinging started. People with sensitive skin might get worse reactions, so long sleeves and a lab coat seem worth the small hassle. In case of a spill, the protocol kicks in: absorb any liquid with inert material (think sand or a spill pad), and use a fume hood wherever possible.
Inhaling vapors creates its own troubles. You don’t want to find out what a headache from organic solvent vapors feels like during a long afternoon. That means good ventilation—fume hoods should never sit unused when pouring or transferring. I make it a habit to check air movement with a strip of tissue for peace of mind.
Pouring leftover Diethyl Maleate down the drain could put a fine dent in your lab’s record and pollute water systems. Most organizations have hazardous waste programs for a reason. Collect used chemical and contaminated items in clearly labeled containers. Properly sealed disposal bins kept separate from regular waste cut down on accidents—my first summer in a lab, someone trashed solvent-soaked towels in the regular bin, and we nearly started a fire.
Training staff on the danger spots—fire risks, inhalation, chemical burns—saves not just time but lives. Emergency showers and eyewash stations should always sit within reach. I test these every week, long after most colleagues stopped caring. Regular reviews and drills keep safety fresh.
Fire extinguishers play a quiet but important role near storage areas, since even one stray spark could turn things ugly. Every quarter, my team checks expiration dates and makes sure everyone remembers operation basics. Clear policies backed by a bit of vigilance and honest-to-goodness teamwork can take a routine task like storing Diethyl Maleate and make it pretty uneventful—exactly what you want from a potentially hazardous chemical.
Diethyl maleate pops up in a surprising number of chemical processes and industrial uses, from making pharmaceuticals to working as a reagent in research labs. You might run into it in some agricultural and cosmetic products, too. Even though it gets used widely, most people have never heard of it until they have to handle it firsthand.
People handling diethyl maleate, especially in labs or manufacturing, should pay close attention to its health risks. Breathing in its vapors, or even getting some on your skin, can set off a cascade of dangerous effects. Contact with skin often leads to irritation—redness, itching, possibly even blisters if contact continues. Eyes can feel a lot worse, stinging painfully, producing tears, and staying red for hours. I’ve seen coworkers underestimate “just a splash,” and pay the price with days of discomfort.
Breathing in its fumes brings bigger problems. Some symptoms look mild, like headaches or dizziness, but there’s a risk of more serious lung irritation. In high-enough concentrations, diethyl maleate vapor can make you cough, struggle to breathe, or even cause chemical pneumonitis. People with asthma or allergies react even faster. Data shows workers exposed without proper protection report respiratory symptoms a lot more often. Over time, repeated exposure might trigger long-term issues, although current research still explores the risks of low-level chronic contact.
Swallowing diethyl maleate seems unlikely outside a lab accident, but accidental ingestion leads to stomach pain, nausea, or even more severe effects like chemical burns inside the throat or stomach.
Most people instinctively think of health before worrying about fire risk, but diethyl maleate is flammable. It forms vapor-air mixtures that ignite easily. Storage rooms with poor airflow, heat sources, or static discharge raise the risk immensely. Fires started by this chemical often burn with thick, toxic smoke that’s just as hazardous to lungs as the chemical itself.
Environmental spills also create long-term problems. Liquid diethyl maleate can contaminate water, harm aquatic life, and cause chain reactions in the food web. Cleaning up after a spill takes more than just a mop, because the chemical sticks around and breaks down slowly in nature.
PPE saves a lot of people from unnecessary pain. Gloves, goggles, and respirators offer real defenses against exposure. Labs and factories using diethyl maleate have to invest in fume hoods, closed systems, and training for their teams. OSHA and other health agencies set strict exposure limits—usually just a fraction of a part per million in the air—to keep workers out of danger.
Clear labeling, regular monitoring of air in workspaces, and well-rehearsed emergency procedures change the game completely. Spills get cleaned quickly, accidents slow down, and nobody needs to guess what they’re handling.
Folks outside of industry might not run into diethyl maleate every day, but if it's in a product, manufacturers should give clear safety information and minimize its use, especially in items that touch skin. For waste, safe disposal is non-negotiable; pouring it down the drain damages much more than pipes. Every step to cut exposure and safe handling adds up. From the people mixing reagents in a lab to those tasked with environmental cleanup, everyone has a role in managing the risks.
Diethyl maleate tends to fly under the radar unless you work in a chemistry lab, but it plays a bigger part in daily life than most people realize. This compound usually appears as a colorless liquid. You won’t catch much of a smell from it—anyone who’s handled organic chemicals with heavy odors can appreciate that small mercy. Its formula, C8H12O4, points to its mix of carbon, hydrogen, and oxygen atoms. But the personality of diethyl maleate really shows up in the way it behaves and interacts with other materials.
Pick up a bottle of diethyl maleate and the first thing you notice—besides the clear, glossy look—is how thin it feels. With a density around 1.057 g/cm³, it pours more like vegetable oil than syrup. Its boiling point sits near 230°C, so it’s not about to vaporize in your hands under normal conditions. The liquid doesn’t freeze easily: its melting point is way down at about -10°C. Water and diethyl maleate don’t mix well, but pour it into alcohol or ether and they’ll blend right away. This gives it a certain flexibility in the lab, especially when dissolving or mixing with other chemicals.
The heart of diethyl maleate lies in its double bonds. These aren’t just chemical trivia—they set the compound up for a wide range of reactions. Double bonds make diethyl maleate more reactive towards other substances, meaning scientists can use it as a building block. The two ester groups on the molecule add another layer. This structure makes it sensitive to hydrolysis, letting water or acid break it into smaller parts. That’s part of the reason why it works so well in plastics, resins, and even some medicines.
Take its role with glutathione, for instance. Doctors sometimes use diethyl maleate to study how our bodies handle toxins, since it reacts directly with glutathione, a key ingredient in detoxifying harmful substances. This reaction creates stress on cells mimicking real-life exposure to pollutants, helping researchers understand how the body defends itself. The compound also acts as a “Michael acceptor,” which means it joins up with nucleophiles in organic synthesis. That makes it handy in pharmaceutical research, plastics, and agricultural chemistry.
No one wants uninvited visitors in their workspace, and diethyl maleate deserves the same respect. It’s not flammable at room temperature, but it can catch fire if heated enough. Skin contact may cause irritation, and it can mess with your eyes or lungs if you’re exposed for too long. Lab safety matters and diethyl maleate is a reminder of why goggles and gloves belong on every chemist’s checklist. For industries, the challenge is setting up systems that stop leaks and control air quality. If you catch even a whiff of chemicals in a workspace, it’s worth asking if the ventilation hits the right mark.
People have found creative uses for diethyl maleate, but with every new application comes the need for careful study. Regulators and scientists alike have to weigh benefits against risks. Green chemistry pushes for safer, less toxic alternatives, or for refining how we use diethyl maleate to cut down waste. Sticking with best practices—proper storage, careful disposal, regular training—helps lower risks and keep things running smoothly. For anyone who works around chemicals, knowing the story behind each one offers a bit of extra insurance, both for personal health and the environment.
| Names | |
| Preferred IUPAC name | Diethyl (2Z)-but-2-enedioate |
| Other names |
Diethyl Maleate DEM Maleic acid diethyl ester Diethyl (Z)-butenedioate |
| Pronunciation | /daɪˈɛθ.əl ˈmeɪ.leɪt/ |
| Identifiers | |
| CAS Number | 141-05-9 |
| Beilstein Reference | 87880 |
| ChEBI | CHEBI:34770 |
| ChEMBL | CHEMBL14185 |
| ChemSpider | 6326 |
| DrugBank | DB02180 |
| ECHA InfoCard | 100.003.374 |
| EC Number | 203-742-5 |
| Gmelin Reference | **82261** |
| KEGG | C01758 |
| MeSH | D002948 |
| PubChem CID | 8217 |
| RTECS number | OI8575000 |
| UNII | 9Z8LA7D8H5 |
| UN number | UN2362 |
| Properties | |
| Chemical formula | C8H12O4 |
| Molar mass | 172.20 g/mol |
| Appearance | Colorless transparent liquid |
| Odor | Fruity odor |
| Density | 1.020 g/cm³ |
| Solubility in water | Slightly soluble |
| log P | 2.2 |
| Vapor pressure | 0.05 mmHg (20°C) |
| Acidity (pKa) | 6.21 |
| Basicity (pKb) | 7.25 |
| Magnetic susceptibility (χ) | -7.57 × 10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.4140 |
| Viscosity | 1.542 mPa·s (at 25°C) |
| Dipole moment | 3.31 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 489.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -489.5 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -2714 kJ/mol |
| Pharmacology | |
| ATC code | V03AB37 |
| Hazards | |
| GHS labelling | GHS02, GHS07 |
| Pictograms | GHS07, GHS08 |
| Signal word | Warning |
| Hazard statements | H302, H315, H319, H335 |
| Precautionary statements | P261, P280, P305+P351+P338, P304+P340, P312 |
| NFPA 704 (fire diamond) | 2-2-1 |
| Flash point | 96 °C (Closed Cup) |
| Autoignition temperature | 415 °C |
| Explosive limits | Explosive limits: 1.1–7.1% |
| Lethal dose or concentration | LD50 oral rat 3,169 mg/kg |
| LD50 (median dose) | LD50 (median dose): Oral rat LD50 = 3,150 mg/kg |
| NIOSH | NIOSH: OY0450000 |
| PEL (Permissible) | PEL: 5 mg/m³ |
| REL (Recommended) | REL 5 mg/m3 |
| IDLH (Immediate danger) | Unknown |
| Related compounds | |
| Related compounds |
Diethyl fumarate Dimethyl maleate Maleic anhydride Maleic acid Diethyl succinate |
