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2-Butenenitrile, especially in its trans form, threads through chemical history with roots in one of the great periods of nitrile chemistry during the previous century. Industrial chemists sorted out its synthesis in earnest during the expansion of organic chemicals after the Second World War, working with alkenes and nitriles as demand for new intermediates in plastics, pharmaceuticals, and specialty chemicals kept rising. For those who chart the progress of commodity chemicals, the study of 2-Butenenitrile often parallels the broader exploration of unsaturated nitriles, as laboratories and plants sought more ways to use shorter-chain nitriles beyond acrylonitrile. Though less famous than its structural cousins, 2-Butenenitrile quietly backs up several chemical processes that rarely make the headlines.
If you get a bottle of pure 2-Butenenitrile [trans], you’ll meet a colorless to pale-yellow liquid with a sharp, sometimes unpleasant whiff—an experience common to nitriles. Its moderate boiling point puts it squarely in the working range for many organic syntheses. On a bench or in a reactor, it showcases enough reactivity to satisfy chemists who want to map out more ambitious molecules.
With its double bond and a nitrile group, this compound offers a playground for functional group chemistries. The trans configuration adds a bit of stability and makes separation from the cis form more manageable. If handled out in the open air, it will evaporate steadily, and with a flash point below many lab solvents, folks pay close attention to how it’s stored.
In a commercial or research setting, purity drives performance. 2-Butenenitrile, sold for research or as an intermediate, arrives with specs that outline water content, color index, and impurity profile. Those who’ve spent time in analytical labs know that even small percentages of contaminants, especially structurally similar isomers or traces of saturated analogs, can steer a reaction off track or affect downstream results. Clear labeling, including the trans designation, keeps things transparent. For most users, the understanding of regulatory tagging—such as hazard markings—shapes not just what is written on the bottle, but how it is treated in storage and transit.
Techniques to make 2-Butenenitrile usually start with simpler unsaturated feedstocks. Industrial producers lean on dehydrocyanation—pulling a hydrogen atom off a precursor like butyronitrile or leveraging elimination reactions from precursors that already contain both the nitrile group and a double bond. Classic routes use catalysts to steer the formation of the trans isomer, which isn’t always nature’s default choice. In smaller-scale syntheses, students and researchers often favor dehydration reactions or work with halide precursors, tossing in a base to push the reaction toward forming the nitrile. The drive to tighten up yields and reduce byproducts tends to dominate technical tweaks in this area.
The true value of 2-Butenenitrile shows up in its willingness to react. The nitrile group invites nucleophiles, sometimes leading to amines or carboxylic acids after a wet workup. The double bond gives opportunities for additions—hydrogenation, hydrohalogenation, or even polymerization under the right conditions. Cross-coupling methods let chemists tack on aromatic or aliphatic fragments, and the world of organometallic chemistry cracks open new derivatives. Anyone who has spent evenings pushing reactions to completion or tuning product ratios finds 2-Butenenitrile’s versatility useful. The symmetry and spacing of the groups make it a reliable building block for more advanced syntheses, especially since small changes in this intermediate can shape the properties of the molecules down the road.
Over the years, 2-Butenenitrile has answered to several titles—crotononitrile, trans-β-butenenitrile, and sometimes simply trans-2-butenenitrile among chemists who don’t want to trip over syllables. Each label signals the same core structure, but trade names and supplier quirks sometimes add to the confusion. In borderless laboratory circles, common names usually win out, as jargon adapts to fit the community at hand.
Experience teaches respect for nitriles. 2-Butenenitrile may not jump off the safety data pages like some of its heavier or more reactive cousins, but it carries real risks. Exposure causes irritation, and inhalation brings on headaches and nausea, thanks in part to its metabolic pathway—body enzymes can convert the nitrile to toxic metabolites, some of which can mess with cellular respiration. Eye and skin contact draw warnings, and laboratories deploy fume hoods and gloves as a matter of routine. I’ve seen students skip simple safeguards and regret it; a whiff in a close room makes for a quick lesson in risk awareness.
Plant operators and workers in chemical industries follow industry standards like those from OSHA or the EU CLP to guide handling, storage, and disposal protocols. Storing these chemicals in tightly sealed, clearly labelled containers away from sources of ignition forms a basic rulebook that leaves little room for shortcuts.
You won’t find 2-Butenenitrile splashed across consumer labels, but it sells its worth where intermediates play an essential role. Its use in synthesizing amines, acids, and specialty agents touches pharmaceuticals, agricultural chemicals, and flavors or fragrances built on nitrogen skeletons. Industrial labs string together several reaction steps, banking on this molecule’s mix of stability and reactivity. Experienced process chemists like how it slots into catalytic and sequence-based transformations, especially when purity makes a difference.
Research into 2-Butenenitrile isn’t about headline-grabbing breakthroughs but more about incremental improvements and clever tweaks. Scientific papers still roll out on improved catalytic methods for its synthesis and the discovery of new reactions that coax out different functional groups or chirality. Development lab teams keep looking for higher-yield routes, greener chemistry, or safer reaction conditions. Environmental impact and worker safety push some of these projects, as industry tries to comply with stricter limits on emissions and waste.
Toxicity research gets personal for lab workers and regulators. Animal studies show that at high enough doses, 2-Butenenitrile hits central nervous systems and can cause respiratory distress, though it takes more than casual exposure to hit acute toxicity markers. Regulatory agencies watch for chronic effects and environmental persistence, and set occupational exposure limits based on available research. Most of us who have worked in the shadow of nitrile bottling know that even low-level exposure, over time, can add up, so the push for regular air quality checks and exposure monitoring remains strong.
Future conversations about 2-Butenenitrile look less like a dramatic shift and more like steady evolution. Stricter regulations on workplace exposure and environmental discharges steer companies toward cleaner synthesis and safer handling. Academic research keeps finding new coupling partners and transformation methods, each tweak translating to efficiencies in larger-scale production. Startups and green chemistry advocates eye opportunities to use bio-based feedstocks, hoping to trim the environmental cost of traditional petrochemical processes. Though it remains just a cog in broader production lines, its ability to pivot between different kinds of reactions keeps it relevant. For those who like to see how humble starting points ripple outward, the evolution of 2-Butenenitrile serves as a reminder that even overlooked molecules can shape where chemistry goes next.
At some point in school, most of us ran into that moment in organic chemistry where one tiny change in a compound’s structure changed everything—how it smelled, how it reacted, or whether it belonged on the shelf or in a locked cabinet. That’s how I learned to pay attention to the details, especially with compounds like 2-Butenenitrile in its trans form. Its chemical formula, C4H5N, seems simple until you dig around and see how tiny differences carry big weight in both science and industry.
Picture two molecules with the same atoms but different shapes—cis and trans isomers. Their health risks, properties, and reactions don’t always match. In 2-Butenenitrile, the trans isomer sets the methyl group and the nitrile group on opposite sides of the double bond. That looks minor on paper, but I remember in lab, trans isomers sometimes brought their own set of challenges and uses, from synthesis outcomes to boiling points and solubility.
Chemical formulas aren’t just trivia—they’re safety essentials. 2-Butenenitrile’s formula, C4H5N, breaks down into four carbon atoms, five hydrogens, and a single nitrogen. Sounds straightforward, right? Anyone who’s had to check an SDS (Safety Data Sheet) knows that getting the formula or stereochemistry wrong doesn’t just lead to theory mistakes, it can make labs and workplaces less safe. Chemical manufacturers, especially those dealing in fine chemicals for pharmaceuticals and plastics, track these formulas closely for both regulatory reasons and to avoid costly mishaps.
2-Butenenitrile isn’t one of those chemicals found stacked on grocery shelves, but it pops up in industrial syntheses—acrylonitrile production, certain pharmaceutical pathways, and research into new materials. Because of its unstable nature and potential health risks (think: toxic fumes, skin irritation), its formula and molecular structure must be verified every time it changes hands or gets used in research. Drawing from my experience, catching a formula error before shipping out a reference standard can mean the difference between a phone call from a happy client and a recall that lands the lab in hot water with regulators.
Trans-2-butenenitrile’s distinct structure also affects purification and identification in quality control. Infrared spectroscopy and NMR don’t just spit out numbers; the technician reads them to confirm the position of groups around the double bond—checking it’s trans, not cis. If you’ve ever run TLCs (thin-layer chromatography) or column purifications, the frustrations of separating isomers is all too familiar. Mislabeling the compound, mixing up stereochemistry, or skipping purity checks can lead to research setbacks or production failures.
Today, automation, better analytical instruments, and certifications keep labs honest about what bottles carry inside. Companies should invest in high-quality standards and robust testing—because understating a detail like the chemical formula of trans-2-butenenitrile can ripple into supply chain headaches or even environmental recalls. For scientists, students, and industry veterans alike, attention to those small chemical details isn’t just a box-checking exercise—it’s the backbone of trust, safety, and progress in the chemical world.
Few people outside of chemical engineering circles talk about nitriles at the dinner table, but 2-Butenenitrile deserves a moment in the spotlight. Known to some as crotononitrile, this colorless to pale yellow liquid features a sharp odor you’ll not soon forget. It’s got a double bond linking carbon atoms and a nitrile group, making it incredibly reactive. This means chemists gravitate toward it as a starting material. The “trans” in the name points to its molecular arrangement, which actually steers many of its practical applications.
Industrial chemists use 2-Butenenitrile mainly for one reason: synthesis. Turn to rubber additives, agricultural chemicals, and dyes, and there’s a good chance this compound sits somewhere in the production chain. For example, it helps produce crotonic acid and crotyl alcohol, two materials that crop up across specialty chemicals and coatings. It acts a bit like a Swiss Army knife for synthetic chemistry — flexible, quick to react, and able to open doors to countless derivatives.
It plays a pivotal part in making quaternary ammonium compounds used in fabric softeners and disinfectants. Demand for sanitizers has grown over the years, especially with heightened attention to public health. That’s brought more raw materials like 2-Butenenitrile into focus.
Rubber and plastic plants tap into 2-Butenenitrile as an intermediate along the way to more complex polymers. Think about the everyday uses of synthetic rubbers, from auto parts to industrial hoses. The basic framework begins with simple molecules, and crotononitrile stands as one of those starting points. It doesn’t make the headlines, but its chemistry lays the foundation for insulation, protective gear, and more.
Modern agriculture depends on precise formulations for pest control. Many chemical manufacturers design active ingredients and intermediates from nitriles, and crotononitrile fits this need. By reacting with other agents, it helps create compounds that protect crop yields or fight invasive weeds. Without such intermediates, the cost and complexity of developing advanced agrochemicals would go up. This direct link between raw materials and food supply highlights why even obscure chemicals matter.
Step inside a textile mill, and the colors jumping off fabrics owe something to another set of reactions involving crotononitrile. Synthetic dyes require molecular backbones with nitrile groups, so producers turn to 2-Butenenitrile when blending the molecules that give hues their staying power. Textile markets demand consistency, which starts not with the color itself, but with high-quality starting chemicals.
Using 2-Butenenitrile calls for respect. Toxicity ranks as a real concern; inhalation or skin exposure raises health risks. Factories must invest in proper ventilation and monitoring. Disposal regulations grow stricter, reflecting our collective push for cleaner water and air. Real progress means balancing industrial advances against practical safeguards, from personal protective equipment to emergency procedures.
While laboratory benches and production lines might change over time, the need for adaptable chemical intermediates remains steady. With pressure on sustainability and tighter regulations, chemical producers should look for greener pathways and better waste management. Safer alternatives and more efficient reactions form the next frontier. The story of 2-Butenenitrile speaks to progress built piece by piece, through careful reactions—and a strong emphasis on health and safety for everyone involved.
2-Butenenitrile, often listed as crotononitrile, shows up in chemical production and sometimes in the work of organic labs. This chemical packs a punch in the hazard department. If you’ve spent time in a chemistry lab or manufacturing plant, you probably haven’t forgotten lessons about handling nitriles. They’re no joke for an unprepared worker.
Breathe in some 2-butenenitrile vapors, and you notice irritation in the nose and throat. Most people won’t need a second warning. At higher exposure, dizziness, headaches, and trouble breathing can set in. No one wants to see a colleague turned pale and stumbling because their mask slipped or ventilation failed. In fact, 2-butenenitrile is a suspected neurotoxin. I remember a research professor talking about “an invisible danger” during my lab days—the kind of risk you don’t notice until it’s already hit.
A splash to the skin doesn’t just sting. Soaking up nitriles through exposed skin has caused rashes, redness, and pain for unlucky folks in poorly maintained facilities. Eyes don’t fare any better. A direct hit means burning and tearing, sometimes full-on damage that needs medical intervention.
Working around this compound for long stretches hikes up the risk of chronic effects. Studies in industrial settings link nitrile exposure to lasting nerve issues and symptoms that don’t disappear long after the shift ends. These aren’t just numbers in a journal article—I’ve watched career chemists change labs after developing allergies or sensitivities from extended exposure.
Safety data from manufacturers and research agencies lay things out clearly: fires and explosions can happen in places where crotononitrile leaks combine with heat, sparks, or open flames. As a flammable liquid, it can flash into flames quicker than an untrained new hire thinks. A report from the Chemical Safety Board described an incident where a minor leak plus a static discharge cost thousands in property damage and left one technician hospitalized with respiratory injuries.
Protective gear isn’t optional once 2-butenenitrile enters the picture. From gloves to goggles to full face shields, skipping a step can have instant consequences. I worked on a team where the rule was simple: no gloves, no work. If someone skipped PPE, the whole project stopped. Direct exhaust ventilation at benches and floor drains that channel fumes away from workers saved us more than once.
Safe storage calls for sealed, clearly labeled containers. No leftover coffee cans or hand-marked jugs. Fire-resistant cabinets and grounding wires don’t get much glory during safety inspections, but every worker who’s faced down a surprise spill values them. Cleanup protocols matter as much as regular handling. Absorbent pads, neutralizing agents, and easily accessible eyewash stations take seconds to check and can make all the difference if a spill occurs.
Accidents often trace back to shortcuts or management skipping hazard education. Consistent training makes employees confident instead of anxious, and it keeps facilities off the incident lists. Sharing case studies or stories from those who’ve experienced near-misses gets the message across more than just reading from a binder.
Better monitoring and routine air checks stop exposures from creeping up on people. Personal sensors and alarms add layers of protection—costly on paper, cheap compared to the price of a chemical injury or fire. Looking out for colleagues, calling out unsafe behavior, investing in health monitoring, and fighting complacency create a culture where everyone walks out healthy at the end of the day.
2-Butenenitrile in its trans form shows up as a colorless to pale yellow liquid. You can catch a whiff of its sharp, slightly sweet, and acrid odor pretty quickly: some say it hints at almonds crossed with industrial chemicals, a smell that doesn’t easily leave the room. Most folks who work around it recognize that scent right away, which matters, because it tells you exactly what you’re dealing with. Unlike solid crystals or powders, this compound spreads out on surfaces and absorbs into rags or gloves, so people pay close attention during handling.
If you’re pouring or transferring 2-butenenitrile, you’ll notice its thin, mobile consistency. It doesn’t stubbornly cling to containers. In a spill or leak, it flows fast, following the tiniest crack, which pushes lab techs to double-check seals and keep absorbent materials nearby. Its light color won’t stain equipment, but the liquid soaks into porous surfaces, sticking around both visually and in odor.
We often talk about boiling point and solubility for a reason: those details make the difference between safe storage and a dangerous situation. Trans-2-butenenitrile boils around 116°C. In rooms with poor ventilation, vapor builds up fast, so folks insist on open windows or fume hoods. This compound vaporizes more readily than many heavier chemicals; if you've ever been in a research or production lab, you probably recall the importance of keeping flammables in tightly closed bottles away from sparks.
On the freezing side, it stays liquid down to about −52°C, which means it rarely freezes in day-to-day use. For places with cold winters, there’s less trouble from blocked pipes or solidified stock. It dissolves reasonably well in common solvents like alcohol and acetone. In water, it only partially dissolves, so runoff and environmental spills don’t disappear with a splash of water—prompt cleanup with the right absorbents keeps workplaces safer and avoids polluting drains.
Flammability is a practical concern. Its vapors catch fire easily, which leads anyone handling it to store it away from heat and electrical equipment. At fire training sessions in chemical plants, the message is clear: keep extinguishers nearby, and nobody ignores the no-smoking signs. You can’t always see or smell vapor buildup, so proper sensors and alarms turn near misses into safe shifts.
Spending time in production settings, it’s easy to see why workers want clear labeling and secure storage. One mistake—wrong bottle, poor ventilation, or forgotten glove—results in headaches, burns, or worse. Chemistry teaches respect, and 2-butenenitrile gives reason to double-check standard operating procedures. Companies rely on robust safety data sheets and regular training. Labeling every bottle and training new hires right from the start makes a direct difference in accident rates.
Sustainable practices matter too. Disposing of residual 2-butenenitrile properly avoids long-term damage to water sources and soil. Internal audits, spill drills, and secondary containment offer real protection. Following established protocols, such as those set out by the EPA and OSHA, provides structure but also builds a culture of accountability.
Chemicals like trans-2-butenenitrile remind anyone involved in handling or research why safety isn’t just a rule—it’s a mindset. Every property, from color to odor to flammability, becomes a daily lesson in respect, caution, and responsibility.
2-Butenenitrile [Trans] holds a spot among the chemicals that call for disciplined storage and careful handling. In labs and production sites, familiarity with its properties isn’t just a bonus—it acts as a first line of defense against avoidable mistakes. This colorless to pale yellow liquid carries a sharp, unpleasant odor, and yes, it can be both toxic and flammable. It tends to evaporate quickly, which turns small spills into bigger problems unless they're managed right away.
Chemicals like 2-Butenenitrile [Trans] don’t mix well with carelessness. Storage should keep the liquid far away from sources of ignition—open flames, sparks, and even hot surfaces can spell disaster. Keeping containers tightly closed matters, not only to stop fumes from leaking but also to reduce chances of contamination from other reactive chemicals.
I remember a situation during my early days in a university lab: a leaky cap led to a persistent odor that took hours to trace. After clearing the mess, the lesson stuck with everyone—never trust a half-tight lid. For this chemical, always choose containers made from materials that resist corrosive liquids. Metal containers without proper lining, for instance, can corrode and fail. Storage areas need ventilation, so any accidental vapor releases don’t linger and build to unsafe levels. Shelving should sit below eye level to avoid accidental spills right into someone’s face.
Storing separate from strong oxidizers and acids also avoids unexpected, violent reactions. Labels on bottles stay clear and visible, because confusion over contents is a shortcut to dangerous accidents. In my experience, a good inventory system—checked weekly—helps spot leaks or misplaced containers before trouble starts.
Gloves made of nitrile, not cheap vinyl, hold up better against leaks and splashes. A well-fitted set of goggles guards against droplets, which can cause real damage on contact with eyes. If you’re pouring or transferring this liquid, a lab coat won’t just save your clothes; it can act as a second barrier for your skin. Chemical fume hoods offer extra insurance, pulling vapors away from your breathing zone. Disposable respirators can play a role, especially if a spill increases airborne concentration above safe limits.
Spills happen, even with the best intentions and protocols. Having kits with absorbent pads and neutralizing agents on standby makes reaction time quicker. Don’t settle for just wiping up with a paper towel—these chemicals need absorbents designed for solvents. Cordoning off spill areas gives others in the lab time to avoid exposure. Once, I saw a team clear a spill in record time by following the drill: contain, absorb, ventilate, and dispose—all clearly taught, all promptly done.
Waste containers require tight-fitting, labeled seals. Disposal runs through hazardous waste channels, following regulations set by local environmental agencies. Pouring leftovers down the drain creates both an accident risk and a public health problem downstream.
Improving chemical safety starts with honest conversations and repeated training. Safety officers do more than monitor—they share mistakes, promote questions, and help everyone stay vigilant. Automation in chemical monitoring—sensors for fumes or temperature shifts—can signal issues before people even smell a thing. In my years working with chemicals, the biggest progress always came from teams who took personal responsibility for storage and handling, treating every bottle with the respect it deserves.
| Names | |
| Preferred IUPAC name | (E)-but-2-enenitrile |
| Other names |
Crotononitrile 2-Butene nitrile Trans-2-Butenenitrile trans-β-Butenenitrile trans-Crotononitrile |
| Pronunciation | /tuː-bjuːˈtiːn.nɪˌtraɪl/ |
| Identifiers | |
| CAS Number | trans-2-Butenenitrile CAS Number is 764-42-7 |
| Beilstein Reference | 1460835 |
| ChEBI | CHEBI:51741 |
| ChEMBL | CHEMBL47658 |
| ChemSpider | 83223 |
| DrugBank | DB04240 |
| ECHA InfoCard | ECHA InfoCard: 100.021.885 |
| EC Number | 202-478-1 |
| Gmelin Reference | 82252 |
| KEGG | C01833 |
| MeSH | D016668 |
| PubChem CID | 7853 |
| RTECS number | UU3675000 |
| UNII | EL2X93J2B7 |
| UN number | UN2313 |
| Properties | |
| Chemical formula | C4H5N |
| Molar mass | 68.095 g/mol |
| Appearance | Colorless liquid |
| Odor | sweet, pleasant |
| Density | 0.804 g/mL at 25 °C (lit.) |
| Solubility in water | Soluble |
| log P | 0.5 |
| Vapor pressure | 12.3 mmHg (25°C) |
| Acidity (pKa) | 11.2 |
| Basicity (pKb) | -8.07 |
| Magnetic susceptibility (χ) | -8.89 × 10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.4010 |
| Viscosity | 0.402 mPa·s (25°C) |
| Dipole moment | 4.29 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 229.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | 109.6 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -282.9 kJ/mol |
| Pharmacology | |
| ATC code | R02AB05 |
| Hazards | |
| GHS labelling | GHS02, GHS06 |
| Pictograms | GHS07 |
| Signal word | Warning |
| Precautionary statements | Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking. Avoid release to the environment. Wear protective gloves/protective clothing/eye protection/face protection. IF ON SKIN: Wash with plenty of water. |
| Flash point | 42 °C (108 °F; 315 K) - closed cup |
| Autoignition temperature | 640 °C |
| Explosive limits | Lower 2.6%, Upper 15% |
| Lethal dose or concentration | LD50 oral rat 253 mg/kg |
| LD50 (median dose) | LD50 (median dose): 260 mg/kg (Oral - Rat) |
| NIOSH | MW3672100 |
| PEL (Permissible) | PEL (Permissible Exposure Limit) of 2-Butenenitrile [Trans] is "3 ppm (8 mg/m3)". |
| REL (Recommended) | 30 ppm |
| IDLH (Immediate danger) | 250 ppm |
| Related compounds | |
| Related compounds |
Cyanogen Acetonitrile Propionitrile Butyronitrile |
