The search for versatile and robust chemical building blocks brought Bis-Piperazine to the attention of industrial chemists decades ago. Back in the latter half of the 20th century, large-scale efforts to synthesize heterocyclic compounds opened the doors to an entire family of piperazines. Researchers needed stable, easily modifiable ring systems, and Bis-Piperazine, with its two linked piperazine rings, offered something few other compounds could match. The pharmaceutical and agrochemical revolutions of the 1970s and 1980s maximized the utility of new ring-based chemistries. Early reports highlighted its role as a catalyst base and an intermediate. But its adaptable structure and high nitrogen content quickly drew attention in polymer research, where it became a key player in toughening up specialty resins and engineering plastics. Over time, its use in research and specialty chemistry never quite hit the mainstream, but for those who know their way around functionalized amines, Bis-Piperazine keeps appearing on laboratory benches for some very good reasons.
Bis-Piperazine brings together two piperazine rings, typically via a short aliphatic or aromatic linker, and most products on the market showcase a white to off-white crystalline solid. Chemists who look for a solid intermediate with good solubility in polar solvents will spot Bis-Piperazine in catalogues under several trade names. It often gets packaged in moisture-proof containers because its ring nitrogens pick up water and acids from air. Formulators dealing with resin systems use it as a crosslinker or curing agent. Advanced research leans on its chemical flexibility when pushing beyond basic polyamines. Its twin rings soak up protons and react with a surprising range of acyl, alkyl, and aryl reagents.
Solid Bis-Piperazine typically melts near 110-120°C, though impurities and linker design shift the melting point up or down. The structure builds in ample basicity, with each nitrogen atom providing a protonation site and a platform for substitution reactions. In the lab, Bis-Piperazine dissolves well in ethanol, methanol, and dimethyl sulfoxide, though water sometimes makes it sticky or pasty at room temperature. Bulk density sits in the mid-range for fine chemicals, making it easy enough to handle by scoop or spatula. Its vapor pressure barely registers in ambient conditions, so spills mean a cleanup rather than an inhalation risk. Unlike many amines, it rarely stinks unless degraded by heating.
Buyers expect labeling to include molecular weight, major impurities, and water content, since trace moisture affects reproducibility in sector applications like epoxide curing. Standard samples typically run above 98% purity with water below 0.5%. Safety sheets warn about possible skin and eye irritation, though toxicity doesn’t reach the levels found in some alkylated peers. Detailed certificates of analysis list individual elemental contents and confirm lot-to-lot consistency. For regulatory compliance, suppliers lay out batch tracking codes, often supporting both GMP (good manufacturing practice) and non-GMP production streams for industrial customers versus research labs.
Several routes exist for synthesizing Bis-Piperazine, choosing depending on scale, purity, and downstream goals. The early methods linked two piperazine rings with a dibromoalkane, relying on strong inorganic bases and controlled temperature profiles to keep yields high and impurities low. A typical method drops dried piperazine into a jacketed reactor, adds the bifunctional alkyl halide slowly, and lets the mixture stir under reflux. Newer approaches swap the halide for a di- or tri-carboxylic acid, going through amidation steps before reduction, trading speed for better control of byproducts. Labs aiming for high-purity intermediates sometimes layer chromatography into the protocol, pulling off side-product amines that would foul up medicinal chemistry work. As process chemists chase atom efficiency and greener protocols, catalytic hydrogenation has drawn interest, but most large plants still hang on to reliable batch synthesis, followed by recrystallization for commercial-grade material.
Core to its appeal, Bis-Piperazine offers multiple reaction handles. The methylene nitrogens support straightforward alkylation with haloalkanes, building routes to branched heterocycles. Acylation unlocks ranges of amide-linked bioconjugates, which found use in initial screens for enzyme inhibition. Due to the ring strain and conformational mobility, selective mono- or di-functionalization gives synthetic chemists plenty of leeway in designing linkers or side chains. Reductive amination works smoothly on its secondary amines for building up novel pharmaceutical scaffolds. Its ability to bridge between hard and soft acid chemistry lets researchers push deep into coordination complexes, some of which support metal-catalyzed reactions or serve as chelators in analytical chemistry. In polymer chemistry, Bis-Piperazine anchors epoxy and polyurea chains, broadening the window of performance for tough, impact-resistant plastics. With its modular structure, modifications almost always focus on opening new points for linking or folding into larger architectures.
A stroll through supplier catalogs shows that Bis-Piperazine hides under several names. Some references stick to the dry IUPAC descriptors, like N,Nʹ-bis(piperazinyl)alkane, while others pull in legacy names tied to bridging groups—such as 1,4-Bis(piperazin-1-yl)butane or 1,2-Bis(piperazin-1-yl)ethane—reflecting different core linkages. To navigate the patent and chemical information landscapes, chemists need to check registry numbers close, since even subtle linker changes change biological or physical function. Some trade products go under proprietary abbreviations, especially in specialty resin and biomedical brands, adding a layer of confusion unless detailed certificates or structural data back up the sale.
Safe laboratory habits matter just as much here as with any multi-amine. Direct contact can lead to skin tingling or mild burns if spilled in the raw form. I’ve always kept nitrile gloves close when measuring out Bis-Piperazine, since like other piperazine derivatives, its basicity etches into tissue after a few minutes. Working beneath a fume hood means spill vapors never linger. Standard operating procedures in handling insist on proper waste collection because trace nitrogenous bases tend to mess up municipal water streams. Emergency response teams lean on the low acute toxicity but prepare for the same kind of rapid decontamination as with other aliphatic amines. GMP-grade products call for stringent environmental monitoring and batch release based on rigorous in-process checks, so operational standards track both safety and environmental impact.
Much of Bis-Piperazine’s action happens as a crosslinker in thermosetting plastics, where it imparts flexibility and toughness to cured systems. Paint and coatings industries mix small amounts in epoxy systems, chasing better chemical resistance and mechanical strength. Pharmaceutically, derivatives sneak into exploration of new antihistamine or antipsychotic scaffolds, usually at the basic building-block stage. Academic labs have used it to probe enzyme active sites or create immobilized affinity supports. Its two rings act as a tight scaffold for chelators, making it a candidate for water-softening or heavy metal removal applications. At the bleeding edge, a handful of research groups embed Bis-Piperazine units in next-generation dendrimer syntheses, chasing custom molecular cages for drug delivery or sensor tech.
Research isn’t standing still. I see new papers every year tackling the reactivity of Bis-Piperazine in asymmetric synthesis, harnessing its bite for constructing complex polycyclic molecules. Recent advances also highlight it as a ligand backbone in supramolecular chemistry, exploiting predictable geometry for precise self-assembly. Teams designing advanced adhesives and sealants bank on the unique physical flexibility, and they continue to tweak substituents looking for that perfect blend of elasticity and resistance. Computational chemists run simulations of Bis-Piperazine’s conformational space, aiming to unlock even more reaction modes or ion-exchange properties. On the biomedical front, early-stage studies hint at promise for customized peptide stapling, where triple and quadruple ring systems lock proteins into new shapes for targeting diseases that have resisted traditional small molecules.
Toxicologists report that basic Bis-Piperazine sits on the lower end of acute toxicity, though modifications alter this picture. High-dose exposures in animal models don’t generate dramatic organ damage, but vigilance is warranted given some piperazine derivatives in pharma have a history of producing off-target effects at high exposure. Chronic exposure data remains thin, and absence of carcinogenicity under controlled dosing hasn’t quieted calls for more independent studies. Waste streams from an amine-packed plant must run through nitrogen treatment, since local aquatic systems suffer from ammonia buildup. In personal work, any odd scents or color changes have always triggered a full waste container swap and a second look at air quality monitoring badges. The structure’s resilience means breakdown is slow without strong oxidants or thermal treatment, so regulators keep a close eye on long-term environmental releases.
Looking forward, chemists expect Bis-Piperazine’s flexibility and reactivity to drive new discoveries across the specialty chemicals sector. As plastics and adhesives move toward greener, higher-strength formulations, deeper use of amine-based crosslinkers promises expanded roles. Synthetic biology and polymer therapeutics stand to benefit from its usefulness as a modular building block for complex architectures. Better predictive tools, driven by computational chemistry, should push application boundaries. New derivatization techniques seek to fine-tune water solubility, biodegradability, and bioactivity. Environmental chemists and regulatory scientists urge for clearer lifecycle analysis as adoption widens, advocating for green manufacturing and end-of-life strategies that keep nitrogen load low in ecosystems. I see an era where Bis-Piperazine cycles back into academic conversation, pushing out into nanotechnology, smart hydrogels, and responsive materials for diagnostics or environmental cleanups. Every surprising turn by this twin-ring molecule reminds us that chemistry’s toolset still has plenty of surprises left.
Bis-piperazine doesn’t show up in most people’s everyday conversations, yet it shapes more lives than most might realize. Chemists know it as an organic compound based on two piperazine rings held together, but that doesn’t tell the real story. It acts both as a building block and as a problem solver, giving researchers choices in medicine, plastics, and water treatment.
Think of many new medicines over the last decade—odds are, some of those started in labs using small pieces like bis-piperazine. Its structure brings stability and flexibility to drugs designed to treat cancer, mental health conditions, and even antibiotics. Having seen how long it can take to develop a new pill or therapy, any shortcut matters. Bis-piperazine offers exactly that: it helps drugs lock onto the right target in the body, making treatments more effective and safer for patients.
This matters to me not only as someone who follows health news closely, but also as someone with a family history of chronic illness. Every better, faster, safer therapy offers hope to millions.
The uses don’t stop at medicine. Manufacturers mix bis-piperazine into tough plastics, coatings, and adhesives. Walk through any hospital, and you’ll spot equipment and surfaces that have to stand up to harsh cleaners. Resins built with bis-piperazine create that kind of ruggedness, standing up to repeated disinfection without breaking down. Good luck finding surface coatings in a high-traffic public building that haven’t relied on compounds like this.
Most people give little thought to the chemistry behind clean water. Municipal water systems often use bis-piperazine-based products to help clean up heavy metal ions and organic pollutants. Communities hit by contamination scandals, where safe drinking water vanished overnight, show just how crucial chemical tools can be. Bis-piperazine helps bind up toxic metals, making it easier for large filters to pull out the worst substances before water heads to taps.
This chemical, like all strong tools, brings risks if handled wrong. Some groups worry about potential toxicity and how waste containing piperazine rings could affect water or soil. Factories need clear guidelines and close oversight. Workers have to respect safety measures, not just to avoid fines, but to make sure no one gets hurt. Health and environmental regulators can draw on studies showing how long these molecules stick around in the environment to set safer standards. I’ve seen firsthand how oversight sometimes misses new chemicals, so researchers and watchdog groups should stay on alert.
Innovation will never stop. Scientists look for safer, greener ways to make bis-piperazine and use less of it in finished products. Some chemists work with plant-based feedstocks or tweak processing steps to reduce waste. I believe we’ll see safer handling technology, smarter recycling, and more research into long-term health effects.
Ask the average person about this chemical, and you’ll get blank stares. Yet bis-piperazine quietly powers progress in health and industry. Paying attention to how we use it, manage its risks, and chase cleaner options makes sense for anyone who cares about safe medicine, clean water, or a sturdy world.
Bis-Piperazine sits in a class of compounds folks often overlook unless they’ve spent hours in a research lab or a university lecture hall. Popular with chemists working on pharmaceuticals and specialty polymers, it’s more than just a jumble of rings and atoms drawn on a whiteboard. Its structure affects how it gets used in the real world, so anyone dealing with chemicals, drug design, or advanced materials ought to know the basics.
Think of bis-piperazine as two piperazine rings linked together. Piperazine itself looks like a six-membered ring with two nitrogen atoms opposite each other — sort of a cousin to the more well-known benzene ring but with some serious differences. In bis-piperazine, you find these rings paired up through a bridging group. The classic arrangement links them either through carbon chains or other connecting atoms, producing a compound with two saturated nitrogen rings. For the popular version, N,N′-Bis(piperazine), there’s a connecting group that holds two piperazine rings together via their nitrogen atoms.
To be clear, piperazine rings have the formula C4H10N2. When two rings connect, chemists create variations by tweaking the bridge between them. Sometimes it’s a simple ethylene (–CH2CH2–) bridge, other times a more complicated chain or an aromatic linker. This simple adjustment triggers different behaviors in a lab or a production plant. In pharmaceuticals, for example, small tweaks like these mean huge differences in how a molecule acts in the body.
Some of the earliest hands-on experience I had with molecular structures came in a crowded college synthesis lab. Piperazine derivatives always popped up in problem sets, but bis-piperazine really made the point about molecular connectivity. You start seeing why manufacturers focus so much on purity and correct linkage — it’s easy to create nasty by-products when rushing this type of chemistry.
Bis-piperazine compounds step up in medical research and industrial applications as robust building blocks. Their structure gives them stability and offers multiple sites for further chemical modification. Drug developers use this backbone to assemble anti-cancer agents, antivirals, and enzyme inhibitors. For polymer makers, the rigid nitrogen rings add thermal strength to finished products.
Lots of chemical information online reads like it exists only for computers or professionals to decipher. That’s a problem because these structures lead directly to the medicines people take or the plastics that touch almost every product in daily life. Chemists — and those teaching chemistry — need to pull back the curtain on why structures like bis-piperazine look the way they do, and what those shapes mean for the world at large.
Safer handling and smarter design start with a strong focus on structure. It pays to develop clearer visuals and plain-language guides, because folks working outside of academic labs get stuck with technical dead-ends far too often. If research organizations share not just what bis-piperazine is, but how its shape can be adapted or why the linkage matters, better decisions about safety and application will follow. Trust stems from transparency, and science moves forward fastest when people know what they’re looking at—no jargon required.
Working with chemicals like Bis-Piperazine never really feels routine, no matter how many times you think you’ve got the drill down. I’ve seen folks underestimate how seriously even small amounts of it can affect health. What begins as a simple day’s work in a lab or manufacturing floor can turn into a scramble if hands or eyes come in direct contact with this stuff.
Bis-Piperazine isn’t exactly a household name, but the dangers are anything but obscure. Direct skin exposure can lead to irritation, sometimes severe. Inhaling dust or fumes, even in low concentrations, pulls nasty surprises like headaches or even long-term lung troubles. Most folks remember gloves, but wrists and forearms often stay bare—and that gap lets in more than just cold air. Long-sleeved chemical-resistant garments and sturdy gloves don’t just check the compliance box; they block some very real harm.
I’ve seen firsthand what happens when goggles are left hanging on a hook instead of sitting on someone’s face. It only takes one splash or unexpected puff wrong to send you to the emergency station, hoping the eyewash is working that day. Proper fit for goggles, with no gaps around the seal, isn’t just nice to have—it turns a potentially life-altering accident into a non-event.
Ventilation feels boring until you walk into a room where someone forgot to flip the switch. Without decent fume hoods or exhaust fans, workers rely on luck rather than good practice. Chemical vapors build up fast, often before anyone smells trouble. Routine maintenance of air controls and staying clear of areas with lingering odors goes a long way. It’s not enough to trust your nose—those vapors usually show up before your senses catch them.
Even a minor spill of Bis-Piperazine brings risks that show up days or weeks later. Quick action matters, but so does using the right material—absorbent granules over paper towels, and double-bagged waste instead of a regular trash bin. I remember an incident where a colleague skipped over the “minor” bit and tried to wipe it up without proper gear. He faced skin problems for months.
New team members pick up habits from the veterans, which makes any shortcut just as dangerous as the mistake itself. Real training goes beyond a printed sheet on a corkboard—it’s about walking through the job, seeing the right gear, and knowing what to do if something goes sideways. Good managers foster a space where stopping the line to put on gloves gets respect, not eye rolls.
Tossing anything with traces of Bis-Piperazine into general waste puts sanitation teams at risk. Dedicated containers for chemical waste, using every label and seal, keep dangerous byproducts out of regular landfills. Following local regulations takes pressure off workers and keeps problems from getting out into the wider community. As recent news incidents have shown, lax disposal invites regulatory headaches and environmental damage.
Safe handling of chemicals like Bis-Piperazine protects not just the person mixing or measuring, but everyone down the line—from the cleaner who empties bins to the neighbors whose water might be affected by leaks. It’s part of a bigger picture that treats safety as a shared promise. No shortcuts, no passing the buck—sticking to the basics saves lives, plain and simple.
Bis-Piperazine isn’t a name that pops up in everyday conversation, but it’s one that’s started gaining some attention among chemists and companies watching the specialty chemicals market. Curiosity about its availability comes from a mix of academic research interests and rising work in custom synthesis shops. On paper, with the explosion of chemical e-commerce and catalog suppliers, it would seem almost any compound is just a few clicks away. Reality isn’t quite that simple.
A few years back, while searching for rare heterocyclic building blocks for a university project, I found that compounds like Bis-Piperazine aren’t easily found on the biggest databases. Large players like Sigma-Aldrich and TCI tend to list the basics: piperazine itself, maybe a few substituted versions. Bis-Piperazine, in contrast, doesn’t usually show up as a catalog item. Instead, forums and Reddit threads fill with chemists trading tips for custom synthesis. This paints a clear picture: standard distributors rarely keep it on the shelf.
Any mention of Bis-Piperazine in supplier catalogs often leads straight to a “request quote” button. That means a chemist needs to explain what it’s for, wait for an answer, and probably agree to minimum order sizes far above the scale of small research labs. In many cases, suppliers ask for institutional credentials or even refuse requests from individuals to avoid legal headaches tied to potential misuse. Anecdotally, I’ve seen requests on mailing lists go unanswered, or researchers left hunting through regional suppliers in Asia who offer small-batch runs with unpredictable lead times.
Commercial supply depends a lot on demand, and in the case of Bis-Piperazine, requests mostly come from niche applications—ligands for catalysts, linkers in specialty polymers, or as chemical intermediates. Without large pharmaceutical or industrial customers placing bulk orders, companies don’t prioritize stocking it. This low-demand scenario leads to higher prices, longer delivery times, and infrequent batch production. Chemical companies look for stable regular purchases, so rare building blocks get pushed down the priority list.
Import regulations and risk controls add to the challenge. Many specialty chemicals fall into a gray area where suppliers need to check customers’ backgrounds, shipping destinations, and intended uses. The hurdles grow higher if you aren’t affiliated with an established institution. These controls aim to keep dangerous compounds out of the wrong hands, but they also slow down legitimate science.
Community-driven initiatives could help. Aggregated purchase programs through professional societies lower the cost per gram for niche materials and save buyers from shady third-party resellers. Larger research universities sometimes centralize procurement and share compounds across affiliated labs, which boosts transparency and efficiency. Open science projects have floated similar ideas, making collections of scarce compounds available for collaborative research.
Better category transparency from chemical suppliers matters, too. A few European vendors do a good job flagging which compounds are “make on demand,” “stocked,” or “custom,” but this practice remains rare. It saves researchers time and helps avoid false hope.
Personal relationships with trusted suppliers and fellow researchers often prove more reliable than any search engine. Early career chemists benefit from mentors who’ve navigated supply challenges. Over time, reputation and word-of-mouth often open doors that simple catalog searches can’t.
Where Bis-Piperazine fits into this landscape shows how chemical procurement is never just about clicking 'buy now.' It’s about networks, trust, shared knowledge, and creative problem-solving. Without a robust network or institutional backing, tracking down rare chemicals still takes persistence—and sometimes, a little bit of luck.
Bis-Piperazine sounds like something out of a chemistry textbook, but for many labs and manufacturers it’s just another building block—used in everything from pharmaceuticals to specialty resins. In the frenzy to order, measure, and mix, the basics like storage sometimes fall off the radar. People might assume chemicals last forever if the lid is tight and the shelf is dry, but that sort of thinking causes trouble.
Many don’t realize that Bis-Piperazine, despite looking like a tough white powder on a shelf, responds to its environment. Humidity sneaks into containers. Heat breaks down molecules over time. Contamination from less-than-clean scoops and containers creates headaches, leading to product recalls, ruined experiments, and safety risks no one wants. I’ve seen well-stocked labs toss out kilograms of valuable material just because the storage room got hotter than expected over a long weekend.
For anyone who has spent time working with chemical inventories, temperature and moisture control aren’t optional. Bis-Piperazine holds up best when kept in cool, dry places—ideally, under 25°C. Humid air shortens shelf life and sometimes causes clumps, making exact weighing a challenge. With every unsealed jar, airborne water finds its way in.
Even without fancy climate control, a dedicated storage area away from direct sunlight and sources of heat gives the best shot at long-term stability. It’s worth remembering that common storage rooms sometimes swing from chilly winters to sweating summers. Inconsistent storage like this invites degradation. The last thing you need is corrosive byproducts forming in a forgotten jar, threatening both research and personnel.
Clean utensils and containers count for more than most give credit. Accidental mixing with other powders, no matter how inert they seem, ruins purity. Labs who take pride in training new staff on these routines save themselves both money and headaches down the line. If you’ve spent time around careless practices, you know that powder-dusted gloves and shared scoops spread contamination further than anyone expects. Trouble emerges in analysis, where unexplained impurities stall projects for weeks.
One fact I picked up early: labels matter. Keeping Bis-Piperazine clearly marked with date of arrival and batch number, plus a visible expiry date, means less confusion. Rotating stock makes sure you use up older material before reaching for new canisters. Locks on storage rooms protect not only against theft but keep unauthorized or untrained hands out of harm’s way. Even in low-risk environments, accidents happen when someone pulls the wrong jar in a hurry.
Recognizing the link between storage and results leads to improvement. Assigning clear protocols for storage drops error rates fast. Auditing storage areas from time to time keeps bad habits from creeping in. Setting up backup AC or dehumidifiers could prevent spoilage if your workspace deals with unpredictable weather. I’ve watched departments cut waste by simply introducing a strict cleaning and labeling routine: what you track, you protect.
Paying attention to these not-so-glamorous details pays off. Safe, careful storage extends Bis-Piperazine’s shelf life, protects staff, and saves money on replacements. It’s about respect for the material and for the work built upon it. That’s a lesson every lab and plant can benefit from.
| Names | |
| Preferred IUPAC name | 1,1'-(Piperazine-1,4-diyl)di(piperazine) |
| Other names |
1,4-Diazacyclohexane Piperazine, bis- Hexahydropyrazine |
| Pronunciation | /ˌbɪs.paɪ.pəˈreɪ.zɪn/ |
| Identifiers | |
| CAS Number | 4431-83-8 |
| Beilstein Reference | 133678 |
| ChEBI | CHEBI:53499 |
| ChEMBL | CHEMBL1090855 |
| ChemSpider | 18744494 |
| DrugBank | DB08320 |
| ECHA InfoCard | ECHA InfoCard: 100.034.285 |
| EC Number | 3.10.1.2 |
| Gmelin Reference | 28918 |
| KEGG | C19599 |
| MeSH | D010887 |
| PubChem CID | 10172007 |
| RTECS number | GS8050000 |
| UNII | H4T9A9NR65 |
| UN number | UN2811 |
| Properties | |
| Chemical formula | C8H18N4 |
| Molar mass | N4H12C8 |
| Appearance | White solid |
| Odor | Odorless |
| Density | 1.18 g/cm³ |
| Solubility in water | Slightly soluble |
| log P | 0.35 |
| Vapor pressure | Negligible |
| Acidity (pKa) | 7.2 |
| Basicity (pKb) | 5.35 |
| Magnetic susceptibility (χ) | -85.0 · 10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.623 |
| Viscosity | 360 cP |
| Dipole moment | 3.5097 Debye |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 274.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of combustion (ΔcH⦵298) | -4949.7 kJ·mol⁻¹ |
| Pharmacology | |
| ATC code | N06AX05 |
| Hazards | |
| Main hazards | Harmful if swallowed. Causes serious eye damage. Causes skin irritation. |
| GHS labelling | GHS07; GHS08; Warning; H302; H373 |
| Pictograms | GHS06, GHS08 |
| Signal word | Warning |
| Hazard statements | H302, H314 |
| Precautionary statements | P261, P264, P271, P272, P280, P302+P352, P305+P351+P338, P321, P362+P364, P333+P313, P337+P313, P362 |
| NFPA 704 (fire diamond) | 2-1-0 |
| Flash point | 102°C |
| Autoignition temperature | 410°C |
| Explosive limits | Upper limit: 9.3% ; Lower limit: 1.6% |
| Lethal dose or concentration | LD50 (rat, oral) > 5000 mg/kg |
| LD50 (median dose) | LD50 (median dose) of Bis-Piperazine: "2510 mg/kg (rat, oral) |
| NIOSH | RTECS: TL6825000 |
| PEL (Permissible) | Not established |
| REL (Recommended) | 0.2 mg/m³ |
| Related compounds | |
| Related compounds |
Piperazine N-Methylpiperazine Ethyleneurea Morpholine |
