Piperazine CAS 110-85-0

What is Piperazine?

Piperazine is a saturated six-membered ring with two nitrogens sitting opposite each other, C₄H₁₀N₂. That symmetry is what makes it distinctive: two secondary amine groups, chemically identical, held rigidly apart by the ring.

Unlike the other common amine heterocycles it is a solid at room temperature, melting at about 106 °C and supplied as white crystalline flakes. It is strongly hygroscopic and will pick up water and carbon dioxide from air readily, which is why it is also widely traded as a 68% aqueous solution and as the hexahydrate — forms that are simply easier to handle than a deliquescent solid.

It is strongly alkaline and highly soluble in water. The two nitrogens are genuinely difunctional, so piperazine can bridge two molecules, crosslink a resin, or hold a drug molecule's two halves together — and the rigid ring keeps the geometry of that bridge predictable, which is something a flexible diamine cannot offer.

Commercially, piperazine has an unusually wide spread of markets. It is a veterinary and human anthelmintic in its own right, it is a pharmaceutical ring found in a great many modern drugs including major antibiotic classes, it is an epoxy hardener and corrosion inhibitor, and — most recently and increasingly — it is the standard rate promoter in amine scrubbing systems for carbon dioxide capture.

Why piperazine specifically

• Two identical reactive sites. Both nitrogens are secondary amines in the same environment, so reactions are clean and symmetrical — useful for bridging and crosslinking where a mixed diamine would give isomers.
• A rigid, predictable bridge. The ring holds the two nitrogens at a fixed distance and geometry, which medicinal chemists exploit to position substituents precisely.
• Exceptional carbon dioxide kinetics. Piperazine reacts with carbon dioxide faster than almost any other amine, which is why it is blended into gas-treating solvents as a rate promoter rather than used alone.
• Active in its own right. Unusually for an industrial intermediate, piperazine salts are themselves a long-established anthelmintic medicine.

How Piperazine is Manufactured

Piperazine is made as part of the ethyleneamine family rather than on a dedicated plant. It comes out of the same reactors that produce ethylenediamine and the higher ethyleneamines, and the separation train determines the cut.

• Ethyleneamine synthesis. Either ethylene dichloride is reacted with ammonia under pressure, or monoethanolamine is aminated with ammonia and hydrogen over a supported metal catalyst. Both routes produce a spectrum of linear and cyclic ethyleneamines.
• Cyclisation. Piperazine arises when the chain closes on itself rather than extending. Catalyst and conditions shift the balance between linear products such as ethylenediamine and diethylenetriamine and the cyclic ones — piperazine and the aminoethylpiperazines.
• Separation. The mixture is resolved by fractional distillation. Piperazine and its N-substituted relatives are close-boiling, so the column train is where product quality is really decided — particularly the aminoethylpiperazine content.
• Finishing. The anhydrous product is flaked or prilled and packed under conditions that limit moisture pickup, or dissolved to make the 68% solution. Hexahydrate grades are crystallised from water.

Typical Commercial Specification

Figures below are representative of anhydrous commercial grade. Pharmaceutical, veterinary and gas-treating grades with tighter limits are available, as are hexahydrate and 68% solution forms — send us the specification you work to and we will quote against it.

Physical & Chemical Properties

Reactivity in practice

Two identical secondary amines on a rigid ring. That symmetry shapes everything piperazine does:

• Symmetrical bis-substitution. Both nitrogens react with alkyl halides, acid chlorides and activated aromatics to give clean symmetrical products, or mono-substituted ones under controlled stoichiometry.
• Salt formation. Forms stable salts with citric, adipic and phosphoric acids — the forms in which it is used as an anthelmintic medicine.
• Carbon dioxide capture. Reacts with carbon dioxide to form carbamate exceptionally quickly, which is why it is added to tertiary amine solvents as a kinetic promoter.
• Epoxy and resin crosslinking. Two active N-H bonds open epoxide rings and condense with dibasic acids, building rigid crosslinks into cured networks and polyamide resins.

Piperazine vs Piperidine, Morpholine and N-Methylmorpholine

The saturated six-membered nitrogen heterocycles are easy to confuse and behave quite differently. What separates them is what else is in the ring: a second nitrogen makes the molecule difunctional and solid, an oxygen pulls electron density away and weakens the base, and methylating the nitrogen removes the N-H altogether.

Stated plainly: piperidine is the strongest base of the four and the most nucleophilic; piperazine is the only difunctional one and the only solid; morpholine's ring oxygen makes it roughly a thousand times less basic than piperidine, which is exactly why it works as a mild neutralising amine; and N-methylmorpholine, having no N-H at all, acts as a catalyst and base rather than a building block — and cannot form a nitrosamine, which matters increasingly in rubber and personal care. They substitute for one another only rarely.

Industries We Supply Piperazine To

The same molecule leaves our warehouse for very different factories. What changes between them is not the CAS number but the form — flake, hexahydrate or solution — the grade, and the documentation each sector expects.

Where Piperazine is Used

Piperazine spans pharmaceutical, industrial and environmental markets. These are the end uses our customers buy it for, roughly in order of volume.

In pharmaceutical synthesis

The piperazine ring is one of the most common structural motifs in modern medicinal chemistry. It appears across antipsychotic, antidepressant, antihistamine and antiretroviral classes, and most prominently in the fluoroquinolone antibiotics, where the piperazinyl group attached to the quinolone core is central to the activity. Chemists favour it because the ring positions substituents predictably and because mono-substitution leaves a second nitrogen available for further elaboration or for salt formation. API producers run the tightest specifications: aminoethylpiperazine, residual ethyleneamines and metals all have to clear ICH limits.

As an anthelmintic

Piperazine salts have been used for decades to treat roundworm infestations, principally in poultry, pigs and horses but also in human medicine. The mechanism is a reversible paralysis of the parasite, which is then expelled. Veterinary formulators buy the citrate, adipate or phosphate salt, and the specifications are pharmacopoeial rather than industrial — a different document set from the technical grades.

In carbon dioxide capture

This is the fastest-growing application. Conventional amine scrubbing solvents based on tertiary amines such as MDEA absorb a lot of carbon dioxide per cycle and regenerate cheaply, but they absorb it slowly, which means tall and expensive absorber columns. Adding a small amount of piperazine fixes that: it reacts with carbon dioxide faster than almost any other amine, shuttling it into the bulk solvent. The result is a solvent with the kinetics of a primary amine and close to the regeneration energy of a tertiary one. Gas-treating customers specify thermal and oxidative degradation behaviour as much as purity.

In epoxy and resin chemistry

Two active N-H bonds on a rigid ring make piperazine a crosslinker that stiffens a cured network more than a flexible aliphatic diamine of the same functionality. It appears in epoxy hardener blends and in polyamide-amine curing agents, and as a chain extender in specialty polyurethane and polyurea systems. Handling the solid is the practical obstacle, which is why solution grades are common in this sector.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis. The methods behind the numbers are standard across the industry, and we are happy to share them or to work to your own in-house test protocol.

• Assay and ethyleneamine profile — gas chromatography, which quantifies aminoethylpiperazine, ethylenediamine, diethylenetriamine and the other close-boiling relatives.
• Water content — Karl Fischer titration. Critical on anhydrous flake, which is strongly hygroscopic and will gain moisture rapidly once a bag is opened.
• Melting point — a fast, revealing check. A depressed melting point usually signals moisture or ethyleneamine contamination before any instrument confirms it.
• Colour of solution — APHA on a made-up 50% solution, since colour on a white flake is hard to judge visually.
• Total and primary amine value — titration. Primary amine content specifically flags aminoethylpiperazine carry-over, which piperazine itself cannot contribute.
• Metals and residue — iron and residue on ignition, both of which matter in pharmaceutical and gas-treating service.

Common Process Problems & Likely Causes

When piperazine misbehaves in a plant, the cause is usually one of a short list of things. This table is the shortcut our technical desk works through before anyone opens a complaint file.

Packaging, Storage & Shipping

• Anhydrous flake packing. 25 kg net in multi-wall paper bags with an inner polyethylene liner, or in HDPE-lined fibre drums. Moisture-barrier packaging is essential rather than optional for this product.
• Solution packing. 68% aqueous solution in 1000 L IBCs and bulk road or ISO tank loads, which most industrial users prefer to handling a hygroscopic solid.
• Hexahydrate. Available where a free-flowing crystalline form with defined water content suits the process better than anhydrous flake.
• Storage. Cool, dry, well-ventilated store away from acids, oxidisers and nitrites. Humidity control matters more than temperature for the flake form.
• Reseal discipline. Reseal bags immediately after withdrawal. An open bag of piperazine flake gains moisture and carbon dioxide continuously, which changes both assay and amine functionality.
• Materials of construction. Stainless steel or suitable lined equipment for solutions. Avoid copper, brass, bronze and aluminium.
• Shelf life. Typically 12 to 24 months in unopened original packing under dry conditions. Beyond that, re-test rather than assume.
• Transport classification. UN 2579, Piperazine, Class 8 corrosive, Packing Group III — shipped with full dangerous-goods documentation.

Hazards & Safe Handling

Piperazine is corrosive and a skin and respiratory sensitiser, and must be handled by trained personnel under a proper risk assessment. The classifications below are indicative — the current SDS supplied with your consignment is the governing document.

• Respiratory sensitisation. Piperazine is a recognised respiratory sensitiser — it can cause occupational asthma. This is the dominant health concern with the product and it distinguishes it from most other amines. Once a worker is sensitised, very low exposures can provoke an attack, so preventing first exposure is what matters.
• Dust control. Handling anhydrous flake generates dust, which is the principal route to respiratory exposure. Enclosed transfer, local exhaust ventilation at charging points and appropriate respiratory protection are the standard controls — and are a strong practical argument for using the solution grade.
• PPE. Chemical-resistant gloves, chemical goggles and face shield, chemical-resistant clothing, and respiratory protection appropriate to a sensitiser rather than merely to a nuisance dust.
• Health surveillance. In several jurisdictions respiratory sensitisers trigger health surveillance obligations for exposed workers. Check the requirement at your site rather than assuming it does not apply.
• Incompatibilities. Strong oxidising agents, strong acids, acid chlorides, nitrites, and copper, brass, bronze and aluminium equipment.
• Spill response. For flake, collect mechanically without raising dust and place in a labelled closed container. For solution, contain and absorb with inert material. Do not wash to drain.
• Environment. Harmful to aquatic life. Do not allow to enter drains, surface water or groundwater. Dispose through a licensed chemical waste contractor.
• First aid. Remove from exposure, remove contaminated clothing, wash skin with plenty of water, flush eyes for at least 15 minutes, and seek medical attention with the SDS to hand. Report any breathing difficulty or skin reaction, which may indicate developing sensitisation.

Regulatory & Compliance Notes

Piperazine is a long-established chemical listed on the major national inventories, but it sits across three regulatory worlds — industrial chemical, veterinary medicine and human pharmaceutical — and which one applies depends entirely on your end use. The notes below are orientation rather than legal advice; confirm your own position with your regulatory adviser before importing.

• Inventory status. Listed on the principal chemical inventories in the major importing regions. Ask us for the inventory confirmation relevant to your destination country.
• Import registration. Several territories require the importer to hold a registration or notification before a consignment lands. Start that process early — it is the most common cause of delay at destination.
• Hazard communication. Supplied with an SDS compliant with the format applicable to your region, and labelled in line with the GHS classification for the product.
• Respiratory sensitiser classification. Classified as a respiratory sensitiser, which triggers specific labelling and, in several jurisdictions, exposure control and health surveillance obligations for workers. These apply downstream as well as at the formulator.
• Veterinary and pharmaceutical use. Material destined for anthelmintic medicines or for API manufacture must meet pharmacopoeial specifications and comes under medicines legislation at destination, not merely chemical control. The document set is different and substantially heavier.
• Dangerous goods. UN 2579, Piperazine, Class 8 corrosive, Packing Group III. Declarations prepared for IMDG (sea) or IATA (air) as appropriate to the mode.
• Feed and food chain. Where piperazine salts are used in medicated feed, withdrawal periods and residue limits apply at destination. Confirm the position before specifying.

We Supply Piperazine Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Piperazine from India to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, dangerous-goods paperwork and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other Indian ports arranged where it suits the routing.
• Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and dangerous-goods declaration issued as a complete set.
• Flexible volumes. A single drum for laboratory qualification, through LCL consolidations, up to repeat full loads on a supply contract.
• Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.

Buying Piperazine from Chelora

We are an independent sourcing and supply partner. For piperazine that means two decisions before quoting: which physical form suits your plant, and which regulatory world your end use sits in. Both change the product, not just the paperwork.

• Documentation on every lot. Batch-specific COA, current SDS and TDS issued with the consignment, not weeks afterward.
• Multiple forms. Anhydrous flake, hexahydrate and 68% solution, matched to how your plant actually handles material.
• Samples before commitment. Trial quantities for process qualification ahead of a commercial order.
• Quantities. From a single 25 kg bag through to bulk solution tank loads on contract supply.
• Export experience. Class 8 dangerous-goods documentation, packing and labelling handled for sea and road freight.
• Related intermediates. Ethylenediamine, DETA, TETA, TEPA, aminoethylethanolamine and the wider ethyleneamine range from one supplier.

How ordering works

• Send the enquiry. Product, grade or specification, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
• We quote. Price, lead time, packing and a sample COA, normally within one working day.
• Sample and qualify. For first orders or critical applications, we send a trial quantity so your lab can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Production and QC. Material allocated and released against a batch-specific COA, with a pre-shipment sample where the application calls for it.
• Ship and document. Packed, labelled and loaded with the full export and dangerous-goods document set, and tracked through to arrival.

Related Heterocyclic & Ethyleneamine Intermediates

Buyers of piperazine usually source several of these alongside it. Consolidating them on one order cuts freight cost and gives you a single point of contact for documentation.