n-Butylamine CAS 109-73-9

What is n-Butylamine?

n-Butylamine is the straight-chain primary amine of the butyl series — an amino group on the terminal carbon of a four-carbon chain, C₄H₉NH₂. It is the linear member of a family of four isomers that share a formula and a molecular weight and very little else.

It is a clear, colourless, mobile liquid boiling at about 78 °C, with a strong ammoniacal and faintly fishy odour. The flash point sits near −12 °C, so it is highly flammable and the vapour space above the liquid is in the flammable range at ordinary temperature — though it is noticeably easier to handle than the propylamines, which boil and flash far lower.

It is miscible with water in all proportions and strongly basic, with a conjugate acid pK_a near 10.6. Four carbons is enough chain length to start giving the molecule and its derivatives some genuine surface activity and oil solubility, which is why butylamine derivatives turn up in emulsifiers and corrosion inhibitors where the shorter amines do not.

Commercially, n-butylamine is a broad fine chemical intermediate. It is best known as the amine half of the sulphonylurea structure used in oral antidiabetic drugs, and it is used across agrochemical synthesis, rubber chemistry, dye intermediates, emulsifiers, tanning auxiliaries and corrosion inhibitors.

Why n-butylamine specifically

• Linear, unhindered nitrogen. The terminal amino group is sterically open, so it reacts readily with isocyanates, acid chlorides, epoxides and carbonyl compounds where the branched isomers are slower.
• Chain length that matters. Four carbons give derivatives real oil solubility and surface activity — enough to make useful emulsifiers and filming inhibitors, which the shorter amines cannot.
• Two reactive N-H bonds. It can form amides, ureas, sulphonylureas, imines and heterocycles that still carry a free N-H for further substitution.
• Manageable volatility. Boiling at about 78 °C it handles far more easily than the propylamines, with no pressure build-up in ordinary storage.

How n-BA is Manufactured

n-Butylamine is made by aminating n-butanol, or by reductive amination of butyraldehyde. Either route produces di- and tri-n-butylamine alongside the mono product, so the separation train determines final quality.

• Amination or reductive amination. n-Butanol and excess ammonia are passed over a supported metal or solid acid catalyst at elevated temperature and pressure with hydrogen present. An alternative route reductively aminates butyraldehyde with ammonia and hydrogen over a nickel or cobalt catalyst.
• Ratio control. A high ammonia-to-substrate ratio suppresses further alkylation and pushes the distribution toward the mono amine. Surplus di-n-butylamine is recycled or taken off as a co-product in its own right.
• Separation. The crude mixture is resolved by fractional distillation with ammonia recovery. Water forms an azeotrope with butylamine, so drying is a distinct operation rather than a by-product of fractionation.
• Drying and finishing. The mono cut is dried to specification and filled into drums, IBCs or tanks, with nitrogen blanketing where colour and water specification matter.

Typical Commercial Specification

Figures below are representative of standard commercial grade. Tighter agrochemical and pharmaceutical grades with lower water and metals are available — send us the specification you work to and we will quote against it.

Physical & Chemical Properties

Reactivity in practice

The chemistry runs through the nitrogen lone pair and the two replaceable N-H hydrogens, with the linear chain leaving the nitrogen sterically open:

• Urea and sulphonylurea formation. Reaction with isocyanates or with sulphonyl isocyanate equivalents gives substituted ureas and sulphonylureas — the latter being the backbone of a major class of oral antidiabetic drugs.
• Amidation and acylation. Reaction with acid chlorides, anhydrides or esters gives N-butyl amides used across agrochemical and pharmaceutical chemistry.
• Reaction with carbon disulphide and isothiocyanates. Gives dithiocarbamates and substituted thioureas used as rubber accelerators and fungicide intermediates.
• Epoxide opening and alkoxylation. Opens epoxide rings to butylamino alcohols, and ethoxylation gives the amine ethoxylates used as emulsifiers and antistatic agents.

n-Butylamine vs the Other Butylamine Isomers

All four butylamine isomers share the formula C₄H₁₁N and a molecular weight of 73.14, and differ only in where the amino group sits on the four-carbon skeleton. That single difference moves the boiling point by more than 30 °C across the set, changes how crowded the nitrogen is, and decides which registered products the molecule can go into. They are separate substances with separate CAS numbers, not grades of one another.

Stated plainly: the more branched the carbon bearing the nitrogen, the lower the boiling point and the more crowded the amine. n-Butylamine is linear and reacts freely; isobutylamine is branched one carbon away and behaves similarly with slightly more bulk; sec-butylamine carries a chiral centre, which matters in pharmaceutical work; tert-butylamine is fully branched at the nitrogen-bearing carbon, which slows some reactions and makes the resulting derivatives notably more hydrolytically stable. Chelora supplies all four.

Industries We Supply n-BA To

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

Where n-BA is Used

n-Butylamine is a broad-use intermediate across several industries. These are the end uses our customers buy it for, roughly in order of volume.

In pharmaceutical synthesis

The sulphonylurea antidiabetics are the classic application: an arylsulphonyl isocyanate or carbamate is reacted with n-butylamine to give the sulphonylurea bridge that defines the drug class. Beyond that, n-butylamine supplies the N-butyl group in a range of amides and heterocycles. API producers run the tightest specifications in the market, with residual butanol, secondary amine carry-over and metals all needing to clear ICH limits, so standard technical grade is rarely acceptable without upgrading.

In agrochemical manufacture

Used across crop protection as the source of the n-butylamino arm and as the amine half of substituted ureas and thioureas. Plants running registered actives specify isomer purity tightly, because an isobutylamino analogue is not an impurity in the ordinary sense — it is a different compound, and in a registered technical active that is a regulatory problem rather than a yield problem.

In emulsifier and surfactant chemistry

Four carbons is the point at which an aliphatic amine starts to behave as a surfactant precursor rather than purely as a base. Ethoxylation of n-butylamine gives amine ethoxylates used as emulsifiers, antistatic agents and textile auxiliaries, and quaternised derivatives serve as cationic actives. Colour is a live specification here, since an off-colour amine carries into a finished surfactant that a customer will reject on appearance alone.

In corrosion inhibitor manufacture

Amide and Mannich chemistry install the butylamino group in film-forming inhibitors for pipeline, refinery overhead and downhole service. The butyl chain gives enough hydrophobicity for the molecule to anchor at a metal surface, which the shorter amines cannot do. Blenders care more about consistency, colour and water content than about the last tenth of a percent of assay.

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 amine distribution — gas chromatography, which resolves mono-, di- and tri-n-butylamine, separates the branched isomers and quantifies residual ammonia and butanol in one run.
• Water content — Karl Fischer titration. Water is the specification that most often decides whether a lot performs in isocyanate and acid-chloride chemistry.
• Distillation range — a fast, revealing check. A broadened range usually signals amine or isomer carry-over before any instrument confirms it.
• Colour — APHA / Hazen against a standard. Colour drift signals air ingress, carbon dioxide pickup or metal contamination, and matters directly in surfactant and dye routes.
• Metals — iron in particular, since it catalyses discolouration and can poison downstream catalysts.
• Non-volatile residue — evaporation residue, a quick check for carry-over of heavies from the column train.

Common Process Problems & Likely Causes

When n-butylamine 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

• Standard packing. 160 kg net in lined steel or HDPE drums, with 1000 L IBCs for larger users.
• Bulk packing. Road tankers and ISO tank containers for continuous processes.
• Inert blanketing. Nitrogen-blanketed at fill where the grade and end use call for it, to protect colour and water specification in storage.
• Storage. Cool, shaded, well-ventilated and bunded area away from heat, ignition sources, oxidisers and acids, with containers kept tightly closed.
• Materials of construction. Stainless steel, carbon steel or suitable lined vessels. Avoid copper, brass, bronze, aluminium and mercury, all of which are attacked by amines.
• Shelf life. Typically 12 months in unopened original packing under those conditions. Beyond that, re-test rather than assume.
• Transport classification. UN 1125, n-Butylamine, Class 3 flammable liquid with subsidiary risk 8 corrosive, Packing Group II — shipped with full dangerous-goods documentation.
• Container loading. Palletised and secured for FCL; LCL consolidation and tank arrangements available by volume.

Hazards & Safe Handling

n-Butylamine is highly flammable and corrosive, 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.

• Exposure control. Handle in a closed system or under local exhaust ventilation. The flash point is below ambient, so the vapour space above the liquid sits in the flammable range in normal storage.
• PPE. Chemical-resistant gloves, chemical goggles and face shield, chemical-resistant clothing, and respiratory protection suited to the task.
• Ignition control. Vapours are heavier than air, travel along the ground to a distant ignition source and flash back. Bonded, earthed and explosion-proof equipment, and no ignition sources in the zone.
• Incompatibilities. Strong oxidising agents, strong acids, acid chlorides, nitrites, mercury, and copper, brass, bronze and aluminium equipment.
• Spill response. Eliminate ignition sources and ventilate. Contain, absorb with inert non-combustible material and collect in a labelled closed container. Do not wash to drain.
• Environment. Do not allow to enter drains, surface water or groundwater. Dispose through a licensed chemical waste contractor.
• Fire. Highly flammable. Use alcohol-resistant foam, dry chemical or carbon dioxide; cool exposed containers with water spray. Decomposition releases nitrogen oxides — use self-contained breathing apparatus.
• First aid. Move to fresh air, remove contaminated clothing immediately, wash skin with plenty of water, flush eyes for at least 15 minutes, and seek medical attention with the SDS to hand.

Regulatory & Compliance Notes

n-Butylamine is a long-established industrial chemical and is listed on the major national chemical inventories. Because obligations differ by territory, volume and 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.
• Isomer identity. The four butylamine isomers are separate substances with separate CAS numbers and separate registrations. Make sure your import documentation, inventory listing and end-use approval all name the isomer you are actually buying.
• 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.
• Dangerous goods. UN 1125, n-Butylamine, Class 3 with subsidiary risk 8, Packing Group II. Declarations prepared for IMDG (sea) or IATA (air) as appropriate to the mode.
• Workplace exposure. Occupational exposure limits apply in most jurisdictions. Set your controls against the limit in force where the material will be handled.

We Supply n-BA Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship n-Butylamine 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 n-BA from Chelora

We are an independent sourcing and supply partner. For n-butylamine that means matching the grade to the application and confirming isomer purity — a plant that also runs isobutylamine can carry it over, and in a registered product that is a different molecule, not an impurity.

• Documentation on every lot. Batch-specific COA, current SDS and TDS issued with the consignment, not weeks afterward.
• Samples before commitment. Trial quantities for process qualification ahead of a commercial order.
• Quantities. From a single 160 kg drum through to tank loads and ongoing contract supply.
• Export experience. Dangerous-goods documentation, packing and labelling handled for sea and road freight to any destination.
• Technical support. Direct access to people who know the chemistry, for questions on isomer purity, colour control or materials compatibility.
• Related intermediates. Isobutylamine, sec- and tert-butylamine, di-n-butylamine and the wider aliphatic amine 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 Amines & Intermediates

Buyers of n-butylamine 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.