Monoethanolamine (MEA) CAS 141-43-5

What is Monoethanolamine (MEA)?

Monoethanolamine is the simplest alkanolamine — a primary amine and a primary alcohol on the same two-carbon chain, H₂NCH₂CH₂OH. Having both functional groups in one small molecule is the whole point: it is water-soluble like an alcohol and basic like an amine, and it can be reacted at either end.

It is a clear, colourless, moderately viscous liquid with a mild ammoniacal odour, boiling at about 170 °C and freezing at about 10 °C — which means it can solidify in cold storage and in winter transit. It is fully miscible with water, strongly hygroscopic, and will darken on exposure to air, particularly when warm.

Its flash point is near 85 °C, so it is combustible rather than flammable and handles far more comfortably than the volatile amines. It remains corrosive, and in hot or acid-gas-loaded service it is aggressive toward carbon steel, which drives the metallurgy choices in a gas plant.

Commercially, MEA is one of the highest-tonnage amines in the world. Its largest outlets are acid gas removal — scrubbing carbon dioxide and hydrogen sulphide from natural gas, refinery streams and flue gas — and surfactant manufacture, where ethanolamides and ethanolamine soaps underpin a great deal of detergent and personal care chemistry. It is also the feedstock from which the ethyleneamine family is made.

Why monoethanolamine specifically

• The fastest carbon dioxide kinetics of the three. As a primary amine it forms a carbamate directly and quickly, which is why it dominates bulk carbon dioxide removal despite the higher regeneration energy.
• Two different reactive groups. The amine and the hydroxyl can be reacted independently — amidation at one end, esterification or ethoxylation at the other — which is what makes it such a versatile surfactant intermediate.
• Strongest base of the ethanolamines. Least substituted and least sterically hindered, so it neutralises hardest per mole.
• Feedstock for the ethyleneamines. Aminated with ammonia it gives ethylenediamine and the higher ethyleneamines, which puts it upstream of a whole product family.

How MEA is Manufactured

Monoethanolamine is made by reacting ethylene oxide with ammonia. All three ethanolamines form together in the same reactor, and the ratio of reactants decides which dominates.

• Ethoxylation of ammonia. Aqueous ammonia is reacted with ethylene oxide, usually at modest temperature and pressure. The reaction is fast and highly exothermic, and it does not stop at the mono product — the ethanolamine formed competes with ammonia for the next molecule of ethylene oxide.
• Ratio control. A large excess of ammonia is the only practical way to favour the mono product. Plants running for MEA use a high ammonia-to-ethylene-oxide ratio and recycle the ammonia, which is energy-intensive but unavoidable.
• Ammonia and water removal. Excess ammonia is stripped and recycled, and water is removed by evaporation. This is where most of the plant's energy goes.
• Separation. The three ethanolamines are resolved by vacuum distillation — vacuum rather than atmospheric because they decompose and discolour at the temperatures atmospheric distillation would require. Column performance here sets the colour and the cross-contamination figures.

Typical Commercial Specification

Figures below are representative of standard commercial grade. Gas-treating, low-colour and detergent grades with tighter limits are available — send us the specification you work to and we will quote against it.

Physical & Chemical Properties

Reactivity in practice

Two functional groups on one small molecule, reactable independently. That is what makes MEA so widely used:

• Carbamate formation with acid gases. The primary amine reacts directly and rapidly with carbon dioxide to form a carbamate, and with hydrogen sulphide by simple acid-base proton transfer. Heating reverses both, which is what makes the solvent regenerable.
• Amidation at the nitrogen. Reaction with fatty acids or their esters gives ethanolamides — the foam boosters and viscosity builders behind a great deal of detergent and personal care formulation.
• Esterification and ethoxylation at the hydroxyl. The alcohol end esterifies with acids and reacts with ethylene oxide, giving surfactants and emulsifiers built from the other end of the molecule.
• Amination to ethyleneamines. Reacted with ammonia over a catalyst it gives ethylenediamine and the higher ethyleneamines — making MEA the upstream feedstock for that entire family.

Monoethanolamine vs Diethanolamine vs Triethanolamine

The three ethanolamines come off the same reactor and are separated by distillation, so they are routinely quoted together and routinely confused. Each additional hydroxyethyl group on the nitrogen raises the boiling point and the viscosity, lowers the basicity, and removes one N-H bond — and that last point decides most of the chemistry.

Stated plainly: monoethanolamine reacts fastest and strips hardest, which is why it dominates bulk carbon dioxide removal and why it costs the most energy to regenerate. Diethanolamine sits between the two and carries the nitrosamine consideration that follows every secondary amine. Triethanolamine has no N-H at all, so it cannot form a carbamate and acts as a base, an emulsifier precursor and a cement additive rather than as a bulk acid-gas absorbent. They are not interchangeable, and in gas treating the choice between them is a plant design decision.

Industries We Supply MEA To

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

Where MEA is Used

MEA is a genuine bulk commodity with several large markets. These are the end uses our customers buy it for, roughly in order of volume.

In gas treating and carbon capture

This is the largest single use. An aqueous MEA solution — typically in the 15 to 30 percent range — is contacted with the gas stream in an absorber, where the amine reacts with carbon dioxide to form a carbamate and with hydrogen sulphide by proton transfer. The rich solvent is heated in a stripper, which reverses both reactions and releases the acid gas for recovery or sequestration. MEA's advantage is speed: as a primary amine it reacts faster than the secondary and tertiary alkanolamines, so absorbers can be shorter. Its disadvantage is regeneration energy and degradation — it is also the most corrosive of the three in hot service, which is why iron and chloride specifications matter so much.

In surfactants and detergents

Reaction with a fatty acid or methyl ester gives a fatty ethanolamide, and these are the foam boosters and viscosity builders that give a shampoo or dish detergent its body. MEA also forms soaps with fatty acids directly, used as emulsifiers across industrial and personal care formulation. Colour is a live specification here: a yellow amine produces a yellow amide, and a customer buying a clear surfactant will reject it on appearance.

In metalworking fluids

A water-based cutting or grinding fluid needs alkalinity to resist bacterial growth and protect the workpiece and machine from corrosion, and it needs emulsifiers to hold oil in water. MEA contributes to all three. Formulators should note that the nitrosamine question around secondary amines led much of this industry away from DEA, and that MEA as a primary amine does not carry the same liability.

As ethyleneamine feedstock

Reacting MEA with ammonia over a catalyst gives ethylenediamine, and onward the diethylenetriamine, triethylenetetramine and piperazine that make up the ethyleneamine family. This places MEA upstream of epoxy hardeners, chelants, fabric softeners and pharmaceutical intermediates — a strategic position that is easy to overlook when buying it as a commodity.

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 ethanolamine distribution — gas chromatography, quantifying DEA and TEA carry-over alongside the main component.
• Colour — APHA / Hazen against a standard. The ethanolamines darken on air contact, so colour on receipt is as much a storage history check as a manufacturing one.
• Iron — critical for gas treating. Iron accelerates oxidative degradation of the solvent and indicates corrosion somewhere in the supply chain.
• Chloride — also critical for gas treating, where chloride drives stress corrosion cracking in stainless circuits.
• Water content — Karl Fischer titration. MEA is strongly hygroscopic, so an open drum drifts.
• Specific gravity and freezing point — quick practical checks that correlate with water and cross-contamination.

Common Process Problems & Likely Causes

When MEA 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. 210 kg net in lined steel or HDPE drums, with 1000 L IBCs for larger users.
• Bulk packing. Road tankers and ISO tank containers for gas plants, surfactant producers and continuous users.
• Cold weather handling. The freezing point is near 10 °C, so drums can solidify in winter transit or unheated storage. Warm gently and homogenise before use — normal behaviour, not degradation.
• Storage. Cool, dry, well-ventilated and bunded, but above the freezing point where practical. Protect from air and moisture.
• Materials of construction. Stainless steel or suitable lined vessels. Carbon steel is used in some service but corrodes more readily when the amine is hot or loaded with acid gas. Avoid copper, brass, bronze and aluminium.
• Oxygen exclusion. The ethanolamines oxidise and darken on air contact, particularly when warm. Nitrogen blanketing is standard for colour-sensitive grades and for any heated storage.
• Shelf life. Typically 12 months in unopened original packing under those conditions. Beyond that, re-test rather than assume.
• Transport classification. UN 2491, Ethanolamine, Class 8 corrosive, Packing Group III — shipped with full dangerous-goods documentation.

Hazards & Safe Handling

Monoethanolamine is 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 under local exhaust ventilation or in a closed system. Vapour pressure is low at ambient, so skin and eye contact is the dominant exposure route — except where the material is hot or sprayed.
• PPE. Chemical-resistant gloves, chemical goggles and face shield, chemical-resistant clothing. Splash protection is the priority.
• Hot amine service. In a gas plant the amine circulates hot and acid-gas loaded, which raises both the corrosion risk and the consequence of a release. Hot amine burns are a recognised hazard and the controls should reflect that, not the ambient-temperature classification.
• Incompatibilities. Strong oxidising agents, strong acids, acid chlorides, and copper, brass, bronze and aluminium equipment. Corrosive to carbon steel when hot or loaded.
• Spill response. Contain, absorb with inert non-combustible material and collect in a labelled closed container. Ventilate. Do not wash to drain.
• Environment. Do not allow to enter drains, surface water or groundwater. Dispose through a licensed chemical waste contractor.
• Fire. Combustible. Use alcohol-resistant foam, dry chemical or carbon dioxide; cool exposed containers with water spray. Decomposition releases nitrogen oxides and ammonia — use self-contained breathing apparatus.
• First aid. Remove contaminated clothing immediately, wash skin with plenty of water, flush eyes for at least 15 minutes, move to fresh air, and seek medical attention with the SDS to hand.

Regulatory & Compliance Notes

Monoethanolamine 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.
• 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.
• Cosmetic and personal care use. Ethanolamine use in cosmetics is subject to concentration limits and conditions in several territories, and the rules differ between the mono, di and tri products. Confirm the position for the specific alkanolamine and the specific product category at destination.
• Dangerous goods. UN 2491, Ethanolamine, Class 8 corrosive, Packing Group III. 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 MEA Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Monoethanolamine (MEA) 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 MEA from Chelora

We are an independent sourcing and supply partner. For MEA that means matching the grade to the service — low iron and chloride for a gas plant, low colour for surfactants and personal care — rather than treating it as an undifferentiated commodity. The assay is the same; the consequences of the trace specifications are not.

• 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 210 kg drum through to repeat tank loads on contract supply.
• Export experience. Class 8 dangerous-goods documentation, packing and labelling handled for sea and road freight.
• Technical support. Direct access to people who know the chemistry, for questions on gas-treating specifications, colour control or cold-weather handling.
• Related intermediates. Diethanolamine, triethanolamine, the isopropanolamines, the ethyleneamines and the wider alkanolamine 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 Alkanolamines & Intermediates

Buyers of MEA 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.