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Amine Ether is a family of organic compounds that carry an ether linkage and an amino group in the same molecule. That pairing is the reason the same chemistry family can capture carbon dioxide in a gas plant, cure an epoxy floor, open the cells of a polyurethane foam and collect silicate minerals in a flotation cell. This guide explains how Amine Ether products behave, how to choose a grade, how our factory makes and tests them, and what to check before the first drum is opened.
4
main Amine Ether families covered in this guide
60%
typical top solution strength in acid gas treating with diglycolamine
0.05 to 0.3
typical parts of bis(2-dimethylaminoethyl) ether per 100 parts polyol
32
parts of polyetheramine D-230 per 100 parts of a 190 EEW epoxy resin
Amine Ether at a Glance
Definition
A molecule containing at least one C–O–C bond and at least one primary, secondary or tertiary nitrogen center. The ether part adds flexibility and polarity; the nitrogen part adds basicity and reactivity.
Core Reactions
Salt formation with acids, addition to epoxides, reaction with isocyanates, quaternization with alkyl halides, and reversible capture of CO₂ and H₂S in water.
Physical Form
Most grades are clear, low color liquids that mix with water. Higher molecular weight polyetheramines are more viscous but stay liquid at room temperature.
Typical Uses
Acid gas removal, epoxy hardening, polyurethane foam catalysis, surfactant synthesis, mineral flotation, corrosion control and intermediate synthesis.
How the Ether Bond Changes Amine Behavior
A plain aliphatic amine such as a short chain alkylamine is a compact, reactive and often volatile molecule. Insert an ether oxygen into the carbon chain and several properties shift at once. The oxygen atom can accept hydrogen bonds from water, so solubility rises. The C–O bonds rotate more freely than C–C bonds, so the backbone becomes more flexible and the glass transition temperature of resulting polymers falls. The oxygen also withdraws a little electron density from nearby carbons, which slightly lowers the basicity of the nitrogen compared with a purely hydrocarbon analog.
These shifts explain why one Amine Ether is a good gas treating solvent while another is a good toughener. In a solvent, the priority is a high solution strength, thermal stability and a freezing point low enough for winter operation. In a hardener, the priority is chain flexibility, low viscosity and a predictable number of active hydrogen atoms. In a catalyst, the priority is a tertiary nitrogen that is accessible to the reactants. The same structural idea is tuned in different directions.
Four Amine Ether Families and Their Roles
Alkoxypropylamines
Made by adding acrylonitrile to an alcohol and then hydrogenating the nitrile. The result is a primary amine with an ether tail. Short chain members such as 3-methoxypropylamine serve as corrosion inhibitor intermediates and pH adjusters, while longer chain members serve as mineral collectors.
Polyetheramines
Polyether backbones built from propylene oxide, ethylene oxide or both, with terminal amino groups. Available as monoamines, diamines and triamines across a wide molecular weight range.
Hydroxy Ether Amines
Diglycolamine, also called 2-(2-aminoethoxy)ethanol, has one hydroxyl group, one ether bond and one primary amino group. It dissolves fully in water and is widely used for acid gas removal.
Tertiary Amine Ethers
Bis(2-dimethylaminoethyl) ether has no active hydrogen. It does not become part of a polymer network; it speeds the blowing reaction in polyurethane foam as a catalyst.
Typical Property Data
The table below lists typical values for four widely used Amine Ether products. Values are representative of standard commercial quality and are provided for orientation. Always confirm against the certificate of analysis supplied with each lot.
| Property | Diglycolamine | 3-Methoxypropylamine | Bis(2-dimethylaminoethyl) ether | Polyetheramine D-230 |
|---|---|---|---|---|
| Molecular weight | 105.14 | 89.14 | 160.26 | about 230 |
| Boiling point, °C | about 221 | about 118 | about 189 | above 200 |
| Density at 20 °C, g/cm³ | about 1.05 | about 0.87 | about 0.85 | about 0.95 |
| Amine type | Primary | Primary | Tertiary | Primary |
| Active hydrogen equivalent weight | about 52 | about 45 | not applicable | about 60 |
| Water solubility | Fully miscible | Fully miscible | Readily soluble | Readily soluble |
| Main use | Acid gas removal | Intermediate, inhibitor | Foam catalyst | Epoxy hardener |
Viscosity and Temperature: Why Heating Helps Processing
Viscosity decides how easily an Amine Ether can be pumped, metered, degassed and mixed. Polyetheramines are Newtonian liquids, so their viscosity falls smoothly as temperature rises. The curve is steepest in the first 30 °C above room temperature, which means a modest warm up of the drum or day tank delivers most of the benefit.
Indicative viscosity of two polyetheramine grades versus temperature
Polyetheramine D-230 typePolyetheramine D-400 type
Practical advice follows from the curve. Warming a D-400 type product from 20 °C to 50 °C cuts its viscosity to less than a third, which noticeably reduces air entrapment in castings. Heating beyond 60 °C brings smaller gains and raises vapor and oxidation exposure, so most workshops hold material between 35 °C and 50 °C.
Amine Ether as an Epoxy Hardener
Polyetheramines react with epoxy groups through their primary amino hydrogens. Each primary amino group offers two active hydrogens, and each active hydrogen opens one epoxy ring. The result is a cross-linked network in which the flexible polyether segments sit between rigid epoxy segments. Cured parts absorb impact better and resist micro-cracking when the temperature cycles.
Calculating the Mix Ratio
The stoichiometric amount of hardener per 100 parts resin equals the amine hydrogen equivalent weight divided by the epoxy equivalent weight, multiplied by 100. The following table applies that formula to a bisphenol A resin with an epoxy equivalent weight of 190.
| Hardener type | Functionality | Amine hydrogen equivalent weight | Parts per 100 parts resin | Cured character |
|---|---|---|---|---|
| Polyetheramine D-230 type | Difunctional | about 60 | about 32 | Balanced hardness and toughness |
| Polyetheramine D-400 type | Difunctional | about 115 | about 60 | Softer, higher elongation |
| Polyetheramine T-403 type | Trifunctional | about 81 | about 43 | Higher cross-link density, harder |
| Polyetheramine D-2000 type | Difunctional | about 514 | used as a flexibilizer share | Elastomeric, blended with faster hardeners |
Calculated ratios are a starting point. Water content, resin purity and the intended use change the best ratio, so a small laboratory trial with a hardness and glass transition check is recommended before scale up.
Gel Time Comparison
Gel time controls working life. The bars below compare indicative gel times for a 100 g mass at 25 °C with the same bisphenol A resin. Longer bars give more time to pour, infuse or level.
Indicative gel time, minutes, 100 g mass at 25 °C
Because primary polyetheramines react more slowly than short chain polyamines, many formulators add a small amount of accelerator such as a phenolic or tertiary amine compound. Even a modest addition can shorten gel time by a third without hurting clarity.
Where Cured Amine Ether Systems Perform Well
Casting and Potting
Low viscosity gives bubble-free fill of electronic housings, coils and sensor bodies. The flexible network protects delicate components from thermal shock.
Vacuum Infusion
Long working life and low viscosity let resin travel through glass or carbon fabric before gelation, which suits large blades, hulls and panels.
Coatings and Flooring
Clear systems resist yellowing better than many aliphatic alternatives, which helps in light colored floors and decorative topcoats.
Adhesives
Peel strength improves because the polyether segments absorb stress at the bond line, especially on metals that expand and contract.
Acid Gas Removal with Hydroxy Ether Amines
In natural gas, refinery gas and synthesis gas plants, diglycolamine solutions strip CO₂, H₂S and some carbonyl sulfide from the gas stream. The primary amine group reacts quickly with the acid gas in the absorber, forming carbamate and bicarbonate species. In the regenerator, steam heat reverses the reaction, releases the acid gas and returns the lean solution to the absorber.
Process Cycle in Four Stages
1
Absorption. Sour gas flows upward through the absorber while lean solution flows downward. The solution picks up CO₂ and H₂S.
2
Heat recovery. Rich solution passes through a cross exchanger, taking heat from the hot lean solution leaving the regenerator.
3
Regeneration. The reboiler supplies steam. Acid gas leaves from the top of the stripper and goes to sulfur recovery or compression.
4
Reclaiming. A slipstream of solution is processed to remove heat stable salts and degradation products, keeping solution quality steady.
Solvent Comparison
| Item | Diglycolamine | Monoethanolamine | Methyldiethanolamine |
|---|---|---|---|
| Amine class | Primary | Primary | Tertiary |
| Typical solution strength, wt% | 50 to 60 | 15 to 20 | 40 to 50 |
| Boiling point, °C | about 221 | about 170 | about 247 |
| CO₂ reaction speed | Fast | Fast | Slower, needs activator |
| Selectivity for H₂S over CO₂ | Low | Low | High |
| Low temperature operation | Good | Fair | Good |
| Circulation rate for the same duty | Lower | Higher | Medium |
A higher allowable solution strength means less water to heat in the reboiler for each mole of acid gas removed, and a lower circulation rate shrinks pumps and piping. The trade-off is a more corrosive rich solution at high loading, which is why carbon steel limits, stress relief of welds and stainless steel in hot zones are standard design points.
Operating Practice Tips
- Hold rich loading within the design limit, because high loading accelerates corrosion in the stripper feed line.
- Filter solution continuously through a particulate and carbon filter train to remove iron sulfide and heavy hydrocarbons that cause foaming.
- Keep make-up water low in chloride and hardness; dissolved salts build up quickly in a closed loop.
- Track heat stable salt content monthly and reclaim before it reaches a few percent of solution mass.
Tertiary Amine Ether Catalysts in Polyurethane Foam
Bis(2-dimethylaminoethyl) ether is one of the strongest blowing catalysts available. In flexible and some rigid foam formulations, water reacts with isocyanate to produce CO₂ gas, and this catalyst speeds that reaction far more than it speeds the polymer-forming reaction. That selectivity lets a formulator build gas and polymer strength at matched rates, which is the basis of a stable rise profile.
Indicative cream time and rise time versus catalyst dosage
Cream timeRise time
The chart shows how both times drop as dosage increases. Doubling the dose from 0.10 to 0.20 parts shortens the rise by roughly a third. Beyond about 0.3 parts the foam may rise before the gel network is strong enough to hold the cells, causing collapse or splits. Pair this blowing catalyst with a gelling catalyst, usually a tertiary amine or an organometallic compound, and adjust in steps of 0.02 to 0.05 parts.
Foam Formulation Quick Reference
| Symptom | Likely cause | Adjustment |
|---|---|---|
| Foam collapses after full rise | Too much blowing action compared with gel strength | Reduce Amine Ether dose or raise gelling catalyst |
| Tight, closed cells and shrinkage | Gel forms before gas is released | Increase blowing catalyst slightly |
| Split along the top of the block | Late gas evolution after gel | Lower water level or lower catalyst dose |
| Strong odor after cure | Residual volatile amine | Lower dose, extend cure, ventilate the curing area |
Surfactant Synthesis and Mineral Flotation
Long chain ether amines made from fatty alcohols and acrylonitrile are the starting point for cationic and amphoteric surfactants. Quaternization with methyl chloride or dimethyl sulfate yields cationic products for antistatic and softening use. Ethoxylation yields nonionic or weakly cationic products that act as emulsifiers.
Iron Ore Reverse Flotation
Partially neutralized ether amines attach to quartz and silicate surfaces, making them hydrophobic so that air bubbles lift them away. Iron oxides remain in the cell tailings stream as the concentrate. Typical collector dosage is in the range of tens to a few hundred grams per tonne of ore, depending on grade and slime content.
Phosphate and Potash Processing
Ether amines separate silica from phosphate and clay from potash. Carbon chain length is matched to ore type; a shorter chain is more water soluble and a longer chain is a stronger collector.
Textile and Fiber Finishing
Quaternized ether amines deposit a thin cationic film on fiber surfaces, which reduces static buildup and gives a soft hand without a greasy residue.
Metalworking Fluids
Water soluble Amine Ether products supply alkalinity reserve, buffer pH drift from bacterial action and reduce ferrous corrosion on machined parts.
How We Make and Verify Amine Ether Products
Consistent chemistry depends on controlled feedstock, closed reactors and tested release. Our factory follows a defined path from raw material receipt to filled container, and every lot carries a traceable batch number.
1
Raw material check. Alcohols, oxides, nitriles and hydrogen are tested for water, purity and inhibitor content before charging.
2
Reaction. Oxide addition or cyanoethylation takes place in jacketed reactors with temperature and pressure interlocks.
3
Hydrogenation or amination. Catalytic conversion produces the amino group; selectivity is monitored by gas chromatography samples.
4
Purification. Vacuum distillation or stripping removes light ends, water and by-products to reach the target specification.
5
Release testing. The laboratory confirms amine value, water, color and purity, then issues a certificate of analysis.
6
Filling under nitrogen. Containers are purged and sealed to limit contact with air, CO₂ and moisture during storage and transit.
Quality Control Items
| Test item | Method | Why it matters |
|---|---|---|
| Total amine value | Potentiometric titration with standard acid | Sets the correct dose in hardener, catalyst and solvent use |
| Water content | Karl Fischer titration | Water interferes with isocyanate and epoxy reactions |
| Purity and impurities | Gas chromatography | Controls by-products that affect odor and reactivity |
| Color | APHA or Gardner scale | Indicates oxidation history and suitability for clear systems |
| Viscosity | Rotational viscometer at 25 °C | Confirms handling behavior for pumping and mixing |
| Density | Digital density meter | Supports accurate mass-to-volume conversion |
Packaging Options
Pails
20 to 25 kg lined steel or high density polyethylene pails suit laboratory trials, small batches and pilot runs.
Drums
200 to 220 kg closed-head drums with nitrogen blanketing are the most common supply format for production lines.
IBC Totes
1000 kg intermediate bulk containers with compatible liners suit continuous consumption and automated dosing.
ISO Tank
Dedicated stainless steel tanks serve very large continuous consumption, with sampling at loading and on arrival.
Custom Support from the Factory
- Tailored amine value, water limit and color to match your formulation window.
- Blended hardeners, such as a D-230 and D-400 type mix, supplied pre-mixed to a fixed ratio.
- Technical data sheets, safety data sheets and certificates of analysis in English with each shipment.
- Sample quantities for laboratory evaluation and a technical contact for formulation questions.
Selecting the Right Amine Ether by Application
| Application | Recommended type | Key selection parameters |
|---|---|---|
| Natural gas sweetening | Diglycolamine | Solution strength, water content, iron and chloride limits |
| Epoxy casting and potting | Polyetheramine diamine | Viscosity, amine hydrogen equivalent weight, color |
| High cross-link epoxy coatings | Polyetheramine triamine | Functionality, gel time, hardness target |
| Flexible polyurethane foam | Bis(2-dimethylaminoethyl) ether blend | Dosage range, odor, compatibility with gel catalyst |
| Iron ore flotation | Long chain ether monoamine | Carbon chain length, neutralization degree, cloud point |
| Corrosion inhibitor synthesis | 3-Methoxypropylamine | Purity, water, assay by titration |
| Cationic surfactant | Ether amine prior to quaternization | Primary amine content, color, melting point |
Storage, Handling and Safety
Amine Ether products are alkaline and may irritate or corrode skin, eyes and the respiratory tract. Treat each grade according to its safety data sheet. The points below summarize routine good practice.
Storage
Keep containers tightly closed in a cool, dry and ventilated area. Exposure to air allows CO₂ absorption and slow oxidation, which cause haze and yellowing. A nitrogen blanket in tanks stops both.
Materials of Construction
Carbon steel, stainless steel and suitable polymer linings are acceptable. Avoid copper, brass, zinc and aluminum, which can be attacked by amines.
Personal Protection
Use chemical resistant gloves, splash goggles, a face shield for transfers and protective clothing. Provide an eyewash and shower close to the work area.
Spill Response
Contain with inert absorbent, collect in labeled containers and rinse the area with plenty of water. Keep spills away from drains and from acids or oxidizers.
Troubleshooting Common Amine Ether Problems
| Observation | Probable cause | Corrective action |
|---|---|---|
| White crust or haze on cured epoxy surface | Amine blush from CO₂ and moisture at low temperature | Cure above 15 °C, reduce humidity, wash with warm water before recoating |
| Sticky cured part | Wrong mix ratio or incomplete mixing | Recalculate with equivalent weights; mix for a full two minutes and scrape sides |
| Yellow drum contents | Oxidation after air exposure | Test amine value; mild color change is often cosmetic. Purge headspace with nitrogen |
| Rising foam in gas treating absorber | Hydrocarbon or solids in solution | Improve inlet separation, increase filtration, review antifoam use |
| Gas plant corrosion at reboiler | High temperature, high loading or heat stable salts | Lower reboiler temperature, reclaim solution, check metallurgy |
| Slow cure of polyurethane foam | Low catalyst activity or cold chemical temperature | Warm components to 25 °C; check dosage and catalyst water content |
Frequently Asked Questions about Amine Ether
What does Amine Ether mean in chemical terms?
Amine Ether describes compounds that have both an ether group and an amino group. The category is broad, from small molecules such as 3-methoxypropylamine to polymers carrying amino end groups.
Is Amine Ether soluble in water?
Most low and medium molecular weight grades dissolve completely or readily. Long chain ether amines are less soluble and are normally neutralized with acid to form dispersible salts.
How should an epoxy hardener dose be calculated?
Divide the amine hydrogen equivalent weight by the epoxy equivalent weight and multiply by 100 to obtain parts per 100 parts resin. Verify the result with a small trial.
Why does the product change color in storage?
Oxygen reacts slowly with amino groups and trace impurities. The effect is faster in warm, half-empty containers. Nitrogen blanketing and tight closure limit the change.
Can Amine Ether be used for CO₂ capture?
Yes. Primary amine grades such as diglycolamine react quickly and reversibly with CO₂, so they suit regenerable absorption cycles. Solution strength and regeneration energy are the main design factors.
What shelf life can be expected?
Sealed original containers stored cool and dry typically remain within specification for 12 to 24 months. Retest amine value and water if a container has been opened repeatedly.
What information should be provided when requesting a quotation or sample?
Share the application, target amine value or equivalent weight, the resin or polyol system, the annual consumption and the preferred packaging. This allows the technical team to recommend a suitable grade.
Are documents available for customs and safety review?
Safety data sheets, technical data sheets, certificates of analysis and origin documents are prepared for each shipment.
Need an Amine Ether Grade for Your Process?
Send us your application, target specification and required quantity. Our technical team replies with a recommended grade, typical data, and sample availability.
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