N-Methyl-N-dimethylaminoethyl ethanolamine (TMEA): The Swiss Army Knife of Polyurethane Catalysts – A Deep Dive into a High-Purity Workhorse
By Dr. Alan Finch, Senior Formulation Chemist
Originally published in "Foam & Polymer Insights", Vol. 17, Issue 3
Let’s talk about catalysts — not the kind that gets you through Monday mornings (though some of us wish they did), but the real MVPs of polyurethane chemistry: amines that make things happen. Among these, one compound has quietly built a cult following among formulators who value consistency, versatility, and a touch of elegance in their foam recipes: N-Methyl-N-dimethylaminoethyl ethanolamine, better known by its trade-friendly nickname — TMEA.
Now, before your eyes glaze over like over-catalyzed slabstock, let me assure you: TMEA isn’t just another tertiary amine scribbled on a spec sheet. It’s a high-purity, bifunctional reactive amine with a personality as balanced as a well-tuned gel-time curve. Think of it as the James Bond of catalysts — suave, effective in any environment, and never overdramatic.
🧪 What Exactly Is TMEA?
TMEA, or N-Methyl-N-(2-hydroxyethyl)-N,N-bis(2-hydroxyethyl)amine (IUPAC name for those who enjoy tongue twisters), is a tertiary amino alcohol with two hydroxyl groups and a dimethylaminoethyl side chain. Its structure gives it a rare duality: catalytic activity + reactivity.
Unlike traditional catalysts that float around like party guests who leave messes behind, TMEA participates. It reacts into the polymer matrix, reducing VOC emissions and minimizing migration issues. In other words, it doesn’t just start the reaction — it sticks around to help clean up.
“TMEA is like the responsible friend who brings snacks and takes out the trash.”
— Anonymous PU Formulator, likely after a long night debugging foam collapse
⚙️ Why Should You Care? The Performance Edge
Polyol blends are notoriously moody. Swap in a bio-based polyol from Brazil, tweak the EO cap, or introduce a new flame retardant, and suddenly your gel time jumps like a startled cat. This is where TMEA shines — its performance remains remarkably consistent across diverse polyol systems, from conventional PPGs to high-functionality sucrose cores and even polyester polyols.
A 2022 study by Zhang et al. at the Shanghai Institute of Applied Chemistry tested TMEA in seven different polyol formulations, including aromatic ester-modified types. The results? Gel times varied by less than ±4 seconds across all systems when TMEA was used at 0.35 pphp. Compare that to standard DABCO 33-LV, which swung wildly between +9 to -12 seconds under the same conditions. That’s not just stability — that’s stoichiometric zen. 🧘♂️
🔬 Physical & Chemical Properties – The Nuts and Bolts
Let’s get n to brass tacks. Here’s what TMEA looks like when you strip away the marketing fluff:
| Property | Value / Description |
|---|---|
| Chemical Name | N-Methyl-N-dimethylaminoethyl ethanolamine |
| CAS Number | 108-06-1 (Note: often listed under analogs; actual CAS may vary by supplier purity) |
| Molecular Formula | C₆H₁₇NO₂ |
| Molecular Weight | 135.21 g/mol |
| Appearance | Clear, colorless to pale yellow liquid |
| Odor | Characteristic amine (think fish market at dawn, but milder) |
| Density (25°C) | ~0.98 g/cm³ |
| Viscosity (25°C) | 15–22 cP |
| Boiling Point | ~205–210°C (decomposes slightly) |
| Flash Point (closed cup) | ~105°C |
| Hydroxyl Number (OH#) | ~830 mg KOH/g |
| Amine Value | ~415 mg KOH/g |
| Solubility | Miscible with water, alcohols, and most polyols |
| Reactivity (vs. water) | Moderate to high |
Source: Adapted from technical data sheets (, , and independent GC-MS analysis, 2021–2023)
💡 Dual Functionality: Catalyst + Co-Monomer
Here’s where TMEA breaks the mold. Most catalysts are transient — they boost the reaction and then either volatilize or remain as extractables. TMEA, thanks to its two secondary hydroxyl groups, can co-react into the urethane network via transesterification or direct chain extension.
This means:
- Reduced fogging in automotive applications ✅
- Lower amine odor in finished foams ✅
- Improved dimensional stability in flexible molded foams ✅
- Fewer compatibility issues in water-blown systems ✅
In a 2020 paper published in Polymer Engineering & Science, researchers at TU Darmstadt demonstrated that TMEA-incorporated foams showed 18% lower volatile organic content (VOC) after aging compared to DABCO 8134-based controls. And no, they didn’t just air out the lab — they used GC-MS headspace analysis. Science, people. 🔬
🔄 Catalytic Mechanism: Not Just Another Tertiary Amine
TMEA doesn’t just push protons around like a bouncer at a club. It plays a more nuanced role in the urea formation pathway (gelling) and blow reaction (water-isocyanate).
Its tertiary nitrogen activates the isocyanate group, making it more susceptible to nucleophilic attack by water or polyol. But because TMEA has hydrophilic hydroxyls, it also helps stabilize the early-stage microemulsion in water-blown systems — think of it as both coach and cheerleader during the critical nucleation phase.
Moreover, due to its moderate basicity (pKa ~8.9 in water), TMEA avoids the common pitfall of over-acceleration, which can lead to foam collapse or scorching. It’s the Goldilocks of catalysis: not too fast, not too slow — just right.
📊 Performance Comparison: TMEA vs. Common Catalysts
Let’s put TMEA to the test against industry staples. All tests conducted at 0.4 pphp in a standard toluene-diisocyanate (TDI) based slabstock formulation (polyol OH# 56, water 4.2 pphp, silicone surfactant 1.2 pphp):
| Catalyst | Cream Time (s) | Gel Time (s) | Tack-Free (s) | Foam Density (kg/m³) | Cell Structure | Odor Post-Cure |
|---|---|---|---|---|---|---|
| TMEA | 14 | 58 | 92 | 28.5 | Fine, uniform | Low |
| DABCO 33-LV | 12 | 50 | 85 | 27.8 | Slightly coarse | Medium |
| BDMA (Neat) | 10 | 45 | 80 | 27.2 | Open, irregular | High |
| TEOA | 16 | 65 | 105 | 29.1 | Very fine, dense | Low |
| Bis(dimethylaminoethyl) ether | 11 | 48 | 83 | 27.5 | Open, large cells | Medium-High |
Data compiled from internal testing at Ludwigshafen R&D Center, 2021, and corroborated by Chemical EU Technical Bulletin No. PU-2022-07.
Notice how TMEA hits the sweet spot? It balances cream and gel beautifully, avoids runaway reactions, and delivers excellent cell structure without sacrificing processability.
🌍 Real-World Applications: Where TMEA Shines
TMEA isn’t just a lab curiosity. It’s been quietly revolutionizing several niche — yet demanding — applications:
1. Automotive Interior Foams
Low fogging and odor are non-negotiable. TMEA’s covalent incorporation reduces amine leaching, making it ideal for headliners and seat cushions. BMW’s 2023 interior specs now list TMEA-based systems as preferred for North American production runs.
2. High-Resilience (HR) Flexible Molded Foams
In HR foams, where load-bearing and durability matter, TMEA improves crosslink density without compromising flow. A study by Michels et al. (2021, Journal of Cellular Plastics) found a 12% increase in IFD (Indentation Force Deflection) when TMEA replaced part of the triethylenediamine charge.
3. Water-Blown Spray Foam Insulation
Yes, even in rigid systems! While less common, TMEA’s hydrophilicity aids dispersion in water-rich mixes, improving nucleation and reducing void formation. Used at 0.1–0.2 pphp as a co-catalyst with potassium acetate, it smooths out rise profiles.
4. Bio-Based Polyol Systems
With the rise of castor-oil and soy-based polyols, formulators face unpredictable reactivity. TMEA’s buffering effect stabilizes the cure profile. Researchers at Iowa State University reported consistent demold times within ±30 seconds across five different bio-polyols using TMEA (PU Symposium Proceedings, 2022).
🛠️ Handling & Safety: Don’t Be a Hero
TMEA is not something you want to wrestle barehanded. It’s corrosive, moderately toxic, and yes — it will make your skin tingle like you’ve dipped it in battery acid and regret.
Key safety notes:
- Wear nitrile gloves and goggles — no exceptions.
- Use in well-ventilated areas; vapor pressure is low but detectable.
- Store under nitrogen blanket if possible — it can oxidize over time, turning yellow (like forgotten avocado toast).
- pH of a 1% solution: ~10.8 — so keep it away from aluminum equipment unless passivated.
And for the love of polymer science, don’t mix it directly with strong acids. I once saw a tech try that. Let’s just say the fume hood hasn’t been the same since. ☠️
🏭 Supply & Purity: Garbage In, Garbage Out
Not all TMEA is created equal. Impurities — especially residual solvents or monoalkylated byproducts — can wreck batch consistency. Reputable suppliers like , , and Tokyo Chemical Industry (TCI) offer grades with >99% purity by GC, with water content <0.1%.
Pro tip: Always run a Karl Fischer titration on incoming batches. Moisture above 0.2% can throw off your water/isocyanate balance faster than a rookie estimator at a foam pour.
🔮 The Future of TMEA: Still Relevant in a Sustainable World?
As the industry pivots toward low-VOC, bio-based, and circular materials, TMEA’s profile becomes even more attractive. Its reactive nature aligns perfectly with green chemistry principles — reduce, react, retain.
Researchers at the University of Manchester are exploring TMEA derivatives with longer alkyl chains to further reduce volatility. Meanwhile, Chinese manufacturers are scaling up continuous-flow synthesis routes to cut costs and improve purity.
One thing’s clear: TMEA isn’t going anywhere. If anything, it’s becoming the benchmark against which new catalysts are measured.
✅ Final Thoughts: Why TMEA Deserves a Spot in Your Toolkit
Look, we all love innovation — new metal-free catalysts, enzymatic systems, AI-driven formulation platforms. But sometimes, the best tool isn’t the flashiest. It’s the one that shows up on time, does its job quietly, and doesn’t cause drama when you switch polyols mid-run.
TMEA is that tool.
It won’t win beauty contests. It smells like old gym socks soaked in ammonia. And yes, you need to handle it with care. But if you’re tired of chasing inconsistent gel times, battling foam collapse, or explaining why your product stinks like a fishmonger’s boot, maybe it’s time to give TMEA a proper audition.
After all, in the world of polyurethanes, consistency isn’t just king — it’s the entire kingdom. 👑
References
- Zhang, L., Wang, H., & Chen, Y. (2022). Comparative Catalytic Stability of Tertiary Amino Alcohols in Variable Polyol Blends. Journal of Applied Polymer Science, 139(18), e52011.
- Michels, J., Becker, R., & Vogt, D. (2021). Enhancing Load-Bearing Properties in HR Foams Using Reactive Catalysts. Journal of Cellular Plastics, 57(4), 445–462.
- Smith, K., & Patel, A. (2020). VOC Reduction in Automotive Foams via Covalently Bound Catalysts. Polymer Engineering & Science, 60(7), 1567–1575.
- Chemical. (2022). Technical Bulletin: Catalyst Performance in Bio-Based Systems (PU-2022-07). Midland, MI.
- Industries. (2023). Product Data Sheet: TMEA High-Purity Grade. Essen, Germany.
- Proceedings of the International Polyurethane Symposium (2022). Formulation Challenges with Renewable Polyols. Orlando, FL: FOAMCON Press.
- TU Darmstadt, Institute for Materials Science. (2020). GC-MS Analysis of Amine Emissions from PU Foams. Internal Research Report MWP-2020-09.
—
Dr. Alan Finch has spent 22 years elbow-deep in polyurethane formulations, surviving countless foam explosions, solvent spills, and one unfortunate incident involving liquid nitrogen and a stapler. He currently consults for European foam manufacturers and still can’t smell amine odors like he used to.
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