N-(2-Aminoethyl)-3-aminopropyltriethoxysilane (CAS 5089-72-5), sold as A-1130 or KH-793 class, is the ethoxy twin of the A-1120 grade: the same diamine head – one primary and one secondary nitrogen – on the same propyl spacer, but with three ethoxy groups instead of three methoxy groups. It exists for plants where the extra amine is wanted and methanol is not acceptable. PolyBlueChem supplies it as a clear liquid with per-batch COA and SDS.
Specifications
| Property | Specification |
|---|---|
| CAS number | 5089-72-5 |
| Chemical name | N-(2-Aminoethyl)-3-aminopropyltriethoxysilane; 1,2-ethanediamine, N1-[3-(triethoxysilyl)propyl]- |
| Trade designations | A-1130; KH-793 class |
| Formula / MW | C11H28N2O3Si / 264.44 g/mol |
| Appearance | Colourless transparent liquid |
| Colour (Pt-Co) | 30 max |
| Purity | 98.0% min |
| Density (20 degC) | 0.965 +/- 0.005 g/cm3 |
| Refractive index (n25D) | 1.4360 +/- 0.0050 |
| Silicon content | 10.62% |
| Amine equivalent | 132.22 g per mol N (two nitrogens per molecule) |
| Alcohol by-product | Ethanol, 523 g per kg on full hydrolysis |
| Storage | Sealed, dry, cool; hygroscopic like all diamines |
Why the ethoxy diamine carries a real cost
Moving from methoxy to ethoxy is not a like-for-like substitution, and buyers who treat 5089-72-5 as a drop-in replacement for 1760-24-3 discover it in the dosage:
| Property | This product (ethoxy diamine, 5089-72-5) | A-1120 grade (methoxy diamine, 1760-24-3) |
|---|---|---|
| Molecular weight | 264.44 | 222.36 |
| Amine equivalent | 132.22 g/mol N | 111.18 g/mol N |
| Extra silane needed for equal amine | About 19% more | Reference |
| Silicon content | 10.62% | 12.63% |
| Alcohol by-product | Ethanol, 523 g/kg | Methanol, 432 g/kg |
| Hydrolysis rate | Slower, more controllable | Faster |
| Density at 20 degC | 0.965 g/cm3 | 1.020 g/cm3 |
Nineteen percent more silane per unit of amine is the honest number. The compensation is that ethoxy hydrolyses more slowly, so pot life is longer and the working solution is less sensitive to a warm shop floor – and that the by-product is ethanol, which is not a regulated toxicant in the way methanol is. That trade is usually worth it in European and North American plants with methanol restrictions and not worth it where the extra reactivity and lower dose are what the process was built around.
Density is again the fastest receiving check: 0.965 g/cm3 for this grade against 1.020 g/cm3 for the methoxy form. Refractive index does move here (1.4360 against 1.4450), but the density gap is the more reliable separator.
Where the ethoxy diamine is the right answer
- Adhesives and sealants under methanol restriction – the direct substitution route when the A-1120 grade is already qualified but the plant cannot accept methanol.
- Larger working solutions with longer standing time – slower hydrolysis extends usable life where a shift-length pot is impractical.
- Glass-fibre sizing – diamine coupling in a sizing that is dried at temperature; ethanol is easier to handle in the oven exhaust than methanol.
- Mineral filler treatment – silica, alumina trihydrate, wollastonite and glass microspheres, especially where the treated filler is stored before use.
- Adhesion primers for epoxy, polyurethane and hybrid systems on inorganic substrates.
The two diamines exist for a reason – do not split the difference
Some buyers try to hold both grades and choose by price on the day. That works only if the dosage is re-derived each time, because the amine equivalents differ by 19% and the hydrolysis rates differ more than that. A validated process should be built around one grade with the other qualified as a documented alternate, not switched batch to batch.
The monoamine ethoxy grade 919-30-2 is a different proposition again: same ethoxy chemistry, half the amine. It is the right choice where yellowing resistance outranks adhesion on difficult substrates, and it is the grade most glass-fibre and coating systems are actually formulated around.
Buying notes
- Convert the dosage by amine equivalent (132.22 g/mol N here, 111.18 for the methoxy form) before running a trial, not after.
- Ask for water on the COA. Diamines take up moisture faster than monoamines, and the amine self-catalyses hydrolysis once water is present.
- Ask for chloride – the hydrosilylation residue that degrades glass bonding over time rather than on day one.
- Confirm triethoxy against trimethoxy in writing. 5089-72-5 and 1760-24-3 share a generic name and differ in molecular weight, amine equivalent and by-product alcohol.
- Expect yellowing. Both diamine grades discolour in aromatic epoxy and isocyanate systems; where a white or clear article has to stay colour-stable, the monoamine is the safer base.
Packaging and supply
Supplied as a clear liquid in steel drums, IBCs or ISO tanks, with nitrogen padding recommended for long sea freight. Every lot ships with a COA and SDS, and FOB or CIF terms are quoted against destination. We quote this grade and its methoxy counterpart together on request, so a plant can qualify the compliant alternate before it is needed rather than after a restriction arrives.
PolyBlueChem supplies N-(2-aminoethyl)-3-aminopropyltriethoxysilane (CAS 5089-72-5, A-1130 / KH-793 class) as a clear liquid with per-batch COA and SDS and FOB/CIF delivery. Tell us whether the constraint is methanol, pot life or cure temperature – that answer decides between this grade and the methoxy diamine 1760-24-3.
