Dear All,
I'm doing some experiments related to Aromatic amine/Epoxy reaction. I want only primary amine reacts with epoxy, and secondary amine does not. Although it's very difficult, I wonder which is the optimum condition (temperature, Catalyst, equivalent of substances, etc.) for dominant reaction of primary amine with epoxy? Could you give me more information about this reaction?
Thank you.
Without knowing any details my suggestion is to decrease reaction time to avoid formation of secondary amines. Also, keep temperature as low as possible to avoid hitting the activation energy of the secondaries. To further favour you wanted product investigate the possibility of using a chemoselective catalyst.
My suggestion is to decrease the amount of the epoxy that will react with the primary "aliphatic" amine & to reduce the temperature of the reaction "or cure" to RT or below.
As you know, the nucleophilicity of the amine determines the reactivity with epoxy resins & the order of this is aliphatic amines>cycloaliphatic amines>aromatic amines. Therefore, aliphatic amines are adequate to cure epoxy resins at low T.
If you wish to use a catalyst, then opt for the least amount.
With my best wishes for success in your research.
Hi,
Aliphatic amine, which rapidly reacts with epoxy resin, is a representative room-temperature curing agent. However, it generates a large quantity of heat and has a short pot life (usable time). Loading of amines containing no tertiary amine is made at the exact or very closed amount that is said in stoichiometry, and use amount of amines containing tertiary amine is made less than that. If latter curing is performed at high temperature, properties of curing agents that cure at room temperature are improved.
Please you do your epoxy/amine reaction at RT and less amount of epoxy you can use.
Please you see the below link for the further details.
https://www.threebond.co.jp/en/technical/technicalnews/pdf/tech32.pdf
Thank you Dr. Nizar Matar and Mr.Vijayakumar Veeraragavan for your answers.
But in my experiment, I use Aromatic Amine and it does not react at low temperature like Rom Temperature, so are there any methods for my circumstance?
Hello Triet,
First of all, need to study the structures of epoxy and aromatic amine. Normally, the primary amine will react with epoxy group than secondary amine. There are several ways to control the reaction, using the right ratio (just enough for the primary amine as attached file), temperature, catalyst. Adduct forming can also help.
Good luck for your research!
TD
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