Dear Giulia,

many thanks for sharing this very interesting chemical question with the RG community. As you can see from the data sheet cited below, very pure tetradecylamine is a solid at room temperature which melts at 38-40 °C:

https://www.chemicalbook.com/ChemicalProductProperty_EN_CB4309907.htm

I assume that your 95% purity tetradecylamine which you purchased from Sigma Aldrich is an oily liquid, right? The boiling point of tetradecylamine is 162 °C/15 mmHg. Thus my suggestion would be to purify the amine by fractional distillation under vacuum. Prior to the distillation you can add one or two small pieces of freshly cut sodium metal (careful!). This will remove traces of water. Let the mixture stir overnight and then start the distillation (without removing the sodium). The procedure has been described in detail for the closely related oleylamine in the following useful article:

Purification of Oleylamine for Materials Synthesis and Spectroscopic Diagnostics for trans Isomers

Article Purification of Oleylamine for Materials Synthesis and Spect...

The article is not available as public full text, but the Supporting Information with all the details is accessible as pdf file (see attachment). In this article an alternative purification method via precipitation of the corresponding hydrochloride salt is also described. However, I think that vacuum distillation from metallic sodium is the most effective way. Be very careful when disposing the residual sodium after the distillation! It can be safely destroyed by dissolving in ethanol. Never add water to the residue!

Good luck with your experiments and best wishes, Frank Edelmann

thank you!

Frank T. Edelmann thank you for the great details you provided, is the use of the sodium inevitable here? any safer option? I was thinking about lithium aluminium hydride and calcium hydride but both of them are hard to handle too. Also, I see that sodium metal is better combined with benzophenon for drying process, good luck Giulia Avino

Dear Hamza Chelali many thanks for your kind response and questions. I think that unlike metallic potassium, metallic sodium can be safely handled by a trained person. Residues can be easily destroyed using ethanol or iso-propyl alcohol etc. The main problem with LiAlH4 is that large ampunts of flammable hydrogen are evolved when it is hydrolyzed. Thus, personally if I had the choice I think I would go for the sodium metal. You are absolutely right in that sodium metal is normally used in combination with benzophenon for the drying process of various organic solvents. I assume that in the case of the long-chain amines it will not only react with water but also destroys other impurities.

With best wishes, Frank Edelmann

This method proved very effective !