Making quaternary ammonium ions

[woelen]

I hope to receive a liter of triethylamine [MATH]N(C_2H_5)_3[/MATH] next weekend. I would like to make some quaternary ammonium compound by adding a fourth ethyl group to this, such that I get ammonium ion with all four H's replaced by ethyl groups [MATH]N(C_2H_5)_4^+[/MATH].

 

Such a quaternary ammonium ion is large and fairly unreactive. This opens up ways for preparing salts of complexes (e.g. the triiodide as mentioned in another thread), which are otherwise not accessible.

 

Any organikers out there, who have an idea how such a methyl group can be attached to the triethylamine, perferrably using reagents, which are available for the home-chemist? Does anyone see a possibility using ethanol?

[budullewraagh]

use any ethyl halide. perhaps you should reflux?

 

EtOH ---(conc HCl)---> EtCl+H2O (protonation, nucleophilic substitution)

[woelen]

use any ethyl halide. perhaps you should reflux?

 

EtOH ---(conc HCl)---> EtCl+H2O (protonation' date=' nucleophilic substitution)[/quote']

 

Would adding some conc. H2SO4 help to move the reaction equilibrium to the right?

 

Does the ethyl chloride separate from the liquid?

[budullewraagh]

if you add conc H2SO4 you'll dessicate the conc HCl, and so you'll lose HCl gas. if you use an excess of the conc HCl, it could help in the protonation, although not particularly much, as the protonation and nucleophilic substitution should proceed easily enough anyway. the EtCl should be miscible with ethanol, but it does boil at 12.3 celsius. i would advise you to just reflux the EtOH and HCl for awhile, then distill your product. EtCl is miscible with ether, so make a solution and add your triethylamine, which also is miscible with ether. reflux for awhile. it should go forward easily enough