# How to replace the 3 hydrogen atoms in phenylammomium with methyl groups [closed]

How would you replace those three hydrogens with methyl ($\ce{CH3}$) groups in its place to make trimethyl phenylammonim? It's been a real head stumper.

## closed as off-topic by Tyberius, M.A.R., Jan, paracetamol, NotEvans.Sep 7 '17 at 10:32

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• Adding excess $\ce{CH_3I}$ should work. – Teoc Sep 7 '17 at 3:49

Adding excess $CH_3I$ to your compound above would result in the formation of a secondary amine. The electron-donating methyl group would increase electron density on the N atom and increase the availability of the lone pair for nucleophilic attack. Not only will the reaction will proceed all the way to form a quaternary ammonium salt, but it also will not be able to stop halfway at the secondary or tertiary amines. This is because with increasing levels of substitution, the lone pair on the N is more available for nucleophilic attack. I believe Master Organic Chemistry's website has some useful information on the mechanism: