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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: kemistree4 on April 17, 2009, 04:05:01 PM

Title: why is there a huge drop in basicity of trimethylamine compared to methylamine a
Post by: kemistree4 on April 17, 2009, 04:05:01 PM
why is there a huge drop in basicity of trimethylamine compared to methylamine and dimethylamine? the trend from methyl to dimethyl is an upward one so you would expect trimethyl to keep going up but it goes way down. I cant figure out why.
2 seconds ago - 4 days left to answer.
Title: Re: why is there a huge drop in basicity of trimethylamine compared to methylamine a
Post by: azmanam on April 17, 2009, 04:09:41 PM
Why is an amine nitrogen atom basic?

Why does adding one methyl group (methyl amine --> dimethylamine) make the nitrogen atom more basic?

What happens with the addition of the third methyl group that might mitigate the factors described in #2 and instead make the nitrogen atom less basic?
Title: Re: why is there a huge drop in basicity of trimethylamine compared to methylamine a
Post by: kemistree4 on April 17, 2009, 04:30:54 PM
I think amines are basic because they have a lone pair which is readily donated to form bonds. Since methyl groups are electron donating when you add one it increases the negative charge of the nitrogen so the comound is more basic. The only thing that i can think of is that might be a factor is steric hinderance but i cant find anything in the text that adresses this specifically.
Title: Re: why is there a huge drop in basicity of trimethylamine compared to methylamine a
Post by: kemistree4 on April 17, 2009, 04:46:35 PM
am i on the right track there?
Title: Re: why is there a huge drop in basicity of trimethylamine compared to methylamine a
Post by: azmanam on April 17, 2009, 04:50:48 PM
yes exactly
Title: Re: why is there a huge drop in basicity of trimethylamine compared to methylamine a
Post by: macman104 on April 17, 2009, 11:32:51 PM
Additionally, what other bonding interaction can a primary and secondary amine be involved in that a tertiary amine could not be?
Title: Re: why is there a huge drop in basicity of trimethylamine compared to methylami
Post by: kemistree4 on April 19, 2009, 09:04:53 PM
Are you just talking about reactions with Lewis acids to form salts?