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Dimethylbenzylamine

Dimethylbenzylamine is the organic compound with the formula C<sub>6</sub>H<sub>5</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub>. The molecule consists of a benzyl group, C<sub>6</sub>H<sub>5</sub>CH<sub>2</sub>, attached to a dimethylamino functional group. It is a colorless liquid. It is used as a catalyst for the formation of polyurethane foams and epoxy resins.

Synthesis

N,N-Dimethylbenzylamine can be synthesized by the Eschweiler–Clarke reaction of benzylamine

Reactions

It undergoes directed ortho metalation with butyl lithium:

[C<sub>6</sub>H<sub>5</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub> + BuLi → 2-LiC<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub>
LiC<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub> + E<sup>+</sup> → 2-EC<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub>

Via these reactions, many derivatives are known with the formula 2-X-C<sub>6</sub>H<sub>4</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub> (E = SR, PR<sub>2</sub>, etc.).

The amine is basic and undergoes quaternization with alkyl halides (e.g. hexyl bromide) to give quaternary ammonium salts:

[C<sub>6</sub>H<sub>5</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub> + RX → [C<sub>6</sub>H<sub>5</sub>CH<sub>2</sub>N(CH<sub>3</sub>)<sub>2</sub>R]<sup>+</sup>X<sup>−</sup>

Such salts are useful phase transfer catalysts.

Uses

As the molecule has tertiary amine functionality, two of the key uses are as an epoxy-amine cure enhancement catalyst and also as a polyurethane catalyst.

References

External links