Alkyl amines polarization energy

Ju and Varma envisioned that the nucleophilic substitution reaction of alkyl halides with amines may be accelerated by microwave energy because of their polar nature [88]. An environmentally friendly synthesis of tertiary amines via direct JV-alkylation of primary and secondary amines by alkyl halides under microwave irradiation was developed (Scheme 21), that pro-... 

When the polarized atoms in an alkyl halide such as the molecule chloromethane come into close proximity to the dipole of another molecule of chloromethane, as shown in Figure 5.11, the 8-F carbon of one molecule is attracted to the 8- chlorine of the second molecule. This electrostatic attraction is called a dipole-dipole interaction and it is stronger than London forces, which are also present. As a consequence of this attraction, more energy (heat) is required to separate two molecules held together by dipole-dipole interactions than is required to separate two molecules held in close proximity by simple London forces. In other words, the boiling point required for molecules with dipole-dipole interactions is higher. The dipole-dipole interaction does not have to be between identical molecules it can be between two entirely different molecules. Dipole-dipole interactions can be envisioned between two alkyl halides, two ethers, or even two amines. 

---