Because primary amines have two $\mathrm{N}$$- H$ bonds, hydrogen bonding is more sign ificant for primary amines than for secondary amines. Tertiary amines cannot form hydrogen bonds with each other because they do not have a hydrogen attached to the nitrogen Consequent ly, if you compare amines with the same molecular weight and similar structures, primary amines have higher boiling points than secondary amines, and secondary amines have higher boiling points than tertiary amines.

$\underset{\begin{smallmatrix} 
 a\,primary\,a\min e \\ 
 b.pt=97{{\,}^{o}}C 
\end{smallmatrix}}{\mathop{\begin{matrix}
   \,\,\,\,C{{H}_{3}}  \\
   |\,\,\,  \\
   C{{H}_{3}}C{{H}_{2}}CHC{{H}_{2}}N{{H}_{2}}  \\
\end{matrix}}}\,$ $\underset{\begin{smallmatrix} 
 a\,\sec ondary\,a\min e \\ 
 b.pt=84{{\,}^{o}}C 
\end{smallmatrix}}{\mathop{\begin{matrix}
   \,\,\,\,C{{H}_{3}}  \\
   |\,\,\,  \\
   C{{H}_{3}}C{{H}_{2}}CHNHC{{H}_{3}}  \\
\end{matrix}}}\,$ $\underset{\begin{smallmatrix} 
 a\,tertiary\,a\min e \\ 
 b.pt=65{{\,}^{o}}C 
\end{smallmatrix}}{\mathop{\begin{matrix}
   \,\,\,\,\,C{{H}_{3}}  \\
   \,\,|\,\,\,  \\
   C{{H}_{3}}C{{H}_{2}}NC{{H}_{2}}C{{H}_{3}}  \\
\end{matrix}}}\,$