A chemist, Mada Meens, treated ammonia with pentanal in the presence of hydrogen gas and a catalyst

Question:

A chemist, Mada Meens, treated ammonia with pentanal in the presence of hydrogen gas and a catalyst in the expectation of obtaining 1-pentanamine by reductive amination.

In addition to 1-pentanamine, however, she also obtained dipentylamine and tripentylamine (see Fig. P23.76). Explain how the by-products are formed. CH3(CH)3CH=0+ NH3 + H Figure P23.76 catalyst CH3(CH)3CHNH + [CH3(CH)3CH)2NH + [CH3(CH)3CH] 3N