Hello Cav.
I propose three alternatives, to prepare the ethylamine.
Alternative A is known as the Gabriel synthesis, which I'm sure you know, only that the necessary halide is prepared from acetylene.
Alternative B, starts from the same acetylene, until reaching a proponamide, which is subjected to the HOfmann rearrangement reaction, to eliminate CO and reach ethylamine.
Alternative C, starts from acetylene, to form an aldehyde with disiamilborane, which then forms an imine with NH3, which will be reduced to arrive at ethylamine.
I beg you to complete the diagrams, analyze it and at your own discretion make an option;) .
Greetings:
wilbert