Word equation of ethanol + butanoic?
This is simply an esterification reaction...which would be performed under conditions that drove off the water...i.e. Dean-Stark distillation with benzene...
Alternatively the acid halide could be made by heating the acid with thionyl chloride, and then adding the alcohol to the acid halide in the presence of one equiv of non-nucleophilic base..
I was just reminded that butyric acid has a really foul, rancid odour, and so if you are careless in the fumehood, you won't be popular with your lab mates.