Amyl alcohol( especially iso amyl) is produced from fusel oil by batch Distillation. Amyl Esters can then be manufactured out of it. Amyl alcohol or esters find many uses and it is a viable business so it makes sense to produce it provided enough fusel oil can be sourced.We have engieered few such plants in India. Packed Columns are best, but vacuum offers no specific advantage as none of the azeotrope will shift or vanish. Going for vacuum will only increase the column diameter. There are many azeotropes of C2 to c4 alcohols with water but amyl which is C5 alcohol specifically iso amyl can be separated at bp range of 128 to 132 deg C at atm pressure. The Fusel oil stream is indeed very nasty one, but it has many uses. Pl refer to attached paper / contact @