Method for preparing caprolactam from high boiling point inert solvent

The invention discloses a method for preparing caprolactam from a high boiling point inert solvent. The method comprises the following steps: 1) dissolving cyclohexanone-oxime into the high boiling point inert solvent to form a cyclohexanone-oxime solution; 2) enabling the obtained solution in a reactor to be in contact with nicotinic acid, so that the cyclohexanone-oxime is delivered into the nicotinic acid for a rearrangement reaction; 3) performing phase separation on the product obtained in the step 2), enabling a rearrangement solution to enter a downstream section for refining and circulating an oil phase to a batching system. According to the method, the cyclohexanone-oxime is dissolved by the inert solvent, and the rearrangement reaction is performed on the obtained solution and the nicotinic acid, so that the concentration of reactants can be diluted, and the adiabatic temperature rise of the system is reduced; the rearrangement reactor can be used for avoiding high circulation ratio heat exchange an