Application of iron powder/halide in catalysis of epsilon-caprolactone ring-opening polymerization reaction

The invention discloses application of iron powder/halide in catalysis of epsilon-caprolactone ring-opening polymerization reaction. Specifically, the process includes: under the protection of inert gas, according to a mole ratio of 50-250:1:0.5-3 between epsilon-caprolactone, iron powder and halide, adding iron powder, halide, epsilon-caprolactone and a solvent into a reaction container in order, conducting sealing, then carrying out reaction at 90-120DEG C for 12-48h; at the end of the reaction, cooling the reaction system to room temperature, adding tetrahydrofuran to conduct dilution, also using a mixed solution of anhydrous methanol and dilute hydrochloric acid to conduct sedimentation, and performing filtering and drying to obtain polycaprolactone. The iron powder/halide catalyst provided by the invention has very high catalytic activity in epsilon-caprolactone ring-opening polymerization reaction, so that the epsilon-caprolactone ring-opening polymerization reaction has very high yield, and the obtained polymer has narrow molecular weight distribution.