Method for purifying 1,5-pentanediamine and 1,5-pentanediamine

A method for purifying 1,5-pentanediamine, comprising:

• providing a mixture containing 1,5-pentanediamine to be purified and 2,3,4,5-tetrahydropyridine;
• and
• treating said mixture by use of a reduction reaction to reduce said 2,3,4,5-tetrahydropyridine to piperidine thereby obtaining a first purified 1,5-pentanediamine composition,
• wherein the reduction reaction comprises an electrochemical reduction or a reduction with use of a reducing agent,
• wherein the reducing agent comprises hydrogen gas, (i) the pressure of the hydrogen gas is 0.5 MPa, and the temperature of the reduction reaction is from 100 to 110° C., or (ii) the pressure of the hydrogen gas is 10 MPa, the temperature of the reduction reaction is from 40 to 60° C., and the reduction reaction process comprises:
• charging the nickel-based supported catalyst in a stainless steel reactor having an inner diameter of 20 mm and a length of 720 mm, wherein the reactor comprises quartz sands with a particle size of 20 to 40 mesh as a support layer in the lower part of the reactor and a small amount of 20 to 40 mesh quartz sands in the upper part of the reactor to adjust the liquid distribution;
• and
• after the catalyst was activated, mixing the 1,5-pentanediamine to be purified with the hydrogen gas and passing resultant mixture through the catalyst bed from top to bottom.