A method for purifying N-methyl-2-pyrrolidone is disclosed. The method comprises treating N-methyl-2-pyrrolidone with an alumina that desorbs less than 100 .mu.mol/g of isobutylene between 225.degree. C. and 400.degree. C. in a standard tert-butyl alcohol dehydration test. The method enables the removal of at least about 80% of amine impurities or at least about 60% of APHA color from the NMP at 4 bed volumes treated.