| 摘要 |
FIELD: chemistry.SUBSTANCE: method involves reacting aniline and formaldehyde in the presence of an acid catalyst, wherein the aniline used contains 0.0001-0.25 wt %, with respect to the weight of the used aniline, of compounds having at least one carbonyl group or which are products of reaction of such carbonyl compounds with aniline. The invention also relates to a method of producing di- and polyisocyanates of the diphenylmethane series, wherein di- and polyamines of the diphenylmethane series obtained using the disclosed method react with phosgene.EFFECT: method considerably improves the colour of the obtained product.6 cl, 1 tbl, 9 ex |
