PROCESS FOR THE PREPARATION OF DI- AND POLYAMINES OF THE DIPHENYLMETHANE SERIES

摘要

The present invention relates to a process for the preparation of di- and polyamines of the diphenylmethane series, and to the preparation of di- and polyisocyanates of the diphenylmethane series from these di- and polyamines. The di- and polyamines of the diphenylmethane series are prepared by the reaction of aniline and formaldehyde in the presence of hydrochloric acid. In the present invention, the formaldehyde employed is used as an aqueous solution which contains less than 0.001 wt % of metal ions which are divalent and/or more than divalent.