Process for the preparation of di- and polyamines of the diphenylmethane series

Patent metadata

Field	Value
Publication number	US-9416094-B2
Application number	US-201414783163-A
Country	US
Kind code	B2
Filing date	Apr 8, 2014
Priority date	Apr 11, 2013
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

The invention relates to a method for producing diamines and polyamines of the diphenylmethane series in which, by using a coalescence auxiliary in the phase separation of the process product obtained in the scrubbing of the neutralized crude product, the fraction of water and thus also of water-soluble impurities in the organic MDA-containing phase is reduced. According to the invention, the coalescence auxiliary used is a filter bed made of coalescence fiber material. The di- and polyamines of the diphenylmethane series obtained after distillative purification of this MDA-containing organic phase are exceptionally suitable for the preparation of the corresponding isocyanates.

First claim

The invention claimed is:

1. A process for the preparation of di- and polyamines of the diphenylmethane series, comprising:
a) reacting aniline and formaldehyde in the presence of an acidic catalyst to give a reaction mixture comprising di- and polyamines of the diphenylmethane series,
b) neutralizing the reaction mixture comprising di- and polyamines of the diphenylmethane series,
c) separating the neutralized reaction mixture comprising di- and polyamines of the diphenylmethane series in a separation container into an organic phase (1) comprising di- and polyamines of the diphenylmethane series and an aqueous phase,
d) further purifying the organic phase (1) comprising di- and polyamines of the diphenylmethane series in a washing container with washing liquid,
e) freeing the mixture obtained in step d) from aqueous constituents, giving an organic phase (2) comprising di- and polyamines of the diphenylmethane series, and
f) freeing the organic phase (2) comprising di- and polyamines of the diphenylmethane series distillatively from water and aniline,
wherein the freeing of the aqueous constituents in step e) comprises:
e.1) separating the mixture obtained in step (d) in a separating container into an aqueous and an organic phase (2a), and then
e.2) passing the organic phase (2a) obtained in step e.1) through a filter bed made of coalescence fiber material and then separating the organic phase obtained thereby into an aqueous phase and the organic phase (2).

2. The process of claim 1 , wherein the fiber diameter of the coalescence fiber material is 1.0 μm to 150 μm.

3. The process of claim 1 , in which the fibers of the coalescence fiber material are prepared from a water-wetting material.

4. The process of claim 3 , in which the water-wetting material comprises glass or metal.

5. The process of claim 4 , in which the water-wetting material is stainless steel.

6. The process of claim 1 , in which the thickness of the filter bed of coalescence fiber material is 1.0 mm to 100 mm.

7. The process of claim 1 , in which the step of passing the organic phase (2a) through a filter bed made of coalescence fiber material is carried out in the temperature range from 50° C. to 120° C.

8. The process of claim 2 , wherein the fiber diameter of the coalescence fiber material is 1.0 μm to 100 μm.

9. The process of claim 8 , wherein the fiber diameter of the coalescence fiber materials is 2.0 μm to 30 μm.

10. A process for preparing di- and polyisocyanates of the diphenylmethane series comprising phosgenation of a di- and/or polyamine of the diphenylmethane series, wherein the di- and/or polyamine of the diphenylmethane series is prepared by the process of claim 1 .

Assignees

• Covestro Deutschland Ag

Inventors

• Knauf Thomas
• Lorenz Wolfgang
• Wershofen Stefan
• Adamson Richard
• Becker Karsten

Classifications

• C07C211/44

  having amino groups bound to only one six-membered aromatic ring · CPC title

• C07C209/78 Primary

  from carbonyl compounds, e.g. from formaldehyde, and amines having amino groups bound to carbon atoms of six-membered aromatic rings, with formation of methylene-diarylamines · CPC title

• C07C265/12

  having isocyanate groups bound to carbon atoms of six-membered aromatic rings · CPC title

• C07C2101/16

  Chemistry & Metallurgy · mapped topic

• C07C263/10

  by reaction of amines with carbonyl halides, e.g. with phosgene · CPC title