公开(公告)号：US20220274923A1

公开(公告)日：2022-09-01

申请号：US17635031

申请日：2020-08-20

Applicant: BASF SE

Inventor： Jessica Nadine HAMANN ,  Lukas Karl METZGER ,  Stefan BLEl

IPC: C07C315/06

Abstract: The invention relates to a process for obtaining 4,4′-dichlorodiphenyl sulfone from an organic mixture comprising 4,4′-dichlorodiphenyl sulfone and a linear C6 to C10 carboxylic acid as organic solvent, comprising: (a) cooling the organic mixture by (a1a) mixing the organic mixture with water in a crystallization vessel to obtain a liquid mixture; (a1b) cooling the liquid mixture obtained in (a1a) to a temperature below the saturation point of 4,4′-dichlorodiphenyl sulfone by (i) reducing the pressure in the crystallization vessel to a pressure at which the water starts to evaporate, (ii) condensing the evaporated water by cooling, (iii) mixing the condensed water into the liquid mixture in the crystallization vessel, to obtain a suspension comprising crystallized 4,4′-dichlorodiphenyl sulfone; or by (a2) bringing the organic mixture into contact with at least one coolable surface and thereby reducing the temperature in the organic mixture with a cooling rate in the range from 5 to 50 K/h until a temperature in the range from 10 to 30° C. is reached, wherein the organic mixture and the at least one coolable surface have a temperature difference which is kept during the whole cooling process in the range from 1 to 30 K to obtain a suspension comprising crystallized 4,4′-dichlorodiphenyl sulfone. (b) carrying out a solid-liquid-separation of the suspension obtained in (a1b) or in (a2) to obtain a residual moisture containing solid 4,4′-dichlorodiphenyl sulfone as product and mother liquor comprising the organic solvent and water.