US 12,168,642 B2
Process for producing 4,4′-dichlorodiphenyl sulfoxide
Jun Gao, Ludwigshafen am Rhein (DE); Indre Thiel, Ludwigshafen am Rhein (DE); Christian Schuetz, Ludwigshafen am Rhein (DE); Lukas Metzger, Ludwigshafen am Rhein (DE); Oliver Bey, Ludwigshafen am Rhein (DE); and Stefan Blei, Ludwigshafen am Rhein (DE)
Assigned to BASF SE, Ludwigshafen am Rhein (DE)
Appl. No. 17/429,210
Filed by BASF SE, Ludwigshafen am Rhein (DE)
PCT Filed Feb. 6, 2020, PCT No. PCT/EP2020/052970
§ 371(c)(1), (2) Date Aug. 6, 2021,
PCT Pub. No. WO2020/161228, PCT Pub. Date Aug. 13, 2020.
Claims priority of provisional application 62/803,045, filed on Feb. 8, 2019.
Claims priority of application No. 19156196 (EP), filed on Feb. 8, 2019.
Prior Publication US 2022/0098147 A1, Mar. 31, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C07C 315/00 (2006.01); C07C 315/02 (2006.01); C07C 315/06 (2006.01)
CPC C07C 315/00 (2013.01) [C07C 315/02 (2013.01); C07C 315/06 (2013.01)] 13 Claims
 
1. A process for producing 4,4′-dichlorodiphenyl sulfoxide comprising:
(I) reacting thionyl chloride, chlorobenzene and aluminum chloride in a molar ratio of thionyl chloride:chlorobenzene:aluminum chloride of 1:(6 to 9):(1 to 1.5) at a temperature in the range from 0 to below 20° C., forming an intermediate reaction product and hydrogen chloride;
(II) mixing aqueous hydrochloric acid and the intermediate reaction product at a temperature in the range from 70 to 110° C. to obtain an organic phase comprising 4,4′-dichlorodiphenyl sulfoxide and an aqueous phase;
(III) cooling the organic phase comprising the 4,4′-dichlorodiphenyl sulfoxide to a temperature below the saturation point of 4,4′-dichlorodiphenyl sulfoxide to obtain a suspension comprising crystallized 4,4′-dichlorodiphenyl sulfoxide, wherein cooling of the organic phase is carried out in a gastight closed vessel by
(i) reducing the pressure in the gastight closed vessel;
(ii) evaporating chlorobenzene;
(iii) condensing the evaporated chlorobenzene by cooling;
(iv) returning the condensed chlorobenzene into the gastight closed vessel;
(IV) solid-liquid-separation of the suspension to obtain a residual moisture containing solid 4,4′-dichlorodiphenyl sulfoxide comprising crystallized 4,4′-dichlorodiphenyl sulfoxide and mother liquor.