Crystal composition (cc) comprising 4,4'-dichlorodiphenylsulfoxide crystals (c)

Abstract

The invention relates to a crystal (C) consisting of at least 95% by weight of 4,4′-dichlorodiphenylsulfoxide, 0 to 2% by weight of impurities and 0 to 3% by weight of an organic solvent (os). Moreover, the present invention relates to a crystal composition (CC) comprising crystals (C) and a process for the production of the crystal composition (CC) and the crystal (C).

1 . Crystal composition (CC) comprising crystals (C), wherein the crystals (C) consist of
 (a) at least 95% by weight of 4,4′-dichlorodiphenylsulfoxide,   (b) 0 to 2% by weight of impurities, and   (c) 0 to 3% by weight of an organic solvent (os),   based on the total weight of the crystals (C) contained in the crystal composition (CC), wherein the crystal composition (CC) has   a d10, 3  -value in the range of 100 to 400 μm,   a d50, 3  -value in the range of 300 to 800 μm and   a d90, 3  -value in the range of 700 to 1500 μm,   wherein the d10, 3 -value is lower than the d50, 3 -value and the d50, 3 -value is lower than the d90, 3 -value.   
     
     
         2 . A crystal composition (CC) according to  claim 1 , wherein the crystal composition (CC) comprises at least 95% by weight of crystals (C), based on the total weight of the crystal composition (CC). 
     
     
         3 . A crystal composition (CC) according to  claim 1 , wherein the crystal composition (CC) shows a bulk density in the range of 600 to 950 kg/m 3 . 
     
     
         4 . A crystal composition (CC) according to  claim 1 , wherein the average aspect ratio of the crystals (C) are in the range of 0.2 to 1. 
     
     
         5 . A crystal composition (CC) according to  claim 1 , wherein the average sphericity of the crystals (C) is in the range of 0.75 to 0.85. 
     
     
         6 . A crystal composition (CC) according to  claim 1 , wherein the Hausner ratio is in the range of 1.05 to 1.27. 
     
     
         7 . A crystal composition (CC) according to  claim 1 , wherein the unit cell of the crystals (C) is monoclinic, space group C 2/m, cell lengths a=16.05 ű0.05 Å, b=9.82 ű0.05 Å, c=7.21 ű0.05 Å, cell angles alpha 90°±0.1°, beta 95.7°±0.1°, gamma 90°±0.1°, and a cell volume 1131.5 Å 3 ±1 Å 3 . 
     
     
         8 . A crystal (C) consisting of
 (a) at least 95% by weight 4,4′-dichlorodiphenylsulfoxide,   (b) 0 to 2% by weight of impurities, and   (c) 0 to 3% by weight of an organic solvent (os),   based in each case on the total weight of the crystal (C), wherein the outer surface of the crystal (C) comprises
 i) a six-sided base surface (bsu) and 
 ii) a six-sided top surface (tsu) and 
 iii) six side surfaces (ssu 1  to ssu 6 ), joining the corresponding sides of the six-sided base surface (bsu) and the six-sided top surface (tsu). 
   
     
     
         9 . A crystal (C) according to  claim 8 , wherein the six-sided base surface (bsu), the six-sided top surface (tsu) and the six side surfaces (ssu 1  to ssu 6 ) account for at least 90% of the outer surface of the crystal (C). 
     
     
         10 . A crystal (C) according to  claim 8 , wherein the diameter (db) of the six-sided base surface (bsu) and the diameter (dt) of the six-sided top surface (tsu) are each independently in the range of 50 to 1500 μm. 
     
     
         11 . A crystal (C) according to  claim 8 , wherein the length (I 1 ) of the first side surface (ssu 1 ), the length (I 2 ) of the second side surface (ssu 2 ), the length (I 3 ) of the third side surface (ssu 3 ), the length (I 4 ) of the fourth side surface (ssu 4 ), the length (I 5 ) of the fifth side surface (ssu 5 ) and the length (I 6 ) of the sixth side surface (ssu 6 ) are each independently in the range of 100 to 3000 μm. 
     
     
         12 . A crystal (C) according to  claim 8 , wherein the ratio of the average of the diameter (db) and the diameter (dt) to the average of the length (I 1 ), the length (I 2 ), the length (I 3 ), the length (I 4 ), the length (I 5 ) and the length (I 6 ) is in the range of 0.2 to 1. 
     
     
         13 . Crystal (C) according to  claim 8 , wherein the impurities (b) comprise at least 90% by weight of one or more compounds selected from the group consisting of 2,4′-dichlorodiphenylsulfoxide, 3,4′-dichlorodiphenylsulfoxide, 2,2′-dichlorodiphenylsulfoxide, 4,4′-dichlorodiphenylsulfide, and one or more aluminum compounds based on the total weight of the impurities (b) contained in the crystal (C). 
     
     
         14 . A crystal composition (CC) according to  claim 1  obtained by a process comprising the steps:
 I) cooling a first liquid mixture comprising 4,4′-dichlorodiphenylsulfoxide dissolved in an organic solvent (os) to obtain a suspension comprising crystallized 4,4′-dichlorodiphenylsulfoxide and the organic solvent (os), 
 II) filtering the suspension obtained in step I) to obtain a filtrate comprising 4,4′-dichlorodiphenylsulfoxide dissolved in the organic solvent (os), wherein the filtrate has a lower concentration of 4,4′-dichlorodiphenylsulfoxide compared to the first liquid mixture, and a filter residue comprising the crystallized 4,4′-dichlorodiphenylsulfoxide, 
 III) concentrating the filtrate obtained in step II) to obtain a second liquid mixture, wherein the second liquid mixture has a higher concentration of 4,4′-dichlorodiphenylsulfoxide compared to the filtrate, 
 IV) recycling at least a part of the second liquid mixture obtained in step III) into step I), and 
 V) drying the filter residue obtained in step II) to obtain the crystal composition (CC), wherein the organic solvent is chlorobenzene, toluene, xylene, mesitylene, methanol or a mixture of two or more of said solvents. 
 
     
     
         15 . A crystal (C) obtained by the process of  claim 14 , further comprising the step:
 VI) separating a crystal (C) out of the crystal composition (CC) obtained in step V).   
     
     
         16 . Use of the crystal composition (CC) as an intermediate for the production of at least one product selected from the group consisting of monomers, polymers and pharmaceuticals.