Purification of poly ether ketone ketone by centrifugal filtration

Abstract

A method for the manufacture of polyether ketone ketone (PEKK), including: (i) reacting 1,4-bis(4-phenoxybenzoyl)benzene and/or diphenylether with at least one difunctional aromatic acyl chloride, in a reaction solvent and in presence of a Lewis acid, to obtain a product mixture comprising a PEKK-Lewis acid complex; (ii) contacting the obtained product mixture with a protic solvent, so as to form a dispersion that includes a liquid phase including Lewis acid and a solid phase including PEKK; and (iii) separating the solid phase from the liquid phase by centrifugal filtration, so as to recover a crude PEKK and a effluent containing Lewis acid, wherein step (iii) includes a step of centrifugal filtration.

1 . A method for the manufacture of polyether ketone ketone (PEKK), comprising:
 (i) reacting 1,4-bis 4-phenoxybenzoyl) benzene) and/or diphenylether with at least one difunctional aromatic acyl chloride, in a reaction solvent and in presence of a Lewis acid, to obtain a product mixture comprising a PEKK-Lewis acid complex;   (ii) contacting the obtained product mixture with a protic solvent so as to form a dispersion that comprises a liquid phase comprising Lewis acid and a solid phase comprising PEKK; and   (iii) separating the solid phase of the dispersion from the liquid phase, so as to recover a crude PEKK and an effluent containing Lewis acid,   wherein step (iii) comprises a step of centrifugal filtration.   
     
     
         2 . The method of  claim 1 , wherein the at least one difunctional aromatic acyl chloride is selected from terephtalic acid chloride, isophtalic acid chloride and the mixtures thereof. 
     
     
         3 . The method of  claim 1 , wherein the reaction solvent is ortho-dichlorobenzene. 
     
     
         4 . The method of  claim 1 , wherein the Lewis acid is aluminum trichloride. 
     
     
         5 . The method of  claim 1 , wherein the protic solvent used in step (ii) is an aqueous solution. 
     
     
         6 . The method of  claim 1 , comprising after step (iii) further one or more steps of washing the crude PEKK in a protic solvent. 
     
     
         7 . The method of  claim 1 , comprising after step (iii) further one or more steps of washing the crude PEKK in a protic solvent. 
     
     
         8 . The method of  claim 1 , comprising after step (iii):
 (iv) one or more steps of washing the crude PEKK in methanol, and subjecting the mixture obtained to a solid/liquid separation comprising a step of centrifugal filtration; and   (v) one or more steps of washing the PEKK obtained in the previous step in water, and subjecting the mixture obtained to a solid/liquid separation comprising a step of centrifugal filtration to obtain a purified PEKK.   
     
     
         9 . The method of  claim 1 , wherein step (iii) and each subsequent washing step is performed in a centrifugal filtration device, without removing the crude PEKK between subsequent steps. 
     
     
         10 . The method of  claim 1 , wherein the step of centrifugal filtration in step (iii) is performed at an acceleration rate of at least 500 g. 
     
     
         11 . The method of  claim 2 , wherein step (iii) and each subsequent washing step is performed for a duration of one hour or less. 
     
     
         12 . The method of  claim 1 , further comprising a subsequent step of drying the purified PEKK. 
     
     
         13 . The method of  claim 1 , wherein the crude PEKK is purified without using a complexing agent. 
     
     
         14 . The method of  claim 1 , wherein the purified PEKK contains less than 1000 ppm of aluminum. 
     
     
         15 . The method of  claim 1 , wherein the effluent containing Lewis acid is recycled.