title: A DFT study of the formation of xanthydrol motifs during electrophilic poly(aryl ether ketone) synthesis.
abstract: The reaction pathway of the cyclization of 2-phenoxybenzophenone into 9-phenyl-9H-xanthen-9-ol in the presence of acid and an excess of AlCl33 was studied using density functional theory. This type of reaction is known to occur during the Friedel-Crafts polycondensation of poly(aryl ether ketones) following the undesired benzoylation of nucleophilic positions ortho- to the growing polymer's ether groups. The formed defect acts as an undesired terminator of the polymer chain, causing severe problems in the polymer's melt state. A branched, multistep mechanism reminiscent of the Friedel-Crafts acylation reaction is discovered; the reaction starts with the protonation of the carbonyl oxygen, followed by intramolecular electrophilic attack on the carbonyl carbon that determines the turnover frequency of the catalytic cycle and ends by deprotonation of the Wheland intermediate.
authors.affiliation: Normandy University, COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesniére, 76821 Mont St Aignan, Cedex, France. sigismund.melissen@ens-lyon.fr.|Arkema CERDATO Laboratories, Route du Rilsan, 27470, Serquigny, France. sigismund.melissen@ens-lyon.fr.|Laboratoire de Chimie, UMR ENSL-CNRS 5182Université de Lyon, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, CNRS, 46 allée d'Italie, 69007, Lyon Cedex, France. sigismund.melissen@ens-lyon.fr.
authors.forename: Sigismund T A G
authors.initials: ST
authors.lastname: Melissen
authors.affiliation: Normandy University, COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesniére, 76821 Mont St Aignan, Cedex, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Tognetti
authors.affiliation: Normandy University, COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesniére, 76821 Mont St Aignan, Cedex, France.
authors.forename: Georges
authors.initials: G
authors.lastname: Dupas
authors.affiliation: Arkema CERDATO Laboratories, Route du Rilsan, 27470, Serquigny, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Jouanneau
authors.affiliation: Arkema CERDATO Laboratories, Route du Rilsan, 27470, Serquigny, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lê
authors.affiliation: Normandy University, COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesniére, 76821 Mont St Aignan, Cedex, France. laurent.joubert@univ-rouen.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Joubert
keywords: Chain termination; Density functional theory; Electrophilic aromatic substitution; Friedel–Crafts reactions; Poly(aryl ether ketones); Polymer defect; Stacking; Xanthydrol; ωB97X-D