Poly Friedel-Crafts acylation

In 1962, Bonner (14) at DuPont was the first one who reported the synthesis of wholly aromatic poly(ether ketone ketone)s (PEKK) by Friedel-Crafts acylation. Isophthaloyl chloride was condensed with diphenyl ether using nitrobenzene as solvent and aluminum trichloride as a catalyst. 

A Novel Reactive Functionalization of Polyolefin Elastomers Direct Functionalization of Poly(isobutylene-co-p-methylstyrene) by a Friedel-Crafts Acylation Reaction... 

This paper deals with a novel approach of functionalizing poly (IB-PMS) copolymers using the Friedel-Crafts acylation reaction. Poly (IB-PMS) copolymer was reacted with an acylating agent, succinic anhydride, using aluminum chloride as a Lewis acid. The reaction involves the aluminum chloride-catdyzed substitution of an acyl group on the aromatic ring. 

Multi-walled carbon nanotubes can be functionalized with PBI via a Friedel-Crafts acylation reaction in a phosphorus pentoxide/methanesulfonic acid medium [23]. The composites have been used as reinforced fillers in 100% acidified poly(hydroxyamino-ether) to prepare mixed composites. The acid-base interaction between the PBI chains attached on multi-walled carbon nanotubes plays a crucial role with regard to good dispersion and effective reinforcement. 

Poly phosphoric acid (PPA), a highly viscous liquid, is a useful reagent and catalyst in various rearrangements and isomerizations, especially in intramolecular reactions (24,25). Cyclization of various compovmds into aromatic rings and formation of heterocycles are the most important transformations where PPA usually ensures high yields. It is especially useful when Friedel-Crafts acylations are carried out with carboxylic acids. 

In the second method, the alkoxyamine-ftmctionalized backbone is prepared by a chemical modification of a preformed polymer. Abbasian and Entezami prepared alkoxyamine-functionalized poly(vinyl chloride) (PVC) in a three-step procedure. PVC was first arylated with toluene by Friedel-Crafts acylation followed by a bromination step using N-bromosuccinimide. The bromine atom was finally reacted via nucleophilic substitution by the TEMPO hydro-xylamine anion. PVC-g-PS was finally obtained after TEMPO-mediated polymerization of styrene. A TEMPO-functionalized isotactic poly(l-butene) macroinitiator was synthesized by Jo et al. who used a rhodium-catalyzed activation of the alkane C-H bonds and subsequent transformations of the boronate ester group into an hydroxyl pendant group. This reactive moiety was then used to attach a TEMPO-based alkoxyamine bearing another hydroxy function by an ether linkage. A method to prepare PE-g-PS from a poly(ethylene-co-m,p--methylstyrene) obtained by metallocene-catalyzed polymerization was also reported. The macroalkoxya-mine was synthesized after bromination with N-bromosuccinimide followed by a nucleophilic reaction with the TEMPO hydroxylamine anion. 

The synthesis of hb-PAEKs via the A2 + B3 approach has been reported by many research groups [67, 68]. Choi et al. [69] reported a self-controlled synthesis of hb-PAEKs from diphenyl ether (or 1,4-diphenoxybenene, B2) and trimesic acid (A3) via the Friedel-Crafts reaction. Baek and coworkers developed optimized conditions for Friedel-Crafts acylation in poly(phosphoric acid)/phosphorus pent-oxide (PPA/P2O5) medium for the preparation of hb-PAEKs [70,71]. Martinez and Hay [72, 73] proposed the efficient synthesis and characterization of hb poly(aryl ether sulfone)s with a K2C03/Mg(0H)2 catalyst system for nucleophilic aromatic substitution. Kim et al. [74] reported the controlled nucleophilic aromatic... 

Di- and poly-acylated products are often water soluble, and so require care in isolation. Low recoveries of desired products from aliphatic Friedel-Crafts monoacylations may suggest that over reaction is leading to water-soluble products that have not been recognized, and therefore lost during work up. 

PPA = polyphosphoric acid al = alkylation ac = acylation chlor = chlorination iso = isomerization halo = halogenation cycl = cyclization poly = polymerization for = formylation dehydr = dehydration nitr - nitration general = active in most Friedel-Crafts reactions deal = dealkylation rearr = rearrangement. 

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