Electrophilic Route

PEKs that are subsequently end capped with nitrile functions have been prepared by Friedel-Crafts polymerization. For example, m-hexaphenyl ether are reacted with p-cyanobenzoyl chloride with AICI3 as catalyst in dry 1,2-dichloroethane to form a nitrile end capped oligomer. In another study, 5-cyanoisophthaloyl chloride was used as a nitrile-containing comonomer for the Friedel-Crafts polymerization.  

The resins can be crosslinked by heating with Friedel-Crafts catalysts. It is assumed that the nitrile groups are forming triazines by heating. Even without Friedel-Crafts catalysts crosslinking is possible however, the reaction proceeds slowly. The materials are intended for use as laminating 

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A poly(arylene ether phenylquinoxaline) of structure 14 was prepared by the aluminum chloride catalyzed reaction of 6,6 -bis[2-(4-phenoxyphenyl)-3-phenylquinoxaline] and isophthaloyl chloride in 1,2-dichloroethane [51]. The polymer had an inherent viscosity of 1.29 dL/g and a Tg of 224 °C. A polymer of the same chemical structure was prepared from the reaction of 3,3, 4,4 -tetraaminobiphenyl with l,3-bis(phenylglyoxalyl-4-phenoxy-4 -benzoyl)-benzene that gave a Tg of 239 °C [16], significantly higher than that prepared by the electrophilic route. In addition, a polymer of the same chemical structure (third polymer in Table 3) prepared via nucleophilic substitution exhibited a Tg of 240 °C. 

These nucleophilic reagents react with most common electrophiles such as organohalides, tosylates, aldehydes, ketones, epoxides, and activated alkenes. It should be noted that many workers have found much higher yields if the phosphides are protected as phosphine oxide or borane anions (see Section 3). Phosphide reagents also react with activated arenes to give mixed aryl phosphines (Protocol 2). Metal phosphides therefore provide an alternative, complementary tertiary phosphine synthesis to the electrophilic routes outlined in Section 2.1. 

Scheme 8.74, path B is reminiscent of the electrophilic attack at oxygen of acylmetal complex shown in Eq. 8.5. Another electrophilic route to carbene complex is the reaction of alkylmetals with Ph3C" , as shown in Eq. 8.25 [136]. An electrophilic attack that is similar to Scheme 8.74, path B but appears potentially more signihcant in catalysis is that of alkynylmetal complex to generate vinyli-dene ligand. Although Scheme 8.17 described direct formation of the vinylidene complex from M+ and terminal alkyne, this complex is sometimes derived by treatment of M-C = CR with H+ via -attack [137]. 

One synthesis of this type has been patented <92MIP1721053>. Dibenzotellurophene Te—dichloride is formed by an electrophilic route when biphenyl and tellurium tetrachloride are reacted neat <95SRI709>. The already known electrophilic cyclization of suitable alkynes is also realized by the same reagent giving amine (25) <90KGS1331>. 

Electrophilic Route Ether Functional Monomer Acid Halogenide... 

The electrophilic route for the production of aromatic polyether ketones involves the use of Friedel-Crafts catalysts. AICI3 is used as a catalyst for the polymerization of p-phenoxybenzoyl chloride as such, or p-phenoxy-benzoyl chloride or terephthaloyl chloride and 1,4-diphenoxybenzene to give a PEK. A PEEK is obtained by the use of p-phenoxyphenoxybenzoyl chloride, respectively. The process is carried out at low temperamres, such as 0-30°C. Due to the heterogeneous nature of this reaction, generally undesirable lower molecular weight polymers are produced. 

Similarly to poly(ether ketone)s (PEK)s, PENs have been prepared according to a nucleophilic route and an electrophilic route. 

A novel electrophilic route to bis(pentafluorophenyI) sulphide involves the reaction of pentafluorobenzene with sulphur, sulphur mono- or dichloride, or pentafluorobenzenesulphenyl chloride in the presence of antimony pentafiuoride. Photochemical reaction of pentafluoroiodobenzene with bis(trifluoromethyl) disulphide yields a mixture of the sulphide CgFg-S-CFj, disulphide CeFg-S-S CFs, and trifluoroiodomethane. Thiourea is suffident-... 

Kerres et al. [38] reported that the sulfonation close to electron-donating substituents (i.e. ortho-to-ether position) of the main aromatic polymer chain is normally more easily activated for hydrolytic desulfonation in acidic media compared to sulfonation close to electron-withdrawing substituents (i.e. ortho-to-sulfone position). An electrophilic route does not allow acidic ionic groups to be located on the ortho-to-sulfone position in the arylene sulfone segment where it should be, at least slightly, more dissociated than an acidic ionic function located at the ortho-to-ether position in the arylene ether segment. 

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