Phase transfer catalysts poly used

In general, if condensation polymers are prepared with methylated aryl repeat units, free radical halogenatlon can be used to introduce halomethyl active sites and the limitations of electrophilic aromatic substitution can be avoided. The halogenatlon technique recently described by Ford11, involving the use of a mixture of hypohalite and phase transfer catalyst to chlorinate poly(vinyl toluene) can be applied to suitably substituted condensation polymers. 

When TBAB is used as a phase-transfer catalyst, sodium hydroxide as a base, and DCE as a solvent, both the molecular weight and yield of the poly(carbonate) are relatively high. Bisphenol AF-derived poly(carbonate) (2) having reduced viscosity of 0.35 dl/g is obtained in a 84% yield at ambient temperature under the... 

Hay et al.w,n have prepared high-molecular-weight a Bisphenol-A-derived poly(formal) (6) using a phase-transfer catalyst in DCM. A Bisphenol-AF-derived poly(formal) (7) is also synthesized by solution polycondensation of Bisphenol AF (1) with DCM in highly polar cosolvents in the presence of potassium hydroyxide (Scheme 3).12 Aprotic polar solvents such as A/W-dimethylformamide... 

Phase-transfer techniques are widely used for the preparation of polymers. For example, potassium fluoride is used to produce poly(etherketone)s under phase-transfer conditions (Scheme 10.18). Use of this reagent allows the chloroaro-matics to be used as starting material as opposed to the more expensive flu-oroaromatics that are usually employed [23]. This method is suitable for the synthesis of high molecular weight semicrystalline poly(ether ketone)s, although the presence of excess potassium fluoride in the reaction mixture can lead to degradation reactions. The use of a phase transfer catalyst can allow the use of water-soluble radical initiators, such as potassium peroxomonosulfate used to promote the free-radical polymerization of acrylonitrile [24],... 

This article reports on the synthesis of photosensitive polymers with pendant cinnamic ester moieties and suitable photosensitizer groups by cationic copolymerizations of 2-(cinnamoyloxy)ethyl vinyl ether (CEVE) (12) with other vinyl ethers containing photosensitizer groups, and by cationic polymerization of 2-chloroethyl vinyl ether (CVE) followed by substitution reactions of the resulting poly (2-chloroethyl vinyl ether) (PCVE) with salts of photosensitizer compounds and potassium cinnamate using a phase transfer catalyst in an aprotic polar solvent. The photochemical reactivity of the obtained polymers was also investigated. 

The most straightforward way to obtain polymeric phosphonium salts involves introducing the phosphonio groups on to a suitable polymeric structure, for example by reacting tertiary phosphines with a poly(chloromethylstyrene) (reaction 99). The polymeric phosphonium salts obtained in this way are mostly used as polymer-supported phase-transfer catalysts for nucleophilic substitutions reactions under triphase conditions. 

Further, methods using phase transfer catalysts are suitable for the production of transparent poly(siloxane)/PC copolymers (27). As phase transfer catalyst a methyltributyl ammonium salt is used. 

Ferrocene has been reported to be very effective as a soot reducing agent in combustion [42 — 44]. Thus, when ferrocene compounds are incorporated in a fire retardant polymer, such as a phenolphthalein-based polymer and poly(phosphate ester)s, they have shown added advantages in that they promote extinction and reduce smoke formation by accelerated char reduction [45, 46]. The synthesis of such ferrocene-containing poly(phosphate ester)s was achieved by interfacial polycondensation using a phase transfer catalyst [47]. Accordingly, l,l -bis(p-hydroxy-phenylamido)ferrocene and l,l -bis(p-hydroxyphenylcarbonyl)ferrocene underwent condensation with various aryl phosphoroic acid dichlorides to yield two series of ferrocene-containing polymers, i.e., poly (amide-phosphate ester)s 38a and poly(ester-phosphate ester)s 38b respectively, as shown in Scheme 10-17. 

Covalent attachment of ligands to polymer supports retains their complexing properties156 and widens their applications. For instance, immobilized crown poly-thers and cryptands used as phase-transfer catalysts can be recycled55. Chiral ligands have been used for a chromatographical separation of D- and L-amino acids75. ... 

Leung, L. M. W. H. Chan, S. K. Leung, and S. M. Fung, Synthesis of Aliphatic and Aromatic Poly(s-dithiocarbonates) Using a Phase Transfer Catalyst, J.M. S.-Pure Appl. Chem., X51,495 (1994). 

Poly(N-alkyl ethyleneimine) was prepared directly from poly(2-alkylOXL) by reduction with LiAllit or A1H3 33). Quatemized poly(N-alkyl ethyleneimine) itself or grafted onto chloromethylated polystyrene have been used as phase transfer catalysts in aqueous-organic heterophase reactions34). 

Etherification. With the use of poly(ethylene glycol) [PEG] as a phase-transfer catalyst (PTC), diaryloxymethanes are readily prepared from ArOK and CHjCl in methanol at room temperature. The same catalyst is used in a synthesis of triaryl cyanurates from cyanuric chloride. 

Poly(ethylene glycol)s (PEG) and their dimethyl ethers have been used as phase-transfer catalysts for the reaction of aryl halides with diphenylamine. Since mixtures of triarylamines were obtained from a single aryl bromide (for example, u-bromotoluene gave both 0- and m-tolyldiphenylamine), arynes are intermediates. A kinetic study led the authors to propose the following mechanism ... 

Polymer phase-tranrfer catalysts (also referred to as triphase catalysts) are useful in bringing about reaction between a water-soluble reactant and a water-insoluble reactant [Akelah and Sherrington, 1983 Ford and Tomoi, 1984 Regen, 1979 Tomoi and Ford, 1988]. Polymer phase transfer catalysts (usually insoluble) act as the meeting place for two immiscible reactants. For example, the reaction between sodium cyanide (aqueous phase) and 1-bromooctane (organic phase) proceeds at an accelerated rate in the presence of polymeric quaternary ammonium salts such as XXXIX [Regen, 1975, 1976]. Besides the ammonium salts, polymeric phosphonium salts, crown ethers and ciyptates, poly(ethy-lene oxide), and quatemized polyethylenimine have been studied as phase-transfer catalysts [Hirao et al., 1978 Ishiwatari et al., 1980 Mohnari et al., 1977 Tundo, 1978]. 

Researchers van der Broeke and coworkers[" created perfluoro-functionalized poly(propyleneimine) dendrimers (23 Fig. 4) and demonstrated their potential as phase-transfer catalysts in supercritical carbon-dioxide-water mixtures and as anionic species extractants. The dendrimers were accessed via reaction of perfluorinated, linear alkyl acid chlorides with the terminal amines. Extraction of perinanganate or dichromate from aqueous to CO2 solution was described as rather low, whereas their use as phase-transfer catalysts in a halogen exchange reaction [benzyl chloride to benzyi bromide (24)] resulted in high rates of conversion. 

The technique of phase-transfer catalysis has been extensively applied to the two-phase polycondensation using various phase-transfer catalysts, such as quaternary ammonium and phosphonium salts, crown ethers and poly(ethylene glycol)s. ... 

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