Poly vinylbenzo- 8-crown

Poly(vinylbenzo-18-crown-6) [54] dissolved in water also acts as an efficient catalyst for the decarboxylation through transfer of the substrate into the aromatic inner core of the tightly coiled polymer (Shah and Smid, 1978). The bound carboxylate decomposes 2300 times faster than in water, the rate constant (0.042 s-1) being the largest of those observed in aqueous media. 

Poly(carboxylic acid)s Poly(vinylbenzo-18-crown-6) 295... 

Moreover, intermacromolecular complex formation is applied to selective recovery of organic and metallic ions. For example, as shown in Table 27, Cu2+ ion is much more effectively precipitated by the polyelectrolyte complex than by one of its components520. Furthermore, polyelectrolyte complexes including some metal ions have been studied in recent years (see Sect. 3.2.). Crown ethers can bind certain cations they especially exhibit high affinity to K+. Smid et al.S21) synthesized poly(vinylbenzo-[18]-crown-6). Such polymers containing crown ether with K+ behave like polycations in solution and can interact with polyanions such as poly(carboxyHc acid) to generate a kind of polyelectrolyte complexes. Moreover, PAA may interact with the ether oxy-... 

Bunton and his co-workers55 have shown that the decarboxylative ring opening of 6-nitroindoxazene-3-carboxylic acid is strongly catalyzed by cationic micelles and by micelles of zwitterionic surfactants such as N,N-dimethyl-JV-dodecylglycine. Later studies by other workers indicate that the decarboxylation is also catalyzed by polysoaps,56 modified polyethylene-imines,57 cycloheptaamylose,9 and by poly(vinylbenzo-18-crown-6).58 The... 

C-allylation of PhO" Na with H2C=CHCH2C1 in a variety of solvents in the presence of different crown ethers is most effective in each case when using poly(vinylbenzo-15-crown-5)polyether. Only in the presence of the crown ethers 15-crown-5 and 18-crown-6 are the anions in potassium phthalimide and sodium saccharinate, respectively, sufficiently activated to bring about nucleophilic aromatic substitution of the 4-fluorine in pentafluoropyridine. The formation of 2,4-dinitrophenol, in addition to the expected ether, from 2,4-dinitrochlorobenzene and potassium 2-propoxide in 2-propanol-benzene (1 1), in the presence of dicyclohexyl-18-crown-6 polyether, has been accounted for on the basis of a nucleophile-radical reaction (5rn1)/ ... 

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