Carboxylated polyethylenimine

Fig. 17. Rate of release of 5-nitro-2-cyanophenolate during decarboxylation of 6-nitrobenzisoxazole-3-carboxylate at 25°C, pH 7.4, p. = 0.05. Initial concentration of substrate, So = 4.18xl0-6M (A) In presence of quaternized polyethylenimine...

Table X summarizes the kinetic parameters derived from the decarboxylation rates of nitrobenzisoxazole carboxylate catalyzed by each of four different lauryl polyethylenimines.

Comparing catalytic effects of different modified polyethylenimines on the decarboxylation of nitrobenzisoxazole carboxylate, we can discern several interesting features. Comparison of the 25% laurylated polymer in the quaternized and nonquaternized forms, A and D, respectively, in Table X, shows that the former is about three times more effective as a catalyst than the latter. For the quaternized polymer the first-order catalytic constant k2 and the second-order rate constant nk2IKM are greater and the binding of substrate (measured by XM ) is stronger. 

The membranes produced from polyelectrolyte complexes on the basis of weak polyelectrolytes, e.g. poly(carboxylic adds) (PAA and PMAA) and polyamines [poly(2-N,N-dimethylaminoethyl methacrylate), polyethylenepiperidine, polyethyl-enepyperasine, polyethylenimine] have been prepared140,141 and used in dialysis and ultrafiltration. Permeability coeffirients of membranes made from poly electrolyte complexes are much higher (4 and 20 times, resp.) in comparison with the cellulose-based membranes (Cuprophane, Film 1(M)). 

A water soluble polyethylenimine support has been developed for peptide synthesis using A -carboxylic anhydrides in a sequential method of peptide synthesis. The final polymer-peptide cleavage was effected by tryptic digestion (Pfaender et aL, 1975). 

Chen, Y., Shen, Z., Gehringer, L., Frey, H. and Stiriba, S.-E. (2006) Supramolecular thermotropic liquid crystalline materials with nematic mesophase based on methylated hyperbranched polyethylenimine and mesogenic carboxylic acid , Macromol. Rapid Comm., 21,69-75. 

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