Polymeric hydrogen acceptor

Association Complexes. The unshared electron pairs of the ether oxygens, which give the polymer strong hydrogen bonding affinity, can also take part in association reactions with a variety of monomeric and polymeric electron acceptors (40,41). These include poly(acryhc acid), poly(methacryhc acid), copolymers of maleic and acryflc acids, tannic acid, naphthoHc and phenoHc compounds, as well as urea and thiourea (42—47). 

Hydrophilic-lipophilic polymeric sorbents have been recently introduced, claiming that no conditioning step is required as the sorbent preserves analyte retention, even if the bed dries out. Commercially available products include Oasis by Waters and Abselut by Varian. These are copolymers of polyvinyl pyrrolidone (a hydrogen acceptor, which increases the water wettability of the polymer) and a cross-... 

N,N-dimethyl-p-phenylenediamine by the method of Bernthsen33 to give poly( -vinyl Methylene Blue), This polymer acts as a hydrogen acceptor in the enzymatic dehydrogenation of ethanol. The carbinol form (XVIl) of polymeric Malachite Green may be prepared by the. nucleophilic attack of poly(p-lithium styrene) on Michler s ketone 3 acidification gives the colored dye (XVIIl). 

Some of the recently reported quinone-based redox polymers (Manecke, 1974) have the structural units represented in Fig. 12-1. In these polymeric quinone s, an attempt has been made to increase the hydrogen acceptor property of the quinone group by introducing electron-withdrawing substituents. Such substituents are known to increase the redox potential of the quinone-hydroquinone system (cf. 2,3-dichloro-... 

Because almost any diacid can be leaddy converted to the acid chloride, this reaction is quite versatile and several variations have been developed. In the interfacial polymerization method the reaction occurs at the boundary of two phases one contains a solution of the acid chloride in a water-immiscible solvent and the other is a solution of the diamine in water with an inorganic base and a surfactant (48). In the solution method, only one phase is present, which contains a solution of the diamine and diacid chloride. An organic base is added as an acceptor for the hydrogen chloride produced in the reaction (49). Following any of these methods of preparation, the polymer is exposed to water and the acid chloride end is converted to a carboxyhc acid end. However, it is very difficult to remove all traces of chloride from the polymer, even with repeated washings with a strong base. 

Polymerization of cyclic compounds may also occur by ionic mechanisms under the influence of strong acids or bases and in the absence of water and alcohols. Thus, in the presence of a strong acid or electron acceptor (BF3), ethylene oxide may polymerize violently. The mechanism may be the following, where the electron acceptor is represented by the hydrogen ion ... 

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