Polyvinyl pyridine

The main results of this miero-mechanical model in the quasi-static regime have been compared with experimental results obtained by placing polystyrene (PS)-polyvinyl pyridine (PVP) diblock copolymers with a short PVP block between PS and PVP homopolymers. The fracture toughness was found to increase linearly with E from that of the bare PS/PVP interface, while the slope of the line increased with the degree of polymerization of the block being pulled out. If the data for the different copolymers were plotted as AG vs. (where... 

SynChropak CATSEC columns are evaluated similarly using a polyvinyl-pyridine standard of molecular weight 600,000 and cytidine. The mobile phase is 0.1 % trifluoroacetic (TEA) acid containing 0.2 M sodium chloride. Minimum plate counts are listed in Table 10.4. 

Direct measurements on metals such as iron, nickel and stainless steel have shown that adsorption occurs from acid solutions of inhibitors such as iodide ions, carbon monoxide and organic compounds such as amines , thioureas , sulphoxides , sulphidesand mer-captans. These studies have shown that the efficiency of inhibition (expressed as the relative reduction in corrosion rate) can be qualitatively related to the amount of adsorbed inhibitor on the metal surface. However, no detailed quantitative correlation has yet been achieved between these parameters. There is some evidence that adsorption of inhibitor species at low surface coverage d (for complete surface coverage 0=1) may be more effective in producing inhibition than adsorption at high surface coverage. In particular, the adsorption of polyvinyl pyridine on iron in hydrochloric acid at 0 < 0 -1 monolayer has been found to produce an 80% reduction in corrosion rate . 

They represent tight ion-pairs solvated externally by some segments of their own chains. This additional binding of the cation to the polymer accounts for the very low dissociation constants of such ion-pairs (Kdiss < 10-9 M). A similar interpretation was evoked in rationalization of the low dissociation constants of the salts of living polyvinyl pyridine 40). 

Several metallophthalocyanines have been reported to be active toward the electroreduction of C02 in aqueous electrolyte especially when immobilized on an electrode surface.125-127 CoPc and, to a lesser extent, NiPc appear to be the most active phthalocyanine complexes in this respect. Several techniques have been used for their immobilization.128,129 In a typical experiment, controlled potential electrolysis conducted with such modified electrodes at —1.0 vs. SCE (pH 5) leads to CO as the major reduction product (rj = 60%) besides H2, although another study indicates that HCOO is mainly obtained.129 It has been more recently shown that the reduction selectivity is improved when the CoPc is incorporated in a polyvinyl pyridine membrane (ratio of CO to H2 around 6 at pH 5). This was ascribed to the nature of the membrane which is coordinative and weakly basic. The microenvironment around CoPc provided by partially protonated pyridine species was suggested to be important.130,131 The mechanism of C02 reduction on CoPc is thought to involve the initial formation of a hydride derivative followed by its reduction associated with the insertion of C02.128... 

Lithium iodide is the electrolyte in a number of specialist batteries, especially in implanted cardiac pacemakers. In this battery the anode is made of lithium metal. A conducting polymer of iodine and poly-2-vinyl pyridine (P2VP) is employed as cathode because iodine itself is not a good enough electronic conductor (Fig. 2.3a). The cell is fabricated by placing the Li anode in contact with the polyvinyl pyridine-iodine polymer. The lithium, being a reactive metal, immediately combines with the iodine in the polymer to form a thin layer of lithium iodide, Lil, which acts as the electrolyte ... 

Figure 33. Pressure dependence of the electronic transition energies of [Cu(dieten)2](BF4)2 polycrystalline (left panel) and in polyvinyl pyridine matrix (right panel).

Methylrheniumtrioxide (MTO) can straightforwardly be immobilized using copolymers consisting of polystyrene and polyvinyl pyridine. The authors proposed two possible structures 18 shown in Scheme 4.10. In the presence of H2O2 these catalysts are efficient and selective heterogeneous catalysts for the epoxidation of alkenes. It was shown that their activity is maintained for at least five recycling experiments [23 dj. In analogy to this work, bipyridyl-functionalized mesoporous silica can be employed for the immobilization of MTO [75]. 

Scheme 4.20 Protonated polyvinyl pyridine — a mild solid acid for THP-ether formation.

Significant research has been directed toward the use of polyelectrolyte complexes as blood compatible materials. Several investigators found that water-insoluble polyelectrolyte complexes can suppress blood coagulation [487-490]. Davison and coworkers reviewed and studied the biological properties of water-soluble polyelectrolyte complexes [491] between quatemized poly(vinyl imidazole) or polyvinyl pyridine) and excess sulfonated dextran or poly(methacrylic acid). By forming complexes with a stoichiometric excess of anionic charge, a more compact conformation with anionic character was obtained. 

Pr Pro ptz pvp py pyca pycaH pyo pyr pys pySH pySSpy iso-propyl = 2-propyl proline phenothiazine polyvinyl pyridine pyridine pyridine-2-carboxylato(l -) pyridine-2-carboxylic acid pyridine iV-oxide pyrimidine pyridine-2-thiolato(l -) pyridine-2-thiol 2,2 -bis(pyridyl) disulfide... 

In some processes, there is a need to immobilize dyes, either temporarily as in the case of filter and antihalation devices or permanently as for the images in colour image transfer processes. Because the dyes normally used in these applications contain acid functional groups, the corresponding mordants are basic in nature and are usually polymeric. Polyvinyl-pyridines have utility as mordants. Other useful compounds are illustrated by the pyridinium salt (95) (49USP2484430), the morpholinium salt (96) (72BRP1245952) and the imidazole (97) (72GEP2150136). 

An interesting class of polyeleclrolytes, denoted by polysoaps, is obtained by attaching soap-like molecules to the polymer chain. Such a polysoap is for instance produced by the quaternization of polyvinyl-pyridine with /r-dodecyl bromide. The polysoap molecules differ from ordinary poly electrolytes in that they may reach protein-like compactness in solution. They behave like prefabricated soap micelles and solubilize hydrocarbons and other compounds insoluble in water,... 

Similar behavior was obtained with other systems such as Ru2/Ru3 in polyvinyl-pyridine or polyhydroxyphenazine on glassy carbon electrodes [95]. 

Liebenow 1996 PC/LiQ04 Li coated with polyvinyl pyridine 97... 

Dyeing of Heparin on PVPyr. The transparent films of polyvinyl-pyridine permit demonstration of the presence of heparin, and some judgment of the uniformity of adsorption, by staining with a basic dye such as toluidine blue or azure A, which combine with heparin to form... 

A range of vinyl and carboxypyridyl derivatives of [Ru(bipy)2]2+ have been prepared and electron transfer reactions and the photochemical activity of these complexes as polymer films at electrode surfaces studied.745,861,953 1058 1138-1148 Some chemical transformations involving polyvinyl pyridine (PVP) are illustrated in Scheme 28.1138,1142-1144,1149 The charge transfer luminescence spectra of cis- and tranA-[Ru(bipy)2py2]2+,1096,1150 czs-[Ru(bipy)2L2]4+ (L = 2-methyl-4,4 -bipyridinium+),1151 cis- and traru-[Ru bipy)(phen)py2]2+, [Ru(bipy)py2(L)]2+ (L = en, (NH3)2, 2-methylaminopyridine, 2-ethylaminopyridine) and [RuCl(bipy)py3]+ have been measured.1096... 

Acetica A process for making acetic acid by the heterogeneous carbonylation of methanol in a bubble column reactor. The catalyst is a rhodium carbonyl iodide, anchored by ion-pairing to a polyvinyl pyridine resin. Developed by Chiyoda Corporation and UOP and first described in 1998. Licensed to Guizhou Crystal Organic Chemical Group, China, in 2002 one plant was under construction in 2005. 

Complexes of aminopolymers such as polyvinyl-pyridine " (PVP) or poly(ethyleneimine) (PEI) are known, for example, a(s -[CoCl(en)2PVP]Cl2 has been prepared with up to 108 repeat units and up to 50 Co atoms, and Ni complexes of PEI are readily formed in solution. 

Recently synthesis and molecular-sieve properties of other kinds of polymers have been described. Cross-linked polyacrylamide, polyvinyl pyridine, and polyvinyl carbitol may turn out to be very useful (Lea and Sehon, 1962 Hjert n and Mosbach, 1962). 

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