Polyvinylpyridine

A series of polyvinylpyridine standards of different molecular weight were analyzed by size-exclusion chromatography, yielding the following results. 

When a preparation of polyvinylpyridine of unknown formula weight was analyzed the retention volume was found to be 8.45. Report the average formula weight for the preparation. 

We have conducted the comparative study of gold (III), platinum (IV) and palladium (II) acidocomplexes solution on macroporous granular sorbents on the basis of polystyrene with functional groups of methyleneamine, 3-methylpyrasolyl, N,N-dimethylaminomethylene, dimethylmethylene-P-oxyethylamine and with functional 6-(3-methylpyridine) groups on polyvinylpyridine basis as well as fibrous polystyrene sorbent with pyrazolyl groups. 

The capacity of studied organopolymeric sorbents depends on metal nature (Pd (II) > Au (III) > Pt (IV)) as well as on the composition and stmcture of sorbent matrix (polyvinylpyridine macroporous > polystyrene macroporous > polystyrene fibrous). 

Reillex 425-HCl, dihydropyran, 86°, 1.5 h, 84-98% yield. The Reillex resin is a macroreticular polyvinylpyridine resin and is thus an insoluble form of the PPTS catalyst. 

FIGURE 9.22 Analysis of poly(vinyl pyrrolidone). Eluent 0.1 M Tris buffer, pH 7. Flow rate I ml/ min. Columns PSS Suprema 10 /itm, 100 + 1000, 8 x 300 mm. Oven temp 30°C. Detection Rl. Standards PSS polyvinylpyridin standards. 

FIGURE 10.4 Calibration curves for polyvinylpyridines on SynChropak CATSEC columns. Mobile phase 0.2 M sodium chloride in 0.1 % trifluoroacetic acid. (From MICRA Scientific. Inc., with permission.)... 

Mobile-phase selection for cationic polymers is similar to that for the other polymers in that ionic strength and pH can change the shape of the solute from linear to globular (9). Mobile phases are often low pH e.g., 0.1% trifluo-roacetic acid, including 0.2 M sodium chloride, has been used successfully for polyvinylpyridines. Sodium nitrate can be substituted for the chloride to avoid corrosive effects. Some salt must be included so that ion exclusion does not occur (3). 

FIGURE 10.14 Analysis of polyvinylpyridines on SynChropak CATSEC 100,300, and 1000 columns in series (250 X 4.6 mm i.d.). Flow rate 0.37 ml/min. Mobile phase 0.1 % trifluoroacetic acid in 0.2 N sodium nitrate. Detection by differential viscometry. (Reprinted from Ref. 9 with permission.)... 

FIGURE 4-13 Structures of common polymeric coatings (a) Nafion, (b) polyvinyllferro-cene (c) polyvinylpyridine id) polypyrrole. 

In the theoretical treatment of ion exchange polymers the roles of charge propagation and of migration of ions were further studied by digital simulation. Another example of proven 3-dimensional redox catalysis of the oxidation of Ks[Fe(CN)5] at a ruthenium modified polyvinylpyridine coated electrode was reported... 

The compounds 12,14 and 15 can be prepared from parent lysergic acid amides by bromination with NBS or PHT, but not the compounds of the type 12. The latter structure is very sensitive and under these circumstances only degradation products were obtained. Besides it was necessary to use much milder reagent, e.g. bromine bonded onto polymeric matrix with polyvinylpyrrolidone or polyvinylpyridine structure (29) ... 

Nanometer size Pd colloids in block copolymer micelles of polystyrene polyvinylpyridine as catalysts have been used is a novel way by Klingelhofer for Heck reaction of C-C coupling of aryl halides with olefins. 

The redox active polymer films might bear the mediator group attached either covalently to the polymer backbone (polyvinylferrocene, Ru(II) complexes of polyvinylpyridine, etc.) or electrostatically within the ion-exchange polymer (e.g. in Nation, cf. Section 2.6). 

Protective Colloids. Another approach in preparing and stabilizing metal colloids is by adsorption of macromolecules on their surfaces. A wide variety of materials have been used including gummy gelatinous liquids,(J 0) albumin,(27) Icelandic moss,(28) latex,(22) polyvinylpyrrolidone, (29) antibodies, ( 30 ) carbowax 20M, ( 31 ) polyvinylpyridine, (31 ) and various polymer-water/oil-water mixtures.( 2) These studies clearly indicate that "steric stabilization of metal colloids is also important (along with electronic stabilization).(33)... 

It should be pointed out that the addition of substances, which could improve the biocompatibility of sol-gel processing and the functional characteristics of the silica matrix, is practiced rather widely. Polyethylene glycol) is one of such additives [110— 113]. Enzyme stabilization was favored by formation of polyelectrolyte complexes with polymers. For example, an increase in the lactate oxidase and glycolate oxidase activity and lifetime took place when they were combined with poly(N-vinylimida-zole) and poly(ethyleneimine), respectively, prior to their immobilization [87,114]. To improve the functional efficiency of entrapped horseradish peroxidase, a graft copolymer of polyvinylimidazole and polyvinylpyridine was added [115,116]. As shown in Refs. [117,118], the denaturation of calcium-binding proteins, cod III parvalbumin and oncomodulin, in the course of sol-gel processing could be decreased by complexation with calcium cations. 

Trimethylsilyl chloride is distilled from calcium hydride and stored under argon or nitrogen in a stoppered bottle over polyvinylpyridine. 

Many borohydrides are highly unstable and have to be used as freshly prepared ethereal solutions. However there are instances where the polymer-supported versions are more stable e. g. an Amberlyst anion exchange resin supported borohydride and cyanoborohydride [61], polyvinylpyridine supported zinc borohydride [62] and the corresponding zirconium borohydride [63]. Such compounds, in their labeled forms, should turn out to be very useful. 

An alternative strategy for catalyst immobilisation uses ion-pair interactions between ionic catalyst complexes and polymeric ion exchange resins. Since all the rhodium complexes in the catalytic methanol carbonylation cycle are anionic, this is an attractive candidate for ionic attachment. In 1981, Drago et al. described the effective immobilisation of the rhodium catalyst on polymeric supports based on methylated polyvinylpyridines [48]. The activity was reported to be equal to the homogeneous system at 120 °C with minimal leaching of the supported catalyst. The ionically bound complex [Rh(CO)2l2] was identified by infrared spectroscopic analysis of the impregnated resin. 

The ionic attachment strategy for catalytic methanol carbonylation has recently seen a resurgence of interest from both industry [49-53] and academic groups [54-57]. Most significantly, in 1998 Chiyoda and UOP announced their Acetica process, which uses a polyvinylpyridine resin tolerant of elevated temperatures and pressures [8,58]. The process attains increased... 

Exhaustive studies on well-defined systems are rather scarce (4) nevertheless 3 systems thoroughly analyzed by independant research groups are of outstanding interest a) the quaternization of polyvinylpyridines by alkyl halogenides (20-25) b) the chlorination of polyethylene (13,26-28) c) the basic or acid hydrolysis of PMMA (29-31). On the other hand, neighbouring groups effects have been quantitatively taken into account for the kinetic analysis of periodate oxidation of amylose (32,33). 

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