Oxidation polyketonates

Hydroboration of a,C0-dienes with monoalkylboranes gives reactive organoboron polymers which can be transformed into polymeric alcohols or polyketones by carbonylation, cyanidation, or the DOME reaction followed by oxidation (446—448). 

Although sequential B-oxidation from the carboxyl end of fatty acids was believed to be the mechanism for their breakdown, other schemes had been proposed, notably by Hurtley in 1915, who suggested multiple alternate oxidation—this idea was not widely accepted because the probable intermediates, polyketonic or polyunsaturated fatty acids, had never been detected. The abnormally high levels of acetoacetate produced by various liver preparations, however, caused multiple... 

The ease of degradation of the polyketone intermediate of Suzuki, obtained by oxidation of poly(vinyl alcohol), has been demonstrated by Wang and Huang(37) at the University of Connecticut. 

Carboxidation of the poly-BD and other rubbers by nitrous oxide opens a simple and effective way for preparing polyketones with a regulated oxygen content and molecular weight. The presence of C=0 and C=C groups provides additional opportunities for application and modification of the material. 

Iraqi A, Cole-Hamilton D J. (1991) Polyketones via oxidation of polybutadienes catalysed by complexes of platinum (II). Polyhedron 10 993-995... 

To the best of our knowledge, only two papers on the oxidation of polyketonates have been published. Lintvedt and coworkers have observed that the binuclear complex Co2(dbba)2py4 (136) reacts with O2 in pyridine/benzene affording the binuclear derivative 137, derived from the oxidation of the 4-methyne carbon of both ligands to carbonyl groups (equation 87). At variance with the S-diketonates, which are decomposed upon oxidation at the methyne carbon atom (Section 1V.A.2), the CH2 C=0 oxidation at C4 in the tetraketonato complex does not destroy the dianion character of the ligand, preserving the complex coordination. 

Continued oxidation would result in the formation of a polyketone followed by ring cleavage and formation of maleic acid, as in the case of the heterogeneous process. 

Or as in the case of the oxidation with silver peroxide in the liquid phase,81 the ring may rupture without polyketones being formed. 

So, when conducting the reaction at 65-85 °C in water, alcohol, ester, acetonitrile, the polyketone particles of size 0.01-100 micrometers transform the polyesters by the oxidation under the peroxide agents per-oxybenzoic, m-chloroperoxybenzoic, peroxyacetic, trifloumperoxyacetic, monoperox rphthalic, monoperox5rmaleine acids, combinations of H2O2 and urea or arsenic acid [405, 406],... 

The proposed biodegradation mechanism is supported by the rapid biodegradation of the polyketone obtained by the chemical oxidation of polyvinyl alcohol [47-49] shown in Scheme 2. 

Poly- imide (Ceni d) Polyketone Poly- methylpentene Poly- phenylene oxide. 

Polyimide (Cont d) Polyketone Polymethylpentene Polyphenylene Oxide,... 

Kadel, Polyketone, Amoco Polymars Kadox, Zinc oxide. Zinc Corp. of America KADY Mill, Rotor-stator dispersion mill, KADY International... 

The combination of photoscission, photo-oxidation, and photorearrangement means that even very high performance polymers, such as epoxy resins, aromatic polyethers polyketones, and polysulfones, and the aromatic polyamides poly(l,3-phenylene isophthalamide) and poly(l,4-phenylene terephthalamide) (Nomex and Kevlar respectively) will degrade significantly on solar exposure. For example, it has been shown (108) that poly(phenylene oxide) and polysulfone both lose about 50% of their initial tensile strength after 2 years of outdoor exposure in Queensland. 

Pri ce. The price of a thermoplastic resin is basically determined by the cost of preparation, which in turn strongly depends on the cost of reagents (monomers, catalysts, etc), the complexity of the manufacturing process, and the dimension of production plants. Aliphatic polyketones, for instance, are made from very cheap raw molecules as ethylene, propylene, and CO their cost is determined by the need for expensive catalysts, based on Pd complexes, and the relatively complex production plant. On the other hand, PEN, which can easily be prepared in the same reactors used for PET, suffers from the difficult availability of its basic monomer dimethyl 2,6-naphthalene dicarboxylate. Most engineering polymers contain aromatic monomers, which are difficult to synthesize and polymerize, with slow and sophisticated mechanisms (condensation, substitution, oxidative coupling). 

The good chemical and hydrolytic resistance of aliphatic polyketone fibers, which has to be balanced with its thermal oxidative stability, provides them new opportunities as filter material, eg papermaking cloth or fuel filters. 

About the nomenclature of like and unlike The meso and racemo nomenclature commonly used for vinyl monomer diads, are not applicable to the head-to-tail polyketone because the junchon unit between the two stereocenters, -CH2-C(=0)-, is not symmetric. Poly(a-amino acid)s and poly(propylene oxide) are other examples of polymers with asymmetric (W. V. Metanomski, Compendium of Macromolecular Nomenclature, lUPAC Macromolecular division). Accordingly, the words like and unlike, which are used in organic chemistry, are applied like (/) is used for the diad consisting of the same configuration (analogous to meso) and unlike ( ) for the opposite (analogous to racemo). 

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