Acid and Lactone Polymers

A variety of oxygen-containing functional groups have been proposed to exist in carbon black (17). The best documented of these are the phenolic hydroxy and quinone functions. These also are the most likely groups capable of entering into reactions with hydrocarbon polymers. The presence of carboxylic acid and lactone groups also appears well established (69-71), but is not universally accepted (72). 

Around 110 megatons (Mt) of CO2 are annually used in commercial synthesis processes, to produce urea, salicylic acid, cyclic carbonates, and polycarbonates. The largest use is for urea production, which reached around 90 Mt/yr in 1997. In addition to these applications, there are a number of promising reactions currently under study in various laboratories, reactions that differ in the extent to which CO2 is reduced during the chemical transformation. They include the synthesis of commodities and intermediates (acetic acid, methanol, carbonates, cyclic carbonates, and lactones), polymers (polyurethanes, polypyrones) and a variety of functionalized carboxylic acids (propenic acid, 3-hexen-l,6-dioic acid). A more detailed description can be found in the cited review. ... 

In addition to its water solubility poly(vinyl pyrrolidone) is soluble in a very wide range of materials, including aliphatic halogenated hydrocarbons (methylene dichloride, chloroform), many monohydric and polyhdric alcohols (methanol, ethanol, ethylene glycol), some ketones (acetyl acetone) and lactones (a-butyrolactone), lower aliphatic acids (glacial acetic acid) and the nitro-paraffins. The polymer is also compatible with a wide range of other synthetic polymers, with gums and with plasticisers. 

In vitro synthesis of polyesters using isolated enzymes as catalyst via non-biosynthetic pathways is reviewed. In most cases, lipase was used as catalyst and various monomer combinations, typically oxyacids or their esters, dicarboxylic acids or their derivatives/glycols, and lactones, afforded the polyesters. The enzymatic polymerization often proceeded under mild reaction conditions in comparison with chemical processes. By utilizing characteristic properties of lipases, regio- and enantioselective polymerizations proceeded to give functional polymers, most of which are difficult to synthesize by conventional methodologies. 

DLSA are rigid diols. They have the same skeleton as isosorbide and LAGA. For instance, 1,4 3,6-dilactone of mannosaccharic acid is a dicarbonyl derivative of iso-mannide and monocarbonyl derivative of the lactone of the anhydromannonic acid. Therefore, DLSA could find applications as diols and their polymers are expected to have similar properties to that of isosorbide and LAGA polymers. 

Under dehydrating conditions, it is probable that, in addition to lactonization, intermolecular esterification also occurs, yielding esters of aldonic acids and polymers. 

Large number of dicarboxylic acids, keto-acids and/or lactones indicated severe degradation of the polyethylene matrix [37, 38, 95]. Dicarboxylic acids were the most abundant products formed during photo-oxidation and their amount increased especially after long irradiation times, i.e. in severely degraded samples [96]. The relationship between the degree of oxidation/ degradation in the polymer matrix and the amount of dicarboxylic acids... 

Tin organohalogenides can be used as catalysts to produce ethers of phosphoric acid and to polymerise lactons forming colourless polyesters. Various halogen derivatives of dibutyltin have been put forward as catalysts for the solidification of silicone elastomers, as agents preventing the cracking of polystyrene, as inhibitors of metal corrosion in silicone polymers. 

Imprinted polyurethanes as coatings for optrodes have been used for the detection of solvent vapours in air (see chapter 20). One per cent of substituted 3,3-diphenylphthalide as indicator has been intercalated within the polymer. The phthalide forms a highly coloured planar carbenium ion by interaction with an acidic component and a subsequent cleavage of the lactone ring - the unreacted phenolic groups in a polyurethane provide enough acidity for this reaction (Fig. 21.4). The incorporation of analytes reduces the acidity and the back-reaction... 

The bydrolysis can be carried out induetrially on a mixture of the lactone and its polymer. Aa a matter of fact, the stracid medium and the high temperature naed cause dehydration to the hydro. y acid, and tine method, which ie a variant of the pcceding ones, ie vaod for the preparatiem of unsaturated tlerivatives. Sorbic acid and its esters have b n prepared iu this way from ketone and crotonaldehyde. 

Theee two reaotiona ( and C) oait be compared to the formation of cyclic anhydro caib< ates or sulfites from a-hydmxy acids these cydic derivatives deoompoee to give a-lactone polymers ... 

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