Polycarboxylic acids, phenolic

As coalification progresses, cross-linking increases and the lignin-derived polymers become more aromatic. Phenolic polycarboxylic acids and hydroxynaphthalene dicarboxylic acids which were identified are not found in the CuO-NaOH oxidation products of lignins and plant materials. 

Catalysts are also required in many stepwise polymerizations. For example, reaction of polycarboxylic acids and polyols (Reaction 7) is catalyzed by acids ester interchange, by metal compounds such as titanium alkoxides. On the other hand, polyurea synthesis (Reaction 6) generally does not require a catalyst. Metallic compounds are also useful in oxidative polymerization of phenols to give poly(phenylene oxides), illustrated in Reaction 14. 

Epoxy resins based on glycidylation of bisphenols, cresol and phenol novolacs, polycarboxylic acids, polyols, amines, and aminophenols have been long known. Epoxidized linear and cyclic olefins have also been used as specialty epoxy resins. More recently, glycidylated heterocycles have been introduced, initially as specialty resins promising improved resistance to weathering. One heterocycle in particular, the hydantoin ring, has become of particular interest as an epoxy substrate (J ). 

Commercial electropainting only dates from the early 1960s and the first processes to be introduced used anodic deposition. Some typical paint formulations would contain (i) polycarboxylic acids based on acrylic acid as monomer solubilized by an organic amine, (ii) alkyds, i.e. branched polyesters based on naturally occurring long-chain carboxylic acids and polyalcohols, e.g. glycerol, and (iii) epoxy resins based on phenols, e.g. 

A review on the use of different stationary phases in polyphenols, polycarboxylic acids, and flavonoids has highlighted the differences in selectivity of these classes of polar or possibly ionized compounds [94, 95]. Figure 69.9 shows the contour plot and the elution conditions of the comprehensive 2D separation of phenolic acids and flavones using parallel gradients of acetonitrile in a 5 mM ammonium acetate buffer on a PEG microcolumn in the first dimension and... 

Also values of alcohols(22,31,33), ethers(11b,34,35a), amines(34, 35b), ketones(11b,36), amides(11b,32,36,37a,b), pyridines and others heterocyclic compounds containing nitrogen(38), phenols (22,39), benzene and derivatives(llc,22b,40), esters(llb), polyethers (28,41), polyamines(35b,41), polyols(42-44), polycarboxylic acids (43), aminoalcohols(41), aminoethers(31,35b,41), hydroxyethers(11a, 28), xanthines(45), ureas(46) have been preferably obtained from direct measurements of the heat capacity of the solutions, but in some cases also by differentiation of the heats of solution with respect to temperature(22a,b,28,43,45) or as second derivatives with respect to temperature of solubility data(33,47). 

An extensive work was carried out by Uchikawa l on the conduction calorimetry of superplasticizers, such as SNF (NS in the figure), lignosulfonate (LS), a co-polymer of acrylic acid with acrylic ester (PC), and a three dimensional polycondensate product of aromatic aminosulfonic acid with trimethyl phenol (AS) (Fig. 11). The first peak in the calorimetry corresponds to the heat of dissolution of alite, the heat of formation of the AFt phase, and the calcium hydroxide formation from free lime. The second peak corresponds to the heat of hydration of alite. The admixtures were found to accelerate the formation ofthe ettringite phase. At w/cratios ofO.3 and 0.5 and a later addition of the admixture, the appearance of the second peak was significantly delayed and the peaks were of lower intensity. Most retardation occurred with polycarboxylic acid and amninosulfonic acid-based admixtures (Fig. 11). DSC was used to determine the amount of lime formed at different times. The DSC results show that the addition of admixtures at different w/c ratios generally decreases the amounts of lime in the presence of superplasticizers (Fig. 12). 

Epoxy resin coatings can be divided into two distinct types (a) ambient cured and (b) heat cured. The ambient-cured systems are crosslinked through the oxirane ring by using polyamines, amine adducts, polyamides, polythiols and catalytic cures, while the heat-cured systems are crosslinked through reactions of the hydroxyl groups, or in some cases a combintion of the epoxy and hydroxyl functionality, by using anhydrides and polycarboxylic acids as well as MF, UF and phenol-formaldehyde resins. 

Additionally to phenolic intermediates, upon the aromatic ring opening, a series of carboxylic acids can be formed. Maleic acid, for instance, has been detected in the oxidation of byphenyls (Bouquet-Somrani et al., 1996), 1,2,4-THB (Li et al., 1991a), 1,2-dimethoxybenzene (Pichat, 1997), and acid orange 7 (Stylidi et al., 2003). Similarly, muconic acid has been reported as an intermediate of byphenyls oxidation (Bouquet-Sormani et al., 1996), while succinic and malonic acids were identified in polycarboxylic benzoic acid oxidation (Assabane et al., 2000). It is therefore expected that these or similar acids be formed during phenol oxidation. 

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