Preparation polycarboxylic acids

By depolymerizing PET waste with a polyol and subsequently condensing the oligomeric product with a polycarboxylic acid or anhydride, polyester resins are produced which have wide industrial applications. Depending on the polyol and polycarboxylic acid or anhydride used, saturated resins, alkyd resins, or unsaturated resins are obtained. PET wastes have been used for the production of alkyd resins in water thinnable paints. The materials obtained from the reaction of PET with a mixture of fatty acids high in linoleic acid content and trimethylolethane have been used in the preparation of water-dispersible coatings. Products of the depolymerization of PET with trimethylolpropane and pentaerythritol are used in the manufacture of high-solids paints. In the first step, PET is depolymerized with trimethylopropane and pentaerythritol at temperatures of 230-240°C. The final paint compositions contain 30-50% of PET depolymerization products.12... 

Citric acid and nitriloacetic acid (NTA) lanthanide complexes were used in the earliest ion exchange separations of lanthanides from fission product mixtures (Kf = 3.2 for Ce(H3 Cit.)3 and Kf = 10.8 for CeNTA2) (Sillen and Martell, 1964). More recently such polyamino-polycarboxylic acids as ethylenediaminetetraacetic acid (EDTA), 1,2-diaminocyclohexaneacetic acid (DCTA), and diethylenetriaminepentaacetic acid (DTPA) have been prepared. Their lanthanide complexes are very stable (Table 3) and have been widely used in analysis and separation of lanthanide mixtures. They have also been used experimentally to remove internally-deposited 144Ce and other radioactive lanthanide nuclides from animals and man (Foreman and Finnegan, 1957 Catsch, 1962 Balabukha et al., 1966 Palmer et al., 1968 among others). 

Microgels have been prepared from epoxy resins which were intramolecular-ly crosslinked by a polyalkylene polyamine/polycarboxylic acid for flexible, corrosion resistant coatings [354]. 

Additional hyperbranched polyesters based on either di-, tri-, or polycarboxylic acids or di-, tri-, or polyols are described by Bruchman et al. (1). For example, the reaction product of adipic acid, pentaerythritol and 1,4-cyclohexanedi-methanol, was prepared using di-n-butyltin oxide as catalyst and then post-reacted with selected diisocyanates and used as a paint additive. 

Modern polyimides are most likely an outgrowth of trying to find increased utilization of aromatic polycarboxylic acids as prepared by oxidation of poly-methylbenzenes, a major component in petroleum feedstocks. Therefore, it is not too surprising that the first commercial application of these materials appeared... 

These are dispersants (e.g., amines, fatty acids, polycarboxylic acids), binders (e.g., wax polyacrylate, polyvinyl alcohol), plasticisers (e.g., stearic acids, dibutyl phthalate, polyethylene glycol) and solvents (e.g., water, organics) [244-250]. They are needed to prepare a suitable suspension or slurry for the subsequent shaping step. They must evaporate during a presintering treatment without causing failures (Table 9). Suspensions as well as slurries should have an uniform distribution of the Si3N4 particles, adequate viscosity, and no... 

Reichert and Mathias prepared related branched aramids, to those of Kim,t5-34] from 3,5-dibromoaniline (23) under Pd-catalyzed carbonylation conditions (Scheme 6.7). These brominated hyperbranched materials (24) were insoluble in solvents such as DMF, DMAc, and NMP, in contrast to the polyamine and polycarboxylic acid terminated polymers that Kim synthesized, which were soluble. This supports the observation that surface functionality plays a major role in determining the physical properties of hyperbranched and dendritic macromolecules J4,36 A high degree of cross-linking could also significantly effect solubility. When a four-directional core was incorporated into the polymerization via tetrakis(4-iodophenyl)adamantanc,1371 the resultant hyperbranched polybromide (e.g., 25) possessed enhanced solubility in the above solvents, possibly as a result of the disruption of crystallinity and increased porosity. 

Imide-Modified Isocyanurate Foams. The imide linkage is a thermally stable linkage, and therefore, imide-modified isocyanurate foams have higher thermal stability and flame retardance than urethane-modified isocyanurate foams. R. Grieve (114) prepared such foams in a one-shot process by reacting a polycarboxylic acid anhydride with an organic polyisocyanate in the presence of a catalytic amount of a monomeric homocyclic polyepoxide and a tertiary amine. 

Benzoic acid prepared catalytically from phthalic anhydride may contain certain undesirable compounds, tars, and coloring materials and must of necessity be purified in some cases to obtain a marketable product. Naphthoquinone impurities are reduced to naphthohydroquinones by treatment of the product with sulfur dioxide or sodium bisulfite at 40° to 50° C. for 3 to 4 hours. Any phthalic anhydride remaining is converted to phthalic acid at the same time. Leaching with water is used to remove the reduced impurities.72 Unconverted phthalic acid may also be separated from benzoic by treatment of the mass with sodium carbonate so as to convert the polycarboxylic acid into a primary salt while leaving the mono-carboxylic acid unreacted. Solvent leaching is then used to separate the salt from the acid.78 Colored impurities in benzoates from synthetic benzoic acid may be removed by oxidation with potassium permanganate.71... 

D M Lewis, B Voncina, Durable press finishing of cotton with polycarboxylic acids. I. Preparation of thiosuccinyl-s-triazine, JAppl Polymer Sci, 1997 66(8) 1465-1474... 

The production of polymers with carboxylated backbones is of particular interest due to potential application of such polymers in films and surface coatiug. t The polycarboxylic acids can now be easily prepared via catalytic hydrocarboxylation of... 

Two of the enzymes of the tricarboxylic acid cycle, aconitase and fumarase, catalyze reactions in which water is added reversibly to an unsaturated polycarboxylic acid. Both enzymes exhibit rigid stereospecificity fumarase forms only L-malate from fumarate and forms only fumarate (trans) and not maleate (czs-ethylenedicarboxylic acid), and aconitase reacts with only cis-, not imns-aconitate, and with D-, not L-isocitrate. Citrate is a symmetrical molecule, with no optical isomers, but it will be shown that steric factors also enter into the reaction of this substrate with aconitase. The enzymes of the tricarboxylic acid cycle, in contrast to the glycolytic enzymes, are associated with intracellular granules known as mitochondria. Studies of the individual enzymes have depended to a large extent on the separation of soluble activities from these particles. Aconitase and fumarase are released from the particles very rapidly under mild conditions often in the preparation of cell-free homogenates these activities are largely solubilized, and special care must be taken to demonstrate their origin in mitochondria. 

TABLE IV Preparation of Polyglycidyl Esters of Polycarboxylic Acids According to Eq. (6) "... 

In recent years the availability of several aromatic polycarboxylic acids has been exploited in specialty alkyd resin preparations [57, 58]. For example, trimellitic acid-based alkyds are used in alkyd-melamine enamels and acrylic lacquers [57]. Isophthalic acid can be used alone or in conjunction with trimellitic anhydride or phthalic anhydride [59]. Pyromellitic acid and pyromellitic anhydride have also been suggested as partial replacements for phthalic anhydride in long or short oil alkyds to give more water-resistant (also caustic- and gasoline-resistant) coatings [60]. 

TABLE VII Preparation of Alkyd Resins Based on Aromatic Polycarboxylic Acids... 

Polyurethanes are prepared in step-growth polymerization processes similar to that used for preparing polyesters. In fact, many polyurethane materials are hybrids of ester linkages and urethane linkages. If a polyisocyanate is substituted for the polycarboxylic acid shown in Figure 2, the result is a polyurethane. The urethane hnkage is obtained by the reaction of an alcohol with an isocyanate. (The urethane linkage is also known as a secondary carbamate.)... 

Related to the sulfoacid esters and amides are materials derived from sulfonated polycarboxylic acids. Such polyacids include succinic, itaconic, phthalic, and iso-phthalic acids and the tricarbaUylates. The presence of several carboxylic acid groups in these materials opens the way for the preparation of a variety of multifunctional surfactant molecules. 

The sulfosuccinimdes may be of two varieties, one analogous to the previously mentioned succinic acid derivatives, where the sulfonate group is added across the double bond of maleic acid and subsequently reacted to produce the cyclic imide. The second variety requires a different synthetic approach, since the locations of their hydrophilic and hydrophobic groups are reversed from those of the succinic acid derivatives. In this case, the starting material is a 2-alkyl, alkenyl, or similar succinic anhydride, which is reacted with the appropriate sulfoalkylamine to produce the amide acid, followed by dehydration to the imide. Similar reaction schemes can be used to prepare di- and higher polyesters and amides of malonic acid, itaconic acid, and other polycarboxylic acids. 

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