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Other dicarboxylic acids

Co(lII) perchlorate oxidations of succinic, aspartic, maleic and fumaric acids all obey the rate expression  [Pg.402]

The oxidation of ethylenediaminetetraacetic acid (EDTA) by Pu02 and Np02 to give the quinquevalent metal ions in perchlorate media is first-order in both oxidant and substrate and the stoichiometry, d[M(VI)]/ A [EDTA], is 6 in both cases. The Np(VI) oxidation shows a fractional dependence on acidity and has parameters E = 23.0 kcal.mole , AS — 12.3 eu. [Pg.402]


As with other dicarboxylic acids, the second ionization constant of carbonic acid is far- smaller- than the first. [Pg.805]

In 1932 Krebs was studying the rates of oxidation of small organic acids by kidney and liver tissue. Only a few substances were active in these experiments —notably succinate, fumarate, acetate, malate, and citrate (Figure 20.2). Later it was found that oxaloacetate could be made from pyruvate in such tissues, and that it could be further oxidized like the other dicarboxylic acids. [Pg.641]

Another important piece of the puzzle came from the work of Carl Martius and Franz Knoop, who showed that citric acid could be converted to isocitrate and then to a-ketoglutarate. This finding was significant because it was already known that a-ketoglutarate could be enzymatically oxidized to succinate. At this juncture, the pathway from citrate to oxaloacetate seemed to be as shown in Figure 20.3. Whereas the pathway made sense, the catalytic effect of succinate and the other dicarboxylic acids from Szent-Gyorgyi s studies remained a puzzle. [Pg.642]

The crystal structure of many compounds is dominated by the effect of H bonds, and numerous examples will emerge in ensuing chapters. Ice (p. 624) is perhaps the classic example, but the layer lattice structure of B(OH)3 (p. 203) and the striking difference between the a- and 6-forms of oxalic and other dicarboxylic acids is notable (Fig. 3.9). The more subtle distortions that lead to ferroelectric phenomena in KH2PO4 and other crystals have already been noted (p. 57). Hydrogen bonds between fluorine atoms result in the formation of infinite zigzag chains in crystalline hydrogen fluoride... [Pg.59]

The examples of oxalic and malonic acids are atypical and are considered separately. Other dicarboxylic acids react essentially as alkanes (p. 297). [Pg.322]

The monomers of PET are TPA and EG. The polymer properties may be modified by other dicarboxylic acids and diols which may be incorporated into the polymer as co-monomers. The most important compounds for PET synthesis are presented in Table 2.1. [Pg.37]

Unsaturated polyesters are prepared through a classical esterification process. Typically, a dihydroxy compound, or mixtures of dihydroxy compounds, are treated with maleic anhydride and/or together with other dicarboxylic acids such as aromatic or aliphatic dicarboxylic acids under elevated temperature to remove the water produced during esterification process. Although various catalysts will catalyze this esterification reaction, there is enough carboxylic acid in the mixture so that it is not necessary to add extra catalyst. [Pg.700]

Similar structures have been found for many other dicarboxylic acids, including succinic acid, COOH(CH ) COOH glutaric acid, COOH(CH ) COOH adipic acid, COOH(CH,) pOOH, and sebacic aoid, COOH(CH )jCOOH. Crystal structure determinations have also been made of many carboxylic acid hydrates in all of the crystals the carboxyl groups form hydrogen bonds, usually with water mole oules. An example is oxalic acid dihydrate in this crystal the 0—H 0 distance is 2.50 A. [Pg.480]

The relative concentration of dicarboxylic acids with respect to aminoacids is higher (by one or two orders of magnitude). As in the case of monocarboxylic acids, every possible isomer seemed to be present, ranging from C2 to C5 molecules. In the case of chiral molecules, the two enantiomers coexisted in nearly equal concentration. Oxalic acid was detected as calcium salt, but the state of the other dicarboxylic acids in the Murchison meteorite remains an open problem 24 >. Dicarboxylic acids, as monocarboxylic acids, seem to be the result of synthetic pathways that give mixtures at random 44-45... [Pg.97]

Knappe, E. and Rohdewald, I., Thin-layer chromatography of dicarboxylic acids. V. Separation and identification of hydroxy dicarboxylic acids, of di- and tricarboxylic acids of the citrate cycle, and some other dicarboxylic acids of plant origin, Z. Anal. Chem., 211, 49, 1965 Chem. Abs., 63, 7333c, 1965. [Pg.189]

Hydroquinone(HQ) or a naphthalenediol in the above reactions can be replaced with other diols such as biphenols and bisphenols. In the same manner, other dicarboxylic acid such as cyclohexane dicarboxylic acid, isophthalic acid, naphthalene dicarboxylic acids can be used in place of terephthalic acid. Of course, these substitutes should not destroy the linearity of the polymer chains if one is to obtain thermotropic compositions. 6-Hydroxy-2-naphthoic acid is a substitute for 4-hydroxybenzoic acid in Reactions 18 and 19. [Pg.38]

Hi. Other dicarboxylic acids. Aqueous solutions of malonate CH2(C00 )2, adipate (CH2CH2COO )2, succinate (CH2COO )2 12, 573, 598), and mercaptosuccinate 516) with aqueous zirconium(IV) solutions leads to the precipitation of solids with composition [ZrO(CH2)K(COO )2]. The 1 1 adipate and succinate species do not dissolve in excess carboxylic acid solution indicating that the dianionic species are not formed. At metal ion concentrations of (1 to 2) x 10 M and hydrogen ion concentrations between 0.087-0.350 M, malonic and succinic acids establish the equilibrium defined by the equation... [Pg.44]

This autoxidation property of carbons leads to a continuous loss of catalyst. When spherical carbon particles of 30 to 100 p,m were used in the oxidation with air of aqueous cyclohexanone solutions at 393 K in a trickle-bed reactor, a weak loss of carbon was observed after four weeks, and the originally smooth particles appeared rough and porous in scanning electron microscopy (SEM) [165]. The catalysts used with a nitrogen content of < 1% had been prepared from nitrogen-containing phenol-formaldehyde resin [166]. In this reaction cyclohexanone is oxidized to adipic acid and other dicarboxylic acids. 2-Hydroxycyclohexanone seems to be an intermediate. A carbon loss of several percent was also reported for other wet-air oxidation reactions of pollutants, mainly of phenol [167-169]. [Pg.254]

The products of different quality categories of AA are available in the market under the brand EMEROX azelaic acids [4]. Products containing 79% (19% other dicarboxylic acid, 2% monocarboxylic acids) [6] and 85% AA are used for the preparation of low-temperature and polymeric type vinyl plasticizers, ester-based... [Pg.333]

The oxidation of the terminal methyl group of PA produced an AA yield of 6% if Debaryomyces pfaffii was used as biocatalyst [117]. Liu and Yi [118] investigated the diterminal oxidation of 1-decene and 1-dodecene by the mutant SD6 from C. tropicalis. Besides other dicarboxylic acids, AA was detected in both product mixtures. Accordingly, the authors proposed the microbial metabolic pathway. [Pg.341]

In this chapter, procedures for the polymerization of allyl acetate and related monocarboxylates of diallyl carbonate types, of diallyl phthalates, and of diallyl esters of other dicarboxylic acids are discussed. [Pg.283]

Because of the ease of synthesis and industrial importance of diallyl esters much of the research has dealt with the behavior of the isomeric phthalates. Some other dicarboxylic acid esters have been studied by Simpson and Holt [41]. The kinetics of the poljmierization of the diallyl esters of oxalic, malonic, succinic, adipic, and sebacic acid have also been considered. In previous kinetie studies, no differentiation was made between the behavior of the uncyclized monomer (or its free radical) and of the cyclic free-radicals. A priori, differences should have been presumed, but evidently Matsumoto and Oiwa [46] were the first seriously to attempt a kinetic analysis based on the concept that the linear and the cyclic units are two different species. In effect, these two species copolymerize with each other. However, the analysis has not been carried so far as to determine reactivity ratios. [Pg.294]

The properties of PBS can be varied over a wide range via copolymerization with other dicarboxylic acids or diols. Amongst the co-monomers studied are adipic acid [83, 93], terephtalic acid [94,95], ethylene glycol [96-98], 1,3-propanediol [99-101] and lactic acid [100, 102]. Of these co-monomers, the introduction of adipic acid for the production of PBS A has received most attention. Elongation at break and impact strength can be significantly... [Pg.259]

Other suitable catalysts are orthobutyl titanate or triisopropyl aluminium (43). Besides sebacic acid, other dicarboxylic acids of natural origin have been proposed, such as azelaic acid and brassyUc acid (54). These acids are shown in Figure 4.10. [Pg.111]

Initially this was not observed, exchan only being measurable when oxaloacetate was also present. This absence of exchange is now believed to result from a need to have oxaloacetate bound to the enzyme before the proper catalytic configuration can be achieved. This function can be served by certain other dicarboxylic acids which are not capable of undergoing the condensation reaction and the exchange activity has been demonstrated. A coenzyme A-facilitated enolization mechanism seems firmly established. [Pg.328]

The photodecarboxylation of isomeric pyridinedicarboxylic acids has been studied. Monocarboxylic acids are photostable in aqueous solution. Dicarboxylic acids with 1,3-related carboxyl groups decarboxylate. Other dicarboxylic acids are photostable. Dissolved oxygen has no effect, which suggests that the photodecarboxylations are related to a tt - s singlet excited state. In contrast to its thermal stabUity the photolability of the 3-carboxyl group is remarkable. [Pg.288]


See other pages where Other dicarboxylic acids is mentioned: [Pg.402]    [Pg.203]    [Pg.92]    [Pg.67]    [Pg.277]    [Pg.168]    [Pg.39]    [Pg.383]    [Pg.490]    [Pg.28]    [Pg.125]    [Pg.800]    [Pg.4254]    [Pg.341]    [Pg.257]    [Pg.214]    [Pg.664]    [Pg.273]    [Pg.186]    [Pg.423]    [Pg.302]   


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