Effects of carboxylate

Huffman, K. R., and Casey, D. J., Effect of Carboxylic end groups on hydrolysis of polyglycolic acid, J. Polym. Sci. 

Fig 22. Templating effect of carboxylates the size of the wheels is tuned by the length of the alkyl chain of the carboxylate (a) (Momrglutarate, (b) Moi2 -pimelate. (c) JMo,)-trimesate, Mo8 -oxalate (see Fig. 17). 

A charge relay system (Blow, 1976) exists in a number of hydrolytic enzymes. In such systems, an aspartate carboxylate group buried in a hydrophobic microenvironment activates a seryl hydroxyl group through hydrogen bonding. Thus, it is interesting to study the effect of carboxylate ions on other nucleophiles in aprotic media. 

Figure 4.8 Effect of carboxyl number on reaction time required to polymerize from 0.45 to 0.72 dl/g IV [39]. From Duh, B., US Patent, 4 238 593 (1980)...

The effect of carboxylate and/or sulfonate ion incorporation on the physical and blood contacting properties of polyurethanes was studied by Cooper and collaborators [476-478]. Specifically, propyl sulfonate and ethyl carboxylate groups were grafted onto polytetramethylene oxide-based polyurethanes. Carboxylate polymers had no statistically significant effect on canine ex vivo blood contact response, but propyl sulfonate incorporation significantly reduced platelet deposition for very short blood contact times. 

Osawa, S., and Weiss, E. R. (1995). The effect of carboxyl-terminal mutagenesis of Gta on rhodopsin and guanine nucleotide binding./. Biol Chem. 270, 31052-31058. 

Nishimura, K., et al. 1985. Studies on the promoting effects of carboxylic acid derivatives on the rectal absorption of 3-lactam antibiotics in rats. Chem Pharm Bull 33 282. 

Zhukovsky, E. Oprian, D. (1989) Effect of carboxylic acid side chains on the absorption maximum of visual pigments Science vol. 246, pp 928-930... 

Figure 7. Effect of carboxyl group content on the yield of copolymer, molecular weight, and apparent number of grafted chains in the pMMA-grafted dicarboxyl-cellulose. Conditions cellulose, 0.3 g H O, 10 mL MMA, 2 mL. Key (reaction tube) open mark, quartz (50°C, 1 h) half closed mark, Pyrex (40°C, 1 h).

Fukada, Y., et al. (1994). Effects of carboxyl methylation of photoreceptor G protein gamma-subunit in visual transduction. J Biol Chem 269 5163-5170. 

Nirmalakhandan, N.N., Speece, R.E. (1988) QSAR model for predicting Henry s constant. Environ. Sci. Technol. 22, 1349-1357. Nishimura, K., Nozaki, Y., Yoshimi, A., Nakamura, S., Kitagawa, M., Kakeya, N., Kitao, K. (1985) Studies on the promoting effect of carboxylic acid derivatives on the rectal absorption of beta-lactam antibiotics in rats. Chem. Pharm. Bull. 33(1), 282-291. OECD (1981) OECD Guidelines for Testing of Chemicals. Section 1 Physical-Chemical Properties. Organization for Economic Co-operation and Development. OECD, Paris. 

Evans and Spurlin have studied the effect of carboxyl groups present in 0-ethylcellulose on its viscosity in dilute solution. Although free carboxyl groups do not affect viscosity, neutralization with metal ions increases the viscosity, especially in non-polar solvents. According to these workers, the effect of bound, metal ions is to produce large electrostatic forces of attraction between the chains to which they are attached. 

Wada, N., Yamashita, K., and Umegaki, T. (1999). Effects of carboxylic acids on calcite formation in tlie presence of Mg- ions. J. Colloid Interface Sci. 212, 357-364. 

EFFECT OF CARBOXYLIC ACIDS AS COCATALYSTS IN TUNGSTATE-CATALYZED EPOXIDATIONS... 

Some microorganisms may have a greater sensitivity to metabolic effects, rather than membrane effects, at near-atmospheric partial pressures of CO2 (32). The overall effect of CO2 partial pressure on metabolism in these organisms is suggested to result from competing effects of carboxylation and decarboxylation activity within the cell and a potential mass action effect (24). At near-atmospheric pressures of CO2, the relative concentrations of aqueous CO2 and carbonate ion are adequately buffered within the cell (24). Therefore, a decrease in internal pH is not expected to directly contribute to CO2 toxicity at these conditions. 

Ceska GW. The effect of carboxylic monomers on surfactant-free emulsion copolymerization. J Appl Polym Sci 1974 18 427—437. 

Scheme 9 Effect of carboxylate additives on palladium-catalyzed direct arylation of benzene...

To the best of our knowledge, only a few studies have attempted to prevent the calcification of HEMA-based hydrogels. It has been reported that introduction of carboxylate anions can either prevent or enhance calcification. Cemy et al. (21) found that copolymers of HEMA with 4 wt% methaciylic acid (MAAc) did not calcify under subcutaneous implantation in a rat for 14 months. A similar result was also observed after the implantation of HEMA/MAAc copolymers in the animal urinary tract (22). Other studies carried out in vitro showed that the presence of carboxylate anions significantly reduced the deposition of calcium phosphate (23) and calcium oxalate (24) on acrylic polymers and certain biopolymers. These findings obviously suggest an inhibitory effect of carboxylate anions on calcification. However, by contrast,... 

To account for the relatively high catalytic effect of carboxylic acids, it has been suggested that they also act as bifunctional catalysts,233,236 as discussed earlier (see p. 27). 

M. Kamigaito, M. Sawamoto, and T. Higashimura, Living cationic polymerization of vinyl ethers by electophile lewis acid initiating systems. 6. Living cationic polymerization of isobutyl vinyl ether by RCOOH/lewis acid initiating systems effects of carboxylate ions and lewis acid activators. Macromolecules 1991, 24(14), 3988-3992. 

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