Showing papers by "Hiroaki Egawa published in 1995"
TL;DR: In this paper, a macroporous chelating resins containing polyol groups (RGB) was prepared by the reaction of poly(glycidyl methacrylate) beads with 2-amino-Zhydroxy-methyl-I,3-propanediol and the behavior of the resulting RGB in the uptake of boric acid was studied.
Abstract: Macroporous chelating resins containing polyol groups (RGB) were prepared by the reaction of poly(glycidyl methacrylate) beads with 2-amino-Zhydroxy-methyl-I,3-propanediol, and the behavior of the resulting RGB in the uptake of boric acid was studied. The RGB exhibited high affinity for boric acid in the pH range of 5 to 9 and took up boric acid selectively from geothermal power waste solutions in which various minerals were contained. The boric acid adsorbed on the RGB was easily eluted with I mol/dm3 hydrochloric acid.
18 citations
TL;DR: In this paper, the acid-dissociation constants of the water molecule axially coordinated to the cobalt(III) are 10-6.65 and 10-7.01 for the L1 and L2 complexes, respectively.
Abstract: Chloride salts of cobalt(III) complexes of 1, 4, 8, 11-tetraazacyclotetradecane-5, 7-dione (L1) and 6-(2-(2-pyridyl)ethyl)-1, 4, 8, 11-tetraazacyclotetradecane-5, 7-dione (L2), acting as a water-soluble anion carrier capable of a selective recognition of nitrite and thiocyanate, were isolated, and their solid state structures and properties in water were studied. IR spectroscopic and X-ray crystallographic approaches have clarified that the isolated complexes have iminol tautomeric structures, in which the amide oxygen atoms are protonated, but the amide nitrogen atoms bound to cobalt(III) are deprotonated. Conductivity and pH titration studies on aqueous solutions of the complexes have revealed that the iminol groups act as a strong acid in water; the acid-dissociation constants of the water molecule axially coordinated to the cobalt(III) are 10-6.65 and 10-7.01 for the L1 and L2 complexes, respectively.
6 citations