title: Synthetic and analytical studies on colour reagents-IX The reactions of phthaleinazo compounds with the alkaline earths.
abstract: Some new phthaleinazo compounds-o,o'-dihydroxyazo compounds-have been prepared by coupling chromotropic acid, R-acid, and 2-hydroxy-3-naphthoic acid with bis-diazotized diaminophthaleins. These compounds have been found to be very sensitive colour reagents for alkaline earths in alkaline media, and in particular, bis(chromotropeazo)phenolphthalein is the most sensitive yet found.
authors.affiliation: Department of Chemistry Faculty of Science, Okayama University Tsushima, Okayama-shiJapan.
authors.forename: T
authors.initials: T
authors.lastname: Kobatake
authors.forename: T
authors.initials: T
authors.lastname: Iwachido
authors.forename: K
authors.initials: K
authors.lastname: Tôei