<報文>キサントゲン酸による硫化鉱物捕収に関する基礎的研究(第1報) : キサントゲン酸の解離およびキサントゲン酸イオンの分解

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The dissociation constants of xanthic acids and the rates of decomposition of xanthic ions in acidified aqueous solutions have been determined by spectrophotometric measurements. It was found that xanthic ion and xathic acid are virtually in equilibrium, and that the dissociation constants of methyl-, ethyl-, n-propyl-, n-butyl-, n-amyl-, iso-propyl-, and iso-butylxanthic acids are respectively 3.4×10^<-2>, 2.9×10^<-2>, 2.5×10^<-2>, 2.3×10^<-2>, 1.9×10^<-2>, 2.0×10^<-2>, and 1.4×10^<-2> at 25℃ and the ionic strength of O. The instability of xanthic ion in acidic range is due to the bimolcular decomposition of xanthic ion and hydrogen ion. The rate constants of decomposition of methyl-, ethyl-, n-propyl-, n-butyl-, n-amyl-, iso-propyl-, and iso-butylxanthic ions are respectively 233,226,214,209,211,207,and 202 mole^<-1> min^<-1> at 25℃ and the ionic strength of O. The dissociation constants of these xanthic acids and the rate constants of these xanthic ions decreased with the increase in carbon numbers of these alkyl groups, and iso-isomer has smaller values of these constants than those of normal ones. Furthermore, it has been shown that the peak of absorption spectrum of xanthic ion is at 301mμ and that of xanthic acid at 270mμ.
1960-08-25