硫水素型捕収剤の酸分解反応の起電力法による研究
1973 年 89 巻 1029 号 p. 733-736
詳細
1973 年 89 巻 1029 号 p. 733-736
The decomposition of sulfhydryl collectors, such as xanthate, diethyldithiophosphate (aerofloat) and diethyldithiocarbamate, in acidified aqueous solutions was studied by means of EMF measurement using silver electrode-SCE couple. Rapid responsibility of silver. electrode for the concentration change of sulfhydryl collector anions proved that the EMF measurement served as a convenient technique for studying the decomposition of sulfhydryl collectors, the rates of which were extremely rapid in strong acid solutions.
The rate constants of monomolecular decomposition (k3) and the dissociation constants (Ka) for xanthic acids were in agreement with those determined by spectrophotometric technique. Diethyldithiophosphate was very stable in strong acid solutions as compared to xanthate and dithiocarbamate; no appreciable EMF change was observed. Diethyldithiocarbamate decomposed in a manner similar to xanthate in acidified solutions; log k3 and pKa were found to be 0.89, the same order of magnitude as that of xanthate, and 3. 4, respectively. The activation energy of monomolecular decomposition for both ethyixanthic acid and diethyldithiocarbamic acid was given as 17kcal/mole, indicating that the rate determinig step of acid decomposition for both acids is substantiallythe same irrespective of the difference in their molecular structures.
