スルホフタレイン系酸性染料と第四級アンモニウム塩との相互作用に関する研究

概要

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The interaction between sulphonephthalein dyes and quaternary ammonium surfactants (Q^+) in an aqueous solution was studied. The addition of Q^+ to a Bromocresol Purple(BCP) solution buffered at about pH 8 resulted in a color change from blue to light-yellow. The mechanism of this color-change reaction was confirmed to involve an ion association of Q^+ with a monovalent dye anion (HBCP^-) produced by the addition of a proton to BCP^<2->, followed by the formation of a precipitate. The extraction behavior of five sulphonephthalein dyes [H_2A : Bromophenol Blue(BPB). Bromochlorophenol Blue (BCPB), BCP, Bromocresol Green (BCG), Bromothymol Blue (BTB)] was examined. The extraction constants (log K_<ex>) for the ion-associates of the dyes with Q^+ distributed between the aqueous and chloroform phases were determined and correlated with the number of carbon atoms in Q^+ (N_c). Linear relationships between log K_<ex> and N_c were positively observed. The value of log K_<ex> could be expressed by two parameters (C and A) related to the extractabilities of the respective cation and anion : log K_<ex>= C+A for 1 : 1 ion-associates. Q^+ HA^-. and log K_<ex>=2C+A for 2 : 1 ion-associates, (Q^+)_2A^<2->. Based on the obtained A values, it was found that the extractability of the dye anions can be expected to be in the order BTB>BCG>BPB>BCPB>BCP for both univalent and bivalent anions.
1994-06-05