Fundamental Study on the Parameters in Order to Quantify Solvent Effects in Solvent Dyeing

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This work has been undertaken to quantify solvent effects in organic solvent and binary mixture solvent. Taft and his co-workers proposed Linear Solvation Energy Relationships ( LSER ) parameters in order to quntify solvent effect : pi*scale of solvent polarity, alpha scale of hydrogen bond donor, beta scale of hydrogen bond acceptor. A conventional method for evaluation of pi*, alpha, beta, scales scales were proposed based on spectroscopic measurements using solavatochromic indicators, 4-nitroaniline, N, Ndimethy-4-nitroaniline and azoniabetain dyes.The solvtochromism of these dyes was observed in nonpolar and polar solvents. The shifts of maximum wave numbers of these dyes by composition of binary mixture of solvents were analyzed by assuming the selective solvation model. The results obtained indicate that the solvation model of dyes is almost explained by the selective model.Formation and absorption spectra of inclusion between cyclodextrin and azoniabetain dyes [ A(o-OH),B(p-OH) and C(Me-p-OH) ] having large negative solvatochromism were investigated. The dyes A(OH) and A(O^-) were not included by alpha-, beta-, gamma-ciclodextrin by steric hindrance of oxygen at o-position of the dyes. Alpha-cyclodextrin can include B(O^-) and C(O^-), but not B(OH) and C(HO). While beta- and gamma- cyclodextrins gave (1 : 1) inclusions B(OH), B(O^-), C(OH) and C(O^-). Structures of inclusions were suggested on basis of their spectra.Absorption spectra of solubilization by surfactants having negative solvatochromism were investigated. Dissociatived dyes of A, B and C could be solubilized by anionic, cationic and nonionic surfactants. The results on basis of their spectra were suggested that dyes were solubilized at outside of micel of anionic surfactant and water included in inner micell of cationic and nonionic surfactants.