Solvent and Pressure Effects on the Tautomeric Equilibrium of 4-Phenylazo-1-naphthol

Norio Nishimura, Keishi Danjo, Yoshimi Sueishi, Shunzo Yamamoto

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The azo-hydrazone tautomerism of 4-phenylazo-l-naphthol has been studied in ethanol-water and acetone-water systems and at high pressures. The hydrazone form is favoured by adding water to organic cosolvents and by applying pressure. The effects of solvent polarity and pressure on the equilibrium constant (KT) between the tautomers were examined by using Kirkwood-type equations applied to chemical equilibrium. Remarkable deviations were observed in the Kirkwood plots for both types of mixtures. Solvent-induced polarization, especially of the hydrazone form in a high polarity region, was suggested. In ethanol-water mixtures, correlation is fair between In KT and ET, while in acetone-water system the In KT against KT plot was curved. The above findings, together with the difference in the volume data for the two systems, suggest an existence of special interactions between acetone molecules and hydrophobic parts of 4-phenylazo-1-naphthol.

Original languageEnglish
Pages (from-to)863-872
Number of pages10
JournalAustralian Journal of Chemistry
Volume41
Issue number6
DOIs
Publication statusPublished - 1988

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Pressure effects
Hydrazones
Acetone
Water
Ethanol
Naphthols
Equilibrium constants
1-naphthol
Polarization
Molecules

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Solvent and Pressure Effects on the Tautomeric Equilibrium of 4-Phenylazo-1-naphthol. / Nishimura, Norio; Danjo, Keishi; Sueishi, Yoshimi; Yamamoto, Shunzo.

In: Australian Journal of Chemistry, Vol. 41, No. 6, 1988, p. 863-872.

Research output: Contribution to journalArticle

Nishimura, Norio ; Danjo, Keishi ; Sueishi, Yoshimi ; Yamamoto, Shunzo. / Solvent and Pressure Effects on the Tautomeric Equilibrium of 4-Phenylazo-1-naphthol. In: Australian Journal of Chemistry. 1988 ; Vol. 41, No. 6. pp. 863-872.
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