Abstract
A new method of measuring the pH of high-temperature aqueous solutions using optical indicators was developed. The absorbance spectrum of acridine changes as a function of pH, allowing its use as an optical indicator for pH. The pKa of acridine were experimentally determined in KOH-AcOH pH-buffer solutions at temperatures from 5 to 250°C at vaporsaturated pressures:
where T is in Kelvin. The technique is demonstrated by experimentally determining the pKa of benzoic acid at temperatures up to 250°C where the result was
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Huh, Y., Lee, JG., McPhail, D.C. et al. Measurement of pH at elevated temperatures using the optical indicator acridine. J Solution Chem 22, 651–661 (1993). https://doi.org/10.1007/BF00646784
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DOI: https://doi.org/10.1007/BF00646784