Characterization of pH in liquid mixtures of methanol/H2O/CO2.
The presence of H2O and CO2 in enhanced-fluidity liquids changes the pH in these mixtures due to the formation of carbonic acid. The acid-base equilibria in enhanced-fluidity liquids will also be affected by the reduction in the dielectric constant with the addition of CO2. The pH of enhanced-fluidity liquid mixtures at room temperature was determined from the UV/visible absorption spectra of several pH indicators. pH values of methanol/H2O/CO2 mixtures with CO2 proportions as high as 19.2 mol% are reported. The effect of adding buffer to methanol/H2O/CO2 mixtures on pH was also studied. It was also shown that pressure variation did not significantly influence the pH of enhanced-fluidity liquids.
Wen
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Department of Chemistry, Ohio State University, Columbus 43210, USA.
Olesik
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D002021:Buffers; D002138:Calibration; D002245:Carbon Dioxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D000432:Methanol / Q000737:chemistry*; D011786:Quality Control; D014867:Water / Q000737:chemistry*
D002021:Buffers; D014867:Water; D002245:Carbon Dioxide; D000432:Methanol