Boric acid equilibria in near-critical and supercritical water
- Univ. of Texas, Austin, TX (United States)
Greater knowledge of acid-base equilibria is crucial to understanding the chemistry of hydrothermal processes including oxidation of organics, corrosion, catalysis, hydrolysis reactions, crystal growth and formation, precipitation of metal complexes and steam power cycles. The pH values of aqueous solutions of boric acid and KOH were measured with the optical indicator 2-naphthol at temperatures from 300 to 380 C. The equilibrium constant K{sub b}{sup {minus}1} for the reaction B(OH){sub 3} + OH{sup {minus}} = B(OH){sub 4}{sup {minus}} was determined from the pH measurements and correlated with a modified Born model. The titration curve for the addition of HCl to sodium borate exhibits strong acid-strong base behavior even at 350 C and 24.1 MPa. At these conditions, aqueous solutions of sodium borate buffer the pH at 9.6 {+-} 0.25.
- Sponsoring Organization:
- Department of the Army, Washington, DC (United States); USDOE, Washington, DC (United States); Welch (Robert A.) Foundation, Houston, TX (United States); Texas Univ., Austin, TX (United States)
- DOE Contract Number:
- FG07-96ER14687
- OSTI ID:
- 624352
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 37, Issue 5; Other Information: PBD: May 1998
- Country of Publication:
- United States
- Language:
- English
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