Apparent and partial molar heat capacities and volumes of aqueous adipic acid, l-tartaric acid, and their sodium salts atT= 298.15 K

Thermodynamics of proton dissociations from aqueous l -tartaric acid at temperatures 278.15⩽⩽⩽ (T/K)⩽⩽⩽ 393.15 and at the pressurep= 0.35 MPa: apparent molar volumes and apparent molar heat capacities ofl -tartaric acid and its sodium salts

“…These parameters were obtained using weighting factors proportional to the reciprocal of the uncertainties in C p,φ given in tables 5 to 7. The C p,φ results from tables 5 to 7 and the surfaces generated by equations (4) and (5) reported twice before (12,15) at T = 298.15 K, and values of C p,φ for both NaHTar(aq) and Na 2 Tar(aq) have been reported at T = 298.15 K. (15) For H 2 Tar(aq) our results are within ±5.0 J · K −1 · mol −1 of those reported by Sijpkes et al (12) and within ±3.6 J · K −1 · mol −1 of those reported by Xie and Tremaine. (15) For NaHTar(aq) and Na 2 Tar(aq) our results agree within ±10.0 J · K −1 · mol −1 of those reported by Xie and Tremaine.…”

“…The C p,φ results from tables 5 to 7 and the surfaces generated by equations (4) and (5) reported twice before (12,15) at T = 298.15 K, and values of C p,φ for both NaHTar(aq) and Na 2 Tar(aq) have been reported at T = 298.15 K. (15) For H 2 Tar(aq) our results are within ±5.0 J · K −1 · mol −1 of those reported by Sijpkes et al (12) and within ±3.6 J · K −1 · mol −1 of those reported by Xie and Tremaine. (15) For NaHTar(aq) and Na 2 Tar(aq) our results agree within ±10.0 J · K −1 · mol −1 of those reported by Xie and Tremaine. (15) It is possible to estimate the change in volume r V m and change in heat capacity r C p,m as functions of T and m for the two stepwise proton dissociation reactions for aqueous L-tartaric acid, reactions (6a) and (6b), by using the parameters in tables 4 and 8 with our equations (1) to (5): (3) to (5) using data in tables 5 to 7.…”

“…15 T /K 393.15 for H 2 Tar(aq) and Na 2 Tar(aq) solutions. Again, solutions of NaHTar(aq) were investigated at temperatures 298.15 T /K 393.15.…”

“…Solutions of NaHTar(aq) were investigated at temperatures 298. 15 T /K 368.15 to avoid precipitation.…”

“…15 T /K 308.15, m = 0.0, reference 13; ♦, for H 2 Tar(aq), T = 298.15 K, m = 0.0, reference 14; , for H 3 Tar(aq), NaHTar(aq), and Na 2 Tar(aq), T = 298.15 K, 0.0 m/(mol · kg −1 ) 0.4, reference 15; , for NaHTar(aq) and Na 2 Tar(aq), T = 298.15 K, 0.03 m/(mol · kg −1 ) 0.4, reference 16. are reported only at infinite dilution. In a continuing effort to expand the availability of precise quantitative information for solutions as a function of molality over a wide temperature range, we have measured the apparent molar volumes V φ and apparent molar heat capacities C p,φ of aqueous L-tartaric acid and of its two sodium salts at temperatures 278.15 T /K 393.15, at molalities 0.006 m/(mol · kg −1 ) 1.0, and at the pressure p = 0.35 MPa.…”