The standard enthalpies of formation of citric and tartaric acids and their dissociation products in aqueous solutions

Properties of Citric Acid and Its Solutions

“…■, ■, ■ - [8]; ■, ■, ■ - [58] [60] using the enzymatic equilibrium data, gives a slightly higher value for the Gibbs free energy of formation of the crystalline monohydrate ΔG f (s, 298.15 K) = − 1168.8 ± 6.3 kJ mol −1 . The Wilhoit and Shiao value ΔH f (s, 298.15 K) = − 1543.9 kJ mol −1 and the Korchergina et al [61] value ΔH f (s, 298.15 K) = − 1551.7 ± 1.3 kJ mol −1 for the enthalpy of formation are lower than these given above because they used in calculations the heat of formation of the standard substance for CO 2 (gas) and not for C(graphite) as in [58,59].…”

“…soln, 3 H + + Cit , 298.15 K) = − 1165.5 ± 0.2 kJ mol −1 [60]). Kochergina et al [61] performed a detailed calorimetric study of formation of citrate ions in water and KOH solutions. They presented the following enthalpies of formations ΔH f (aq.…”

Green synthesis and characterization of Ag1/2Al1/2TiO3 nanoceramics

“…It undergoes interesting pattern of optical isomerism. Recently, mean value of heat of combustion for tartaric acid was calculated to be 1124.5 kJ/mol [30]. In addition, the value of heat of dissociation was calculated to be 27.17 kJ/mol for the temperature above 50°C [31].…”

Ανάπτυξη Και Σχεδιασμός Καινοτόμου Βιοδιυλιστηρίου Που Βασίζεται Στην Αξιοποίηση Της Οινολάσπης Και Της Ακατέργαστης Γλυκερόλης Προς Παραγωγή Προϊόντων Προστιθέμενης Αξίας Και Πολυ-3-Υδροξυ-Βουτυρικού Εστέρα Μέσω Μικροβιακών Ζυμώσεων

“…Experimental and calculated values are compared in Figure 10.3 as an indication of the accuracy of the process simulation. The heat of formation of tartaric acid given is 1,295.7 kJ/mol (Kochergina et al, 2006) and corresponds to the hypothetical state of undissociated tartaric acid at finite dilution. The value used for the heat of formation is validated with the calculated in UniSim Design heat of combustion (calculated: -1,135 kJ/mol) which compares well with the experimental value (−1,120.3 ± 0.9 kJ/mol) also given in the same reference.…”