Enthalpy-Concentration Diagram for Aqueous Sulfuric Acid at 1 atm Fig

2-31 Enthalpy -concentration diagram for aqueous sulfuric acid at 1 atm. Reference states enthalpies of pure-liquid components at 32° F and vapor pressures are zero. NOTE It should be observed that the weight basis includes the vapor, which is particularly important in the two-phase region. The upper ends of the tie lines in this region are assumed to be pure water. (Hougen and Watson, Chemical Process Principles, part I, Wiley, New York, 1943.) 

DuPont bulletin T-AC-9000-SI, 1994 (16 pp.) gives tables and a chart to 100 bar, 235°C. With a stated composition of 23% wt CH2F2 (R23), 25% wt CHF2CF3 (R125), and 52% wt CH2FCH3 (R134a) this is apparently identical to KLEA 66, to which the reader is referred. 

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