Version v1.2 · 2026-10-14
Ten method sets are on record for this pair; they fall into three formal families — per-property polynomials, Dühring-type relations, and one Gibbs-energy equation.
Patterson & Perez-Blanco (1988) fitted seven properties (enthalpy, dew/bubble temperature, vapour pressure, thermal conductivity, viscosity, density, surface tension, plus a crystallisation boundary given as two piecewise-linear tests) to one template, F(X, T) = Σ Xⁱ·[Aᵢ + T·Aᵢ₊ₖ₊₁ + T²·Aᵢ₊₂ₖ₊₂], with X the LiBr weight-percent number and T in °C. Ranges differ per function: enthalpy X 0–70%, T 0–180 °C; dew point/vapour pressure/conductivity 4.4–182.2 °C; viscosity X 5–60%, 0–90 °C; density X 10–60%, 0–100 °C; surface tension X 5–60%, 0–60 °C. The paper does not state its enthalpy reference state; back-calculation gives h(0%, 25 °C) = 104.615 kJ/kg. The library's C and Python versions agree point-by-point (36 points × 8 functions). One internal inconsistency of the paper is registered as TE-016 (Section 5).
Chua et al. (2000) gave a Dühring-form vapour-pressure correlation — (T − 273.15) = AD(x)·(Tdp − 273.15) + BD(x), with AD and BD 17-term polynomials in x plus a ⟨x − 60⟩ correction — and a density polynomial valid 0–200 °C, x 0–70 wt%. The stated range extends to 75 wt%, but the printed ⟨x − 60⟩ correction diverges above x = 60 (AD(65) = 4.45×10⁹, where Fig. 1 implies ≈1.225); the verifiable range is x ≤ 60 wt%, and the implementation is limited to 0–190 °C, 0–60 wt%. The reference state is water's triple point, h(0 °C, 0%) = −0.04 kJ/kg. Cross-checks against Patterson: vapour pressure −1.4% to +0.9% (five points), density −0.26% to +0.50%, enthalpy +0.07% to +0.83% (three points each). A missing minus sign in the printed table is TE-015.
Pátek & Klomfar (2006) formulated vapour pressure and enthalpy (30-term enthalpy equation) on a mole-fraction basis, valid 273–500 K and 0–75 wt%, with author-reported uncertainties of ±2.1% in p and ±10 kJ/kg in h. The set was verified in this survey by back-calculation at the paper's six Table 9 points — (x, T/K) = (0.05, 300), (0.05, 450), (0.10, 300), (0.10, 450), (0.30, 350), (0.40, 450) — which also arbitrated a misprinted exponent in the printed coefficient list (TE-014). The set is verified but not yet built into the library; its remaining properties and reference state are not covered by the verification report [to be verified].
A high-temperature set transcribed in Li Jing's 2009 thesis (dew-point polynomial, Antoine-type vapour pressure, specific heat, enthalpy, and a molar density equation) covers 20–210 °C at 40–65 wt%. Its attribution to Kaita (2001 or 2002 — two distinct papers) is not settled [to be verified]. Four independent back-checks are on record: the dew-point→vapour-pressure chain gives P = 0.02193 MPa at (100 °C, 55%), against 0.02246 MPa from the Chua correlation at the same point (−2.4%); solution density differs from Chua by −0.24% (25 °C, 55%) and +0.32% (100 °C, 55%). Its enthalpy surface differs from Patterson's by 30.1 kJ/kg at (100 °C, 55%) and 24.3 kJ/kg at (25 °C, 50%) — a non-constant difference, so the two enthalpy sets are used only internally, never spliced.
Kim & Ferreira (2006) built a single molar Gibbs free-energy equation from which enthalpy, entropy, specific heat and activity (hence vapour pressure) follow by differentiation — the only set on record for this pair that yields entropy and activity. The constant table survives complete in a 2017 thesis transcription, but the equation faces are damaged in the OCR layer and the printed unit of the reference-state constants (kJ/kmol) is inconsistent with their magnitude [to be verified]. The set is registered, not yet computable.
The remaining sets are shorter-range. McNeely (1979) is a linear Dühring relation, t = t′·ΣAₙxⁿ + ΣBₙxⁿ; two independent transcription chains agree after conversion between the weight-percent and mass-fraction bases, and back-checks give 57.6 °C at (x = 55, t′ = 25 °C) and 85.7 °C at (x = 60, t′ = 40 °C). Jia Mingsheng (2002) fitted a per-property polynomial cluster (mass-fraction basis; enthalpy 0–160 °C, ξ 0.40–0.65) including a mutually inverse solubility/crystallisation pair; its crystallisation temperature at ξ = 58.07% is 7.5 °C, against 1.1 °C from the Patterson boundary at the same composition — a ≈6 K difference between the two sources, recorded as it stands. Its printed surface-tension equation returns a non-physical 1.61 N/m at (25 °C, 0.55) [to be verified]. A textbook compilation (Wu Yezheng, 2004), an assembled set (Zhao Di, 2019) traced equation-by-equation to the McNeely and Jia families, and the ASHRAE Handbook (2009) Dühring pair (bubble point 5–175 °C, ξ 45–70 wt%; its two equations use different concentration bases — percent in one, fraction in the other) complete the register. Two records are negative: theses computing all properties from the EES built-in library or the Aspen Properties package print no coefficients and do not constitute methods.
Ionic liquid. H₂O/[emim][DMP] (2018, NRTL) is grade B in the census — VLE only.
References are numbered in Section 7 of the overview page.