Abstract In order to support scientific reviewing in the area of material property research and make the reviewing process easier and more efficient, checklists covering typical problems, lists of available resources, and computer-based and online tools to help compose reviewers’ reports have been created. Our intention is to ensure that scientific communications show necessary and sufficient primary and supporting information about substances studied, conditions, properties, and techniques of interest with understandable terminology, in detail assuring reproducibility of the obtained results. The principles and ideas of this project can be extended to other scientific areas.

A thermodynamic model has been developed for calculating solubilities and speciation in aqueous Nd-Na-F-H2O systems. The model combines experimental data from the literature for NdF3 and NaF in aqueous environments with new measurements of the solubility of both NdF3 and NaNdF4 as a function of pH at room temperature. For NaNdF4, the solubility data complement the recently reported solid state property data, thus establishing a comprehensive database for this hitherto poorly characterized compound. The solubilities of NdF3 and NaNdF4 have been measured through the dissolution method in HCl (0.1, 0.01 molkg-1 H2O) solutions at target pH of similar to 1 and similar to 2 over an equilibration period of up to 12 weeks at room temperature. The composition of the solution phase was determined through Inductively Coupled Plasma-Optical Emission Spectrometry. X-ray diffraction was performed to determine the remaining equilibrated solid phases. For modeling, the Mixed-Solvent Electrolyte framework has been used, which was previously parametrized and validated for various rare earth systems. The model combines a comprehensive speciation treatment in the aqueous phase with solid-state thermodynamics to reproduce the solubility of solids at varying processes conditions, thus providing a foundation for designing novel processes.

Experimental foundation has been established for improving corrosion models for stainless steels exposed to neutral aqueous chloride media with low levels of dissolved oxygen (DO). Accurate repassivation potentials were measured for UNS S31603 and UNS S32205 alloys in chloride electrolytes at room and elevated temperatures using Tsujikawa-Hisamatsu electrochemical (THE) and cyclic potentiodynamic polarization (CPP) methods. It was observed that the repassivation potential values measured using the CPP method were lower than the ones obtained from THE method for the same environmental conditions. Cyclic polarization scans in aqueous chloride media were conducted at different reverse scan rates resulting in varied repassivation potentials. Medium-term corrosion potentials were measured in chloride media with controlled dissolved oxygen levels ranging from 20 ppb to 400 ppb. These results were used as inputs for improving model prediction for repassivation and corrosion potentials. In an extension of previous modeling studies, an improved mechanistic repassivation model was developed based on a new generalized theory that explicitly accounts for the adsorption of water rather than treating it as an ever-present background. With a flexible definition of the repassivation current density, the new repassivation model reproduces the experimental repassivation potentials obtained using THE and CPP methods. The dependence of corrosion potential on DO has been modeled using a mixed-potential model. It has been demonstrated that the effect of agitation (caused by the bubbling of oxygen) needs to be accounted for to describe the corrosion potential, especially at low DO, where mass transport is important. The combined model correctly predicts the occurrence of localized corrosion when tested against exposure data from the literature.

•A thermodynamic model has been developed for rare earth elements in the presence of hydroxide, acetate, citrate and oxalate ions.•Speciation and solubility are simultaneously reproduced.•Effects of pH, temperature and complexation on solubility are accurately reproduced.•Effect of crystallinity on REE hydroxide solubility is modeled for limiting cases of crystalline and amorphous hydroxides.

The status of thermophysical property needs of the chemical industry is reviewed and updated relative to similar observations from 20 years ago. The paper is informed by a series of symposia held over several years in conjunction with the American Institute of Chemical Engineers (AIChE) national meetings. Experiences of the authors are also incorporated, including a discussion of the state of the art in this area, as well as references to several of the articles included in a recent special issue of Ind. Eng. Chem. Res. (2022, volume 61, issue 42) devoted to the subject. In general, the trend is toward more rigorous molecular methods but ingrained empirical methods tend to hold on for extended times by adding increasingly sophisticated multiparameter correlations. There is also a tendency for research in newer methods to end prematurely with anecdotal proofs of principle, undermining their ability to supersede tried and true methods. Significant gaps exist in experimental data, for the development of estimation methods and validation of models besides a general need for technical knowledge development. Although progress is clear, some of the goals articulated 20 years ago remain to be achieved, even as new needs are identified in estimation. modeling, and measurements. One possible solution, to close experimental data gaps and to provide a continuous stream of trained personnel, is to establish multidisciplinary research centers of excellence in this important methodology.

Critical temperature for localized corrosion can be a good design parameter because localized corrosion is not likely to occur below that temperature. The critical temperature depends on alloy composition, microstructure, and environment chemistry (including its redox potential). This paper reviews the literature on critical temperature for localized corrosion, expressed either as Critical Pitting Temperature (CPT) or Critical Crevice Temperature (CCT). A history of various testing methods is presented. Different approaches for modeling the temperature of transition to active pit growth are reviewed, including probabilistic aspects of critical temperature. A semi-empirical, electrolyte-based, model is described that can be useful in predicting CCT in service environments that differ from standard laboratory test environments. The model predictions are compared to experimental data for various alloys. The effect of solvent on CCT/CPT is described briefly and future avenues of research are recommended.

To address the needs for thermodynamic simulation of nuclear power reactor chemistry, geothermal fluid chemistry, and critical materials (Li, B) recovery processes from brines, a comprehensive model has been developed for simultaneous phase equilibrium and speciation calculations. The new model extends a previously developed model for boric acid and selected borates (Wang, P.; Kosinski, J., J.; Lencka, M., M.; Anderko, A.; Springer, R., D. Thermodynamic modeling of boric acid and selected metal borate systems. Pure & Applied Chemistry, 2013, 85, 2117) by utilizing detailed speciation results from recent electrical conductivity measurements in dilute solutions of boric acid and alkali metal borates and quantitative Raman spectroscopic studies at moderate concentrations. For this purpose, the Mixed-Solvent Electrolyte (MSE) framework has been adopted and parametrized for systems containing boric acid, lithium borate, sodium borate, and potassium borate by incorporating the new speciation data together with vapor-liquid equilibrium and solid solubility data. The MSE model combines a treatment of standard-state properties of simple and complex aqueous species with an excess Gibbs energy model that is valid up to solid-liquid saturation or the fused electrolyte limit. This approach ensures the correct prediction of the formation of experimentally identified polyborate species, while reproducing extensive experimental solubility and vapor-liquid equilibrium data. The model has been validated for the B2O3 + H2O, Li2O + B2O3 + H2O, Na2O + B2O3 + H2O, and K2O + B2O3 + H2O systems at temperatures up to 623 K at widely varying alkali metal/boron ratios. In particular, the model aligns with the new experimental speciation results to provide reliable predictions under the conditions of pressurized water reactors for nuclear power generation.

The need for sustainable power generation has increased interest in the use of hydrothermal fluids for industrial applications. New high-enthalpy geothermal systems and biowaste-to-fuel processes are two relevant examples that employ supercritical fluids which require an in-depth understanding of complex chemical reactions occurring near the supercritical temperature of water (374 degree celsius). As these processes operate in thermodynamic regimes that are not currently covered by a standard molar Gibbs energy of formation model, only empirical fits for single reaction systems are available which limit the use of multi-component phase equilibria cal-culations that are standard practice for less extreme environments. Here, we advance a standard molar Gibbs energy of formation model able to operate in these otherwise inaccessible thermodynamic states to include species needed for key mineral solubility systems and ion association reactions. This work extends a model based on molecular statistical thermodynamics (MST) into four new systems (Na3PO4-H2O, LiOH-H2O, KOH-H2O, and BaSO4-H2O) by extending the model to cover 10 new species. For each of these systems, model predictions were consistently within the experimental uncertainties for the new systems covered. A breakdown of MST contributions to the model revealed that electrostatic and hard sphere contributions were key to reproducing density dependencies of standard molar Gibbs energy of formation values around the critical point of water.

Critical pitting and crevice temperatures have been measured for many alloys using open-circuit potential tests in standard electrolytes, such as the 10 % FeCl 3 or mixtures of NaCl with FeCl 3 and CuCl 2 for many years. Although these measurements are primarily used for alloy ranking purposes, there is interest in using them for applications with different solution chemistries. On the other hand, critical pitting temperature has been modeled in terms of the threshold condition for the formation of metal-chloride salt film or the maintenance of a critical metal-chloride concentration in the pit environment, using artificial pit electrodes and relatively simple solutions, such as NaCl. This paper addresses a modeling approach to bridge the gap between the immersion tests, electrochemical measurements, and theory. An irreversible thermodynamics model is combined with concentrated electrolyte speciation model to predict the critical crevice temperature of several Ni-Fe-Cr-Mo-W alloys. The model computes the repassivation and corrosion potentials of alloys as functions of solution composition and temperature. The superposition of these parameters provide a conservative estimate of the critical crevice corrosion temperature. The predicted values are validated against critical crevice temperature data reported in the literature. The effect of aqueous electrolyte composition on critical crevice temperature is calculated and compared to field experience. The model is further extended to mixed solvent systems, where the solvent is a non-aqueous environment. The implications of the model are discussed.

The thermodynamic stability of rare earth (RE)materials plays a key role in the design of separation and recyclingprocesses for RE elements. Thermodynamic stability is fundamentallyinfluenced by the lanthanide contraction, as observed in the systematicreduction of unit cell volumes with increasing atomic number. REmaterials are found in the form of solids having primary bonds in threedimensions (3D materials) as well as ones with primary bonds in twodimensions (2D materials) whose layers are held together by weak vander Waals (vdW) forces. While studies of synthesis, structure, andphysical properties of 2D RE materials are numerous, no systematicresearch has compared their thermodynamic stability to that of 3Dmaterials. In the present work, RE oxychlorides (REOCls), whichdisplay a structural transition from a 3D-polyhedral network (PbFCl-type) to a vdW-bonded layered one (SmSI-type) as the RE size decreases, were all synthesized by theflux method. High-temperatureoxide melt solution calorimetry was used to determine their formation enthalpies to enable Born-Haber cycles to calculate latticeenergies. Our results indicate that REOCl compounds are thermodynamically stable when compared to their binary oxides andchlorides. The lattice energies of 3D REOCls increase with decreasing RE size yet are insensitive to unit cell volumes for 2DREOCls. This is caused by interatomic interactions parallel and perpendicular to layers in the SmSI-type REOCls, causing a differentstructure response to the lanthanide contraction than 3D RE materials.

The corrosion behavior of stainless steels and Ni-based alloys in nonoxidizing sulfuric acid mixtures at concentrations below approximately 30 mol/kg H2O is modeled. The redox potential in sulfuric acid across a broad concentration range, from 0 to 80 mol% (0 to 95.6 wt%), is determined by the proton reduction reaction. Thus, in the absence of other oxidizing species, sulfuric acid behaves as a nonoxidizing (reducing) acid. The calculated corrosion rates, using an electrochemical model up to about 30 mol/kg H2O (about 75 wt%), are in agreement with experimental values. The predicted polarization curves of anodic and cathodic processes show that the alloys in these environments are in active dissolution regime, consistent with experimental data. The model predictions of corrosion rates in H2SO4+HCl, H2SO4+HF, and H2SO4+HCl+HF mixtures are in agreement with weight-loss corrosion data. The corrosion rate of alloys in the nonoxidizing sulfuric acid mixtures correlated to an equivalent alloy composition given by (Ni0.7-Cr0.1+Mo+0.5 W). The effect of alloying elements under these conditions may be related to their beneficial effect on active dissolution and proton reduction reaction rates.

Scientific projects frequently involve measurements of thermophysical, thermochemical, and other related properties of chemical compounds and materials. These measured property data have significant potential value for the scientific community, but incomplete and inaccurate reporting often hampers their utilization. The present IUPAC Technical Report summarizes the needs of chemical engineers and researchers as consumers of these data and shows how publishing practices can improve information transfer. In the Report, general principles of Good Reporting Practice are developed together with examples illustrating typical cases of reporting issues. Adoption of these principles will improve the quality, reproducibility, and usefulness of experimental data, bring a better level of consistency to results, and increase the efficiency and impact of research. Closely related to Good Reporting Practice, basic elements of Good Research Practice are also introduced with a goal to reduce the number of ambiguities and unresolved problems within the thermophysical property data domain.

As important upconversion materials, sodium rare-earth fluorides (nominally NaREF4 in composition but actually often harboring sodium deficiency, especially in nanophase materials) have been subjected to intensive studies, particularly in the synthesis and applications of nanocrystals. However, the mechanisms of the conversion between the two phases (alpha and beta) of NaREF4 nanocrystals during the synthesis are still controversial and lack thermodynamic investigations, which limit the rational design, synthesis, and processing of these materials. In this work, aiming at NaREF4 with light rare-earth elements, the thermochemistry of the NaF-NdF3 system, including the alpha and beta phases in nanocrystalline/nanophase and bulk stoichiometric samples, is systematically studied by thermogravimetry and differential scanning calorimetry and high-temperature oxide melt solution calorimetry. With the help of compositional analysis and structural characterization, a strong Na deficiency is found in nanocrystals with small crystal sizes, which leads to the formation of cubic (alpha) crystallographic polymorphs at the nucleation stage, possibly because of the relative thermodynamic stability of the a phase compared to the beta phase in such compositions. After converting to the hexagonal (beta) structure, the crystal growth is accompanied by an increase of Na content in nanocrystals with increasing energetic stability until the formation of the stoichiometric compound (beta-NaNdF4). On the contrary, the stoichiometric alpha phase (alpha-NaNdF4) is metastable at room temperature but is the intermediate phase as the temperature increases. We show that the alpha -> beta phase conversion in aqueous solution synthesis is distinct from the beta -> alpha transition driven by temperature because of composition differences.

Research has shown that strong acids (i.e., sulfuric and nitric acids) may be produced as a result of reactions between impurities during CO2, transport within carbon capture, utilization, and storage (CCUS) systems even when today's impurity specifications and recommendations are followed. Strong acids are corrosive to carbon steel, which is a very common construction material for CO2, transport pipelines. To establish acceptable impurity limits and to ensure the integrity of pipelines, experimental data are needed as input for modeling possible scenarios and as a foundation for constructing modeling tools. To assess the possibility of formation of concentrated acid-bearing phases in CO2, environments, acid solubility in dense phase CO2, needs to be determined. The nitric and sulfuric acid solubilities in dense phase CO2, were determined by first saturating the CO2, phase with the acids and by subsequently scrubbing the acids using water-filled autoclaves. The water was then analyzed using ion chromatography. The experiments were conducted at two temperatures (25 and 48 degrees C) with four different pressures (80, 100, 120, and 170 bar). The new solubility measurements have been used in conjunction with available literature data to construct a thermodynamic model for predicting the thermodynamic behavior of acid-CO2 mixtures over wide ranges of temperatures, pressures, and compositions. The model is based on the previously developed Mixed-Solvent Electrolyte (MSE) framework and incorporates speciation and phase equilibria in CO2-rich as well as water-rich environments.

Leaching of six individual rare earth (yttrium, cerium, neodymium, samarium, europium, and ytterbium) doped synthetic phosphogypsum samples using a suite of lixiviants was conducted. The lixiviants chosen for this study were phosphoric acid, sulfuric acid, gluconic acid, and a "biolixiviant" consisting of spent medium containing organic acids from the growth of the bacterium Gluconobacter oxydans on glucose. The biolixiviant had a pH of 2.1 and the dominant organic acid was determined to be gluconic acid, present at a concentration of 220 mM. The leaching behaviors of the studied lixiviants were compared and rationalized by thermodynamic simulations. The results suggest that at equivalent molar concentrations of 220 mM the biolixiviant was more efficient at rare earth element (REE) extraction than gluconic acid and phosphoric acid but less efficient than sulfuric acid. Unlike the organic acids, at pH 2.1 the mineral acids failed to extract REE, likely due to different complexation and kinetic effects. (C) 2019 Elsevier Ltd.

A model has been developed for calculating thermodynamic properties and phase equilibria in binary and multicomponent aqueous systems containing rare earth element chlorides. Here, the rare earth elements encompass the lanthanides except promethium plus yttrium. The model is based on a comprehensive database of solid-liquid equilibria, osmotic and activity coefficients, enthalpies of dilution and heat capacities of solutions. The computational framework relies on the previously developed Mixed-Solvent Electrolyte (MSE) model. The model accurately reproduces the properties of binary rare earth chloride – water systems and of ternary mixtures that additionally include HCl, NaCl, or CaCl2. Solid-liquid phase diagrams have been obtained to provide a convenient summary of the solubility of stable and metastable hydrated solid phases. Analysis of the stability of solid hydrates reveals systematic trends within the rare earth series. At ambient and elevated temperatures, the calculations show an increase in the stability range of rare earth chloride hexahydrates with decreasing cation radius, accompanied by a gradual disappearance of the heptahydrate. At low temperatures, the stable solid phases transition from the decahydrate at higher cation radii to octahydrate in an intermediate range and a combination of pentadeca- and nonahydrates at lower radii. The calculated standard-state enthalpies of formation of the hydrates agree with independently obtained values from calorimetric measurements, thus verifying the internal consistency of the model.

Mineral scale prediction is an important tool for effective scale management in oil and gas flow assurance. Accurate prediction of scale formation is particularly challenging at high temperatures and pressures that are encountered as the industry develops progressively deeper and overpressured reservoirs. To address the need to predict scaling at conditions ranging from ambient to extreme, a comprehensive thermodynamic model has been developed. This model has been designed to represent the solubility of scaling minerals at temperatures up to 300 °C and pressures up to at least 1,700 atm. The model is based on the previously developed Mixed-Solvent Electrolyte (MSE) thermodynamic framework and relies on a detailed treatment of speciation in the liquid phase. It represents the standard-state properties of individual species using the Helgeson-Kirkham-Flowers equation of state and it predicts the species activity coefficients by accounting for long-range electrostatic, short-range ionic, and non-ionic interactions. The model has been parameterized to reproduce the solubility of sulfate, sulfide, and carbonate scales in water and in multicomponent brines ranging from dilute to highly saline (typically up to ~6 m Cl). The model accurately represents the effects of temperature, pressure and common salt components on the solubility of the minerals. Additionally, it takes into account the effect of metastability for scales that may occur in multiple crystalline forms. Application of the model to zinc sulfide, lead sulfide and calcium sulfate scales is analyzed in detail.

The concentration of H2O dissolved in CO2-CH4 supercritical fluids is an important parameter that can control shale permeability, affect CH4 transmissivity, and ultimately impact the efficiency of CO2 enhanced gas recovery (EGR) operations. Here, we use in situ high-pressure infrared (IR) spectroscopic titrations to quantify the solubility of H2O in six CO2-CH4 mixtures, ranging from pure CO2 to pure CH4, at shallow shale reservoir conditions of 323.2 K and 9.000 MPa. Measured concentrations of H2O at saturation increase with increasing mole percent CO2, and our results are in agreement with limited data available in the literature. We use these experimental results to benchmark three current thermodynamic multiphase routines: the mixed-solvent electrolyte (MSE), STOMP-COMP, and the Statistical Associating Fluid Theory for variable range Mie potentials (SAFT gamma-Mie) equations of state. Of these models, MSE and STOMP-COMP accurately predict maximum H2O solubilities of the binary CO2-H2O and CH4-H2O systems, and they also reproduce the shape of the water solubility curve as a function of mole percent CO2. Hence, these routines should work well to predict H2O content in reservoir simulations and help to make informed decisions concerning injection strategies for CO2 EGR in shale plays at shallow depths.