N′-[(1E)-(2,6-Difluoro­phen­yl)methyl­idene]thio­phene-2-carbohydrazide

In the title compound, C12H8F2N2OS, the thienyl ring is disordered over two positions, with the S atom of the major component [occupancy = 75.03 (18)%] oriented away from an ortho-F atom of the benzene ring. The mol­ecule is nearly planar, the dihedral angle between the thio­phene and benzene rings being 6.19 (18) (in the major component) or 3.5 (6)° (in the minor component). The azomethine C=N double-bond in the mol­ecule is of an E configuration. In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, generating inversion dimers

Thermodynamic modeling of hydrogen–water systems with gas impurity at various conditions using cubic and PC-SAFT equations of state

Hydrogen (H2) has emerged as a viable solution for energy storage of renewable sources, supplying off-seasonal demand. Hydrogen contamination due to undesired mixing with other fluids during operations is a significant problem. Water contamination is a regular occurrence; therefore, an accurate prediction of H2-water thermodynamics is crucial for the design of efficient storage and water removal processes. In thermodynamic modeling, the Peng–Robinson (PR) and Soave Redlich–Kwong (SRK) equations of state (EoSs) are widely applied. However, both EoSs fail to predict the vapor-liquid equilibrium (VLE) accurately for H2-blend mixtures with or without fine-tuning binary interaction parameters due to the polarity of the components. This work investigates the accuracy of two advanced EoSs: the Schwartzentruber and Renon modified Redlich–Kwong cubic EoS (SR-RK) and perturbed-chain statistical associating fluid theory (SAFT) in predicting VLE and solubility properties of H2 and water. The SR-RK involves the introduction of polar parameters and a volume translation term. The proposed workflow is based on optimizing the binary interaction coefficients using regression against experimental data that cover a wide range of pressure (0.34 to 101.23 MPa), temperature (273.2 to 588.7 K), and H2 mole fraction (0.0004 to 0.9670) values. A flash liberation model is developed to calculate the H2 solubility and water vaporization at different temperature and pressure conditions. The model captures the influence of H2-gas (CO2) impurity on VLE. The results agreed well with the experimental data, demonstrating the model\u27s capability of predicting the VLE of hydrogen-water mixtures for a broad range of pressures and temperatures. Optimized coefficients of binary interaction parameters for both EoSs are provided. The sensitivity analysis indicates an increase in H2 solubility with temperature and pressure and a decrease in water vaporization. Moreover, the work demonstrates the capability of SR-RK in modeling the influence of gas impurity (i.e., H2–CO2 mixture) on the H2 solubility and water vaporization, indicating a significant influence over a wide range of H2–CO2 mixtures. Increasing the CO2 ratio from 20% to 80% exhibited almost the opposite behavior of H2 solubility compared to the pure hydrogen feed solubility. Finally, the work emphasizes the critical selection of proper EoSs for calculating thermodynamic properties and the solubility of gaseous H2 and water vaporization for the efficient design of H2 storage and fuel cells

Evaluation of cubic, PC-SAFT, and GERG2008 equations of state for accurate calculations of thermophysical properties of hydrogen-blend mixtures

Hydrogen (H2) is a clean fuel and key enabler of energy transition into green renewable sources and a method of achieving net-zero emissions by 2050. Underground H2 storage (UHS) is a prominent method offering a permanent solution for a low-carbon economy to meet the global energy demand. However, UHS is a complex procedure where containment security, pore-scale scattering, and large-scale storage capacity can be influenced by H2 contamination due to mixing with cushion gases and reservoir fluids. The literature lacks comprehensive investigations of existing thermodynamic models in calculating the accurate transport properties of H2-blend mixtures essential to the efficient design of various H2 storage processes. This work benchmarks cubic equations of state (EoSs), namely Peng–Robinson (PR) and Soave Redlich–Kwong (SRK) and their modifications by Boston–Mathias (PR-BM) and Schwartzentruber–Renon (SR-RK), for their reliability in predicting the thermophysical properties of binary and ternary H2-blend mixtures, including CH4, C2H6, C3H8, H2S, H2O, CO2, CO, and N2, in addition to Helmholtz-energy-based EoSs (i.e., PC-SAFT and GERG2008). The benchmarked models are regressed against the experimental data for vapor–liquid equilibrium (VLE) that covers a wide range of pressures (0.01 to 101 MPa), temperatures (92 K to 367 K), and mole fractions (0.001 to 0.90) of H2. The novelty of this work is in benchmarking and optimizing the parameters of the mentioned EoSs to study VLE envelopes, densities, and other critical transport properties, such as heat capacity and the Joule–Thomson coefficient of H2 mixtures in a wide range of associated conditions. The results highlight the significant effect of the temperature-dependent binary interaction parameters on the calculations of thermophysical properties. The SR-RK EoS demonstrated the highest agreement with VLE data among the cubic EoSs with a low root mean square error and absolute average deviation. The PC-SAFT VLE models demonstrated results comparable to the SR-RK. The sensitivity analysis highlighted the high influence of impurity on changing the thermophysical behavior of H2-blend streams during the H2 storage process

Development of Two Charge-Transfer Complex Spectrophotometric Methods for Determination of Tofisopam in Tablet Dosage Form

Purpose: To develop an easy, fast and sensible spectrophotometric method for determination of tofisopam in tablet dosage form.Methods: Tofisopam as n-electron donor is react with two π-acceptors namely: chloranilic acid (ChA), and 7,7,8,8 tetracyanoquinodimethane (TCNQ) to form charge-transfer complexes. The obtained complexes were tested spectrophotometrically at 520 and 824 nm for ChA and TCNQ, respectively. The optimal conditions affecting the reaction status were surveyed and optimized, and the results compared with Japanese Pharmacopeia method.Results: The calibration curve were obeyed Beer`s low in the ranges 25 – 125 and 30 – 150 μg/mL for ChA and TCNQ, respectively. The lower limit of detection was 8.0 and 10.0 μg/m for ChA and TCNQ, respectively. The slope and intercept of the calibration graphs were 0.0025 and 0.011, and 0.0115 and -0.237 for ChA and TCNQ, respectivelyConclusion: The proposed methods have successfully been applied to determination of tofisopam with good accuracy and precision. The methods are accurate as the Japanese pharmacopeial method amd may be applied for routine analysis in quality control laboratories.Keywords: Charge-transfer complex, Tofisopam, Chloranilic acid, Tetracyanoquinodimethane, Spectrophotometr

Residual trapping of CO2, N2, and a CO2-N2 mixture in Indiana limestone using robust NMR coreflooding: Implications for CO2 geological storage

Carbon capture and sequestration (CCS) in geological formations is a prominent solution for reducing anthropogenic carbon emissions and mitigating climate change. The capillary trapping of CO2 is a primary trapping mechanism governed by the pressure difference between the wetting and nonwetting phases in a porous rock, making the latter a key input parameter for dynamic simulation models. During the CCS operational process, however, the CO2 is prone to contamination by impurities from various sources such as surfaces (e.g., pipelines and tanks) and the subsurface (e.g., existing natural gas). Such contamination can strongly influence the overall CO2 wettability, storage capacity, and containment security. Hence, the present study uses the nuclear magnetic resonance (NMR) core flooding technique to investigate and compare the residual saturations of pure CO2, pure N2, and a 50:50 CO2/N2 mixture in an Indiana limestone. The longitudinal and transverse relaxation times (T1 and T2) are measured to examine the displacement process of the pore network, and the trapping mechanism is evaluated at the pore scale as a determinant of the field-scale flow behavior. The NMR T1-T2 and 2D maps are used to observe the fluid configurations in the pore network, and the T1/T2 ratios are used to evaluate the microscopic wettability of the limestone grains by the pore-space fluids following each drainage/imbibition process step. The results indicate substantial residual gas trapping in the rock for the CO2-brine, N2-brine, and CO2/N2-brine systems, corresponding to gas saturations of 25%, 27%, and 26%, respectively. In the CO2-brine system, the intermolecular interplay between the CO2-enriched brine and limestone grains results in a higher T1/T2 ratio and significantly reduces the hydrophilicity of the limestone. Furthermore, the NMR T2 distribution reveals the occurrence of preferential water displacement into the large pores (r \u3e 1 m) and from the intermediate pores (0.03 m \u3c r \u3c 1 m), whereas water remains immobile in the smaller pores (r \u3c 0.03 m). The insignificant difference in residual trapping saturation between pure CO2 and the CO2-N2 mixture indicates the potential to allow for impurities in the CO2 phase in CCS without reducing the residual trapping capacity. Thus, the present work provides comprehensive information on the impact of gas injection on residual gas trapping in subsurface geological formations at the pore scale, thereby aiding in the development of CCS and other potential applications in enhanced oil recovery (EOR)

Organizational culture and Nitaqat status in Saudi Arabia

The Nitaqat program is the latest in the Saudization policies to increase the number of Saudi workforce in the local labor market and to reduce the heavy reliance on foreign labors in the Kingdom of Saudi Arabia.We argue that hiring decisions made by private sector organizations are not entirely based on government mandates alone. We propose that the internal organizational characteristics are also important in determining the hiring decision. Applying resource-based view, we demonstrate how organizational culture, leadership style, and human resource management practices could play a key role toward such decision and hence the Nitaqat status

Saudi Arabian basalt/CO2/brine wettability: Implications for CO2 geo-storage

The geological sequestration of carbon dioxide, including mineralization in basaltic formations, has been identified as a promising method of attaining a low-carbon economy. However, successful CO2 storage depends on both the CO2 wettability of the basaltic rocks and the basalt rock-fluid interfacial interactions. The contact angles of brine/CO2 systems for Western Australian (WA) and Iceland basalts have been recently reported in the literature. However, contact angle datasets for evaluating the CO2 wettability of Saudi Arabian (SA) basalt have not been previously reported. Moreover, there is limited information on the impact of organic acids on the wettability of the basalt/CO2/brine system. In the present study, the contact angles of supercritical CO2/brine systems on SA basalt are measured at temperatures of 298 and 323 K, and at various pressures of 0.1 – 20 MPa in the absence and presence of organic acid (10 − 2 mol/L stearic acid). Various analytical methods are used to characterize the SA basalt surface, and the wetting behavior of the SA basalt is compared with that of the WA and Iceland basalts. The quantity of CO2 that can be safely trapped underneath the SA basalt (in terms of CO2 column height) is then computed from the experimental data. At the highest tested temperature and pressure (20 MPa and 323 K), the pure SA basalt is found to remain strongly water-wet, with advancing (θa) and receding (θr) contact angles of 46.7° and 43.2°, respectively, whereas the Iceland basalt becomes moderately water-wet (θa = 85.1° and θr = 81.8°), and the WA basalt becomes CO2-wet (θa = 103.6° and θr = 96.1°). However, the organic-aged SA basalt attains a CO2-wet state (θa = 106.8° and θr = 95.2°). In addition, the CO2 column height of the pure SA basalt is higher than that reported for the WA and Iceland basalts. Further, at 323 K, the CO2 column height decreases from 835 m at 5 MPa to −957 m at 20 MPa. These results suggest that there could be both freer plumb and lateral movement of CO2 into the SA basalt in the presence of organic acid, thus resulting in lower residual and mineral trapping capacities, and fewer eventual leakages of CO2, across the geological formation

N′-[(1E)-(4-Fluoro­phen­yl)methyl­idene]thio­phene-2-carbohydrazide

In the title compound, C12H9FN2OS, the thienyl ring is disordered over two positions, with the S atom of the major component [occupancy = 87.08 (16)°] oriented towards the ortho-H atom of the benzene ring. The mol­ecule is nearly planar, the dihedral angle between the thio­phene and benzene rings being 13.0 (2)° in the major component. The azomethine C=N double bond in the mol­ecule is of an E configuration. In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers

Hydrogen, carbon dioxide, and methane adsorption potential on Jordanian organic-rich source rocks: Implications for underground H2 storage and retrieval

Hydrogen (H2) storage in geological formations offers a potential large-scale solution suitable for an industrial-scale hydrogen economy. However, the presence of organic residuals can significantly influence the H2 storage efficiency, as well as cushion gas performance, such as CO2 and CH4, injected to maintain healthy reservoir pressure. Thus, the H2 storage efficiency and cushion gas selectivity were thoroughly investigated in this work based on H2, CO2, and CH4 adsorption measurements using, for the first time, actual organic-rich carbonate-rich Jordanian source rock samples (TOC = 13 % to 18 %), measured at 60 °C temperature and a wide range of pressure (0.1 – 10.0 MPa). Initially, the samples were characterized using various analytical methods. Results demonstrated that H2 adsorption capacities reached up to 0.47 mol/kg at 9.0 MPa. The measured adsorption of CO2 was four times higher than H2. An increase in TOC significantly decreased H2 adsorption compared to CO2 and CH4. Additionally, CO2 demonstrated preferential behavior as a cushion gas compared to CH4, attributed mainly to the calcite content and presence of carboxyl and sulfonyl groups. This study provides fundamental data for understanding H2 potential storage issues in an organic-rich rock formation and thus aids in the industrial implementation of an H2 supply chain