Solubility Product Research Articles

Solubility, thermodynamic investigation and molecular dynamics simulation of guanidine hydrochloride in four binary solvents

Solubilities of guanidine hydrochloride (GuHCl) in organic solvents are of great importance for its development and optimization of industrial process. The study of the dissolution characteristics of GuHCl in DMF/2-meoxyethanol/methanol/NMP + n-propanol at different temperatures were experimentally investigated by using laser monitoring method. Results showed that GuHCl solubilities were observed to be increasing with the increment in experimental temperature and rising with higher mass fraction of DMF/2-meoxyethanol/methanol/NMP. Molecular dynamics (MD) simulation technique was utilized to reveal the microscopic behaviors of GuHCl and solvent mixtures and its effect on the dissolving capability of GuHCl in involved solvent systems. Also, five thermodynamic models were selected to regress the observed GuHCl equilibrium solubility. A comparison of the experimental values with corresponding estimated data indicated that the modified Apelblat equation provided the most excellent correlation in modelling GuHCl solubility. Finally, through the analyses of enthalpy change, entropy change and Gibbs free energy change, the dissolution thermodynamic features were evaluated.

Equilibrium solubility, solvent effect, equation correlation, and thermodynamic properties of cyclododecanone in twelve organic solvents

The solubility of cyclododecanone (CDON) was determined in twelve solvents containing acetonitrile, acetone, toluene, ethyl acetate, cyclohexane, 1,2-dichloroethane, methanol, ethanol, n-propanol, i-propanol, n-butanol and i-butanol. The temperature range for the remaining solvents used in the experiment was 278.15–313.15 K, except for cyclohexane (283.15–313.15 K). The CDON solubility in solvents measured increased with growing temperature. The CDON solubility varies considerably in different solvents. Among the single solvents selected, CDON was most soluble in 1,2-dichloroethane and least in acetonitrile. The solubility in 1,2-dichloroethane is about 2–3 times higher than in acetonitrile. The carbonyl oxygen of CDON readily combines with alcoholic solvents to form hydrogen bonds. Hansen solubility parameters (HSP) and the physiochemical properties of the solvents explain the solvent effect in diverse solvents. To understand CDON dissolution, the electrostatic potential energy surfaces of CDON and the solute–solvent interactions were analyzed at the molecular level on the basis of density functional theory (DFT). Analysis of solvation effects revealed that variations in the CDON dissolution are influenced by a combination of factors rather than a single one. In addition, the Van't Hoff equation, modified Apelblat equation, Yaws equation, λh equation, Wilson model and Jouyban model were utilized to correlate the experimentally obtained value. The computational data show that the ARD (0.88%) and RMSD (0.24%) of Wilson model are the smallest among the selected equations with the best correlation. The apparent thermodynamic properties of CDON dissolution were further accounted for Van't Hoff equation, and the CDON dissolution was observed to be endothermic and entropy-driven.

A Modern Twist on an Old Measurement: Using Laboratory Automation and Data Science to Determine the Solubility Product of Lead Iodide

A Modern Twist on an Old Measurement: Using Laboratory Automation and Data Science to Determine the Solubility Product of Lead Iodide

New insights into the structure-activity relationship for CO2 capture by tertiary amines from the experimental and quantum chemical calculation perspectives

In comparison with primary and secondary amines, tertiary amines exhibit higher CO2 equilibrium and lower CO2 absorption heat, making them attractive for CO2 capture applications. However, the relationship between the structure of tertiary amines and their CO2 capture capacity needs to be further studied. This study aimed to investigate the structure–activity relationship between the molecular configuration of representative tertiary amines, and their CO2 equilibrium solubility, as well as CO2 absorption heat. The CO2 absorption heat of nine tertiary amines with distinct structures was measured using a high-precision microcalorimeter, while quantum chemical calculations were employed to explore this relationship. The reactivity of tertiary amines was assessed by visualizing the effects of electron density and steric hindrance by using natural population analysis and dual descriptor analysis, respectively. The findings revealed that the stronger electron-donating effect of ethyl groups than the methyl groups enhanced the reactivity of tertiary amines. Additionally, the presence of methyl groups on the side chain of tertiary amines promoted the reactivity. By contrast, the presence of too many hydroxyl groups resulted in steric hindrance thus reducing the reactivity of tertiary amines. Furthermore, interaction region indicators were employed to visually evaluate the influence of intramolecular hydrogen bonds on the reactivity of tertiary amines. The results show that the presence of intramolecular hydrogen bonds enhanced the equilibrium solubility of CO2 while facilitating the reduction of the CO2 absorption heat. The results obtained from this study are important for the selection and development of efficient tertiary amines that are suitable for industrial applications in CO2 capture.

Solid-liquid phase equilibrium and thermodynamic properties analysis of Bazedoxifene acetate in fifteen kinds of mono-solvents

Crystallization is widely used for the isolation and purification of active pharmaceutical ingredients (APIs) in the final manufacturing stage. Bazedoxifene (BZD) acetate, classified as a third-generation selective estrogen receptor modulator, is employed in the treatment of postmenopausal osteoporosis. This work reports the equilibrium solubility data of BZD acetate in fifteen different mono-solvents, including methanol, ethanol, n-propanol, i-propanol, n-butanol, ethyl formate, methyl acetate, ethyl acetate, acetone, 2-butanone, cyclohexanone, tetrahydrofuran (THF), 2-methyltetrahydrofurane (2-MeTHF), 1,4-dioxane and acetonitrile (ACN), within the temperature range “T = 283.15–323.15 K” under p = 0.1 MPa. The solubilities of BZD acetate in various solvents increase with increasing temperature. Among the alcoholic solvents, the solubility order is as follows: methanol > ethanol > n-propanol > n-butanol > i-propanol. In esters solvent, the solubility of BZD acetate decreases in the following order: methyl acetate > ethyl acetate > ethyl formate. For ketones solvent, the solubility decreases in the following order: cyclohexanone > acetone > 2-butanone. The maximum value of BZD acetate solubility was 0.011 mol·mol−1 in tetrahydrofuran at T = 323.15 K, but the least data was found in ethyl formate at 283.15 K. Four thermodynamic models, i.e., the Yaws model, modified Apelblat model, λh model, and Wilson model were applied to fit the solubility data of BZD acetate in different solvents. Among them, the Wilson model represents the most accurate fitting outcomes. Finally, the thermodynamic functions of mixing (including enthalpy, entropy, and Gibbs energy) were calculated, and the results indicate a mixing process that is both spontaneous and driven by entropy. The solubility data, correlated models, and derived thermodynamic functions present essential thermodynamic fundamentals for the industrial production of BZD acetate crystallization, facilitating efficient separation and purification.

Determination of the solubility profile of isophthalic acid in some aqueous solutions of betaine-based deep eutectic solvents: Study the extent of H-bonding interactions between starting materials of deep eutectic solvents in aqueous medium

The equilibrium solubility of isophthalic acid (IPA) in three aqueous solutions of betaine/propylene glycol (Bet/PG, 1:5 M ratio), betaine/ethylene glycol (Bet/EG, 1:3 M ratio) and betaine/glycerol (Bet/Gly, 1:3 M ratio) deep eutectic solvents (DESs) (1) was determined experimentally by utilizing a shake-flask method at 293.15–313.15 K covering the whole composition range at atmospheric pressure (≈85 kPa). For three investigated systems, an increase in solubility was observed by decreasing water mass fraction; so that, the lowest and highest solubilities were in water at 293.15 K and pure DESs at 323.15 K, respectively. Also, the mixtures containing PG presented the higher values of the solubility than that of EG or Gly which may be attributed to its lower dipole moment and dielectric constant (2.27 D, 32.0) than the others. By representation the derived equilibrium solubilities with models of Jouyban-Acree, Jouyban-Acree-van't Hoff, NRTL and Wilson a maximum overall mean relative deviation of 15.9% was achieved. Moreover, the solubilities of IPA in ternary (Bet + PG, EG or Gly + water) mixtures at 298.15 were measured to investigate the extent of H-bonding interactions of Bet with PG, EG or Gly into DESs in the presence of water by comparing IPA solubility data for each binary (DES + water) system and the corresponding ternary mixtures. The results suggested that the H-bonding interactions between two components of DESs were disappeared when the water content was exceeded 60% (g/g). This result more explored by recording 1H NMR spectra of diluted DESs with deuterium dioxide. Eventually, an endothermic and enthalpy-driven process in most mixtures was determined by thermodynamic analysis of IPA dissolution and mixing processes based on the modified van't Hoff equation.

Equilibrium absorption of CO2 in aqueous solution of N-dimethylamino ethanol and 2-(ethylamino)ethanol, measuring and thermodynamic modeling

The equilibrium carbon dioxide solubility in aqueous solutions of N-dimethylaminoethanol (DMAE) 40 wt% + 2-(ethylamino) ethanol (EAE) 5 wt% and DMAE 30 wt% + EAE 5 wt% was measured at various temperatures (313.15, 328.15, 343.15, 358.15 K) in the range of pressures from 6.5 to 236 kPa. The enthalpy of absorption of carbon dioxide was measured for the mixture of DMAE (40 wt%) + EAE (5 wt%), at 328.15 K. The Deshmukh-Mather model was used to correlate the equilibrium solubility of carbon dioxide data, and the model parameters were optimized. The optimized model could correlate the vapor-liquid equilibrium with the 9.4 average absolute percentage deviation (AAD%), and the obtained AAD% for enthalpy of absorption in aqueous solution of DMAE (40 wt%) + EAE (5 wt%) was 24.0.

Comments on “Solid-liquid equilibrium solubility prediction of sulfanilamide in four binary solvent mixtures by using pure solvents solubility data from 278.15 to 318.15 K with the Abraham solvation parameter model, Yalkowsky Log-Linear and extended log-linear solubility thermodynamic models”

The experimental solubility data of sulfanilamide in binary solvent mixtures at temperature ranging from (278.15 to 318.15) K have carefully been reanalyzed and some additional recommendations were discussed.

Equilibrium solubility, solvation and dissolution thermodynamics, and density functional theory study of albendazole in solutions of acetone/methanol/isopropanol + water

In this work, albendazole was dissolved in mixtures of acetone/methanol/isopropanol + water to examine its solubility, dissolution thermodynamics, solvation behavior, and intermolecular interactions. The shake-flask method was used to conduct solubility tests at a pressure of 101.0 kPa and temperatures from 278.15 to 323.15 K. In water and pure organic solvents, respectively, the lowest and greatest levels of albendazole solubility were found. XRD analysis-based experiments found no evidence of crystal solvation or transition. Jouyban-Acree, modified Wilson, QSPR and modified van't Hoff-Jouyban-Acree models correlated the solubility to solvent composition and temperature with the relative average deviations (RAD) of no more than 8.99 %. The equilibrium solubility at 298.15 K was examined using the approach of extended Hildebrand solubility parameter, which produced an average relative deviation of 3.63 %. The dipolarity-polarizability and solubility parameter of solutions have a considerable impact on the solubility fluctuation, according to the analysis of linear solvation energy relationship. The preferred solvation of albendazole by water and different organic solvents was quantitatively examined with the help of the inverse Kirkwood-Buff integrals. Albendazole was preferentially solvated by the organic solvents in moderate and rich organic solvent compositions in blends, where albendazole served as a Lewis acid. An enthalpy-driven mechanism and an endothermic process were identified by thermodynamic analysis of the entropy-enthalpy compensation and dissolution properties for albendazole dissolving in blends. The electrostatic characteristics of albendazole acidity/basicity were highlighted using analysis of Hirshfeld surface and molecular surface. The primary targets of nucleophilic and electrophilic assault are the –NH and -S-groups. An independent gradient model based on Hirshfeld partition analysis was used to visual the weak interactions between albendazole and different solvents.

Development of Teaching Materials to Support Merdeka Curriculum Learning on Solubility and Solubility Product in F Phase

By the Covid-19 pandemic which shows that students' interest in learning is decreasing and cause learning loss, the Ministry of Education and Culture is trying to restore learning given the difficulties that have arisen with launching an merdeka curriculum, the teachers and students need using learning tools as learning resources in accordance with the merdeka curriculum. This research aims to develop teaching materials to support merdeka curriculum learning on the solubility and solubility product in the F phase and reveal the validity and practicality developed. This type of research is development research using the Plomp model. This research is limited to the formation of a valid and practical prototype IV. The instrument used in this study was a questionnaire in the form of a questionnaire of validation and practicality sheets. This study conducted a validity test using the Aiken's V formula and a practicality test using the practicality using the category of practicality level adaption from Purwanto. Validation was carried out by 5 experts, namely 3 lecturers and 2 chemistry teachers. The practicality sheet was filled in by 2 chemistry teachers and 9 Phase F students at SMAN 7 Padang. Also one to one evaluation by 3 students. The validity test data processing results are 0.89 which shows the valid category. For the results of data processing for the practicality test of students, namely 88% and the teacher's practicality test is 94% which shows a very practical category. It can be concluded that teaching materials to support merdeka curriculum learning on solubility and solubility product are valid and practical

Enhancing the equilibrium solubility of salicylic acid in aqueous media by using polyethylene glycols 200, 400 and 600 as cosolvents: Correlation and dissolution thermodynamics

The solubility of salicylic acid in three mixtures of polyethylene glycol (PEG) with different molar masses of 200 to 600 g/mole were experimentally determined by a shake flask method at temperature range of (293.15 to 313.15) K under ambient pressure (≈85 kPa). The experimental results indicated that the solubility of salicylic acid enhanced by the introduction of PEGs to the water, and that could be explained with Hansen’s parameters and like-dissolves-like rule. Based on the results, PEG 600 had the best solubilization power, whereas PEG 200 displayed the lowest solubilization power, and generally the solubility decreased with decreasing molar mass of PEG and also decreasing temperature. Moreover, the equilibrium solid phase crystal of salicylic acid is characterized with X-ray powder diffraction analysis to identify no polymorphic transformation, solvate formation or crystal transition during the whole solvent crystallization process. A number of linear and nonlinear cosolvency models including the Jouyban-Acree based models along with the equations of van’t Hoff, the mixture response surface, the combined nearly ideal binary solvent/Redlich-Kister, λh and the modified Wilson-van’t Hoff were challenged to correlate/predict the solubility of salicylic acid in these mixtures. The computed values of the Jouyban-Acree based models presented a good agreement with the experiment data than the others, as a consequent of a low mean percentage deviation (MPD ≤ 15.7%). According to the enthalpy–entropy compensation analysis, there observed slope changes indicating that two mechanisms, enthalpy or entropy controlled the solubility increment depending on the PEG mass fraction in each solution.

Disordered Crystal Structure and Anomalously High Solubility of Radium Carbonate.

Radium-226 carbonate was synthesized from radium-barium sulfate (226Ra0.76Ba0.24SO4) at room temperature and characterized by X-ray powder diffraction (XRPD) and extended X-ray absorption fine structure (EXAFS) techniques. XRPD revealed that fractional crystallization occurred and that two phases were formed─the major Ra-rich phase, Ra(Ba)CO3, and a minor Ba-rich phase, Ba(Ra)CO3, crystallizing in the orthorhombic space group Pnma (no. 62) that is isostructural with witherite (BaCO3) but with slightly larger unit cell dimensions. Direct-space ab initio modeling shows that the carbonate oxygens in the major Ra(Ba)CO3 phase are highly disordered. The solubility of the synthesized major Ra(Ba)CO3 phase was studied from under- and oversaturation at 25.1 °C as a function of ionic strength using NaCl as the supporting electrolyte. It was found that the decimal logarithm of the solubility product of Ra(Ba)CO3 at zero ionic strength (log10 Ksp0) is -7.5(1) (2σ) (s = 0.05 g·L-1). This is significantly higher than the log10 Ksp0 of witherite of -8.56 (s = 0.01 g·L-1), supporting the disordered nature of the major Ra(Ba)CO3 phase. The limited co-precipitation of Ra2+ within witherite, the significantly higher solubility of pure RaCO3 compared to witherite, and thermodynamic modeling show that the results obtained in this work for the major Ra(Ba)CO3 phase are also applicable to pure RaCO3. The refinement of the EXAFS data reveals that radium is coordinated by nine oxygens in a broad bond distance distribution with a mean Ra-O bond distance of 2.885(3) Å (1σ). The Ra-O bond distance gives an ionic radius of Ra2+ in a 9-fold coordination of 1.545(6) Å (1σ).

Increased In Vivo Exposure of N-(4-Hydroxyphenyl) Retinamide (4-HPR) to Achieve Plasma Concentrations Effective against Dengue Virus.

N-(4-hydroxyphenyl) retinamide (4-HPR, or fenretinide) has promising in vitro and in vivo antiviral activity against a range of flaviviruses and an established safety record, but there are challenges to its clinical use. This study evaluated the in vivo exposure profile of a 4-HPR dosage regime previously shown to be effective in a mouse model of severe dengue virus (DENV) infection, comparing it to an existing formulation for human clinical use for other indications and developed/characterised self-emulsifying lipid-based formulations of 4-HPR to enhance 4-HPR in vivo exposure. Pharmacokinetic (PK) analysis comprising single-dose oral and IV plasma concentration-time profiles was performed in mice; equilibrium solubility testing of 4-HPR in a range of lipids, surfactants and cosolvents was used to inform formulation approaches, with lead formulation candidates digested in vitro to analyse solubilisation/precipitation prior to in vivo testing. PK analysis suggested that effective plasma concentrations could be achieved with the clinical formulation, while novel lipid-based formulations achieved > 3-fold improvement. Additionally, 4-HPR exposure was found to be limited by both solubility and first-pass intestinal elimination but could be improved through inhibition of cytochrome P450 (CYP) metabolism. Simulated exposure profiles suggest that a b.i.d dosage regime is likely to maintain 4-HPR above the minimum effective plasma concentration for anti-DENV activity using the clinical formulation, with new formulations/CYP inhibition viable options to increase exposure in the future.

Solubility, density, conductivity, and phase equilibrium of NaBr - Ba(H2PO2)2 - H2O ternary system at 298 K

Solubility, density, conductivity, and phase equilibrium of NaBr - Ba(H2PO2)2 - H2O ternary system at 298 K

Solubility of ciprofloxacin in different solvents at several temperatures: Measurement, correlation, thermodynamics and Hansen solubility parameters

BackgroundCiprofloxacin is a commonly prescribed antibiotic drug whose solubility has not yet been completely studied. In this research, its equilibrium solubility at temperatures from T = (278.15 to 318.15) K in 13 neat solvents, namely, namely: 1,4-dioxane, polyethylene glycol (PEG) 600, PEG400, PEG300, N-methyl-2-pyrrolidone (NMP), PEG200, acetonitrile, N,N-dimethylformamide (DMF), ethanol, dimethyl sulfoxide (DMSO), methanol, ethylene glycol and water, is reported. MethodsFlask shake and UV–vis analysis were used for solubility determinations at different temperatures. Bottom solid phases were analyzed by DSC. Significant findingsMole fraction solubility of ciprofloxacin (x2) increases when temperature arises in all solvents. It varies from x2 = 4.11 · 10–6 in neat water to x2 = 1.55 · 10–3 in neat PEG200 at T = 298.15 K. Solubility behavior was adequately correlated by van't Hoff, van't Hoff-Yaws and Apelblat model. From the variation of solubility with temperature the apparent thermodynamic analysis of dissolution was performed in all the solvents. Total Hildebrand solubility parameter of ciprofloxacin (δ2) was calculated based on groups’ contributions by means of both the Fedors and the Hoftyzer-van Krevelen methods as δ2 = (26.4 and 25.7) MPa1/2, respectively. Otherwise, Hansen solubility parameters and total Hildebrand solubility parameter were also determined by using the Bustamante method from experimental solubility values in 16 neat solvents obtaining δ2 = 25.2 MPa1/2. Finally, KAT-LSER model was also employed to evaluate the role of different intermolecular interactions on the dissolution of ciprofloxacin.

Comprehensive analysis of thermodynamic models for CO2 absorption into a blended N,N‐diethylethanolamine‐1,6‐hexamethyl diamine (DEEA‐HMDA) amine

AbstractIn this work, CO2 equilibrium solubility of 1M N,N‐diethylethanolamine (DEEA):2M 1,6‐hexamethyl diamine (HMDA), 1.5M DEEA:1.5M HMDA and 2M DEEA:1M HMDA was studied with a temperature range of 298–333 K and CO2 partial pressure range of 8–100 kPa. Seven thermodynamic models including Empirical model, Kent and Eisenberg (KE) model, Hu–Chakma model, Austgen model, Helei Liu model, Liu et al. model, and Li–Shen model were developed by correlating reaction equilibrium constants with observed equilibrium solubility of CO2 in mixed amine solvents. The evaluation of those models was conducted in terms of the average absolute relative deviation (AARD). The results indicated that Liu et al. model considering T, [Amine], Ptotal and [CO2(aq)] can better represent this complex system with an AARD of 8.06%. Meanwhile, comprehensive comparison and analysis were also performed to identify the contribution of parameters to develop models, which could provide a guideline for the development of accurate thermodynamic models for representation of thermodynamic behaviors.

Monolayer High-Entropy Layered Hydroxide Frame for Efficient Oxygen Evolution Reaction.

High-entropy materials with tailored geometric and elemental composition provide a guideline for designing advanced electrocatalysts. Layered double hydroxides (LDHs) is a most efficient oxygen evolution reaction (OER) catalyst. However, due to the huge difference in ionic solubility product, an extremely strong alkali environment is necessary to prepare high-entropy layered hydroxides (HELHs), which results in the uncontrollable structure, poor stability and scarce active sites. Here, wepresent a universal synthesis of monolayer HELH frame in a mild environment, regardless of the solubility product limit. Mild reaction conditions allow usto precisely control the fine structure and elemental composition of the final product. Consequently, the surface area of the HELHs is up to 380.5 m2 g-1 . The current density of 100mA cm-2 is achieved in 1M KOH at an overpotential of 259mV. And after 1000 hours operation at the current density of 20mA cm-2 , the catalytic performance shows no obvious deterioration. The high-entropy engineering and fine nanostructure control open opportunities to solve the problems of low intrinsic activity, very few active sites, instability, low conductance during OER for LDH catalysts. This article is protected by copyright. All rights reserved.

Electroplating wastewater treatment by in-situ formation of organic anions and inorganic anions intercalated layered double hydroxides

The electroplating wastewater containing various metal ions was treated by adding sodium dodecyl benzene sulfonate (SDBS) and regulating pH value, and the resulting precipitates were characterized by X-ray diffraction (XRD). The results showed that organic anions intercalated layered double hydroxides (OLDHs) and inorganic anions intercalated layered double hydroxides (ILDHs) were in-situ formed to remove heavy metals during the treatment process. In order to reveal the formation mechanism of the precipitates, SDB− intercalated Ni–Fe OLDHs, NO3− intercalated Ni–Fe ILDHs and Fe3+-DBS complexes were synthsized by co-precipitation at various pH values for comparison. These samples were characterized by XRD, Fourier Transform infrared (FTIR), element analysis as well as the aqueous residual concentrations of Ni2+ and Fe3+ were detected. The results showed that OLDHs with good crystal structures can be formed as pH≤7, while ILDHs began to form at pH = 8. When pH < 7, complexes of Fe3+ and organic anions with the ordered layered structure were formed firstly, and then with increase in pH value, Ni2+ inserted into the solid complex and the OLDHs began to form. However, Ni–Fe ILDHs were not formed when pH ≤ 7. The Ksp (Solubility Product Constant) of OLDHs was calculated to be 3.24 × 10−19 and that of ILDHs was 2.98 × 10−18 at pH = 8, which suggested that OLDHs might be easier to form than ILDHs. The formation process of ILDHs and OLDHs were also simulated through MINTEQ software, and the simulation output verified that OLDHs could be easier to form than ILDHs at pH ≤ 7. Information from this study provides a theoretical basis for effective in-situ formation of OLDHs in wastewater treatment.

Experimental study of gas evolution and dissolution process

Changes in pressure above the saturated liquid in an airtight container can cause gas evolution and dissolution. In this study, a mathematical model was developed based on the relationship between the amount of dissolved gas and saturated solution pressure according to Henry’s law. The model can be utilized to predict changes in the pressure above the liquid, the rate of gas evolution and dissolution, and variations in free gas as the under- (over-)saturated solution reaches the saturated solution. The proposed model was built according to the solubility constant, gas-liquid volume ratio, initial equilibrium pressure of the saturated solution, and the half-life of gas evolution and dissolution. An experiment was also conducted to investigate gas evolution and dissolution; the setup included an electric vibration platform and an airtight container used to generate vibration. When the measured pressure above the liquid showed no change in the airtight container under sustained vibration, an equilibrium state was considered to be achieved. With industrial gear oil, anti-wear hydraulic oil, and water, respectively, as subjects, changes in the pressure and half-life period of gas evolution and dissolution in each liquid were measured under various gas-liquid volume ratios. Comparison against the experimental data and mathematical model pressure curves validated the models feasibility and effectiveness, and revealed that the half-life of gas evolution and dissolution decreases as the gas-liquid volume ratio increases.

Novel molecular hybrid geometric-harmonic-Zagreb degree based descriptors and their efficacy in QSPR studies of polycyclic aromatic hydrocarbons

ABSTRACT The physicochemical characteristics of polycyclic aromatic compounds critical to environmental modelling such as octanol partition coefficients, solubility, lipophilicity, polarity and several equilibrium constants are functions of their underlying molecular structures, prompting the development of mathematical models to predict such characteristics for which experimental results are difficult to obtain. We propose twelve novel descriptors derived from geometric, harmonic and Zagreb degree-based descriptors and then test the effectiveness of these descriptors on a data set consisting of 55 benzenoid hydrocarbons of environmental importance. Our computations show that the proposed descriptors have a good linear correlation and predictive power when compared to the degree and distance type descriptors. We have also derived the QSPR expressions for four properties of a large series of polycyclic aromatics arising from circumscribing coronenes and show that a scaling factor can be deduced to derive physicochemical properties of such series up to 2D graphene sheets.