A phosphorus flame retardant named resorcinol bis(cyclic 2,2-dimethyl-1,3-propanediol phosphate) (RCDMPP) was synthesized and characterized by high-performance liquid chromatography (HPLC), elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), mass spectra (MS), and nuclear magnetic resonance (NMR). Its thermal stability was evaluated via thermogravimetric analysis (TGA), and the fusion enthalpy and melting point of RCDMPP were detected by differential scanning calorimetry (DSC). The solubilities of RCDMPP in selected solvents at T = 293.15 to 333.15 K and atmospheric pressure were measured via a static-analytic method. The solubility data were correlated with modified Apelblat, Scatchard–Hildebrand, Buchowski-Ksiazczak (λh), nonrandom two liquid (NRTL), Wilson, and universal quasichemical (UNIQUAC) equations. The calculated results obtained from these models showed good agreement with the experimental data, and the NRTL, Wilson, and UNIQUAC models give better correlation results compared with modified Apelblat and λh models. The solubility parameter of RCDMPP was calculated by use of the Scatchard–Hildebrand methodology.

Simulating the typical carbonation step in a mineral CO2 sequestration, precipitated calcium carbonate (PCC) was prepared by bubbling CO2 gas into a rich Ca solution. These carbonation reactions were conducted at three pH ranges, namely 10.0–9.0, 9.0–8.0, and 8.0–7.0, in which temperature and CO2 flow rate are additional experimental variables. The PCC obtained in experiments was examined by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). It was found that supersaturation determined by pH value and flow rate of CO2 has significant influence on polymorph of PCC. Vaterite was preferably formed at high supersaturation, while dissolution of metastable vaterite and crystallization of calcite occurred at low supersaturation. High temperature is a critical factor for the formation of aragonite. At 70 °C, vaterite, calcite and aragonite were observed to coexist in PCC because transformation from vaterite to aragonite via calcite occurred at this temperature. Scanning electron microscopy (SEM) technology was performed on prepared PCC, and various morphologies consistent with polymorphs were observed.

A phosphorous flame retardant of phosphoric acid, P,P′-1,4-phenylene P,P,P′,P′-tetraphenyl ester (PAPTE) was synthesized by diphenyl chlorophosphate and hydroquinone. The structural features of PAPTE were investigated with mass spectra (MS), infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and high-performance liquid chromatograph (HPLC) methods. The thermal behavior of PAPTE was analyzed with differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) instruments. A static analytic method was used to measure the solubilities of PAPTE in the several selected pure solvents, which are methanol, ethanol, acetone, ethyl acetate, acetonitrile, methyl acetate, toluene, ether, n-propanol, i-propanol, where the temperatures range is from 288.25 to 333.45 K. The experiments were also performed in the binary mixed solvents of acetone and methanol. Several thermodynamic models were used to correlate the experimental solubility data, such as Wilson, nonrandom two-liquid (NRTL), UNIQUAC equations. The solubility data of PAPTE in binary solvents were correlated with the modified Wilson model. The calculated results showed that those models can excellently reproduce the experimental data and the UNIQUAC equation reveals the better ability in correlation. Using the Scatchard–Hildebrand methodology, the activity coefficients, solubility parameter of the solute and the partial molar excess enthalpies at infinite dilution were calculated.

•The solubilities of DPAP in twelve selected solvents were first performed in this work from 293.15 to 333.15 K.•The solubility parameter of the solute was obtained. The dissolution enthalpy, entropy, and Gibbs energy were calculated.•The measured results were correlated by λh, NRTL, Wilson, and UNIQUAC models. The model parameters were given in paper.A phosphorus flame retardant named diphenyl anilinophosphonate (DPAP) was synthesized using diphenyl chlorophosphate and aniline. Its structural features and purity were investigated by mass spectrometry (MS), infrared spectroscopy (IR), nuclear magnetic resonance (NMR) spectroscopy, and high-performance liquid chromatography (HPLC). The thermal properties of DPAP were evaluated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A static-analytic method was used to measure the solubilities of DPAP in acetonitrile, methanol, chloroform, ethanol, acetone, toluene, i-propanol, n-propanol, methyl acetate, ethyl acetate, 1,2-dichloroethane, and tetrahydrofuran from 293.15 to 333.15 K. Several thermodynamic models were used to correlate the experimental solubility data, such as the van’t Hoff equation, Buchowski–Ksiazczak (λh), Scatchard–Hildebrand, Wilson, nonrandom two-liquid (NRTL), and UNIQUAC. The calculated results showed that these models can reproduce the experimental data well, and that the NRTL equation gives the best correlation. The activity coefficients and solubility parameters of the solute were calculated using the Scatchard–Hildebrand methodology.

Using a static analytical method, the solubilities of phosphonic acid, P,P′-(1,4-piperazinediyl)bis-P,P,P′,P′-tetraphenyl ester (PAPBE), N,N′-[1,3-phenylenebis(methylene)]bis(phosphoramidic acid)P,P,P′,P′-tetraphenyl ester (PNBE), and 4-(hydroxymethyl)-1-oxido-2,6,7-trioxa-1-phosphabicyclo [2.2.2] octane (PEPA) were measured from 293.15 K to 343.15 K in four selected organic solvents. Several thermodynamic models were used to correlate the experimental solubility data, such as Scatchard–Hildebrand, Wilson, nonrandom two-liquid (NRTL), and UNIQUAC. The calculated results showed that all the models reproduced the experimental data very well, and the UNIQUAC equation gives the best correlation. Using the group contribution methods, the solubility parameters of phosphorus flame retardants can be calculated, which were compared with the previous values calculated with the Scatchard–Hildebrand model.

Dissolution trend and solubility data of calcium sulfate dihydrate (CaSO4·2H2O gypsum) in aqueous Na, Ca, Mg, and Al chloride salt solutions have been studied at 278.15 K to 308.15 K. The concentration ranges were up to 4.5 mol·L–1 for NaCl, 3.0 mol·L–1 for MgCl2, 2.0 mol·L–1 for CaCl2, and 1.6 mol·L–1 for AlCl3, respectively. Measurement results show that except for CaCl2, the other three salts allow the solubility of gypsum to rise a lot first and then descend smoothly after attaining the maximum. Because of common ions effect, the solubility of CaSO4·2H2O drops sharply in CaCl2 solution at low concentration and continues to fall almost linearly as concentration exceeds 0.2 mol•kg–1. Impacts of Na, Mg, Al chloride salts on solubility of CaSO4·2H2O are explained on the basis of dissolution and thermodynamic equilibrium. The solubility of CaSO4·2H2O in AlCl3 solution is highest compared with that in NaCl and MgCl2 solution because two sulfur-bearing chemical complex Al(SO4)2–(aq) and AlSO4+(aq) are expected to be formed in solution. Besides, a number of H+ ions produced in AlCl3 solution further promote the dissolution of CaSO4·2H2O. In addition, it is demonstrated that CaSO4·2H2O is fairly stable in the above chloride salts solution of high concentration (4.5 mol·L–1 for NaCl, 3.0 mol·L–1 for MgCl2, 2.0 mol·L–1 for CaCl2 and 1.6 mol·L–1 for AlCl3) for 2 weeks at 308.15 K by the evidence that no new peaks emerged in X-ray power diffraction results.

•We collect a database on activity coefficients of organic solutes at infinite dilution in ionic liquids.•We model activity coefficients to correlate the solubility parameter of ionic liquids.•Higher selectivity is achieved when using ionic liquids to separate xylene isomers.A database on activity coefficients of organic solutes at infinite dilution in ILs was collected from literature sources. The activity coefficient model with the combinatorial term represented by the Kikic et al. was used as a modification to Flory's equation. The activity coefficients had been used to correlate the solubility parameter of ionic liquids. The obtained solubility parameters of ionic liquids had been further correlated based on a concept of the group contribution method. Through the analysis of the database and the prediction results of selectivities at infinite dilution of xylene isomers, we showed that higher selectivity can be achieved by using ILs as working solvents for separation of xylene isomer mixtures.

•We measured the solubilities of DOPNP in different pure solvents.•Several models were applied to correlate the solubility data.•ΔHd, ΔSd, and ΔGd of DOPNP are predicted in different pure solvents.Using a static analytic method, experimental solubility data were obtained for tetra(5,5-dimethyl-1,3-dioxaphosphorinanyl-2-oxy) neopentane (DOPNP) in acetonitrile, acetone, methanol, ethanol, ethyl acetate, methyl acetate and methylethylketone at temperatures ranging from 293 to 333 K. Several commonly used thermodynamic models, including the ideal, modified Apelblat, Wilson, UNIQUAC and NRTL models, were applied to correlate the experimental solubility data. The binary interaction parameters of the above models were found to have a linear dependency on temperature and the coefficients were regressed. It can be seen that NRTL model is more suitable in describing the solubility data of DOPNP, compared with the other models. By using the van’t Hoff equation, the dissolution enthalpy, dissolution entropy, and Gibbs free energy change of DOPNP are predicted in different pure solvents.

•We measured the solubilities of flame retardant BSDOPE in selected solvents.•Several thermodynamic models were applied to correlate the experimental data.•The thermal stability of BSDOPE was investigated by TGA.A phosphorus-containing flame retardant, bisphenol S-bis (5,5-dimethyl-1,3-dioxaphosphorinanyl-2-oxy phosphate ester) (BSDOPE), was synthesized and characterized by elemental analysis (EA), mass spectra (MS), infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). The thermal stability of BSDOPE was investigated by thermogravimetric analysis (TGA). The solubilities of flame retardant BSDOPE in selected solvents are measured. Several thermodynamic models, including the ideal, modified Apelblat, Wilson, NRTL, UNIQUAC, the combined Nearly Ideal Binary Solvent (NIBS)/Redlich–Kister, and Scatchard–Hildebrand models, were applied to correlate the experimental solubility data. The results show that the calculated values indicated good agreement with the experimental data.

N,N′-[1,3-Phenylenebis(methylene)]bis(phosphoramidic acid) P,P,P′,P′-tetraphenyl ester (PNBE) was synthesized and characterized by elemental analysis, mass spectrometry, and IR and NMR spectroscopy. The melting point and the enthalpy of fusion of PNBE were obtained by differential scanning calorimetry, and the thermal stability of PNBE was measured by thermogravimetric analysis. The solubilities of PNBE in selected solvents were determined by a gravimetric method. The experimental data were correlated with the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) equations. The calculated results showed good agreement with the experimental data. Among them, the Wilson model gave the best description of the solubility data. The solubility parameter of PNBE was evaluated using the Scatchard–Hildebrand model. The data presented in this work will be helpful for the choice of solvents for the solution-casting process and optimization of the dissolution or purification of PNBE.

A phosphorus flame retardant of 4-(hydroxymethyl)-1-oxido-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (PEPA) was synthesized by pentaerythritol and phosphorus oxychloride at a certain condition. The structural features of PEPA were investigated with Fourier transform infrared spectroscopy and 1H NMR methods. The thermal behavior of PEPA was carried out with differential scanning calorimetry and thermogravimetric analysis instruments. A static analytic method was used to measure the solubilities of the PEPA in several organic solvents. The measurements were accurately acted in ethyl acetate, acetonitrile, isopropyl alcohol, ethanol, n-propyl alcohol, acetone, methanol, and chloroform at the temperature range from 292.75 K to 333.45 K. Using the Scatchard–Hildebrand methodology, the activity coefficients of the solute have been calculated, and the partial molar excess enthalpies at infinite dilution were also predicted.

N,N′-(Methylenedi-4,1-phenylene)bis(phosphoramidic acid) tetraphenyl ester (PNBTE), a flame retardant with high thermal stability, was synthesized and characterized by elemental analysis (EA), mass spectrometry (MS), infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). The thermal properties of PNBTE were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The solubilities of PNBTE in selected solvents were measured by a gravimetric method. The experimental data were correlated with Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) equations. The calculated results showed good agreement with the experimental data. The solubility parameter of PNBTE was estimated by the Scatchard–Hildebrand model; meanwhile, the dissolution enthalpy and entropy, and molar Gibbs energy of PNBTE in the selected solvents are also calculated by the van’t Hoff equation.

Phosphonic acid, P,P′-(1,4-piperazinediyl)bis-,P,P,P′,P′-tetraphenyl ester (PAPBE), as a versatile flame retardant, was prepared by a literature method. The solubilities of PAPBE in selected solvents have been measured under a range of temperatures from 283.15 K to 343.15 K. The experimental data were correlated with the Buchowski–Ksiazczak (λh), Scatchard–Hildebrand, Wilson, nonrandom two liquid (NRTL), and universal quasichemical (UNIQUAC) equations. The calculated results showed good agreement with the experimental data. The differential values of enthalpy and entropy of dissolution at saturation were also calculated by the van’t Hoff equation. Toluene and acetone are shown to be good candidates as reaction solvents that can be applied to optimize the reactive crystallization process.

The solubility of tris(3-hydroxypropyl)phosphine oxide (THPPO) in selected solvents was measured by a static analytic method over the temperature range from (293 to 328) K in methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, acetone, and a binary solvent mixture of ethanol + acetone. Several widely used thermodynamic models, such as the empirical equation and the Buchowski–Ksiazaczak (λh), Scatchard–Hildebrand, Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) equations were applied to represent the measurement results. The binary interaction parameters of the above models were found to have a linear dependency on temperature, and the coefficients were regressed. The results show that all of these models can satisfactorily reproduce the experimental data and the NRTL equation can provide the best correlation with an overall relative standard deviation of 0.46 %.

The solubilities of 2-[(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)methyl]butanedioic acid (DDP) in selected solvents were measured by a static analytic method. The measurements were carried out over the temperature range from 293 to 353 K in methanol, ethanol, 1-propanol, tetrahydrofuran, 1,4-dioxane, ethyl acetate, toluene, benzene, and cyclohexane. Several commonly used thermodynamic models, including the empirical equation and the Scatchard–Hildebrand, Wilson, nonrandom two-liquid, and UNIQUAC equations, were applied to correlate the experimental solubility data. The binary interaction parameters of the above models were found to have a linear dependence on the temperature, and the coefficients were regressed. It was found that all of these models can satisfactorily reproduce the experimental data and the UNIQUAC equation can provide the best correlation results with an overall relative standard deviation of 1.52%.

Solubilities of hexaphenoxycyclotriphosphazene and tri(2-cyanoethyl)phosphine in selected solvents were measured in this work using a static analytical method. The solubilities of a series of phosphorus-containing flame retardants in organic solvents and water were recently measured in our laboratory. Based on these data and the solid–liquid equilibrium equation for the solute, the activity coefficients of these flame retardants were derived in pure solvents. The Scatchard–Hildebrand activity coefficient model was used to correlate these activity coefficients and the solubility parameters of the solutes were obtained. With the help of the analysis of the solubility parameters for the solute and solvents, solubility enhancement can be achieved due to the occurrence of the synergetic effect of the mixed solvent.

The solubility of lithium bromide and lithium nitrate in solvents methanol, ethanol, 1-propanol, 2-propanol and 1-butanol were measured in the range between 298.15 and 338.15 K using an analytical gravimetric method. An empirical equation was used to fit the experimental solubilities and the Pitzer model with inclusion of Archer's ionic strength was used for the calculation of osmotic coefficients. The experimental data of system pressures (p) for the correlation of LiBr + ethanol, LiBr + 2-propanol at T (298.15–333.15 K) and LiNO3 + ethanol at T (298.15–323.15 K) were obtained from published literatures. Moreover, the parameters of the Pitzer model were re-correlated and were used to predict mean ion activity coefficients. A procedure was also presented to predict the solubility products of salts in pure organic solvent.Highlights► Solubility data of LiBr and LiNO3 in alcohols. ► Temperature range is between 298.15 and 338.15 K. ► Solubility products of the salts in pure organic solvent. ► Osmotic coefficients calculated based on Pitzer model.

Activity coefficients at infinite dilution of pentane, hexane, heptane, octane, nonane, cyclohexane, methylcyclohexane, 2,2,4-trimethylpentane, cyclohexene, styrene, benzene, toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene in 1-decyl-3-methylimidazolium tetrafluoroborate have been determined using gas−liquid chromatography over a temperature range of (303.15 to 363.15) K with the ionic liquid as the stationary phase. The partial molar excess enthalpies at infinite dilution were also determined for the solutes from the temperature dependence of the experimental activity values.

Mutual solubilities of water and the ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium hexafluorophosphate, and 1-octyl-3-methylimidazolium hexafluorophosphate were measured between (278.15 and 364.15) K at atmospheric pressure. The temperature dependence of the solubilities of ILs in water and water in ILs have calculated from experimental data. The proposed correlations showed a relative maximum deviation from the experimental mole fraction data of 4.7 %. The liquid−liquid equilibrium data were correlated by the nonrandom two-liquid (NRTL) equation, and the average root-mean-square deviation of the mole fractions for the three ionic liquid + water mixtures is 0.0025.

Ionic liquid 1-methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate ([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy (IR), nuclear magnetic resonance (1H and 13C NMR) and ultraviolet-visible (UV-Vis) spectra. Its thermal stability was also examined by thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). The mole fraction solubilities of [C3SO3HMIM][HSO4]) in 12 selected solvents (n-pentane, n-hexane, n-heptane, benzene, toluene, ethylbenzene, acetone, 2-butanone, 3-methyl-2-butanone, tetrahydrofuran, ethyl acetate and dichloromethane) in the temperature range from 289.15 to 363.15 K were measured using a static analytical method and correlated with an empirical equation.