The solubility of theobromine, theophylline, and caffeine in water and five organic solvents including methanol, ethanol, 1-propanol, ethyl acetate, and acetone was determined by a high performance liquid chromatography method at T = (288.15 to 328.15) K and atmospheric pressure. It was found that the solubility of theobromine, theophylline, and caffeine in these solvents increased with increasing temperature. The empirical Apelblat equation and universal quasichemical model were used to correlate the experimental solubility. The results showed that both models can satisfactorily correlate the solubility data. The crystal forms of the solutes in equilibrium with the saturated solution were analyzed using scanning electron microscopy and powder X-ray diffraction.

Thermophysical properties including densities and viscosities of naringenin in aqueous solutions of ethanol/1-propanol with alcohol concentrations of (24.00 to 40.00) mol·kg–1 have been measured as a function of concentration of naringenin at temperatures from (293.15 to 323.15) K and atmospheric pressure. Also, refractive indices for studied systems have been determined at 298.15 K. The measured data were used to calculate the apparent molar volume (Vϕ), standard partial molar volume (Vϕ0), partial molar volume (V̅), viscosity B-coefficients, and molar refractions (Rm). The viscosity and refractive index data have been analyzed by Jones–Dole and Lorentz–Lorenz equations, respectively. The trends of variation of experimental and calculated parameters have been discussed according to the interactions between solvents and solute. The obtained results imply that naringenin acts as a structure maker in the studied system.

The solubilities of 4′,5,7-triacetoxyflavanone in eight different alcohols, 2-methoxyethanol, 2-propoxyethanol, 2-butoxyethanol, ethyl acetate, tetrahydrofuran, and acetone have been measured with an HPLC (high-performance liquid chromatography) analysis method at the experimental temperature from 278.2 to 318.2 K. The solubilities of 4′,5,7-triacetoxyflavanone in selected solvents increase with an increasing of temperature. The solubilities of 4′,5,7-triacetoxyflavanone were correlated with the modified Apelblat equation and universal quasichemical (UNIQUAC) equation, respectively. The correlated solubilities were in good accordance with the measured data at the experimental temperature. Furthermore, the crystal habits of 4′,5,7-triacetoxyflavanone in selected solvents were studied in this work.

•Reference standard extract was used to assess quality of functional food.•The main components in reference standard extract were standardized.•Batches of Platycodi Radix were evaluated by the reference standard extract method.•The results characterized by this method were compared with that characterized by conventional method.Platycodi Radix, the root of Platycodon grandiflorum A. De Candolle, is a widely used functional food in East Asia. Reference standard extract, a mixture of marker compounds, is used as a reference substance to quantify platycosides from Platycodi Radix. The convenience and consistency of using reference standard extract as a reference substance was evaluated. The qualitative and quantitative results of platycoside contents in Platycodi Radix characterized by this method were compared with that characterized by the conventional external standards method. The Pearson correlation coefficient test of these two methods was between 0.985 and 0.999. A more comprehensive chemical information including relative retention time, relative peak area and contents of active components were obtained simultaneously from raw material using reference standard extract method. The application of this method may relieve the stress in increasing demands for pure marker compounds.

•QAMS may be more effective and practicable than normal external standard method.•The verified QAMS could be an alternative and promising method for quality control.•The inherent quality was distinct between the extracts from different origins.•Hierarchical cluster analysis and canonical discriminant analysis were employed.•Taguchi Design was introduced to evaluate the fluctuations and applicability of QAMS.The quality of tea is mainly attributed to tea polyphenols and caffeine. In this paper, a new strategy for quality evaluation of green tea extracts was explored and verified through qualitative and quantitative analysis of multi-components by single marker (QAMS). Taguchi Design was introduced to evaluate the fluctuations of the relative conversion factors (fx) of tea catechins, gallic acid and caffeine to epigallocatechin gallate. The regression model (Sig. = 0.000) and the deviations (R2 > 0.999) between QAMS and normal external standard method proved the consistency of the two methods. Hierarchical cluster analysis and canonical discriminant analysis were employed to classify 26 batches of commercial Longjing green tea extracts (LJGTEs) collected from different producers. The results showed a significant difference in component profile between the samples from different origins. The QAMS method was verified to be an alternative and promising method to comprehensively and effectively control the quality of LJGTEs from different origins.

•Nine platycosides were simultaneously separated.•Linear scale-up of the separation variables.•Post-HPLC treatment stopped the acetyl migration.•First time to obtain unstable platycosides by HPLC.A method of using semi-preparative HPLC coupling with a post-HPLC flash freezing treatment to separate platycosides from Platycodi Radix is developed. Nine platycosides including unstable acetyl platycosides were separated from Platycodi Radix by semi-preparative HPLC. Separation variables of flow rate and loading amount of sample were linearly scaled up from analytical HPLC to semi-preparative HPLC. Variables of semi-preparative HPLC separation including flow rate and loading amount of sample were calculated as 29.8 mL/min and 297.7 mg, respectively. Under the optimized conditions of separation, nine platycosides were simultaneously separated on semi-preparative scale within 1 h. Separation resolutions of the peaks of platycosides were all above 0.85, of which seven platycosides were separated with resolutions above 1.00. With regards to sample pretreatment before chromatography separation, we propose a post-HPLC treatment to the unstable compounds. A post-HPLC treatment by using liquid nitrogen to flash freeze the eluent fractions from semi-preparative HPLC was used to stop the unstable platycosides transformation. By freezing treatment, the pure unstable acetyl platycosides were obtained without transformation. This was the first time that unstable acetyl platycosides were simultaneously separated by preparative HPLC. This method is fast and efficient to separate platycosides from Platycodi Radix, especially for purifying unstable platycosides.

•Rh(III)-catalyzed double molecular alkyne imine C–H activation.•Obtained functionalized benzo[c]acridine and thieno[3,2-c]acridine compounds.•The readily accessible starting materials and simple operation.The construction of a new nitrogen heterocyclic ring via the C–H activation is a facile and efficient protocol to afford polysubstituted acridine compounds from simple, readily available starting materials. In this Letter, functionalized benzo[c]acridine and thieno[3,2-c]acridine compounds have been accomplished by the method of Rh(III)-catalyzed double molecular alkyne imine C–H activation.

Naringin dihydrochalcone (naringin DC) is an intense sweetener and a strong antioxidant with potential applications in many food and pharmaceutical products. However, the poor solubility and stability of naringin DC in aqueous systems at room temperature severely limits its applications in these areas. The solubility of naringin dihydochalone was quantified in water, ethyl acetate, binary solvent mixtures of methanol + water and ethanol + water by a synthetic method at different temperatures. The solubility of naringin DC in a given solvent increases with the rising temperature. The experimental data were well correlated with an Apelblat equation and Universal Quasichemical model. Moreover, the physical properties and crystal habit of naringin DC were discussed through a thermogravimetric analyzer, a differential scanning colorimeter, and a scanning electron microscope.

The solubilities of phloretin, phlorizin, and naringin dihydrochacone (naringin DC) respectively were determined in a ternary system made of natural deep eutectic solvents (NADES) at the temperature range from 288.15 to 328.15 K with an analytical method. Compared with the solubility of phloretin in water, there was a dramatic improvement in the solubility of phloretin in the selected NADES, especially in CCiH and CSH. The density and viscosity of four kinds of NADES choline chloride + glucose + H2O, choline chloride + citric acid + H2O, citric acid + glucose + H2O, and choline chloride + sucrose + H2O were studied in this work. The solubility data were correlated with Apelblat equation and λh equation. The fitted results showed that the models are capable of representing the data with high accuracy.

Epigallocatechin gallate (EGCG) is the most abundant and active components in tea. In this text, the density and viscosity of ternary aqueous solution of EGCG containing LiCl/NaCl/KCl were determined at temperatures ranging from 288.15 to 308.15 K at atmospheric pressure. The density data was used to compute the apparent molar volumes (Vφ), limiting partial molar volumes (Vφ0), and transfer partial molar volumes (ΔtrsVφ0). The viscosity B-Coefficients were calculated from the measured viscosity data using the extended Jones–Dole equation. The values of density and viscosity increased continuously with the increasing of molality of EGCG and decreased with the temperature increasing. The positive values including (Vφ, Vφ0, ΔtrsVφ0, viscosity B-Coefficients, the free energies of activation for solvent Δμ10≠, and for solute Δμ20≠) and Helper’s constant (∂2Vφ0/∂T2)p close to zero indicated the presence of strong solute–solvent interactions and the structure–making effect of EGCG in the investigated solutions. The apparent molar isobaric expansions (Eφ0) decreasing with temperature suggested that the solute–solvent interactions became weaker as temperature increased. These significant parameters could provide necessary data about molecular interactions occurring in simulated body fluids.

A modified synthetic method with a high definition visual camera technique for measuring the solubility of solutes in solvents or mixed solvents was proposed. To verify the reliability of the experimental apparatus, the solubility of NH4Cl in water was determined at different temperatures. The relative standard errors were less than 1%, compared to the literature data. The solubilities of betulonic acid in six organic solvents from (278.15 to 313.15) K were measured and correlated with the Apelblat equation and universal quasichemical equation, respectively. The modified method was quite concise and user-friendly, and made the process of dissolution to become visualized and automatic.

•The solubilities of betulinic acid in the THF + water were determined at different temperatures.•The highest solubility value is obtained in the pure THF.•The thermodynamic properties of the solution process and the crystal habit of betulinic acid were discussed.The solubilities of betulinic acid in binary solvent mixtures of THF + water in the temperature range of (278.2–318.2) K were determined by an analytical method. The solubility of betulinic acid in a binary solvent mixture increased with the increase of molar fraction of THF and the temperature. The solubilities data were correlated with a semi-empirical equation. The calculated solubilities showed good agreement with the experimental data. According to the Van’t Hoff equation and the Gibbs equation, the thermodynamic properties for the solution process including Gibbs energy, enthalpy, and entropy were obtained. The crystal habit of betulinic acid changes in morphology at different solvent mixtures was observed using SEM.

•The excess molar enthalpies for four binary systems of diethyl oxalate + alcohols were determined.•The densities of the diethyl oxalate at different temperature were measured.•The excess molar enthalpies increase with temperature and the molecular size of the alcohols.•The experimental data were correlated by two local-composition models (NRTL and UNIQUAC).A flow-mixing isothermal microcalorimeter was used to measure excess molar enthalpies for four binary systems of {diethyl oxalate + (methanol, + ethanol, + 1-propanol, and + 2-propanol)} at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa. The densities of the diethyl oxalate at different temperature were measured by using a vibrating-tube densimeter. All systems exhibit endothermic behaviour over the whole composition range, which means that the rupture of interactions is energetically the main effect. The excess molar enthalpies increase with temperature and the molecular size of the alcohols. The experimental results were correlated by using the Redlich–Kister equation and two local-composition models (NRTL and UNIQUAC).

The solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in water, methanol, ethanol, 1-propanol, 1-butanol, acetone, and ethyl acetate from T = (288.2 to 328.2) K were measured. The solubilities of apigenin and apigenin 7-O-rhamnosylglucoside in selected solvents increase with increasing temperature, respectively. The experimental solubility data were correlated by a simplified thermodynamic equation and a three-parameter empirical equation.

Excess molar enthalpies for four binary systems of methyl acetoacetate + (methanol, + ethanol, + 1-propanol, and + 2-propanol) at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa were determined by using a flow-mixing isothermal microcalorimeter. The excess molar enthalpies increase with temperature and the molecular size of the alcohols. The experimental data were correlated by using the Redlich–Kister equation. The densities of the methyl acetoacetate at different temperatures were measured by using a vibrating-tube densimeter.

The solubilities of betulinic acid in methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 1-hexanol, ethyl formate, ethyl acetate, butyl acetate, acetone, and tetrahydrofuran were measured by an analytical method in the temperature range of (278.2 to 318.2) K. The experimental data were correlated with a three-parameter empirical equation and UNIQUAC model, respectively. The calculated solubilities showed good agreement with the experimental data over this temperature range. Furthermore, the relation of the solubilities and the crystal habit were discussed.

The solubilities of phloretin in methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol, pentan-1-ol, hexan-1-ol, ethyl acetate, butyl acetate, 1,4-dioxane, and water were measured at T = (288.2, 298.2, 308.2, 318.2, and 328.2) K and atmosphere pressure. The experimental results show that the phloretin is soluble in methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol, pentan-1-ol, hexan-1-ol, ethyl acetate, butyl acetate, and 1,4-dioxane but insoluble in water. The solubilities of phloretin in selected solvents increase with increasing temperature. A simplified thermodynamic equation and a three-parameter Apelblat equation were used to correlate the experimental data.

The solubility of luteolin in ethanol + water was measured at (273.15 to 323.15) K using high-performance liquid chromatography (HPLC). The solubility of luteolin in ethanol + water mixed solvents presents a maximum-solubility effect. The modified Apelblat equation was used to correlate the experimental data and exhibited good agreement. A relatively appropriate process was given for the purification of luteolin, with rutin as an impurity.

The solubilities of apigenin in ethanol + water mixtures at T = (273.2 to 323.2) K were measured by using high-performance liquid chromatography (HPLC). The solubilities of apigenin increase with increasing temperatures and go through a maximum at a specific solvent composition. The experimental data of solubilities were correlated by a three-parameter empirical equation.

Excess molar enthalpies for four binary systems of diethyl malonate + (methanol, + ethanol, + 1-propanol, and + 2-propanol) at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa were determined by using a flow-mixing isothermal microcalorimeter. The excess molar enthalpies increase with temperature and the molecular size of the alcohols. The experimental data were correlated by using the Redlich−Kister equation and two local-composition models (NRTL and UNIQUAC). The densities of the diethyl malonate at different temperature were measured by using a vibrating-tube densimeter.

Excess molar enthalpies of five binary systems for ethyl acetoacetate + (1-butanol, + 2-butanol, + 1-pentanol, + water, and + ethyl acetate) at T = (298.15, 313.15, 328.15, 338.15, and 348.15) K and p = 0.1 MPa were determined by a flow-mixing isothermal microcalorimeter. The excess molar enthalpies increase with an increase in the temperature. The experimental data were correlated by the Redlich−Kister equation.

The solubilities of rutin in ethanol + water were measured by using high-performance liquid chromatography (HPLC) in the temperature range from (273.15 to 323.15) K. The experimental data were correlated with a three-parameter equation. Four crystal forms of rutin obtained in different compositions of ethanol + water were characterized by TG, DSC, and scanning electron microscopy (SEM).

Excess molar enthalpies of six binary systems for acetophenone + (1-butanol, + 2-methyl-1-propanol, + 1-pentanol, + n-heptane, + cyclohexane, and + water) at T = (298.2, 313.2, 328.2, 338.2, and 348.2) K and p = 101.3 kPa and two binary systems for acetophenone + (n-hexane, and + ethyl acetate) at T = (298.2, 313.2, and 328.2) K and p = 101.3 kPa were determined by a flow-mixing isothermal microcalorimeter. The excess molar enthalpies increase with an increase in the temperature. The experimental data were correlated by the Redlich−Kister equation and two local composition models (NRTL and UNIQUAC).

A high-pressure flow-mixing isothermal calorimeter was used to determine the excess molar enthalpies of four binary systems for N,N-dimethylethanolamine + (methanol, ethanol, 1-propanol, and 2-propanol) at T = (298.2, 313.2, and 328.2) K and p = (0.1 and 10.0) MPa. The experimental data were correlated by the Redlich−Kister equation and three local composition models (Wilson, NRTL, and UNIQUAC).

Molar excess enthalpies of four binary systems for 2,4-pentanedione + (methanol, + ethanol, + 1-propanol, and + 2-propanol) at T = (298.15, 313.15, and 328.15) K and p = (0.1 and 10.0) MPa were determined by a high-pressure flow-mixing isothermal microcalorimeter. The molar excess enthalpies increased with an increase in the temperature and the molecular size of alcohols and decreased slightly with an increase in pressure. The experimental data were correlated by the Redlich–Kister equation and three local composition models (Wilson, NRTL, and UNIQUAC).

The solubilities of trans-resveratrol in different compositions of ethanol + water mixtures and acetone + water mixtures were measured at different temperatures. The solubilities of trans-resveratrol in ethanol + water mixtures increase with increasing mole fraction of ethanol, whereas the solubility curve (the solubilities vs the mole fraction of acetone on solute-free basis) of an acetone + water mixed system presents a maximum. The solubilities of trans-resveratrol in both mixture systems increase with increasing temperature. The experimental solubility data were correlated by a three-parameter empirical equation and UNIQUAC model, respectively.

Excess molar enthalpies of four binary systems for acetophenone + (methanol, + ethanol, + 1-propanol, and + 2-propanol) at T = (298.15, 313.15, 328.15, 338.15, and 348.15) K and p = (0.1 and 10.0) MPa were determined by a high-pressure flow-mixing isothermal microcalorimeter. The excess molar enthalpies increased with an increase in the temperature, pressure, and the molecular size of alcohols. The experimental data were correlated by the Redlich–Kister equation and three local composition models (Wilson, NRTL, and UNIQUAC).

Enthalpies of dilution of formamide in aqueous n-propanol, 1,2-propanediol and glycerol solutions have been determined by isothermal calorimetry at 298.15 K. The values of dilution enthalpy were used to determine homogeneous enthalpic interaction coefficients which characterize the interactions of formamide in alcohol solutions. The variations of the enthalpic pairwise interaction coefficients with the mass fraction of alcohol in mixtures are interpreted in terms of solute–solute and solute–solvent interactions.

The solubilities of rutin in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, and ethyl acetate were determined at T = 283.15, 298.15, 313.15, 323.15, and 333.15 K using RP-HPLC. The solubilities of rutin in pure solvents increase with increasing temperature except ethyl acetate. A simplified thermodynamic equation and an empirical equation were used to correlate the experimental data. These data of solubility can be used to purify the reaction mixture system.