Thermodynamic Difference between Protocatechualdehyde and p-Hydroxybenzaldehyde in Aqueous Sodium Chloride Solutions

Abstract

The enthalpies of dilution of protocatechualdehyde and p-hydroxybenzaldehyde in the aqueous sodium chloride solutions were measured by using a mixing-flow microcalorimeter at 298.15 K. Densities of the ternary homogeneous systems at different temperatures (293.15, 298.15, 303.15, 308.15, and 313.15 K) were also measured with a quartz vibrating-tube densimeter. The homogeneous enthalpic interaction coefficients (h 2, h 3, and h 4) were calculated according to the excess enthalpy concept based on the calorimetric data. The apparent molar volumes (V ϕ) and standard partial molar volumes (V ϕ 0) of the investigated system were computed from their density data. The variation trends in h 2 and V ϕ 0 with increasing salt molality were obtained and discussed in terms of the (solute + solute) and (solute + solvent) interactions. The experimental results showed that the molecular structures of protocatechualdehyde and p-hydroxybenzaldehyde, especially the number of hydroxyl groups, have evident influence on their thermodynamic properties. The thermodynamic data obtained in this work may be helpful for exploring the structure–function relationship of protocatechualdehyde and p-hydroxybenzaldehyde.

Volumetric, Viscometric, and Refractive Index Studies of Drug Nicotinic Acid in Aqueous d-Xylose/l-Arabinose Solutions from 293.15 to 313.15 K: Insights into Solute–Solute and Solute–Solvent Interactions

“…Second, the data presented in Table show that the values of both V ϕ 0 and Δ trs V ϕ 0 are positive in the research systems, which indicates that the hydrogen bond interactions (d) between the hydrophilic sites of the nicotinic acid molecule and the hydroxyl groups of carbohydrates dominate the overall solute–solvent interaction processes in the ternary systems investigated in this study . Notably, similar results were also observed by Pandit et al .…”

“…Second, the data presented in Table 4 show that the values of both V ϕ 0 and Δ trs V ϕ 0 are positive in the research systems, which indicates that the hydrogen bond interactions (d) between the hydrophilic sites of the nicotinic acid molecule and the hydroxyl groups of carbohydrates dominate the overall solute−solvent interaction processes in the ternary systems investigated in this study. 4 Notably, similar results were also observed by Pandit et al 29 for nicotinic acid in aqueous sodium malonate solutions and by Tyunina et al 23 for nicotinic acid in aqueous amino acid buffer solutions, wherein V ϕ 0 and Δ trs V ϕ 0 values were positive. Third, the study shows that in the aqueous solutions of carbohydrate with the same molality and at the same temperature, the values of both V ϕ 0 and Δ trs V ϕ 0 in L-arabinose solution are greater than those in D-xylose solution; however, the S v value is smaller than that in D-xylose solution.…”

“…Volumetric analysis is a crucial method of elucidating the physicochemical phenomena of solutes in solution. − Moreover, the viscosity and refractive index of the mixed solution are two other important parameters that can provide valuable information for a better understanding of intermolecular interactions. − It is well known that most biochemical processes occur in aqueous media. Therefore, research on the volumetric properties, viscometric properties, and refractive indices of drugs in aqueous media is helpful for deepening the understanding of drug molecular interactions, which contributes significantly to advancements in the fields of pharmacy and pharmaceutical chemistry. − However, the drug–solvent interactions that can elucidate the solvation behavior of drugs in vivo are difficult to investigate directly because of the presence of various cosolutes, such as carbohydrates, amino acids, salts, proteins, and so forth in biosystems.…”

Study on the Interactions of a Promising Cancer-Preventive Drug Ferulic Acid in Aqueous Ethanol/1-Propanol Solutions Using Volumetric, Viscometric, and Refractive Index Approaches

“…The densities of binary solutions (ethanol + water and 1-propanol + water) and ternary solutions (FA + ethanol + water and FA + 1-propanol + water) were measured at different temperatures (293.15, 298.15, 303.15, 308.15, and 313.15 K) and atmospheric pressure with a precision of 1 × 10 –6 g·cm –3 on an Anton Paar DMA 5000 M digital constant temperature liquid densimeter with automatic temperature control with a standard uncertainty of 0.01 K. The instrument is calibrated annually using dry air and the standard liquid supplied by the manufacturer, according to the manufacturer recommendations. Before each measurement, air and water density checks at atmospheric pressure using dry air and freshly prepared double distilled water were also performed to confirm that the measurement precision did not decrease over the measurement period. ,,− All density measurements were performed in triplicate, and corresponding average values were calculated. The standard uncertainty in measured density values was estimated to be 5 × 10 –4 g·cm –3 .…”

“…Therefore, the prevention and treatment of cancer is one major concern of the modern society . Cancer chemoprevention using dietary phytochemicals is an effective strategy to reduce cancer incidence rate and mortality and has attracted extensive attention. − Moreover, numerous studies have reported that phenolic compounds that are commonly found in fruits, vegetables, and nuts exhibit anticancer and immunomodulatory effects. , …”