Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX
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Effect of Citrate Salts on the Volumetric and Ultrasonic Properties of Sucrose in Aqueous Solutions at Temperatures T = (288.15−318.15) K Harsh Kumar,*,† Monisha Sharma,‡,§ and Vaneet Kumar‡,∥ †
Department of Chemistry, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar 144011, Punjab, India IKG Punjab Technical University, Jalandhar, Kapurthala Highway, Kapurthala 144603, Punjab, India § MRPD Govt. Arts and Science College, Talwara 144216, Punjab, India ∥ Department of Applied Sciences, CT Group of Institutions (CTIEMT), Shahpur, Jalandhar 144020, Punjab, India
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‡
ABSTRACT: The volumetric and ultrasonic properties of sucrose in aqueous solutions of citrate salts trisodium citrate (TSC) and tripotassium citrate (TPC) were studied at temperatures T = (288.15−318.15) K and at atmospheric pressure. Apparent molar volumes Vϕ and apparent molar isentropic compressibilities Kϕ,s were calculated from measured density ρ and speed of sound u data. Partial molar volumes Voϕ and partial molar isentropic compressibilities Koϕ,s at infinite dilution, transfer parameters ΔVoϕ and ΔKoϕ,s of sucrose from water to aqueous solutions of TSC and TPC, expansion coefficients (∂Vϕ0/∂T)p, (∂2 Vϕ0 /∂2 T)p, and interaction coefficients (VAB, KAB)(VABB , KABB) were also evaluated. These parameters are discussed in terms of solute−cosolute interactions to understand the solvation behavior of sucrose in theses salts. Positive and increasing values of ΔVoϕ with increasing citrate salt concentrations were obtained. This indicated the dehydration of the sucrose in the presence of the citrate salts due to the predominance of solute−cosolute interactions. Hydration number Nw was also calculated for the mixtures in this study.
1. INTRODUCTION The knowledge of thermophysical properties of aqueous systems with citrate anions is of great importance in beverage, cosmetics, chemical industries, and in the colloid synthesis of gold and silver nanoparticles.1 Saccharides and their derivatives are the most resource-full class of biomolecules, known for versatility and great diversity of their biological functions. Saccharides, polyalcohols, and salt solutions are commonly used in several food industries to adjust the water activity and pH to reduce the growth of contaminating microorganisms.2−4 Animals tolerate dehydration stress by accumulation of disaccharides.5 Disaccharides, trehaloses, sucrose and maltose, etc. found their application as the most suitable cryo- or lyoprotective excipient for maintaining the viability of plants and animals under adverse conditions as well as the stability of pharmaceutical products.6−8 Green and Angell attributed this peculiarity of trehalose to the fact that it has the highest glass transition temperature, Tg, for its aqueous solutions among the homologous disaccharides, which protects desert animals from dehydration and allows them to survive for decades in these drought conditions by producing trehalose intracellularly during desiccation.9 This has been demonstrated by ultrasonic measurements,10 Raman scattering,11 neutron scattering,12 etc. Sucrose affects the properties of surfactants such as lowering © XXXX American Chemical Society
cloud point, increasing hydrophobicity, and changing phase behavior, hence affecting the droplet size of nanoemulsion formation in an aqueous phase/nonionic surfactant/oil system.13−16 Saccharides have also been exploited in pharmaceuticals, foods, and biomedical applications.17,18 Binary and ternary aqueous solutions containing saccharides (e.g., sucrose, glucose, and fructose) and additives (ethanol, glycerol, salts, etc.) have been widely used as a suitable immersion media for freezing fruits.19 The thermochemical methods of energy production from sucrose biomass are gaining interest, and the possibility of hydrogen production from the catalytic reforming of sucrose biomass has been reported.20 The hydration behavior of saccharides is a key feature to understand their structural and functional properties. In the past few years, the thermodynamic properties (apparent specific volumes and apparent specific isentropic compressibilities) of different sapid substances (including saccharides) have been studied21−24 in aqueous and mixed aqueous solutions25−27 to understand the role of water−solute interactions and the influence of additives on the solute−solvent interactions. Received: May 8, 2018 Accepted: August 31, 2018
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DOI: 10.1021/acs.jced.8b00370 J. Chem. Eng. Data XXXX, XXX, XXX−XXX
Journal of Chemical & Engineering Data
Article
Table 1. Specifications of the Chemicals Used compound sucrose trisodium citrate dihydrate (TSC·2H2O) b tripotassium citrate monohydrate (TPC· H2O) b
CAS no.
molecular weight (g/mol)
source
purification method
57-50-1 6132-04-3 6100-05-6
342.30 294.10 324.41
Himedia Laboratories Pvt Ltd. SD Fine Chem Ltd. India SD Fine Chem Ltd. India
drying over P2O5 drying over P2O5 drying over P2O5
a
mass fraction purity >0.99 >0.99 >0.99
a
As declared by supplier. bThe molality calculation was done using the molecular weight of anhydrous salt.
the sound wave. A density check or an air/water adjustment was performed at 293.15 K with triple distilled, degassed water and with dry air at atmospheric pressure. Before each series of measurements, the densimeter was calibrated with triple distilled and degassed water in the experimental temperature range. The density and speeds of sound values are extremely sensitive to temperature, so it was controlled to ±1 × 10−3 K by a built-in Peltier device. The standard uncertainty of the temperature was within ±0.03 K. The sensitivity of the instrument corresponds to a precision in density and speed of sound measurements of ±1 × 10−3 kg·m−3 and 1 × 10−2 m·s−1, respectively. The standard uncertainty of the density and speed of sound estimates was found to be within ±1 kg·m−3 and 1.5 m· s−1, respectively.
Moreover, the role of water in sweet taste chemoreception has also been reported,28 and the taste quality of aqueous solutions of salts has been found to vary with the cationic and anionic parts (anion effects) of salt.29 So, in the present work, trisodium citrate and tripotassium citrate were used as additives to understand the effect of its cationic and anionic parts on the volumetric and ultrasonic properties of sucrose.
2. EXPERIMENTAL SECTION 2.1. Materials. Sucrose with mass fraction purity >0.99 was purchased from Himedia Laboratories Pvt. Ltd. India. Trisodium citrate dehydrate and tripotassium citrate monohydrate with mass fraction purities >0.99 were purchased from SD Fine Chem. Ltd. India. All chemicals were used after drying in a desiccator over P2O5 at room temperature for 48 h. The detailed specifications are given in Table 1. 2.2. Apparatus and Procedure. The density ρ and speed of sound u of aqueous sucrose solutions and aqueous ternary solutions containing citrate salts and sucrose were measured at T = (288.15, 298.15, 308.15, and 318.15) K and experimental pressure p = 0.1 MPa using an Anton Paar DSA 5000 M densimeter. The concentration of aqueous citrate solutions was taken as (0.20, 0.40, and 0.60) mol·kg−1. Freshly prepared triple distilled and degassed water (specific conductance
