INTRODUCTION:
Malonic acid [propanedioic acid with
structure CH2(COOH)2, molar mass: 104.061 gmol-1,
CAS:141-82-2 as shown in Fig. 1)] is an important acid in a series of aliphatic
dicarboxylic acid. In food and drug applications, malonic acid can be used to
control acidity, either as an excipient in pharmaceutical formulation or
natural preservative additive for foods. Malonic acid is used as a building
block chemical to produce numerous valuable compounds1. The
solubility data of such important organic compounds can be used in industrial,
pharmaceutical, separation, purification, and environmental applications2.
It is well-known that solid−liquid phase equilibrium data play an
important role in the development and operation of crystallization processes3.
To determine proper solvents and to design an optimized production process, it
is necessary to know the solubility in different solvents. In these
investigations, the solubilities of Malonic acid in pure water, methanol,
ethanol and their binary mixtures (water + methanol, water + ethanol) over
different composition were determined at various temperatures.
The experimental solubility data were
correlated by using Apelblat and van’t Hoff equation. Thermodynamic properties
of the solutions were calculated by using van’t Hoff equation. The activity
coefficients were calculated to evaluate molecular solute-solvent interaction.
(a)
(b)
Figure.
1 Chemical Structure of Malonic Acid (a) three dimensional structure (b)
EXPERIMENTAL:
Materials and Apparatus:
Malonic Acid (99%) was obtained from sigma
Aldrich. Methanol (99.8%) and Ethanol (99.9%) was supplied by Merck. They were
used without any further purification. Triple distilled water was used
throughout of all these investigations. The method of solubility measurement
has been used earlier4-6. In this work; an excess amount of malonic
acid was added to the binary solvents mixtures prepared by weight (Shimadzu,
Auxzzo) with an uncertainty of ± 0.1mg, in a specially designed 100mL double
jacketed flask. Water was circulated at constant temperature between the outer
and inner walls of the flask. The temperature of the circulating water was
controlled by thermostat to within (±0.1) K. The solution was continuously
stirred using a magnetic stirrer for long time (about 1 h) so that equilibrium
is assured and the solution was allowed to stand for 1 h. Then a fixed quantity
of the supernatant liquid was withdrawn from the flask in a weighing bottle
with the help of pipette which is hotter than the solution. The weight of this
sample was taken and the sample was kept in an oven at 343 K until the whole
solvent was evaporated. This was confirmed by weighing two or three times until
a constant weight was obtained. The solubility has been calculated using weight
of solute and weight of solution. Each experimental value of solubility is an
average of at least three different measurements. The saturated mole fraction
solubility (Xb), initial the mole fraction of methanol/ethanol (
), and
initial the mole fraction of water (
) were
calculated using usual Eq. 1 and 2:
(1)
and
(2)
Where mb,
ma, and mc are the mass of solute, water,
methanol/ethanol respectively, and Mb, Ma, and Mc
are the molecular weight of the solute, water, and methanol/ethanol,
respectively.
DFT Study:
Density functional
theory (DFT) calculations were carried out using Gaussian 03 method7,8
to correlate difference in solubilities in pure solvents. Geometry
optimizations for all structures carried out at the B3LYP/6-311+ G (d, p)
levels. After the geometries of all involving molecules were optimized at this
level, the interaction energy Einter was calculated as9:
Einter = EMA-sol
– EMA − Esol (3)
Where EMA, Esol, and
EMA−sol are the total energies of malonic acid, solvent and
malonic acid with each solvent, respectively.
RESULTS
AND DISCUSSION:
Verification of the experimental methods:
To verify the reliability and accuracy of
the experimental apparatus and method, the solubilities of malonic acid in pure
water were measured and compared with the literature data10. Our
results agree well with the published data. Fig.2 shows the experimental
apparatus and method used in this work is reliable.
Fig.
2 Comparison between experimental solubility (Xb) of malonic acid in
water with literature values: □ – experimental solubility, ◊-
literature values10
Solubility results:
The mole fraction solubilities (Xb)
data of malonic acid in pure water, methanol and ethanol and the solubilites of
maloinc acid in binary solvent mixture (water + methanol and water + ethanol)
are presented in Table 1 and 2. Table 1 and 2 shows that positive correlation
of the solubilities in pure solvents with temperature because of endothermic
dissolution phenomenon. The solubility trend in pure solvents is methanol >
ethanol > water. These indicate that solubility increases with initial the
mole fraction of methanol () at
all temperatures. But in case of water + ethanol system, maximum solubility
effect has found at = 0.6100. Table 1
and 2 also indicates that solubility in water + methanol is higher than water +
ethanol binary mixtures as a function of temperature.
In
other words, for all the solvents investigated, the molecular interactions
between malonic acid and solvent molecules are significantly higher than those
between the solvent–solvent and solute-solute molecules27,28.
Positive 
values
for the dissolution of malonic acid in all solvents revealed that this process
is entropy driven29-31. Table 5 also shows that ζH%
> ζTS%, which indicates that the main contributor
to the positive standard molar Gibbs energy D
of
solution of malonic acid is the enthalpy during dissolution.
CONCLUSION:
The
solubility of malonic acid in pure water, methanol and ethanol and binary
solvent mixtures was investigated over the entire composition range between 0
to 1 weight fraction of methanol/ethanol at (293.15, 295.15, 298.15, 300.15,
303.15, 305.15, 308.15, and 313.15) K. The positive correlation of the
solubilities in pure solvents with temperature was observed indicates
endothermic dissolution process. The solubility trend of malonic acid in pure
solvents was methanol > ethanol > water. However the solubilites of
maloinc acid in binary solvent mixture (water + methanol and water + ethanol)
were found to increases with initial the mole fraction of methanol () at
all temperatures. But in case of water + ethanol system, maximum solubility
effect has found at = 0.6100. The γ
for malonic acid is in good agreement with solubility results that the
solubility of malonic acid increases with mole fraction (
) of methanol/ethanol.
The values of correlation coefficient (R2) for Apelblat equation and
van’t Hoff equation indicated that these equations fit quite well in pure and
binary solvents. The values of (
,
) are
all positive which indicates that solution process is endothermic and
entropy-driven. ζH% > ζTS%, which indicates main
contributor to the positive standard molar Gibbs energy Dof
solution of glutaric acid is the enthalpy during dissolution.
ACKNOWLEDGEMENTS:
The
authors are thankful to Principal of MSG Arts, Science and Commerce College
Malegaon for providing laboratory facilities. We also thanks to Prof. Arun B.
Sawant for his computational guidance. The authors also express their sincere
thanks to Dr Apoorva Hiray (Co-Ordinator, M.G. Vidyamandir, Malegaon).
REFERENCES:
1. Hildbrand, S.; Pollak, P. Malonic Acid and Derivatives. March
15, 2001. Ullmann's Encyclopedia of Industrial Chemistry.
2.
Lu J., Wang
X.J., Yang X., Ching C.B., Solubilities of Glycine and Its Oligopeptides in
Aqueous Solutions, J. Chem. Eng. Data 51 (2006) 1593–1596.
3.
Singrey, S.
L.; Thomas, S. C. U.S. Patent 3,338,959, August 29, 1967.
4.
Pawar, R.
R.; Nahire, S. B.; Hasan, M. Solubility and Density of Potassium Iodide in
Binary Ethanol-Water Solvent Mixture at (298.15, 303.15, 308.15, and 313.15) K
J. Chem. Eng. Data, 54, 1935−37 (2009).
5.
Pawar, R.
R.; Golait, S. M.; Hasan, M; Sawant, A. B. Solubility
and Density of Potassium Iodide in a Binary Propan-1-ol−Water Solvent
Mixture at (298.15, 303.15, 308.15, and 313.15) K J. Chem. Eng. Data.
55, 1314−16 (2010).
6.
Pawar, R.
R.; Aher C.S.; Pagar J. D.; Nikam S.L.; Hasan, M. Solubility,
Density and Solution Thermodynamics of NaI in Different Pure Solvents and
Binary Mixtures J. Chem. Eng. Data. 57, 3563−3572, (2012)
7.
Frisch M J, et
al. Gaussian 03, Rev. E. 01, Gaussian Inc, Wallingford, CT, 2004.
8.
Lee C, Yang
W, Parr R. Development of the Colle-Salvetti correlation-energy formula into a
functional of the electron density Phys. Rev. B., 1988; 37: 785.
9.
Zhu P, Chen
Y, Fang J, et.al. Solubility and solution thermodynamics
of thymol in six pure organic solvents J. Chem. Thermodynamics, 92,
2016, 198-206
10.
Apelblat A
and Manzurola E. Solubility of oxalic, malonic, succinic, adipic, maleic, malic, citric,
and tartaric acids in water from 278.15 to 338.15 K J. Chem. Thermodynamics 1987,
19, 317-320.
11.
Ruidiaz M A,
Delgado D R, Martínez F Y. Marcus Solubility and
preferential solvation of indomethacin in 1,4-dioxane + water solvent
mixtures Fluid Phase Equilib., 2010; 299: 259–265.
12.
Hildebrand J
H, Prausnitz J M, Scott R L. Regular and Related Solutions, Van Nostrand
Reinhold, New York, 1970.
13.
Manrique Y.
J., Pacheco D. P. Martínez F, Thermodynamics of Mixing and Solvation of
Ibuprofen and Naproxen in Propylene Glycol + Water Cosolvent
Mixtures J. Solut. Chem. 37 (2008) 165–181.
14.
Aragón D.
M., Sosnik A., Martínez F., Solution Thermodynamics of Triclocarban in Organic
Solvents of Different Hydrogen Bonding Capability J. Solut. Chem. 38 (2009)
1493–1503.
15.
Neau S. H.,
Flynn G. L., Solid and Liquid Heat Capacities of n-Alkyl
Para-aminobenzoates Near the Melting Point. Pharm. Res. 7 (1990) 1157–1162.
16.
Ruidiaz M.
A., Delgado D. R., Martínez F., Marcus Y., Solubility
and preferential solvation of indomethacin in 1,4-dioxane + water
solvent mixtures Fluid Phase Equilib. 299 (2010) 259–265.
17.
Wilhoit, R.C.; Shiao, D., Thermochemistry
of Biologically Important Compounds. Heats of Combustion of Solid Organic
Acids. J. Chem. Eng. Data, 1964, 9, 595.
18.
Hansen, Anne R.; Beyer, Keith D., Experimentally Determined Thermochemical
Properties of the Malonic Acid/Water System: Implications for
Atmospheric Aerosols J.
Phys. Chem. A, 2004, 108, 16,
3457-3466,
19.
Apelblat A,
Manzurola E. Solubilities ofo-acetylsalicylic, 4-aminosalicylic, 3,
5-dinitrosalicylic, andp-toluic acid, and magnesium-DL-aspartate in water from T=(278
to 348) K J. Chem. Thermodyn., 1999; 31: 85–91.
20.
Yang Z H,
Shao D F, Zhou G Q. Solubility parameter of lenalidomide for predicting the
type of solubility profile and application of thermodynamic model J. Chem.
Thermodyn., 2019; 132: 268–275.
21.
Yu Y, Zhang
F, Gao X Q, Xu L, Liu G, J. Experiment, correlation and molecular simulation
for solubility of 4-methylphthalic anhydride in different organic solvents
from T = (278.15 to 318.15) K J. Mol. Liq., 2019; 275:
768–777.
22.
Shakeel F,
Haq N, Alanazi F K, Alsarra I A. Solubility and thermodynamics of apremilast in
different mono solvents: Determination, correlation and molecular interactions
Int. J. Pharm., 2017; 523: 410–417.
23.
Zhao W, Yang
W, Hao J. Determination and Thermodynamic Modeling of Solid–Liquid Phase
Equilibrium for Esomeprazole Sodium in Monosolvents and in the (Ethanol + Ethyl
Acetate) Binary Solvent Mixtures J. Chem. Eng. Data, 2017; 62: 1965-1972.
24.
Kim K H, Oh
H K, et al. Solubility evaluation and thermodynamic modeling of
β-lapachone in water and ten organic solvents at different temperatures
Fluid Phase Equil., 2018; 472: 1-8.
25.
Buchowski H,
Ksiazczak A, Pietrzyk S. Solvent activity along a saturation line and
solubility of hydrogen-bonding solids J. Phys. Chem., 1980; 84: 975 −
979.
26.
Patel A,
Vaghasiya A, Gajera R, Baluja S. Solubility of 5-Amino Salicylic Acid in
Different Solvents at Various Temperatures J. Chem. Eng. Data, 2010; 55:
1453−1455.
27.
Dong X., Cao
Y., Lin H., Yao Y., Guo Y., Wang T., Wu S., Wu Z., Solubilities
of formononetin and daidzein in organic solvents: Effect of molecular structure
and interaction on solvation process J. Mol. Liq. 231 (2017) 542–554.
28.
Mahali K.,
Guin P.S., Roy S., Dolui B.K., Solubility and solute–solvent interaction
phenomenon of succinic acid in aqueous ethanol mixtures J. Mol. Liq. 229 (2017)
172–177.
29.
Kalam M.A.,
Khan A.A., Alshamsan A., Haque A., Shakeel F., Solubility of a poorly soluble
immunosuppressant in different pure solvents: Measurement, correlation,
thermodynamics and molecular interactions J. Mol. Liq. 249 (2018) 53–60.
30.
Ha E.S., Lee
S.K., Jeong J.S., Shim W.Y., Yang J.I., Kim J.S., Kim M.S., Solvent effect and solubility modeling of rebamipide in twelve solvents
at different temperatures J. Mol. Liq. 288 (2019), 111041.
31.
Zhou G.,
Wang B., Dong L.J., Wang F., Feng C., Measurement and correlation of the
solubility of Lidocaine in eight pure and mixed solvents at temperatures from
(292.15 to 332.15) K J. Mol. Liq. 242 (2017) 168–174.
%ζH,
%ζTS) of solution were calculated using van’t Hoff equation.
