Experimental and Molecular Modeling Evaluation of the Physicochemical Properties of Proline-Based Deep Eutectic Solvents.

The liquid range and applicability of deep eutectic solvents (DESs) are determined by their physicochemical properties. In this work, the physicochemical properties of glycolic acid:proline and malic acid:proline were evaluated experimentally and with MD simulations at five different ratios. Both DESs exhibited esterification upon preparation, which affected the viscosity in particular. In order to minimize oligomer formation and water release, three different experimental preparation methods were explored, but none could prevent esterification. The experimental and calculated densities of the DESs were found to be in good agreement. The measured and modeled glass transition temperature showed similar trends with composition, as did the experimental viscosity and the calculated diffusivities. The MD simulations provided additional insight at the atomistic level, showing that at acid-rich compositions, the acid-acid hydrogen bonding (HB) interactions prevail. Malic acid-based DESs show stronger acid-acid HB interactions than glycolic acid-based ones, possibly explaining its extreme viscosity. Upon the addition of proline, the interspecies interactions become predominant, confirming the formation of the widely assumed HB network between the DESs constituents in the liquid phase.

[1]  P. Kollman,et al.  An approach to computing electrostatic charges for molecules , 1984 .

[2]  F. Mjalli,et al.  Acoustic investigation of choline chloride based ionic liquids analogs , 2014 .

[3]  Junmei Wang,et al.  Development and testing of a general amber force field , 2004, J. Comput. Chem..

[4]  Catarina Florindo,et al.  Insights into the Synthesis and Properties of Deep Eutectic Solvents Based on Cholinium Chloride and Carboxylic Acids , 2014 .

[5]  Mohd Ali Hashim,et al.  Prediction of deep eutectic solvents densities at different temperatures , 2011 .

[6]  P. Kollman,et al.  A Second Generation Force Field for the Simulation of Proteins, Nucleic Acids, and Organic Molecules , 1995 .

[7]  P. P. Ewald.  Die Berechnung optischer und elektrostatischer Gitterpotentiale , 1921 .

[8]  Paul Painter,et al.  Molecular dynamic simulations and vibrational analysis of an ionic liquid analogue. , 2013, The journal of physical chemistry. B.

[9]  L. Gladden,et al.  Molecular motion and ion diffusion in choline chloride based deep eutectic solvents studied by 1H pulsed field gradient NMR spectroscopy. , 2011, Physical chemistry chemical physics : PCCP.

[10]  A. Abbott,et al.  Application of hole theory to define ionic liquids by their transport properties. , 2007, The journal of physical chemistry. B.

[11]  G. Rothenberg,et al.  Understanding solid/solid organic reactions. , 2001, Journal of the American Chemical Society.

[12]  R. Benson,et al.  Charge transport and structural dynamics in carboxylic-acid-based deep eutectic mixtures. , 2014, The journal of physical chemistry. B.

[13]  I. Arends,et al.  Are Natural Deep Eutectic Solvents the Missing Link in Understanding Cellular Metabolism and Physiology?[W] , 2011, Plant Physiology.

[14]  C. Breneman,et al.  Determining atom‐centered monopoles from molecular electrostatic potentials. The need for high sampling density in formamide conformational analysis , 1990 .

[15]  P. Bouř,et al.  Proline zwitterion dynamics in solution, glass, and crystalline state. , 2006, Journal of the American Chemical Society.

[16]  S. Aparicio,et al.  An approach for the rationalization of melting temperature for deep eutectic solvents from DFT , 2015 .

[17]  J. Valderrama,et al.  Critical Properties, Normal Boiling Temperatures, and Acentric Factors of Fifty Ionic Liquids , 2007 .

[18]  M. K. Rathod,et al.  Thermal stability of phase change materials used in latent heat energy storage systems: A review , 2013 .

[19]  S. Nagel,et al.  Supercooled Liquids and Glasses , 1996 .

[20]  Kaveh Shahbaz,et al.  Modified Rackett equation for modelling the molar volume of deep eutectic solvents , 2015 .

[21]  L. Gladden,et al.  Do group 1 metal salts form deep eutectic solvents? , 2016, Physical chemistry chemical physics : PCCP.

[22]  P. Kollman,et al.  Atomic charges derived from semiempirical methods , 1990 .

[23]  E. Maginn.  Molecular Simulation of Ionic Liquids: Current Status and Future Opportunities , 2009 .

[24]  Effect of drought stress on metabolite contents in barley recombinant inbred line population revealed by untargeted GC–MS profiling , 2017, Acta Physiologiae Plantarum.

[25]  Mohd Ali Hashim,et al.  Prediction of refractive index and density of deep eutectic solvents using atomic contributions , 2013 .

[26]  Maaike C. Kroon,et al.  New natural and renewable low transition temperature mixtures (LTTMs): screening as solvents for lignocellulosic biomass processing , 2012 .

[27]  Geoffrey W. Stevens,et al.  Estimation of Normal Boiling Temperatures, Critical Properties, and Acentric Factors of Deep Eutectic Solvents , 2015 .

[28]  U. Suter,et al.  Detailed molecular structure of a vinyl polymer glass , 1985 .

[29]  F. Mjalli,et al.  Prediction of the surface tension of deep eutectic solvents , 2012 .

[30]  J. Andanson,et al.  Impact of water on the melting temperature of urea + choline chloride deep eutectic solvent , 2016 .

[31]  F. Mjalli,et al.  Effect of water on the thermo-physical properties of Reline: An experimental and molecular simulation based approach. , 2014, Physical chemistry chemical physics : PCCP.

[32]  David Shan-Hill Wong,et al.  Densities of a deep eutectic solvent based on choline chloride and glycerol and its aqueous mixtures at elevated pressures , 2012 .

[33]  Raymond K. Rasheed,et al.  Deep eutectic solvents formed between choline chloride and carboxylic acids: versatile alternatives to ionic liquids. , 2004, Journal of the American Chemical Society.

[34]  David L Davies,et al.  Novel solvent properties of choline chloride/urea mixtures. , 2003, Chemical communications.

[35]  M Gibaldi,et al.  Increasing dissolution rates and gastrointestinal absorption of drugs via solid solutions and eutectic mixtures. IV. Chloramphenicol--urea system. , 1966, Journal of pharmaceutical sciences.

[36]  Meiri Wang,et al.  L-proline-based deep eutectic solvents (DESs) for deep catalytic oxidative desulfurization (ODS) of diesel. , 2017, Journal of hazardous materials.

[37]  L. Gladden,et al.  Molecular and ionic diffusion in aqueous - deep eutectic solvent mixtures: probing inter-molecular interactions using PFG NMR. , 2015, Physical chemistry chemical physics : PCCP.

[38]  J. M. Sala,et al.  Determination of the phase diagram and main thermophysical properties of the erythritol–urea eutectic mixture for its use as a phase change material , 2016 .

[39]  Supreet Kaur,et al.  Nanoscale Spatial Heterogeneity in Deep Eutectic Solvents. , 2016, The journal of physical chemistry. B.

[40]  J. C. Denton,et al.  Thermal energy storage for solar heating and off-peak air conditioning , 1975 .

[41]  Y. Choi,et al.  Natural deep eutectic solvents providing enhanced stability of natural colorants from safflower (Carthamus tinctorius). , 2014, Food chemistry.

[42]  M. Gutiérrez,et al.  Freeze-drying of aqueous solutions of deep eutectic solvents: a suitable approach to deep eutectic suspensions of self-assembled structures. , 2009, Langmuir : the ACS journal of surfaces and colloids.

[43]  Yan Li,et al.  Theoretical study on the structures and properties of mixtures of urea and choline chloride , 2013, Journal of Molecular Modeling.

[44]  Geert-Jan Witkamp,et al.  Natural deep eutectic solvents as new potential media for green technology. , 2013, Analytica chimica acta.

[45]  Meng-Hui Li,et al.  High-pressure density measurements for choline chloride: Urea deep eutectic solvent and its aqueous mixtures at T =(298.15 to 323.15)K and up to 50MPa , 2012 .

[46]  Y. Choi,et al.  Tailoring properties of natural deep eutectic solvents with water to facilitate their applications. , 2015, Food chemistry.

[47]  Coray M. Colina,et al.  Experimental and Computational Studies of Choline Chloride-Based Deep Eutectic Solvents , 2014 .

[48]  Lijun Zhou,et al.  Stabilization of zwitterionic versus canonical proline by water molecules , 2016, SpringerPlus.

[49]  Rui L. Reis,et al.  Natural Deep Eutectic Solvents – Solvents for the 21st Century , 2014 .

[50]  K. Row,et al.  Recent developments in deep eutectic solvents in chemical sciences , 2013, Monatshefte für Chemie - Chemical Monthly.

[51]  Iuliia V. Voroshylova,et al.  Improved Force Field Model for the Deep Eutectic Solvent Ethaline: Reliable Physicochemical Properties. , 2016, The journal of physical chemistry. B.