Impact of [BMIm] [Cl] on the thermophysical and FTIR properties of protein model compounds in aqueous solutions

Ionic liquids (ILs) have gained popularity in recent years due to their wide range of applications in chem-ical synthesis. They can be used in advancing technologies such as protein solubilization, increased pro-tein activity, biocatalysis replication, and enzyme stability. Because of this, ILs can shed light on the ability of proteins to maintain stability. The present paper outlines the impact of IL on the thermophysical and FTIR properties of specific protein model compounds in aqueous solutions. Thus, densities (q)and vis-cosities (eta)of some protein model compounds in aqueous solutions of ionic liquid, 1-butyl-3-methylimidazolium chloride, [BMIm] [Cl], at various temperatures have been carried out at atmospheric pressure. These studies are aimed at gaining new insights into the ability of biomolecules to interact with IL, which is critical for understanding protein behaviour in solutions. Various parameters such as appar-ent molar volumes (V(sic)), partial molar volumes (V-2(O)), viscosity B-coefficients, temperature coefficients (dB=dT), transfer parameters, i.e.; Delta V-tr(2)o and Delta B-tr, interaction parameters,Y-AB and Y-ABB, hydration number i.e.n(H) and N-h, partial molar expansibilities (partial derivative V-2(O)/partial derivative P)(p),their second-order derivatives (partial derivative V-2(O)/partial derivative P)(p), and isobaric thermal expansion coefficients (a(IL) ) have been calculated from density and viscosity data. In aqueous [BMIm] [Cl], partial molar expansibilities and temperature coefficients are used to predict the structure maker/breaker behaviour of amino acids. Volume transfer values indicate the dominance of ionic-hydrophilic interactions. Thermodynamic parameters suggest that the formation of the transition state is less favoured in the presence of [BMIm] [Cl] solutions. Also, the effects of the hydrophilic ionic liq-uid, 1-butyl-3-methylimidazolium chloride,[BMIm] [Cl] on the ion-hydrophilic, hydrophobic-hydrophilic, and hydrophobic-hydrophobic interactions present in ternary systems, as well as the effects of temper-ature and alkyl chain length, have been discussed. FTIR spectra were measured to analyze the structural changes that occurred in the system. The current work provides some important fundamental experi-mental data and theoretical support for further exploring the interactions of various amino acids with ILs. (c) 2022 Published by Elsevier B.V.