Molecular dynamics of binary deep eutectic solvents as biocompatible working fluids in heat and mass transfer systems

Abstract

Non-biocompatibility, volatility, toxicity, and corrosiveness are associated with conventional working fluids in heat and mass transfer systems. These issues can be mitigated using binary deep eutectic solvent (DES) fluids. This study aims to characterize and evaluate different DES as bio-working fluids. Eleven binary DES samples were prepared by mixing different ratios of compounds and then classified into four groups. Group DES A was developed from C5H14ClNO and (CH2OH)2, DES B from C6H16ClNO and (CH2OH)2, DES C from C8H15ClN2 and ZnCl2 (CH2OH)2, and DES D from C8H15ClN2 and (CH2OH)2. The molecular structures of each category of binary DES were built using the BIOVIA material studio software 6.0 (ACCELRYS). The samples' molecular dynamics, rheology and physiochemical properties were numerically evaluated to predict the material's profile. The chemical fingerprint, inter-molecular behavioral properties, functional groups, rheology, thermal stability, conductivity, electrophoretic properties, and possible emissions at elevated temperatures of the samples have been evaluated. The measured viscosities of the eleven samples, between 0.015 and 0.04 Pa∙s are low compared to conventional ionic liquids and some nanofluids reported in the literature. The average thermal conductivity of the investigated binary DESs was between 0.228 and 0.17 W/m·K at 25 °C. Group DES C thermally decomposes after 350 °C, while other DESs exhibited thermal stability until about 150 °C. Additionally, toxicity analyses of the DESs revealed their bio-friendliness. This property is owed to the emitted compounds with health benefits, including triacetin, procainamide, monoacetate, and 2, 2 difluoroethyl acetates, witnessed at 250 °C of injection temperature.