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## Binary aqueous systems of phosphonium ionic liquids as working fluids in absorption refrigeration – physicochemical and thermodynamic studies

### Marcin Orawiec

#### Abstract

In the present thesis, entitled “Binary aqueous systems of phosphonium based ionic liquids as working fluids in absorption refrigeration – physicochemical and thermodynamic studies”, studies of physicochemical and thermodynamic properties of ionic liquids (ILs) and their binary aqueous systems are described. The aim of conducted measurements is strictly connected with the plausible application of ionic liquids mixtures with water as working fluids in absorption cycle. In the first, theoretical part of the thesis, the absorption cycle and the requirements for working fluids are explained using the available literature. These were followed by brief description of ionic liquid properties and an analysis of their toxicity and biodegradation. The whole part is summarized by theoretical advantages of using [IL + H2O] binary systems as working fluids in comparison with currently popular choices. The following chapters include information about theoretical foundations of phenomena that are of interest to this thesis. These are: excess functions (excess molar volume and excess enthalpy of mixing) and phase equilibrium conditions – where the explication was on [solid – liquid phase equilibrium]. The subsequent part of the thesis contains descriptions of conducted experiments. Firstly, information about studied ionic liquids’ structure and their preparation to the measurements. Then the methods and apparatuses for the following measurements are described: differential scanning calorimetry analysis (DSC), density, viscosity, solid state – liquid phase equilibrium (SLE) and the enthalpy of mixing. What is more, the equations used to fit the measured data: VFT, Redlich – Kister, NRTL, UNIQUAC and Wilson are presented. Binary aqueous systems of two different ionic liquids are subjects of interest to this thesis: Tributhylethylphosphonium diethylphosphate, [P2,4,4,4][DEP] and N-hydroxyethyl-N-methylpyrrolidinium dimethylphosphate, [C2OHC1PYR][DMP]. These mixtures are to compete with traditional working fluids such as [H2O + LiBr] and [NH3 + H2O] which are known to have serious issues. The first system is corrosive and tend to crystallize while the other is flammable and toxic. Prior to the measurements the ionic liquids had been held in vacuum dryer in order to remove water and organic solvents and the viscometer had been calibrated. The first experiments included: density measurements of binary systems in wide range of composition and temperature; viscosity measurements of pure ionic liquids within wide range of temperature and differential scanning calorimetry measurements within wide temperature range from (-100 to 100)°C of pure ILs. Then the SLE measurements were conducted using dynamic method and the excess enthalpy of mixing in binary systems was measured with microcalorimeter using titration technique. Thanks to density measurements of binary systems and clean substances, the excess molar volume was calculated and fitted using the Redlich – Kister’s equation. NRTL, UNIQUAC and Wilson’s equations were applied to fitting the solid – liquid phase equilibrium. The present thesis is an important addendum to the current state of knowledge about ionic liquids. Most of the physicochemical and thermodynamic data presented here was measured for the first time and is vital to analyse whether aqueous binary systems of ionic liquids can find application in absorption refrigeration and many others proposed applications.
Diploma type
Engineer's / Bachelor of Science
Diploma type
Engineer's thesis
Author
Marcin Orawiec (FC) Marcin Orawiec,, Faculty of Chemistry (FC)
Title in Polish
Układy dwuskładnikowe fosfoniowych cieczy jonowych z wodą jako płyny robocze w chłodnictwie absorpcyjnym - badania fizykochemiczne i termodynamiczne
Supervisor
Marta Królikowska (FC/DPC) Marta Królikowska,, Department Of Physical Chemistry (FC/DPC)Faculty of Chemistry (FC)
Certifying unit
Faculty of Chemistry (FC)
Affiliation unit
Department Of Physical Chemistry (FC/DPC)
Study subject / specialization
, Technologia Chemiczna
Language
(pl) Polish
Status
Finished
Defense Date
01-02-2016
Issue date (year)
2016
Reviewers
Aldona Zalewska (FC/CofIC) Aldona Zalewska,, Chair Of Inorganic Chemistry (FC/CofIC)Faculty of Chemistry (FC) Marta Królikowska (FC/DPC) Marta Królikowska,, Department Of Physical Chemistry (FC/DPC)Faculty of Chemistry (FC)
Keywords in Polish
ciecze jonowe, chłodnictwo absorpcyjne, dietyloortofosforan tributyloetylofosfoniowy, dimetyloortofosforan N-hydroksyetylo-N-metylopyrolidyny, ciecze roobocze
Keywords in English
ionic liquids, absorption refrigeration, tributhylethylphosphonium diethylphosphate, N-hydroxyethyl-N-methylpyrrolidinium dimethylphosphate, woorking liquids
Abstract in Polish
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Identyfikator pracy APD: 8473

Uniform Resource Identifier
https://repo.pw.edu.pl/info/bachelor/WUT23d8f9198dc74b4abee32e3fb90f84c6/
URN
urn:pw-repo:WUT23d8f9198dc74b4abee32e3fb90f84c6

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