Ionic liquids in microemulsions [Elektronische Ressource] : a concept to extend the conventional thermal stability range of microemulsions / Oliver Zech

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• Publié par: universitat_regensburg
• Publié le: 01 janvier 2010
• Nombre de lectures: 5
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Ionic Liquids in Microemulsions – a
Concept to Extend the Conventional
Thermal Stability Range of
Microemulsions







Dissertation Presented for the Degree of
Doctor of Natural Sciences
(Dr. rer. nat.)


University of Regensburg
Natural Sciences Faculty IV
Chemistry & Pharmacy


Oliver Zech
Regensburg 2010



































Official Registration: 27.11.2009
Defense: 15.01.2010
Ph.D. Supervisor: Prof. Dr. Werner Kunz
Adjudicators: Prof. Dr. We
PD. Dr. Rainer Müller
Prof. Dr. Jörg Daub
Chair: Prof. em. Dr. Dr. h. c. Josef Barthel


Contents
Contents
Contents................................................................................................................ i
Preface ............................................................................................................... vii
Constants and Symbols..................................................................................... ix
I. Introduction ..............................................................................................- 1 -
II. Fundamentals............................................................................................- 5 -
1. Ionic Liquids ........................................................................................................... - 5 -
1.1. General aspects and types of ionic liquids........................................................ - 5 -
1.2. Physicochemical properties .............................................................................. - 8 -
1.2.1. Melting points and liquid range of ILs ..................................................... - 8 -
1.2.2. Viscosity and ionic conductivity .............................................................. - 9 -
1.2.3. Solvent properties................................................................................... - 11 -
1.3. Applications.................................................................................................... - 13 -
2. Microemulsions..................................................................................................... - 15 -
2.1. Definition........................................................................................................ - 15 -
2.2. Types of microemulsions and phase behavior................................................ - 16 -
2.2.1. Oil-in-water and water-in-oil microemulsions ....................................... - 16 -
2.2.2. Other structures ...................................................................................... - 18 -
2.2.3. Winsor phase classification .................................................................... - 19 -
2.2.4. Phase diagrams of microemulsions ........................................................ - 21 -
2.2.5. Microemulsions with non-ionic surfactants ........................................... - 22 -
2.2.6. ulsions with ionic surfactants................................................... - 26 -
2.3. Applications.................................................................................................... - 27 -
2.4. Methods to characterize microemulsions ....................................................... - 28 -
2.4.1. Electrical conductivity............................................................................ - 28 -
2.4.2. Viscosity................................................................................................. - 34 -

i Contents
2.4.3. Dynamic light scattering (DLS)..............................................................- 35 -
2.4.4. Small angle scattering (SAS) ..................................................................- 39 -
2.4.5. Other methods.........................................................................................- 49 -
III. Experimental...........................................................................................- 51 -
1. Chemicals...............................................................................................................- 51 -
2. Synthesis.................................................................................................................- 51 -
2.1. Ethylammonium nitrate (EAN).......................................................................- 51 -
2.2. 1-Butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF ])....................- 52 - 4
2.3. hexafluorophosphate ([bmim][PF ])..............- 53 - 6
2.4. 1-Alkyl-3-methylimidazolium chloride ([C mim][Cl], n = 12, 14, 16,18).....- 54 - n
2.5. 1-Ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO ]).........................- 55 - 4
2.6. 2,5,8,11-Tetraoxatridecan-13-oic acid (TOTOA)...........................................- 56 -
2.7. TOTOA alkali salts .........................................................................................- 57 -
3. Experimental methods..........................................................................................- 60 -
3.1. Analytical methods- 60 -
3.2. Electrical conductivity ....................................................................................- 61 -
3.3. Dynamic light scattering .................................................................................- 63 -
3.4. Densities..........................................................................................................- 64 -
3.5. Viscosities .......................................................................................................- 65 -
3.6. Small angle X-Ray scattering (SAXS) ...........................................................- 65 -
3.7. Small angle neutron scattering (SANS)..........................................................- 66 -
IV. Results and Discussion ...........................................................................- 69 -
1. The conductivity of imidazolium-based ionic liquids over a wide temperature
range. Variation of the anion ...............................................................................- 69 -
1.1. Abstract ...........................................................................................................- 69 -
1.2. Introduction.....................................................................................................- 69 -
1.3. Synthesis and sample handling .......................................................................- 70 -
1.4. Results and discussion ....................................................................................- 71 -

ii Contents
1.5. Concluding remarks........................................................................................ - 78 -
2. Microemulsions with an ionic liquid surfactant and room temperature ionic
liquids as polar phase ........................................................................................... - 79 -
2.1. Introduction .................................................................................................... - 79 -
2.2. Investigations at ambient temperature............................................................ - 81 -
2.2.1. Abstract................................................................................................... - 81 -
2.2.2. Sample handling and experimental path................................................. - 82 -
2.2.3. Results and discussion............................................................................ - 82 -
2.2.3.1. Microregions and phase behavior....................................................... - 82 -
2.2.3.2. Conductivity ....................................................................................... - 84 -
2.2.3.3. Viscosity............................................................................................. - 88 -
2.2.3.4. Dynamic light scattering (DLS) ......................................................... - 89 -
2.2.3.5. Small angle X-ray scattering (SAXS) ................................................ - 90 -
2.2.4. Concluding remarks................................................................................ - 97 -
2.3. Ethylammonium nitrate in high temperature stable microemulsions............. - 99 -
2.3.1. Abstract................................................................................................... - 99 -
2.3.2. Sample handling and experimental path................................................. - 99 -
2.3.3. Results and discussion.......................................................................... - 100 -
2.3.3.1. Density.............................................................................................. - 100 -
2.3.3.2. Visual observations - 101 -
2.3.3.3. Solubility of EAN in dodecane......................................................... - 101 -
2.3.3.4. Conductivity ..................................................................................... - 103 -
2.3.3.5. Dynamic light scatt