Ionic liquids derived from nonafluorobutan 1 sulfonyl fluoride

IONIC LIQUIDS DERIVED FROM NONAFLUOROBUTAN-1-SULFONYL FLUORIDE QUEK SER KIANG NATIONAL UNIVERSITY OF SINGAPORE 2006 IONIC LIQUIDS DERIVED FROM NONAFLUOROBUTAN-1-SULFONYL FLUORIDE QUEK SER KIANG (B.Sc (Hons.), NUS) A THESIS SUBMITED FOR THE DEGREE OF MASTERS OF SCIENCE DEPARTMENT OF CHEMISTRY NATIONAL UNIVERSITY OF SINGAPORE 2006 ACKNOWLEDGEMENTS It gives me great pleasure to express my deepest sense of esteem and my most sincere gratitude to my supervisor, Dr Huynh Han Vinh (National University of Singapore), for his invaluable guidance, encouragement, support and his complete dedication throughout this work I will always be grateful to my research guide, Dr Ilya M Lyapkalo (Institute of Chemical and Engineering Sciences), for his guidance and encouragement, care and friendship This thesis would not have been possible if not for his insight I would also like to thank my colleagues and the staff members at ICES for their generous help, especially Ms Wong Shwo Mun for providing excellent technical support for mass spectrometric data, and Dr C Jacob for obtaining the 15N-NMR spectrum of the salt 1g I would also like to acknowledge all staff members of NMR, Microanalysis, and Library staff for their assistance during my research work With that, I am truly indebted to the Agency for Science Technology and Research (A*STAR Singapore) for the financial support and to Bayer AG (Germany) for the generous donation of nonafluorobutane-1-sulfonyl fluoride Finally, I am very grateful to my parents for their unquestioning love and stupendous motivation over the years; it has not been easy on them to dedicate the best that they could possibly provide to their only child, and I hope that I can made them proud some day And to all my friends who have brightened up some of my gloomiest days by being there for me, thank you i TABLE OF CONTENTS Acknowledgements i Summary v List of Tables viii List of Figures ix List of Illustrations x List of Symbols xi Chapter 1: Introduction 1.1 Preamble 1.2 What are ionic liquids? 1.3 Historical developments of ionic liquids 1.4 Synthesis of ionic liquids 1.5 Physical properties of ionic liquids 1.5.1 Effects of structures on the melting points and viscosity of ionic liquids 1.5.2 Liquidus range of ionic liquids 12 1.5.3 Upper temperature limits of ionic liquids 14 1.6 Desirability of ionic liquids as alternative media 14 1.7 Toxicological and environmental concerns pertaining to industrial use of ionic liquids 16 Scope of the thesis 16 1.8 Chapter 2: Results and Discussion 2.1 Prelude 18 2.2 Synthesis of potassium nonafluorobutane-1-sulfonate 19 ii 2.3 Synthesis of potassium bis(nonafluorobutane-1-sulfonyl)imide 20 2.4 Synthesis of ionic liquids by combination of N-methyl-N'-alkyl imidazolium cations with bis(nonafluorobutane-1-sulfonyl)imide and nonaflate anions 21 2.5 General protocol for the synthesis of N,N'-dialkyl imidazoliums ionic liquids 23 Determination of the properties of ionic liquids 24 2.6.1 Melting points of ionic liquids 24 2.6.2 Decomposition temperatures of ionic liquids 24 Specific properties of the ionic liquids obtained 26 2.6 2.7 Chapter 3: Conclusion 3.1 Conclusion 28 3.2 Publications 29 Chapter 4: 4.1 Experimental and Procedures General 4.1.1 Synthesis of sulfonyl)imide 4.2 30 potassium bis(nonafluorobutane-131 4.1.2 Attempts to prepare the potassium salt by interaction of acetamide with NfF in the presence of K2CO3 or K3PO4: potassium nonafluorobutanesulfonate 32 Synthesis of N-methyl-N’-alkyl imidazolium bis(nonafluorobutane1-sulfonyl)imides and nonaflates 34 4.2.1 Synthesis of 1-ethyl-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 34 4.2.2 Synthesis of 1-propyl-3-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 35 4.2.3 Synthesis of 1-butyl-3-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 36 iii 4.3 4.2.4 Synthesis of 1-pentyl-3-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 36 4.2.5 Synthesis of 1-(3-methyl-butyl)-3-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 37 4.2.6 Synthesis of 1-isobutyl-3-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 38 4.2.7 Synthesis of 1-isopropyl-3-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 38 4.2.8 Synthesis of 1-sec-butyl-3-methylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 39 4.2.9 Synthesis of 1-propyl-3-methylimidazolium nonafluorobutanesulfonate 40 4.2.10 Synthesis of 1-butyl-3-methylimidazolium nonafluorobutanesulfonate 40 4.2.11 Synthesis of 1-isopropyl-3-methylimidazolium nonafluorobutanesulfonate 41 4.2.12 Synthesis of 1-sec-butyl-3-methylimidazolium nonafluorobutanesulfonate 42 Synthesis of N-propyl-N'-alkyl imidazolium bis(nonafluorobutane1-sulfonyl)imides 42 4.3.1 Synthesis of 1-propyl-3-ethylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 43 4.3.2 Synthesis of 1-butyl-3-propylimidazolium bis(nonafluorobutane-1-sulfonyl)imide 44 Bibliography and Notes 46 iv SUMMARY Low-melting salts containing lipophilic quaternary organic cations, ionic liquids, have attracted much interest in the area of electrochemistry as well as novel solvents and reaction media These fluids consisting of only ions were found to have no detectible equilibrium vapor pressure In recognition of this remarkable property they were termed as environmentally benign or "green" solvents Many classical organic reactions were successfully modeled and often optimized in these media The first generation of ionic liquids comprised mainly the derivatives of inorganic halogen-ligated ate-complexes such as BF4\, PF6\ and AlCl4\ as the anionic moieties These anions, especially the latter two, are prone to releasing harmful and corrosive HF and HCl upon interaction with traces of moisture which in turn imposes significant restrictions on applications of the corresponding ionic liquids Moreover, uncontrolled halogenide content often affects and/or deteriorates transition metal catalysis To circumvent these difficulties, other types of anions were introduced including n-alkyl sulfates, trifluoromethanesulfonates, bis(trifluoromethanesulfonyl)imides and tetraalkylborates Alternative alkylating reagents, alkyl sulfates and sulfonates were employed in place of "traditional" alkyl halogenides for synthesis of the N,N'-dialkylimidazolium moieties in order to completely eliminate the possibility of generating heavy halogenides (Cl\, Br\, I\) Special attention has been paid to ionic liquids containing N,N'-dialkylimidazolium cations combined with fluoroanions As recently reviewed, much diversity and availability of fluorine-containing anions ensure a broad range of properties and applications of the respective ionic liquids Recently, v N,N'-dialkylimidazolium bis(trifluoromethanesulfonyl)imides have received interest as remarkably thermo- and chemically stable ionic liquids In this respect, the anions combining high stability of bis(trifluoromethanesulfonyl)imide with much higher hydrophobicity due to higher fluorine content are of interest for design of novel ionic liquids as special solvent components for bi- and triphasic solvent systems Herein, I report in this thesis the synthesis and properties of N,N'-dialkylimidazolium bis(nonafluorobutane-1-sulfonyl)imides (1 and 3) and N,N'-dialkylimidazolium nonafluorobutane-1-sulfonates (2) as new series of ionic liquids (Figure a) R1 N N Alkyl X 1-3 1: R1 = CH3, X = NNf2 2: R1 = CH3, X = ONf 3: R1 = CH3(CH2)2, X = NNf2 Nf: CF3(CF2)3SO2 Figure (a) A representation of the ionic liquids synthesized and described in this thesis My thesis involved the one-pot synthesis of ionic liquids starting from affordable commercial precursors: nonafluorobutan-1-sulfonyl fluoride, tertiary nitrogen bases, and alkylating reagents This approach would lead to a series of new chemically and thermally stable ionic liquids under straightforward one-pot protocol A series of N,N'-dialkylimidazolium bis(nonafluorobutane-1-sulfonyl)imides was synthesized in high yields by quaternization of imidazole derivatives with various readily available alkylating reagents, followed by anion exchange with highly stable and nonhygroscopic potassium bis(nonafluorobutane-1-sulfonyl)imide The latter was obtained by an improved method starting from ammonium chloride and nonafluorobutane-1- vi sulfonyl fluoride The quaternary imidazolium salts thus obtained constitute a new subfamily of thermally stable and remarkably hydrophobic ionic liquids with melting points in the range 0–40°C and solubilities in water and organic solvents (aromatic hydrocarbons, dialkyl ethers) in the range of 0.5–1.5 wt.% The ionic liquids can be easily purified from ionic byproducts (e.g halogenide salts) by aqueous extraction followed by thorough drying in a high vacuum without loss of yield Due to the above features, these new ionic fluids may be considered as promising recyclable media in repeated catalytic processes vii LIST OF TABLES Table 1.1 Table 1.2 Table 2.1 A comparison of some of the important physical properties of some known N-N'-dialkyllimidazolium based cations A comparison of the physical properties of some commonly used solvents 13 Synthesis and properties of N-methyl-N’-alkyl bis(nonafluorobutane-1-sulfonyl)imides and nonaflates 25 imidazolium viii 2CF3); *further splitting due to the multiple 19F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 153.2 [C9H17N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 580.0 [(C4F9SO2)2N–] (100) and lighter fragments 4.2.6 Synthesis of 1-isobutyl-3-methylimidazolium bis(nonafluorobutane-1sulfonyl)imide (1f) The title compound was prepared from N-methylimidazole (1.20 g, 14.6 mmol), Me2CHCH2Br (1.42 g, 15.3 mmol) and the salt A (8.61 g, 13.9 mmol) as described in GP1; yield 9.99 g (>99%) as a clear yellowish viscous liquid 1f, 1HNMR (400.23 MHz): δ 0.94 (6H, d, 3J = 6.7 Hz, Me2CH), 2.15 (1H, nonet, 3J = 6.8 Hz, Me2CH), 3.95 (3H, s, NCH3), 4.00 (2H, t, 3J = 7.4 Hz, NCH2), 7.39 (1H, t, J = 1.8 Hz) and 7.41 (1H, t, J = 1.8 Hz) (both CH=CH), 8.72 (1H, br s, N–CH=N) 13C-NMR (100.65 MHz): δ 18.6 (Me2CH), 29.1 (Me2CH), 35.8 (NCH3), 56.7 (NCH2), 122.7 and 123.6 (both CH=CH), 135.9 (N–CH=N) 19 F-NMR (376.59 MHz): δ –127.0 (4F, t*, J = 14 Hz, 2CF2-3), –122.0 (4F, mc, 2CF2-2), –113.8 (4F,br t, J = 14 Hz, 2CF2-1), – 82.0 (6F, tt, J1 = 9.9 Hz, J2 = 2.3 Hz, 2CF3); *further splitting due to the multiple 19 F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 139.1 [C8H15N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 580.0 [(C4F9SO2)2N–] (100) and lighter fragments 4.2.7 Synthesis of 1-isopropyl-3-methylimidazolium bis(nonafluorobutane-1sulfonyl)imide (1g) The title compound was prepared from N-methylimidazole (1.22 g, 14.9 mmol), Me2CHBr (1.93 g, 15.7 mmol) and the salt A (8.79 g, 14.2 mmol) as 38 described in GP1; yield 9.87 g (99%) as a slightly yellowish deliquescent crystalline solid, melting point 28–29°C 1g, 1H-NMR (400.23 MHz, DMSO-d6): δ 1.48 (6H, d, J = 6.7 Hz, Me2CH), 3.85 (3H, s, NCH3), 4.63 (1H, heptet, 3J = 6.7 Hz, NCHMe2), 7.71 (1H, t, J = 1.8 Hz) and 7.87 (1H, t, J = 1.8 Hz) (both CH=CH), 9.17 (1H, br s, N–CH=N) 13C-NMR (100.65 MHz, DMSO-d6): δ 22.3 (Me2CH), 35.7 (NCH3), 52.2 (NCHMe2), 120.5 and 123.7 (both CH=CH), 135.4 (N–CH=N) 15 N-NMR (40.57 MHz, DMSO-d6): δ –183.6 and –210.4 (both endocyclic N) 19F-NMR (376.59 MHz, DMSO-d6): δ –128.1 (4F, t*, J = 14 Hz, 2CF2-3), –123.3 (4F, mc, 2CF2-2), –115.6 (4F,br t, J = 14 Hz, 2CF2-1), –82.8 (6F, tt, J1 = 9.8 Hz, J2 = 2.6 Hz, 2CF3); *further splitting due to the multiple 19F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 125.114 [C7H13N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 579.950 [(C4F9SO2)2N–] (100) and lighter fragments 4.2.8 Synthesis of 1-sec-butyl-3-methylimidazolium bis(nonafluorobutane-1sulfonyl)imide (1h) The title compound was prepared from N-methylimidazole (1.20 g, 14.6 mmol), MeCH2CH(Me)Br (2.10 g, 15.3 mmol) and the salt A (7.25 g, 11.7 mmol) as described in GP1; yield 8.38 g (>99%) as a clear viscous tawny liquid 1h, 1H-NMR (400.23 MHz, DMSO-d6): δ 0.78 (3H, t, 3J = 7.4 Hz, CH3CH2), 1.47 (3H, d, 3J = 6.9 Hz, CH3CH), 1.80 (2H, mc, CH3CH2), 3.86 (3H, s, NCH3), 4.41 (1H, sextet, 3J = 6.9 Hz, NCH), 7.73 (1H, t, J = 1.7 Hz) and 7.86 (1H, t, J = 1.7 Hz) (both CH=CH), 9.17 (1H, br s, N–CH=N) 13 C-NMR (100.65 MHz, DMSO-d6): δ 9.9 (CH2CH3), 20.2 (CH3CHN), 29.1 (CH2CH3), 35.8 (NCH3), 57.8 (NCH), 120.4 and 123.9 (both CH=CH), 135.7 (N–CH=N) 19F-NMR (376.59 MHz, DMSO-d6): δ –128.1 (4F, t*, J = 14 Hz, 2CF2-3), –123.4 (4F, mc, 2CF2-2), –115.7 (4F,br t, J = 14 Hz, 2CF2-1), –82.8 39 (6F, tt, J1 = 9.8 Hz, J2 = 2.6 Hz, 2CF3); *further splitting due to the multiple 19F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 139.1 [C8H15N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 580.0 [(C4F9SO2)2N–] (100) and lighter fragments 4.2.9 Synthesis of 1-propyl-3-methylimidazolium nonafluorobutanesulfonate (2a) The title compound was prepared from N-methylimidazole (2.044 g, 24.9 mmol), Me(CH2)2Br (3.21 g, 26.1 mmol) and the salt B (8.00 g, 23.7 mmol) as described in GP1; yield 8.25 g (82%) as a slightly yellowish crystalline solid, melting point 33–34°C 2a, 1H-NMR (400.23 MHz): δ 0.94 (3H, t, 3J = 7.4 Hz, CH2CH3), 1.90 (2H, sextet, 3J = 7.4 Hz, CH2CH3), 3.96 (3H, s, NCH3), 4.15 (2H, t, 3J = 7.4 Hz, NCH2), 7.41 (1H, t, J = 1.8 Hz) and 7.43 (1H, t, J = 1.8 Hz) (both CH=CH), 9.09 (1H, br s, N–CH=N) 13 C-NMR (100.65 MHz): δ 10.4 (CH2CH3), 23.4 (CH2CH3), 36.3 (NCH3), 51.5 (NCH2), 122.1 and 123.6 (both CH=CH), 136.9 (N–CH=N) 19F-NMR (376.59 MHz): δ –127.1 (2F, t*, J = 14.2 Hz, 2CF2-3), –122.7 (2F, mc, 2CF2-2), – 115.9 (2F, t*, J = 14.2 Hz, 2CF2-1), –82.0 (3F, tt, J1 = 9.9 Hz, J2 = 2.7 Hz, 2CF3); * further splitting due to the multiple 19F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 125 [C7H13N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 298.9 [C4F9SO3–] (100) and lighter fragments 4.2.10 Synthesis of 1-butyl-3-methylimidazolium nonafluorobutanesulfonate (2b) The title compound was prepared from N-methylimidazole (2.04 g, 24.9 mmol), Me(CH2)3Cl (2.42 g, 26.1 mmol) and the salt B (8.00 g, 23.7 mmol) as described in GP1; yield 8.52 g (82%) as a clear yellow viscous liquid 2b, 1H-NMR 40 (400.23 MHz): δ 0.94 (3H, t, 3J = 7.4 Hz, CH2CH3), 1.35 (2H, sextet, 3J = 7.5 Hz, CH2CH3), 1.85 (2H, mc, NCH2CH2), 3.96 (3H, s, NCH3), 4.19 (2H, t, 3J = 7.5 Hz, NCH2), 7.37 (1H, t, J = 1.8 Hz) and 7.41 (1H, t, J = 1.8 Hz) (both CH=CH), 9.13 (1H, br s, N–CH=N) 13 C-NMR (100.65 MHz): δ 13.1 (CH2CH3), 19.3 (CH2CH3), 31.9 (NCH2CH2), 36.2 (NCH3), 49.8 (NCH2), 122.2 and 123.6 (both CH=CH), 136.7 (N– CH=N) 19 F-NMR (376.59 MHz): δ –127.1 (2F, t*, J = 14 Hz, 2CF2-3), –122.7 (2F, mc, 2CF2-2), –115.9 (2F, t*, J = 14 Hz, 2CF2-1), –82.0 (3F, tt, J1 = 9.9 Hz, J2 = 2.7 Hz, 2CF3); *further splitting due to the multiple 19F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 139.1 [C8H15N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 298.95 [C4F9SO3–] (100) and lighter fragments 4.2.11 Synthesis of 1-isopropyl-3-methylimidazolium nonafluorobutanesulfonate (2c) The title compound was prepared from N-methylimidazole (2.04 g, 24.9 mmol), Me2CHBr (3.22 g, 26.2 mmol) and the salt B (8.00 g, 23.7 mmol) as described in GP1; yield 8.14 g (81%) as a clear yellowish viscous liquid 2c, 1H-NMR (400.23 MHz): δ 1.56 (6H, d, 3J = 6.7 Hz, Me2CH), 3.97 (3H, s, NCH3), 4.65 (1H, heptet, 3J = 6.7 Hz, NCHMe2), 7.42 (1H, t, J = 1.9 Hz) and 7.45 (1H, t, J = 1.9 Hz) (both CH=CH), 9.12 (1H, br s, N–CH=N) 13C-NMR (100.65 MHz): δ 22.6 (Me2CH), 36.1 (NCH3), 53.3 (NCHMe2), 120.2 and 123.7 (both CH=CH), 135.3 (N–CH=N) 19 F- NMR (376.59 MHz): δ –127.1 (2F, t*, J = 14.2 Hz, 2CF2-3), –122.7 (2F, mc, 2CF2-2), –115.9 (2F, t*, J = 14.2 Hz, 2CF2-1), –82.0 (3F, tt, J1 = 10.0 Hz, J2 = 2.8 Hz, 2CF3); * further splitting due to the multiple 19F,19F couplings MS (ESI positive, ion energy 41 0.3 eV), m/z (%): 125 [C7H13N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 298.9 [C4F9SO3–] (100) and lighter fragments 4.2.12 Synthesis of 1-sec-butyl-3-methylimidazolium nonafluorobutanesulfonate (2d) The title compound was prepared from N-methylimidazole (2.04 g, 24.9 mmol), MeCH2CH(Me)Br (3.58 g, 26.1 mmol) and the salt B (6.74 g, 19.9 mmol) as described in GP1; yield 6.89 g (79%) as a tawny crystalline solid, melting point 42– 43°C 2d, 1H-NMR (400.23 MHz): δ 0.87 (3H, t, 3J = 7.4 Hz, CH3CH2), 1.55 (3H, d, J = 6.9 Hz, CH3CH), 1.86 (2H, quintet, 3J = 7.4 Hz, CH3CH2), 3.98 (3H, s, NCH3), 4.41 (1H, sextet, 3J = 6.9 Hz, NCH), 7.41 (1H, t, J = 1.8 Hz) and 7.46 (1H, t, J = 1.8 Hz) (both CH=CH), 9.17 (1H, br s, N–CH=N) 13 C-NMR (100.65 MHz): δ 9.9 (CH2CH3), 20.4 (CH3CHN), 29.8 (CH2CH3), 36.2 (NCH3), 59.1 (NCH), 120.2 and 123.8 (both CH=CH), 135.7 (N–CH=N) 19 F-NMR (376.59 MHz): δ –127.1 (2F, t*, J = 14.2 Hz, 2CF2-3), –122.7 (2F, mc, 2CF2-2), –115.9 (2F, t*, J = 14.2 Hz, 2CF2-1), – 82.0 (3F, tt, J1 = 9.9 Hz, J2 = 2.7 Hz, 2CF3); *further splitting due to the multiple 19 F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 139 [C8H15N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 298.9 [C4F9SO3–] (100) and lighter fragments HRMS (FAB negative, Cs, 20 keV, direct, glycerin, m/z), found: 298.9395 Calculated (C4F9O3S–): 298.9419 4.3 Synthesis of N-propyl-N'-alkyl imidazolium bis(nonafluorobutane-1sulfonyl)imides (3) (see Scheme 5): general procedure (GP2) Imidazole (1 equivalent) was placed into the reaction flask and dried in high vacuum (0.05 mbar, room temperature) to remove traces of moisture before adding a 42 solution of MeONa (1.05 equivalent) in MeOH (4.026 mmol/g, prepared from MeOH and Na) The reaction mixture was stirred for 15–20 at room temperature, MeOH was then removed in vacuum followed by drying the residue in high vacuum (0.05 mbar, room temperature) for hour MeCN (0.5 mL per mmol substrate) followed by the Me(CH2)2Br (1.0–1.1 equivalent) were added to the resulting sodium imidazolide at 0°C, and the reaction mixture was stirred for hours at 0°C and 15 hours at ambient temperature After the completion of the first alkylation step (NMRcontrol), the volatiles were removed in vacuum followed by the addition of the second alkylating reagent After the completion of the second alkylation step (NMR-control), the residue was combined with the salt A (0.95 equivalent) in two-phase water/CH2Cl2 mixture and treated as described in GP1 furnishing the compounds 3a,b 4.3.1 Synthesis of 1-propyl-3-ethylimidazolium bis(nonafluorobutane-1- sulfonyl)imide (3a) The title compound was prepared from imidazole (1.00 g, 14.7 mmol), MeONa (0.83 g, 15.4 mmol) in MeOH (10 mL), Me(CH2)2Br (1.80 g, 14.7 mmol) as a first alkylating reagent in MeCN (8 mL), (EtO)2SO2 (2.16 g, 14.0 mmol) as a second alkylating reagent employed at 0°C to room temperature for 17 hours, and the salt A (8.61 g, 13.9 mmol), as described in GP2; yield 9.90 g (99%) as a clear yellow viscous liquid 3a, 1H-NMR (400.23 MHz): δ 0.94 (3H, t, 3J = 7.4 Hz, CH2CH2CH3), 1.52 (3H, t, 3J = 7.4 Hz, NCH2CH3), 1.89 (2H, sextet, 3J = 7.4 Hz, CH2CH2CH3), 4.14 (2H, t, 3J = 7.4 Hz, NCH2CH2), 4.25 (2H, q, 3J = 7.4 Hz, NCH2CH3), 7.32 (1H, t, J = 1.8 Hz) and 7.35 (1H, t, J = 1.8 Hz) (both CH=CH), 8.82 (1H, br s, N–CH=N) 13 C-NMR (100.65 MHz): δ 10.2 (CH2CH2CH3), 15.0 (CH2CH2CH3), 23.4 43 (CH2CH2CH3), 45.2 (NCH2CH3), 51.5 (NCH2CH2), 121.9 and 122.3 (both CH=CH), 135.2 (N–CH=N) 19 F-NMR (376.59 MHz): δ –127.1 (4F, t*, J = 14 Hz, 2CF2-3), – 122.2 (4F, mc, 2CF2-2), –114.0 (4F,br t, J = 14 Hz, 2CF2-1), –81.9 (6F, tt, J1 = 9.9 Hz, J2 = 2.4 Hz, 2CF3); *further splitting due to the multiple 19 F,19F couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 139.1 [C8H15N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 580.0 [(C4F9SO2)2N–] (100) and lighter fragments HRMS (FAB negative, Cs, 20 keV, direct, glycerin, m/z), found: 579.8994 Calculated (C8F18NO4S2–): 579.8976 4.3.2 Synthesis of 1-butyl-3-propylimidazolium bis(nonafluorobutane-1- sulfonyl)imide (3b) The title compound was prepared from imidazole (1.021 g, 15.0 mmol), MeONa (0.851 g, 15.8 mmol) in MeOH (10 mL), Me(CH2)2Br (2.03 g, 16.5 mmol) as a first alkylating reagent in MeCN (7.5 mL), Me(CH2)3Br (2.62 g, 19.1 mmol) as a second alkylating reagent employed for hours at 70°C, and the salt A (8.30 g, 13.4 mmol), as described in GP2; yield 10.04 g (>99%) as a yellowish crystalline solid, melting point 36–37°C 3b, 1H-NMR (400.23 MHz): δ 0.936 and 0.940 (both 3H, t, 3J = 7.4 Hz, CH2CH3), 1.34 (2H, sextet, 3J = 7.4 Hz, CH2CH3 of n-C4H9), 1.83 (2H, mc, NCH2CH2 of n-C4H9), 1.89 (2H, sextet, 3J = 7.4 Hz, NCH2CH2 of n-C3H7), 4.14 and 4.17 (both 2H, t, 3J = 7.4 Hz, NCH2), 7.340 and 7.344 (both 1H, br s, CH=CH) 8.82 (1H, br s, N–CH=N) 13C-NMR (100.65 MHz): δ 10.2 and 13.0 (both CH3), 19.2 and 23.4 (both CH2CH3), 32.0 (NCH2CH2 of n-C4H9), 49.9 and 51.5 (both NCH2), 122.3 (both CH=CH), 135.5 (N–CH=N) 19 F-NMR (376.59 MHz): δ –127.1 (4F, t*, J = 14 Hz, 2CF2-3), –122.2 (4F, mc, 2CF2-2), –114.0 (4F,br t, J = 14 Hz, 2CF2-1), –81.9 (6F, tt, J1 = 9.9 Hz, J2 = 2.3 Hz, 2CF3); *further splitting due to the multiple 19F,19F 44 couplings MS (ESI positive, ion energy 0.3 eV), m/z (%): 167 [C10H19N2+] (100) and lighter fragments MS (ESI negative, ion energy 0.3 eV), m/z (%): 580 [(C4F9SO2)2N– ] (100) and lighter fragments 45 BIBILOGRAPHY AND NOTES Wasserscheid, P.; Welton, T (eds) Ionic Liquids in Synthesis, Wiley-VCH Verlag GmbH & Co KGaA, Weinheim, Germany, 2003 Earle, M J.; Esperanca, J M S S.; Gilea, M A.; Lopes, J N C.; Rebelo, L P N.; Magee, J W.; Seddon, K R.; Widegren, J A Nature 2006, 439, 831–834 Earle, M J.; Seddon, K R Pure Appl Chem 2000, 72, 1391–1398 (a) Wasserscheid, P Org Synth Highlights V 2003, 105–117 (b) Dzyuba, S V.; Bartsch, R A Angew Chem., Int Ed 2003, 42, 148–150 (c) Baudequin, C.; Baudoux, J.; Levillain, J.; Cahard, D.; Gaumont, A.-C.; Plaquevent, J.-C Tetrahedron: Asymmetry 2003, 14, 3081–3093 (d) Xu, W.; Angell, C A Science 2003, 302, 422–425 (e) Zhao, H S.; Malhotra, V Aldrichimica Acta 2002, 35, 75– 83 (f) Dupont, J.; de Souza, R F.; Suarez, P A Z Chem Rev 2002, 102, 3667– 3691 (g) Wasserscheid, P.; Keim, W Angew Chem., Int Ed 2000, 39, 3772–3789 (h) Welton, T Chem Rev 1999, 99, 2071–2083 (a) Rogers, R D.; Seddon, K R (eds) Ionic Liquids IIIB: Fundamentals, Progress, Challenges, and Opportunities—Transformations and Processes, American Chemical Society, Washington DC, 2005 (b) Dyson, P J.; Geldbach, T J Metal Catalysed Reactions in Ionic Liquids, Springer, The Netherlands, 2005 ‘Room temperature molten salts,’ ‘low temperature molten salts,’ ‘ambient temperature molten salts,’ ‘ionic fluids’, ‘liquid organic salts’ and ‘non-aqueous ionic 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chloride/aluminium chloride ionic liquid at a 0.66 molar fraction was found to have a melting point of -80oC with a viscosity of 16 cP at 25oC; cited in Ref 4f; water has a viscosity of 0.890 cP at 25oC, while glycerol has a viscosity of 934 cP at 25oC; cited from Ref 8: Handbook of Chemistry and Physics 81st edition, pp 6–180 to 6–181 16 Wilkes, J S.; Zaworotko, M J J Chem Soc., Chem Commum 1992, 965–966 17 Hagiwara, R.; Ito, Y J Fluorine Chem 2000, 105, 221–227 18 Bonhôte, P.; Dias, A.-P.; Papageorgiou, N.; Kalyanasundaram, K.; Grätzel, M Inorg Chem 1996, 35, 1168–1178 47 19 Adams, A J.; Dyson, P J.; Tavener, S J Chemistry in Alternative Reaction Media, John Wiley Sons Ltd, Chichester, England, 2003 20 Wilkes, S J.; Zaworotko, M Chem Commun 1990, 965 21 Fuller, J.; Carlin, R T.; De Long, H C.; Haworth, D Chem Commun 1994, 299 22 Oliver, H.; Favre, F United States Patent 6, 245, 918, 2001; cited in Ref 5b 23 The most efficient method for measuring the melting points (and decomposition temperatures) of ionic liquids is differential scanning calorimetry (DSC) Other methods though to a lesser extent, such as cold-stage polarizing microscopy, NMR, and X-ray scattering, could also be employed; cited Ref 24 1,3-Dimethylimidazolium chloride was recrystallized from a solvent system of ethyl acetate and acetonitrile; Harlow, K J.; Hill, A F.; Welton, T Synthesis 1996, 6, 697–698 25 1-Ethyl-3-methylimidazolium chloride was recrystallized from distilled acetonitrile with the yield of 71%; Smith, G P.; Dworkin, A S.; Pagni, R M.; Zingg, S P J Am Chem Soc 1989, 111 , 525–530 26 Huddleston, J G.; Visser, A E.; Reichert, M.; Willauer, H D.; Broker, G A.; Rogers, R D Green Chem 2001, 3, 156–164 27 Domanska, U.; Bogel-Lukasil, E.; Bogel-Lukasik, R; Chem Europ J 2003, 9, 3033–3041 28 1,3-Dibenzylimidazolium chloride was recrystallized from a solvent system of toluene and acetonitrile; Ref 24 29 Henry, R A J Org Chem 1968, 33, 899–900 30 1,3-Dimethylimidazolium bromide was precipitated by diethyl ether from ethanol; Nifantyev, E E.; Gratchev, M K.; Burmistrov, S Y.; Vasyanina, L K.; Antipin, M Y.; Struchkov, Y T Tetrahedron, 1991, 47, 9839–9860 48 31 Nishida, T.; Tashiro, Y.; Yamamoto, M J Fluorine Chem 2003, 120, 135–142 32 Kitaoka, S.; Nobuoka, K.; Ishikawa, Y Tetrahedron, 2005, 61, 7678–7685 33 Ohta, S.; Hayakawa, S.; Nishimura, K Okamoto, M Tetrahedron Lett., 1984, 25, 3251–3254 34 Stark, A.; MacLean, B L.; Singer, R D J Chem Soc Dalton Trans., 1999, 1, 63– 66 35 Padilla-Martinez, I I.; Ariza-Castolo, A.; Contreras, R Magn Reson Chem., 1993, 31, 189–193 36 Godefroi, E F J Org Chem., 1968, 33, 860–861 37 Dzyuba, S V.; Bartsch, R A Chem Commun 2001, 16, 1466–1467 38 Singh, R P.; Manandhar, S.; Shreeve, J M Synthesis, 2003, 10, 1579–1585 39 Merrigan, T L.; Bates, E D.; Dorman, S C.; Davis, J H Chem Commun 2000, 20, 2051–2052 40 Holbery, J D.; Seddon, K R J Chem Soc Dalton Trans., 1999, 13, 2133–2410 41 Ref 5b pp.17 42 Fredlake, C P.; Crosthwaite, J M.; Hert, D G.; Aki, S N V.; Brennecke, J F J Chem Eng Data 2004, 49, 954–964 43 Anderson, J L.; Armstrong, D W Anal Chem 2003, 75, 4851–4858 44 Stenzel, O Raubenheimer, H G.; Esterhuysen, C.; J Chem Soc Dalton Trans 2002, 6, 1132–1138 45 Tseng, M C.; Liang, Y M; Chu, Y H.; Tetrahedron Lett 2005, 45, 6131–6136 46 Zhang, J.; Martin, G R.; DesMarteau, D D Chem Commun 2003, 18, 2334–2335 47 Matsumoto, H.; Kageyama, H; Miyazaki, Y Chem Commun 2002, 16, 1726– 1727 49 48 Ohlin, C.; Andre, D; Dyson, P J.; Laurenczy, G Chem Commun 2004, 9, 1070– 1071 49 McLean, A J.; Mu;doon, M J.; Gordon, C M.; Dunkin, I R Chem Commun 2002, 17, 1880–1881 50 Dzyuba, S V.; Bartsch, R A Tetrahedron Lett 2002, 43, 4657–4660 51 Lide, D R (eds) Handbook of Chemistry and Physics: Chapter 6, 81st ed 2000– 2001, CRC Press LLC, 2000 52 Varma, R S.; Namboodiri, V V Chem Commun 2001, 7, 643–644 53 Pernak, J.; Sobaszkiewicz, K.; Mirska, I Green Chem 2003, 5, 52–56 54 Docherty, K M.; Kulpa, C F Green Chem 2005, 7, 185–189 55 Pretti, C.; Chiappe, C.; Pieraccini, D.; Gregori, M.; Abramo, F.; Monni, G.; Intorre, L Green Chem 2006, 8, 238–240 56 NfF is available from many suppliers It is produced in technical scale by the electrochemical fluorination of 2,5-dihydrothiophene 1,1-dioxide According to 19 F-NMR, our sample of NfF contains mol.% of side product, perfluorosulfolane: Bürger, H.; Heyder, F.; Pawelke, G.; Niederprüm, H J Fluorine Chem 1979, 13, 251–260 57 Sogabe, K.; Hasegawa, Y.; Wada, Y.; Kitamura T.; Yanagida, S Chem Lett 2000, 29, 944–945 58 pKa[HCO3−]aq = 10.33, pKa[HPO42−]aq = 12.32; cited from Ref 8: Handbook of Chemistry and Physics 81st edition, pp 8-44 to 8-45 59 CH3C(O)NNf\K⊕, 1H-NMR (400.23 MHz, DMSO-d6): 1.81 (3H, s, CH3) 19 F- NMR (376.59 MHz, DMSO-d6): δ –128.0 (2F, mc, CF2-3), –123.5 (2F, mc, CF2-2), – 115.8 (2F, mc, CF2-1), –82.75 (3F, tt, J1 = 9.8 Hz, J2 = 2.9 Hz, CF3) MS (ESI negative, ion energy 0.3 eV), m/z (%): 339.94 [C4F9SO2NC(O)CH3]– 50 60 See Ref 56 and Lyapkalo, I M.; Webel, M.; Reissig, H.-U Eur J Org Chem 2002, 1015–1025 61 O-sulfonylation of metal enolates or N-sulfonylation of lithium dialkylamides with NfF occurs instantaneously even at –78°C, see (a) Lyapkalo, I M.; Webel, M.; Reissig, H.-U Synlett 2001, 1293–1295 or (b) Lyapkalo, I M.; Reissig, H.-U.; Schäfer, A.; Wagner, A Helv Chim Acta, 2002, 85, 4206–4215 respectively, whereas no evidences of F\ release were noticed upon activation of NfF with highly nucleophilic 4-(N,N-dimethylamino)pyridine 62 Et3N failed to produce the desired NNf2\ ion when used as a base for sulfonylation of amides RC(O)NH2 with NfF (see Ref 57) 63 At the later stage of the optimization of KNNf2 synthesis, we found out that a similar method was used for preparation of LiNNf2 by heating of liquid NH3 with NfF in access of Et3N as an auxiliary base and solvent at 90°C in autoclave: Conte, L.; Gambaretto, G P.; Caporiccio, G.; Alessandrini, F.; Passerini, S J Fluorine Chem 2004, 125, 243–252 The protocol reported in this thesis seems more convenient as it simplifies dosing of ammonia (in form of solid NH4Cl) and is carried out at smoother conditions in normal laboratory glassware giving a better yield of the intermediate Et3NH⊕NNf2\ 64 The 19F-NMR spectrum contains no detectable signal of side product(s) that might result from perfluorosulfolane (cf Ref 60) 65 The samples of the salts neither change appearance nor gain in weight upon storage in open vial for a long period of time 66 The AgNO3 test used qualitatively based on the formation of AgCl or AgBr precipitate when an AgNO3 acid solution is in contact with a halogenide source In 51 the case of the hydrophobic ionic liquids in this work, the test is obtained on samples of the aqueous washing of the ionic liquids 67 First representatives of the salts 1, N,N'-dimethyl- and N-methyl-N'- ethylimidazolium bis(nonafluorobutane-1-sulfonyl)imides were obtained earlier in a different way: Ref 46 68 A few N,N'-dialkylimidazolium nonaflates were prepared earlier (see Ref 18) 69 Thomazeau, C.; Olivier-Bourbigou, H.; Magna, L.; Luts, S.; Gilbert, B J Am Chem Soc 2003, 125, 5264–5265 70 Fan, Q.-H.; Li, Y.-M.; Chan, A S C Chem Rev 2002, 102, 3385–3465 71 Among some data that are desired in reports are the melting points (or glass transition temperatures), viscosity, density, refractive index, conductivity, and diffusion coefficients of the ionic liquids 72 Hong, X.; Verma, R.; Shreeve, J M J Fluorine Chem 2006, 127, 159–176 73 Naumann, D.; Wilkes, B.; Kischkewitz, J J Fluorine Chem 1985, 30, 73–87 52 [...]... 17 .9 /18 9 17 1 .1 1.987 (HOCH2)2 Ethylene glycol -12 .7 /19 7.3 210 .0 16 .1 (CH3)2CO Acetone -94.7/56 .1 150.8 0.306 (CH3)2NCO N,N-Dimethylformamide -60.5 /15 3 213 .5 0.794 HOCH(CH2OH)2 Glycerol 18 .1/ 290 2 71. 9 934 C4H8O Tetrahydrofuran -10 8.4/65 17 3.4 0.456 CH3CO2C2H5 Ethyl acetate -83.8/77 .1 160.9 0.423 (C2H5)2O Diethyl ether -11 6.2/34.5 15 0.7 0.224 C6H6 Benzene 5.5/80 .1 74.6 0.604 C6H14 Hexane -95.4/68.7 13 4 .1. .. decomposition temperature, c ρ = density and d V = viscosity 9 (v) where X = BF4, R1 R2 R3 Mpa (oC) Tdb (oC) ρc (gcm-3) V c (cP) CH3 H CH3 10 3.440 – – – C2H5 H CH3 13 31 447 31 1.28 (25oC) 31 37 (25oC) 31 CH3(CH2)2 H CH3 -17 31 435 31 1.24 (25oC) 31 103 (25oC) 31 CH3(CH2)3 H CH3 - 812 6 435 31 1. 21 (25oC) 31 180 (25oC) 31 CH3(CH2)5 H CH3 -82 41 – – 314 (20oC)26 CH3(CH2)7 H CH3 -785b – – – CH3(CH2)9 H CH3 -4 5b – – – Where... N,N'-dialkylimidazolium bis(nonafluorobutane -1- sulfonyl) imides (1 and 3) and N,N'-dialkylimidazolium nonafluorobutane -1- sulfonates (2) as two new series of ionic liquids (Figure 1. 2) R1 N N Alkyl X 1- 3 1: R1 = CH3, X = NNf2 2: R1 = CH3, X = ONf 3: R1 = CH3(CH2)2, X = NNf2 Nf: CF3(CF2)3SO2 Figure 1. 2 A representation of the ionic liquids synthesized and described in this thesis 17 CHAPTER 2 RESULTS AND DISCUSSION 2 .1 Prelude... 12 944 – – – C2H5 CH3 CH3 11 344 – – – C2H5 C2H5 CH3 11 318 – – – d Where a Mp = melting point, b Td = decomposition temperature, c ρ = density and V = viscosity 10 (vii) where X = CF3(CF2)3SO3, R1 R2 R3 Mpa (oC) Tdb (oC) ρc (gcm-3) V d (cP) C2H5 H CH3 2826 – – – CH3(CH2)3 H CH3 2 017 – 1. 473 (18 oC )17 373 (25oC)26 CH3(CH2)3 H C2H5 211 7 – 1. 427 (18 oC )17 323 (18 oC )17 CH3(CH2)3 CH3 CH3 59– 614 5 – – – d Where a... (CF3SO2)2N, R1 R2 R3 Mpa (oC) Tdb (oC) ρc (gcm-3) V d (cP) CH3 H CH3 2546 44546 1. 559 (22oC )17 44 (20oC )17 C2H5 H CH3 -17 46 43846 1. 52 (25oC)47 34 (25oC)47 CH3(CH2)2 H CH3 – 45226 – – CH3(CH2)3 H CH3 -242 43926 1. 44 (23.3oC)42 50.2 (22oC)32 CH3(CH2)7 H CH3 – – 1. 337 ( 21. 85oC)48 92.7 (24.85oC)49 CH3(CH2)9 H CH3 -2950 – 1. 2 71 (25oC)50 – C2H5 H C2H5 14 18 – 1. 452 (22oC )18 35 (20oC )18 CH3(CH2)3 H C2H5 e18 – 1. 404... CF3SO3 , R1 R2 R3 Mpa (oC) Tdb (oC) ρc (gcm-3) V d (cP) CH3 H CH3 3 918 – – – C2H5 H CH3 926 ~44026 1. 38 (25oC )17 42.7 (25oC )17 CH3(CH2)3 H CH3 13 42 – 1. 30 (22.6oC)42 93.2 (22oC)32 PhCH2 H CH3 2743 – 1. 3 (22.6oC)43 – C2H5 H C2H5 2 318 – 1. 330 (22oC )18 53 (20oC )18 CH3(CH2)3 H C2H5 218 – – – CF3CH2 H CH3 4538 – – – CF3(CH2)2 H CH3 513 8 – – – CF3(CH2)2 H CH3(CH2)3 -6438 – 1. 52 (24oC)38 – CH3 CH3 CH3 12 944 –... TABLE 1. 2 A comparison of the physical properties of some commonly used solvents. 51 Mol Form Name Mpa /Bpb (oC) Liq Rangec (oC) V d (cP) H2O Water 0 /10 0.0 10 0.0 0.890 CHCl3 Trichloromethane -63.4/ 61. 2 12 4.6 0.537 CH2Cl3 Dichloromethane -97.2/40 13 7.2 0. 413 CH3OH Methanol -97.5/64.6 16 2 .1 0.544 CH3CN Acetonitrile -43.8/ 81. 7 12 5.5 0.369 C2H5OH Ethanol -14 4 .1/ 78.3 222.4 1. 074 (CH3)2SO Dimethyl sulfoxide 17 .9 /18 9... [(CF3SO2)2N] \ Figure 1. 1 A representation of the cations and anions that are commonly used in the preparation of ionic liquids 1. 3 Historical development of ionic liquids Room temperature ionic liquids are not something new; some of them have been known for many years, for instance the first room temperature ionic liquid ethylammonium nitrate (mp 12 oC) was first described in 19 14 .11 However this did... CH3(CH2)3 H C2H5 e18 – 1. 404 (22oC )18 48 (20oC )18 C2H5 CH3 CH3 2 017 – 1. 495 (21oC )17 88 (20oC )17 C2H5 C2H5 CH3 2 818 – – – CF3CH2 H CH3 e18 – 1. 656 (20oC )17 248 (20oC )17 CF3(CH2)2 H CH3 -7438 – 1. 44 (24oC)38 – Where a Mp = melting point, crystallized (ix) b Td = decomposition temperature, c ρ = density, d V = viscosity, e could not be where X = [CF3(CF2)3SO2]2N, R1 R2 R3 Mpa (oC) Tdb (oC) ρc (gcm-3)...LIST OF FIGURES Figure (a) Figure 1. 1 Figure 1. 2 Figure 2 .1 A representation of the ionic liquids synthesized and described in this thesis vi A representation of the cations and anions that are commonly used in the preparation of ionic liquids 2 A representation of the ionic liquids synthesized and described in this thesis 17 A demonstration of the immiscibility of ionic liquids with water and toluene ... -97.5/64.6 16 2 .1 0.544 CH3CN Acetonitrile -43.8/ 81. 7 12 5.5 0.369 C2H5OH Ethanol -14 4 .1/ 78.3 222.4 1. 074 (CH3)2SO Dimethyl sulfoxide 17 .9 /18 9 17 1 .1 1.987 (HOCH2)2 Ethylene glycol -12 .7 /19 7.3 210 .0 16 .1. .. Chapter 1: Introduction 1. 1 Preamble 1. 2 What are ionic liquids? 1. 3 Historical developments of ionic liquids 1. 4 Synthesis of ionic liquids 1. 5 Physical properties of ionic liquids 1. 5 .1 Effects... X = BF4, R1 R2 R3 Mpa (oC) Tdb (oC) ρc (gcm-3) V c (cP) CH3 H CH3 10 3.440 – – – C2H5 H CH3 13 31 447 31 1.28 (25oC) 31 37 (25oC) 31 CH3(CH2)2 H CH3 -17 31 435 31 1.24 (25oC) 31 103 (25oC) 31 CH3(CH2)3