Speciation of Actinides and Lanthanides with Ligands Proposed for Next Generation Partitioning ...

226 Pages·2014·7.22 MB·English

by  Dan Whittaker

Speciation of Actinides and Lanthanides with
Ligands Proposed for Next Generation
Partitioning Processes

A thesis submitted to The University of Manchester for the
degree of Doctor of Philosophy in the Faculty of
Engineering and Physical Sciences

2014

Daniel Whittaker

The School of Chemistry
Table of Contents
TABLE OF CONTENTS

Table of Figures ............................................................................................... 6
Table of Tables ................................................................................................ 9
Table of Equations ........................................................................................ 10
Abstract .......................................................................................................... 11
Declaration ..................................................................................................... 12
Copyright Statement ..................................................................................... 12
Acknowledgements ........................................................................................ 13
Table of Abbreviations ................................................................................. 14
1 Introduction ............................................................................................. 15
1.1 Introduction to the Actinides .............................................................................. 15
1.1.1 Abundance and Isolation/Synthesis of the Actinides .......................................................... 15
1.1.2 Nuclear Fission ................................................................................................................... 16
1.1.3 Nuclear Fuel and Spent Nuclear Fuel ................................................................................. 18
1.1.4 The f-Elements .................................................................................................................... 20
1.1.5 Ln/An-Contraction and Relativistic Effects ........................................................................ 22
1.1.6 Oxidation States of the Ln/An Elements ............................................................................ 23
1.1.7 Other Uses of the Actinides ................................................................................................ 26
1.2 Introduction to Nuclear Fuel (Re)Processing ..................................................... 27
1.3 Waste Disposal and Partitioning and Transmutation .......................................... 27
2 Introduction to Solvent Extraction ....................................................... 30
2.1 Uranium Solvent Extraction ............................................................................... 31
2.2 Parameters Used in Solvent Extraction............................................................... 32
2.3 Nuclear Reprocessing ......................................................................................... 33
2.3.1 PUREX Process .................................................................................................................. 34
2.3.2 DIAMEX Process ............................................................................................................... 36
2.3.3 TRUEX Process .................................................................................................................. 37
2.3.4 TALSPEAK Process ........................................................................................................... 38
2.3.5 SANEX Process .................................................................................................................. 39
2.3.6 GANEX Process ................................................................................................................. 40
2.3.7 i-SANEX Process ............................................................................................................... 41
2.3.8 Process Summary ............................................................................................................... 43
2.4 Reprocessing Summary ...................................................................................... 44
3 Previous Work ......................................................................................... 46
3.1 Evolution of Ligand Design ................................................................................ 46
3.2 Solid and Solution State Characterisation........................................................... 52
3.2.1 MA/Ln Behaviour ............................................................................................................... 52
3.2.2 Uranium Behaviour ............................................................................................................ 54
3.3 Extraction Studies ............................................................................................... 58
3.4 Previous Work Summary .................................................................................... 61
4 Aim of Investigation ................................................................................ 63
5 CyMe -BTPhen and CyMe -BTBP ....................................................... 65
4 4
5.1 (Re-)Crystallisation of CyMe -BTPhen and CyMe -BTBP ............................... 65
4 4
5.2 Purification of CyMe -BTX ................................................................................ 66
4
5.3 1H NMR Titrations of CyMe -BTPhen............................................................... 67
4
5.4 Conclusions ......................................................................................................... 68
5.5 Experimental ....................................................................................................... 69
5.5.1 Synthesis and Purification of CyMe -BTPhen and CyMe -BTBP ..................................... 69
4 4
5.5.2 Recrystallisation of CyMe -BTX ........................................................................................ 69
4
5.5.3 1H NMR Titration of CyMe -BTPhen with H+ ................................................................... 70
4
2
Table of Contents
6 Uranyl Interaction with CyMe -BTX.................................................... 71
4
6.1 Solution Studies of UO 2+ with CyMe -BTPhen ................................................ 71
2 4
6.1.1 1H NMR Analysis of the Interaction of UO (NO ) and CyMe4-BTPhen ......................... 71
2 3 2
6.1.2 1H NMR Analysis of the Interaction of UO (ReO ) and CyMe -BTPhen ......................... 73
2 4 2 4
6.1.3 UV/vis Analysis of the Interaction of UO 2+ and CyMe -BTPhen ..................................... 75
2 4
6.2 Syntheses and Characterisation of UO 2+ Complexes of CyMe -BTPhen ......... 77
2 4
6.2.1 Characterisation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ] ........................................... 77
2 4 2 2 3 2
6.2.2 Investigation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ] Formation ............................... 82
2 4 2 2 3 2
6.2.3 Characterisation of [UO (CyMe -BTPhen)(ReO )][ReO ].CH CN.H O ........................... 86
2 4 4 4 3 2
6.3 Solution Studies of UO 2+ with CyMe -BTBP ................................................... 88
2 4
6.3.1 UV/vis Spectroscopic Analysis of the Interaction of UO 2+ and CyMe -BTBP ................. 88
2 4
6.4 Synthesis and Characterisation of UO 2+ Complexes of CyMe -BTBP ............. 89
2 4
6.4.1 Behaviour of UO (NO ) and CyMe -BTBP ...................................................................... 89
2 3 2 4
6.4.2 Characterisation of [UO (CyMe -BTBP)(ReO )][ReO ].½CH CN ................................... 91
2 4 4 4 3
6.5 XAS Analysis of UO (NO ) Interaction with CyMe -BTX .............................. 93
2 3 2 4
6.6 Conclusions ....................................................................................................... 101
6.7 Experimental ..................................................................................................... 102
6.7.1 Preparation of UO (ReO ) Stock Solution ........................................................................ 102
2 4 2
6.7.2 Synthesis and Characterisation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ]..................... 102
2 4 2 2 3 2
6.7.3 Synthesis and Characterisation of [UO (CyMe -BTPhen)(ReO )][ReO ].CH CN.H O .... 103
2 4 4 4 3 2
6.7.4 Investigation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ] Formation ............................... 103
2 4 2 2 3 2
6.7.5 Studies of UO (NO ) .6H O with CyMe -BTBP ................................................................ 105
2 3 2 2 4
6.7.6 Synthesis and Characterisation of [UO (CyMe -BTBP)(ReO )][ReO ].½CH CN ............ 106
2 4 4 4 3
6.7.7 1H NMR Studies of CyMe -BTPhen and UO (NO ) .6H O ............................................... 107
4 2 3 2 2
6.7.8 1H NMR Studies of CyMe -BTPhen and UO (ReO ) ....................................................... 107
4 2 4 2
6.7.9 UV/vis Spectroscopic Studies of CyMe -BTX and UO 2+ ................................................. 108
4 2
6.7.10 UO 2+ Extractions with CyMe -BTX .................................................................................. 108
2 4
6.7.11 Uranium L -edge XAS ...................................................................................................... 109
III
7 An4+ Interaction with CyMe -BTX ...................................................... 111
4
7.1 Solution Studies of Th4+ with CyMe -BTPhen ................................................. 111
4
7.1.1 1H NMR Studies of the Interaction of CyMe -BTPhen and Th(NO ) ............................... 111
4 3 4
7.1.2 UV/vis Analysis of the Interaction of Th4+ and CyMe -BTPhen ........................................ 112
4
7.2 Synthesis and Characterisation of Th(CyMe -BTPhen)(NO ) .X .................... 114
4 3 4
7.3 1H NMR Studies of Th4+ with CyMe -BTBP ................................................... 117
4
7.4 Synthesis and Characterisation of
[Th(CyMe -BTBP) (NO ) ][Th(NO ) ].4CH CN ............................................ 119
4 2 3 2 3 6 3
7.5 Synthesis and Characterisation of [U(CyMe -BTPhen)Cl (OTf).3CH CN] .... 121
4 3 3
7.6 Synthesis and Characterisation of U4+ Complexes of CyMe -BTPhen ............ 122
4
7.7 Solution Studies of Pu4+ Complexation with CyMe -BTX .............................. 127
4
7.7.1 Pu4+-CyMe -BTPhen Interaction with TBP ........................................................................ 129
4
7.8 Conclusions ....................................................................................................... 130
7.9 Experimental ..................................................................................................... 131
7.9.1 Synthesis of Th(CyMe -BTPhen)(NO ) ............................................................................ 131
4 3 4
7.9.2 Synthesis and Characterisation of Th-CyMe -BTBP Species............................................. 132
4
7.9.3 Synthesis of [U(CyMe -BTPhen)(OTf)Cl ] ........................................................................ 133
4 3
7.9.4 Synthesis of U(OTf) Complexes of CyMe -BTPhen ........................................................ 134
4 4
7.9.5 Synthesis of Pu(NO ) Complexes with CyMe -BTX ........................................................ 134
3 4 4
8 Trivalent Ln/An Interactions with CyMe -BTX ................................ 136
4
8.1 Solution Studies of Ln3+ Complexes with CyMe -BTX ................................... 136
4
8.1.1 UV/vis Measurements ........................................................................................................ 136
8.1.2 Luminescence Measurements ............................................................................................. 142
8.2 Characterisation of Ln with CyMe -BTX ......................................................... 146
4
8.3 Solution Studies of Am3+ with CyMe -BTX .................................................... 152
4
8.3.1 Interactions of Am3+ Complexes with TBP ........................................................................ 156
8.4 Conclusions ....................................................................................................... 162
8.5 Experimental ..................................................................................................... 163
8.5.1 Synthesis of Ln3+ Complexes of CyMe -BTX .................................................................... 163
4
3
Table of Contents
8.5.2 Synthesis of Am(NO ) Complexes of CyMe -BTX .......................................................... 166
3 3 4
9 XAS Measurements of Tri/Tetravalent An/Ln with CyMe -BTX ... 168
4
9.1 EXAFS Measurements of the Interaction of Ln3+ with CyMe -BTX ............... 168
4
9.1.1 Eu(NO ) Extraction with CyMe -BTX .............................................................................. 171
3 3 4
9.1.2 Tb(NO ) Extraction with CyMe -BTX .............................................................................. 176
3 3 4
9.1.3 Pr(NO ) Extraction with CyMe -BTX............................................................................... 178
3 3 4
9.2 EXAFS Measurements of Extracted An3/4+ with CyMe -BTX and TBP ......... 182
4
9.2.1 Am(NO ) Extraction with CyMe -BTPhen ....................................................................... 183
3 3 4
9.2.2 Pu(NO ) Extraction with CyMe -BTX .............................................................................. 186
3 4 4
9.2.3 Th(NO ) Extraction with CyMe -BTX .............................................................................. 189
3 4 4
9.2.4 Np(NO ) Extraction with CyMe -BTX ............................................................................. 193
3 4 4
9.3 Conclusions ....................................................................................................... 195
9.4 Experimental ..................................................................................................... 196
9.4.1 XAS Sample Measurement Procedure................................................................................ 196
9.4.2 Preparation of Ln Samples for XAS Measurement ............................................................ 197
9.4.3 Preparation of An Samples for XAS Measurement ............................................................ 198
10 Investigations of GANEX Extractions of An3+/4+ ............................... 201
10.1 Conclusions and Further Work ......................................................................... 204
10.2 Experimental ..................................................................................................... 204
10.2.1 Extraction of Am3+, Eu3+, Th4+ and Pu4+ by CyMe -BTPhen(/TBP) in n-octanol .............. 205
4
11 Conclusions and Further Work ........................................................... 206
12 Generic Experimental Procedures ...................................................... 210
12.1 Synthesis ........................................................................................................... 210
12.2 NMR Spectroscopy ........................................................................................... 211
12.3 XAS Analysis.................................................................................................... 212
12.4 X-Ray Diffraction Data..................................................................................... 213
13 References .............................................................................................. 216

Word Count: 62,540 (including this)
4
Tables
Table of Figures

Figure 1-1: Periodic Table of the elements ...................................................................................................... 15
Figure 1-2: Graphical distribution of the product from neutron fission of 235U ............................................... 17
Figure 1-3: Depiction of the orbitals of the An series ...................................................................................... 21
Figure 1-4: Graphical representation of the relativistic effects on orbital radius ............................................. 23
Figure 1-5: Trends of the metal radius (black line) and the ionic radii (coloured lines). Reproduced from
reference . ................................................................................................................................................... 25
Figure 1-6: Depiction of a closed nuclear fuel cycle. ....................................................................................... 27
Figure 1-7: Relative radiotoxicity over time of the various components in SNF. Reproduced from reference .
.................................................................................................................................................................... 28
Figure 2-1: Process of solvent extraction ......................................................................................................... 30
Figure 2-2: Flowsheet of uranium mining and solvent extraction. Reproduced from reference ...................... 31
Figure 2-3: Graphical representation of counter-current processes .................................................................. 32
Figure 2-4: Structural diagram of TBP (left) of DMDOHEMA (middle) and CMPO (right). ......................... 34
Figure 2-5: Generic flowsheet of the PUREX process ..................................................................................... 35
Figure 2-6: Solutions of plutonium in a variety of oxidation states and environments. ................................... 36
Figure 2-7: Flowsheet of the DIAMEX process used in tests for feasibility studies. ....................................... 37
Figure 2-8: Structures of Ln extracting reagent, HDEHP (left) and An hold-back reagent, DTPA ................. 38
Figure 2-9: Flowsheet of the SANEX process used in testing. ........................................................................ 40
Figure 2-10: CyMe -BTBP .............................................................................................................................. 41
4
Figure 2-11: Structure of TODGA ................................................................................................................... 41
Figure 2-12: Proposed flowsheet for the i-SANEX process. ............................................................................ 42
Figure 3-1: Structure of the molecule studied by Kolarik et al. ....................................................................... 46
Figure 3-2: Acidic hydrolysis pathways of PBTP (Propyl-BTP) ..................................................................... 47
Figure 3-3: iPBTP molecules developed to improve acid stability................................................................... 47
Figure 3-4: Examples of the annulated BTP molecules ................................................................................... 48
Figure 3-5: Molecular depiction of the isomerisation upon complexation of the BTP molecules ................... 49
Figure 3-6: Molecular depiction of C2-BTBP.................................................................................................. 49
Figure 3-7: Depiction of the isomerisation possible with R-BTBP molecules. ................................................ 50
Figure 3-8: CyMe -BTPhen ............................................................................................................................. 50
4
Figure 3-9: Crystal structure of the common cation species (Ln(PBTP) 3+) .................................................... 52
3
Figure 3-10: Depiction of Eu(C2-BTBP)(NO ) .............................................................................................. 53
3 3
Figure 3-11: Depiction of the cation (UO (CyMe -BTBP)I)+ .......................................................................... 55
2 4
Figure 3-12: Depictions of the cation in the species ((UO (CyMe -BTBP)) O)I . .......................................... 56
2 4 2 2
Figure 3-13: Depiction of the uranium containing species, [UO (MBTP)(OTf) ] ........................................... 57
2 2
Figure 3-14: U(CyMe BTBP) (O)(UO )(NO ) (OTf).2MeCN ....................................................................... 58
4- 2 2 3 3
Figure 3-15: log(D) values of some of the FPs recorded ................................................................................. 60
Figure 3-16: log(D) values of some of the CPs recorded ................................................................................. 61
Figure 5-1: ORTEP representation (50 % probability ellipsoids displayed) of CyMe -BTBP. ....................... 66
4
Figure 5-2: a) Stacked 1H NMR spectra of titration of HCl in D O against CyMe -BTPhen in d -MeOD ..... 68
2 4 4
Figure 6-1: Numbered depiction of CyMe -BTPhen. ...................................................................................... 72
4
Figure 6-2: Stacked, full range, 1H NMR spectra of a titration of UO (NO ) against CyMe -BTPhen in d -
2 3 2 4 4
MeOD at 40 °C. .......................................................................................................................................... 72
Figure 6-3: Stacked, zoomed, 1H NMR spectra of a titration of UO (NO ) against CyMe -BTPhen in d -
2 3 2 4 4
MeOD at 40 °C. .......................................................................................................................................... 73
Figure 6-4: Stacked, zoomed, 1H NMR spectra of titration of UO (ReO ) against CyMe -BTPhen in d -
2 4 2 4 4
MeOD at 40 °C. .......................................................................................................................................... 74
Figure 6-5: Stacked, zoomed, 1H NMR spectra of a titration of CyMe -BTPhen against UO (ReO ) in d -
4 2 4 2 4
MeOD at 40 °C. .......................................................................................................................................... 74
Figure 6-6: UV/vis absorption spectra of the titration of UO (NO ) against CyMe -BTPhen. ....................... 76
2 3 2 4
Figure 6-7: ORTEP representation (50 % probability ellipsoids displayed) of
[UO (CyMe -BTPhen)(O )(UO )(NO ) ]. .................................................................................................. 78
2 4 2 2 3 2
Figure 6-8: Depiction, in Mercury, of the planes in the [UO (CyMe -BTPhen)(O )(UO )(NO ) ]. ................ 79
2 4 2 2 3 2
Figure 6-9: IR and Raman spectra of the CyMe -BTPhen complex [UO (CyMe -BTPhen)(O )(UO )(NO ) ].
4 2 4 2 2 3 2
.................................................................................................................................................................... 81
Figure 6-10: Stacked IR spectra of the samples used to investigate the effect of light and protic solvent on the
formation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ]. ............................................................................. 83
2 4 2 2 3 2
Figure 6-11: Stacked, zoomed in (8.2-10 ppm – aromatic region), 1H NMR spectra of the samples used to
investigate the effect of light/dark and (a)protic solvents on the formation of
[UO (CyMe -BTPhen)(O )(UO )(NO ) ]. .................................................................................................. 84
2 4 2 2 3 2
5
Tables
Figure 6-12: Stacked, zoomed in (8.45-10.1 ppm – aromatic region), 1H NMR spectra in d -MeOD of the
4
samples used to investigate the effect of O on the formation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ].
2 2 4 2 2 3 2
.................................................................................................................................................................... 85
Figure 6-13: Stacked, zoomed in (7.7-10.3 ppm – aromatic region) 1H NMR spectra of the samples used to
investigate the effect of O on the formation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ]. ...................... 86
2 2 4 2 2 3 2
Figure 6-14: ORTEP representation (50 % probability ellipsoids displayed) of
[UO (CyMe -BTPhen)(ReO )][ReO ].CH CN.H O. ................................................................................. 87
2 4 4 4 3 2
Figure 6-15: UV/vis absorption spectra of the titration of UO (NO ) against CyMe -BTBP. ........................ 89
2 3 2 4
Figure 6-16: IR and Raman spectra of the CyMe -BTBP complex of UO (NO ) .......................................... 91
4 2 3 2
Figure 6-17: ORTEP representation (50 % probability ellipsoids displayed) of the complex mono-cation in
[UO (CyMe -BTBP)(ReO )][ReO ].½CH CN .......................................................................................... 92
2 4 4 4 3
Figure 6-18: Graph of the 𝐷 versus time of the extraction of UO (NO ) from n-octanol with
𝑈𝑂2 2 3 2
CyMe -BTPhen with and without TBP ...................................................................................................... 94
4
Figure 6-19: k2-weighted χ(k)-function of U L -edge EXAFS data for UO 2+ complexes/solutions containing
III 2
CyMe -BTX with(out) TBP. ...................................................................................................................... 95
4
Figure 6-20: Fourier transform of U L -edge EXAFS data for UO 2+ complexes/solutions containing
III 2
CyMe -BTX with(out) TBP. ...................................................................................................................... 95
4
Figure 6-21: k3-weighted χ(k)-function (top) and Fourier transform (bottom) of U L -edge EXAFS data for
III
[UO (CyMe -BTPhen)(O )(UO )(NO ) ] and {UO (CyMe -BTBP)} ....................................................... 97
2 4 2 2 3 2 2 4
Figure 6-22: k3-weighted χ(k)-function (top) and Fourier transform (bottom) of U L -edge EXAFS data for
III
amorphous {UO (CyMe -BTPhen)(H O)} ................................................................................................. 98
2 4 2
Figure 6-23: Depiction of the experimental setup for investigating the effect of light and protic solvents on
the formation of [UO (CyMe -BTPhen)(O )(UO )(NO ) ]. ..................................................................... 104
2 4 2 2 3 2
Figure 7-1: Stacked 1H NMR spectra of titration of Th(NO ) against CyMe -BTPhen................................ 112
3 4 4
Figure 7-2: UV/vis absorption spectra of the titration of Th(NO ) against CyMe -BTPhen. ....................... 113
3 4 4
Figure 7-3: ORTEP representation (50 % probability ellipsoids displayed) of the complex molecule
[Th(CyMe -BTPhen)(NO ) ]. ................................................................................................................... 115
4 3 4
Figure 7-4: Stacked vibrational spectra of [Th(CyMe -BTPhen)(NO ) ], Th(NO ) .5H O and CyMe -BTPhen
4 3 4 3 4 2 4
with inset zoomed in spectra .................................................................................................................... 117
Figure 7-5: Stacked 1H NMR spectra of titration of Th(NO ) against CyMe -BTBP. .................................. 118
3 4 4
Figure 7-6: Proton numbered depiction of CyMe -BTBP. ............................................................................. 119
4
Figure 7-7: ORTEP representation (50 % probability ellipsoids displayed) of the complex cation
[Th(CyMe -BTBP) (NO ) ]2+. .................................................................................................................. 120
4 2 3 2
Figure 7-8: 50 % probability ORTEP representation of complex species [U(CyMe -BTPhen)(Cl) (OTf)]. . 121
4 3
Figure 7-9: 30 % probability ORTEP plot of complex species
[U(CyMe -BTPhen)(H O)(SO ) (U O (OTf) (THF)(CH CN))] . ........................................................... 122
4 2 4 3 3 4 3 3 2
Figure 7-10: 30 % probability ORTEP plot of complex species {(SO ) (U O (OTf) (THF)(CH CN))} . .... 123
4 3 3 4 3 3 2
Figure 7-11: U O core (left) characterised by Duval et al. and the U O core ............................................ 124
6 13 6 8
Figure 7-12: 50 % probability ORTEP plot of the U4+ complex [U(CyMe -BTPhen)(H O)(OTf) F]. .......... 126
4 2 3
Figure 7-13: 1H NMR of Pu-CyMe -BTPhen complex. ................................................................................. 127
4
Figure 7-14: 1H NMR of the Pu-CyMe -BTPhen complex with the large residual solvent (water) suppressed.
4
.................................................................................................................................................................. 128
Figure 7-15: 1H NMR of Pu-CyMe -BTBP complex ..................................................................................... 129
4
Figure 7-16: Overlaid 1H NMR spectra of Pu-CyMe -BTPhen ..................................................................... 130
4
Figure 8-1: UV/vis absorption spectrum of the titration of Pr(NO ) (top), Eu(NO ) (bottom left) and
3 3 3 3
Tb(NO ) (bottom right) against CyMe -BTPhen. ................................................................................... 138
3 3 4
Figure 8-2: UV/vis absorption spectra of redissolved (potentially reorganised) complexes of the Ln3+ and
CyMe -BTPhen ........................................................................................................................................ 139
4
Figure 8-3: UV/vis absorption spectrum of the titration of Pr(NO ) (top), Eu(NO ) (bottom left) and
3 3 3 3
Tb(NO ) (bottom right) against CyMe -BTBP. ...................................................................................... 140
3 3 4
Figure 8-4: Emission (excitation at 280-320 nm), excitation (monitoring emission at 616 nm) and absorption
spectra of [Eu(CyMe -BTBP) (X)]n+ (top) and [Eu(CyMe -BTPhen) (X)]n+ (bottom) ............................ 143
4 2 4 2
Figure 8-5: Time resolved emission spectrum of [Eu(CyMe -BTBP) (X)]n+ following excitation ............... 145
4 2
Figure 8-6: Emission (excitation at 280-320 nm), excitation (monitoring emission at 545 nm) and absorption
spectra of [Tb(CyMe -BTBP) (X)]n+ top and [Tb(CyMe -BTPhen) (X)]n+ (bottom) .............................. 146
4 2 4 2
Figure 8-7: Numbering scheme of complexes with CyMe -BTPhen. ............................................................ 147
4
Figure 8-8: ORTEP plots (50 % probability ellipsoids displayed) of X-ray crystal structures of Ln with
CyMe -BTPhen (top) and CyMe -BTBP (bottom). .................................................................................. 149
4 4
Figure 8-9: Stacked 1H NMR of CyMe -BTBP (top) and Am(CyMe -BTBP) (bottom) species. ................ 154
4 4 2
Figure 8-10: 13C DEPT-135 NMR of Am(CyMe -BTBP) species ............................................................... 155
4 2
Figure 8-11: 13C,1H HSQC 2D NMR spectrum of Am(CyMe -BTBP) ........................................................ 155
4 2
Figure 8-12: Overlaid 1H NMR spectra of [Am(CyMe -BTPhen) (Y) ](3-Z)+ with (top) and without (bottom)
4 2 Z
~0.6 eq. of TBP added. ............................................................................................................................. 156
6
Tables
Figure 8-13: 31P NMR spectrum of [Am(CyMe -BTPhen) (Y) ](3-Z)+ ~0.6 eq. of TBP added. ..................... 157
4 2 Z
Figure 8-14: 1H NMR DOSY spectrum of [Am(CyMe -BTPhen) (Y) ](3-Z)+. ............................................... 158
4 2 Z
Figure 8-15: 1H NMR DOSY spectrum of [Am(CyMe -BTPhen) (Y) ](3-Z)+ with ~0.6 eq. of TBP added. .. 159
4 2 Z
Figure 8-16: 1H NMR DOSY spectrum of [Am(CyMe -BTBP) (Y) ](3-Z)+. .................................................. 160
4 2 Z
Figure 8-17: Overlaid 1H NMR spectra of [Am(CyMe -BTBP) (Y) ](3-Z)+ with (top) and without (bottom)
4 2 Z
~0.6 eq. of TBP added. ............................................................................................................................. 161
Figure 8-18: 31P NMR spectrum of [Am(CyMe -BTBP) (Y) ](3-Z)+ ~0.6 eq. of TBP added ......................... 161
4 2 Z
Figure 8-19: 1H NMR DOSY spectrum of [Am(CyMe -BTBP) (Y) ](3-Z)+ with ~0.6 eq. of TBP added. ..... 162
4 2 Z
Figure 9-1: Schematic of the X-ray absorption sample holders. .................................................................... 169
Figure 9-2: L -edge absorption spectra of Eu-CyMe -BTPhen complexes. ................................................. 170
III 4
Figure 9-3: Depiction of the shell occupancy of complexes formed with CyMe -BTPhen (or CyMe -BTBP).
4 4
.................................................................................................................................................................. 171
Figure 9-4: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Eu L -edge EXAFS data for
III
crystalline [Eu(CyMe -BTPhen) (H O)][NO ] complex. ........................................................................ 172
4 2 2 3 3
Figure 9-5: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Eu L edge EXAFS data for
III-
cyclohexanone solutions of Eu3+ extracted by CyMe -BTBP (left) and CyMe -BTBP with TBP (right)
4 4
from acidic HNO solution. ...................................................................................................................... 175
3
Figure 9-6: L -edge absorption spectra of Tb-CyMe -BTPhen/CyMe -BTBP complexes, formed in various
III 4 4
conditions. ................................................................................................................................................ 176
Figure 9-7: L -edge absorption spectra of Pr-CyMe -BTPhen/CyMe -BTBP complexes, formed in various
III 4 4
conditions. ................................................................................................................................................ 179
Figure 9-8: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Pr3+ L -edge EXAFS data for
III
Pr3+ extracted by CyMe -BTPhen (left) and CyMe -BTPhen with TBP (right) into cyclohexanone
4 4
solution. .................................................................................................................................................... 180
Figure 9-9: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Pr3+ L -edge EXAFS data for
III
Pr3+ extracted by CyMe -BTBP (left) and CyMe -BTBP with TBP (right) into cyclohexanone solution.
4 4
.................................................................................................................................................................. 181
Figure 9-10: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Am3+ L -edge EXAFS data
III
for Am3+ extracted by CyMe -BTPhen (left) and CyMe -BTPhen with TBP (right) into n-octanol
4 4
solution. .................................................................................................................................................... 183
Figure 9-11: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Pu L -edge EXAFS data for
III
Pu(NO ) extracted into an organic phase of CyMe -BTPhen and TBP in n-octanol. ............................. 187
3 4 4
Figure 9-12: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Pu L -edge EXAFS data for
III
Pu(NO ) extracted into an organic phase of CyMe -BTBP and TBP in n-octanol. ................................. 189
3 4 4
Figure 9-13: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Th L -edge EXAFS data for
III
n-octanol solutions of Th(NO ) extracted by CyMe -BTPhen with TBP ................................................ 191
3 4 4
Figure 9-14: k2-weighted χ(k)-function (top) and Fourier transform (bottom) of Th L -edge EXAFS data for
III
n-octanol solutions of Th(NO ) extracted by CyMe -BTBP with TBP ................................................... 192
3 4 4
Figure 9-15: UV/vis spectra of the bulk reduction of Np in 4M HNO . ........................................................ 193
3
Figure 9-16: Stacked plot of sequential X-ray absorption scans of Np solutions extracted with
CyMe -BTPhen into n-octanol. ................................................................................................................ 194
4
Figure 9-17: Depiction of the apparatus used to reduce Np in the bulk aqueous phase. ................................ 198
Figure 9-18: Sample vials post-extraction using CyMe -BTPhen and TBP................................................... 200
4
Figure 10-1: Distribution ratios, D, as a function of phase contact time for Pu4+ and Th4+. .......................... 202
Figure 10-2: Distribution ratios, D, as a function of phase contact time for Am3+ and Eu3+ .......................... 203
Figure 12-1: Picture demonstrating the evaporation procedure of active liquors. Here, Pu(NO ) is being
3 4
concentrated for an NMR experiment. ..................................................................................................... 211
Figure 12-2: Graphical depiction of CyMe -BTPhen and CyMe -BTBP with labelled carbon atoms to allow
4 4
discussion of 13C and 1H assignment. ....................................................................................................... 211

Table of Tables

Table 1-1: Table of selected t of some of the An elements found in SNF. .................................................... 19
½
Table 1-2: Table of the concentration of the FPs and CPs in dissolved SNF liquor. Reproduced from .......... 20
Table 1-3: Table of the electronic configurations of the charge neutral Ln and An atoms. ............................. 21
Table 1-4: Table of the observed oxidation states of the An ions. ................................................................... 24
Table 1-5: Table of the known ionic forms of the An ions. Reproduced from reference . ............................... 25
Table 2-1: Table of the major points of the processes developed for nuclear waste reprocessing ................... 43
Table 3-1: Selected data (D/SF) for selected ligands discussed ....................................................................... 51
7
Tables
Table 5-1: Table of the inter-planar angles (°) of the aromatic rings in the solid-state structures of
CyMe -BTBP ............................................................................................................................................. 65
4
Table 6-1: Parameters obtained from EXAFS fits in k1, 2 and 3-space for
[UO (CyMe -BTPhen)(O )(UO )(NO ) ]/{UO (CyMe -BTBP)}. ............................................................. 96
2 4 2 2 3 2 2 4
Table 6-2: Parameters obtained from EXAFS fits in k1, 2 and 3-space for {UO (CyMe -BTX)(H O} and
2 4 2
[UO (CyMe -BTX)(O )(UO )(NO ) ] species. ........................................................................................ 100
2 4 2 2 3 2
Table 7-1: Selected bond lengths for the Th(CyMe -BTPhen)(NO ) .X species. .......................................... 116
4 3 4
Table 7-2: Selected bond distances in
[U(CyMe -BTPhen)(OTf)(H O)(SO ) (U O (OTf) (THF)(CH CN))] .1½CH CN. ................................ 125
4 2 4 3 3 4 3 3 2 3
Table 8-1: Table of logβ values fitted from UV/vis titrations in MeOH. ....................................................... 141
Table 8-2: Lifetimes of Eu3+ complexes recorded in MeOH and CD OD. .................................................... 144
3
Table 8-3: Selected interatomic distances (Å) for CyMe -BTPhen containing complexes ............................ 150
4
Table 8-4: Selected interatomic distances (Å) for CyMe -BTBP containing complexes ............................... 152
4
Table 9-1: Parameters obtained from EXAFS fits in R-space for crystalline
[Eu(CyMe -BTPhen) (H O)][NO ] . ........................................................................................................ 173
4 2 2 3 3
Table 9-2: Parameters obtained from EXAFS fits in R-space for cyclohexanone Eu containing systems..... 174
Table 9-3: Parameters obtained from EXAFS fits in R-space for cyclohexanone Eu containing systems..... 176
Table 9-4: Parameters obtained from EXAFS fits in R-space for cyclohexanone Tb containing systems..... 178
Table 9-5: Parameters obtained from EXAFS fits in R-space for cyclohexanone Pr containing systems. .... 182
Table 9-6: Parameters obtained from EXAFS fits in R-space for n-octanol Am containing solutions. ......... 185
Table 9-7: Parameters obtained from EXAFS fits in R-space for Pu containing systems.............................. 188
Table 9-8: Parameters obtained from EXAFS fits in R-space for Pu containing systems.............................. 189
Table 9-9: Parameters obtained from EXAFS fits in R-space for Th containing systems. ............................ 191
Table 9-10: Parameters obtained from EXAFS fits in R-space for Th containing systems. .......................... 192
Table 12-1: A summary of crystallographic data. .......................................................................................... 215

Table of Equations

Equation 1-1: Relativistic mass (m) of an electron in a 1s-orbital of uranium. ................................................ 22
Equation 2-1: Definition of Distribution coefficient, D. .................................................................................. 32
Equation 2-2: Definition of SF. Here defined for Am/Cm. .............................................................................. 33
Equation 6-1: (a) Equation for the complexation of UO 2+ by CyMe -BTPhen............................................... 77
2 4
Equation 7-1: Equation for the complexation of Th4+ by CyMe -BTPhen ..................................................... 114
4
Equation 8-1: Horrocks equation. .................................................................................................................. 142
Equation 8-2: Stokes-Einstein equation for the hydrodynamic radius of a sphere. ........................................ 157

8
Abstract
Abstract
Speciation of Actinides and Lanthanides with Ligands Proposed for Next Generation
Partitioning Processes
The University of Manchester, Daniel Mark Whittaker, 2014, Doctor of Philosophy.

Lanthanide(III) and actinide complexes with the N-donor extractants which are proposed
for use in next generation separation processes, CyMe -BTPhen and CyMe -BTBP, have
4 4
been synthesised and characterised in idealised synthetic and real extraction conditions.
Next generation spent nuclear fuel reprocessing is necessary in order to reduce the
longevity of activity (from 100,000’s to 100-1,000’s years) through re-use as fuel in GenIV
reactor programs. The N-donor extractants have been previously shown to preferentially
extract the trivalent An ions over the Ln ions in biphasic acidic extraction processes, a
necessary task due to the large neutron capture cross-sections of the lanthanides, and the
reasons behind this selectivity have been investigated here.
Proposed processes that use these extractants are called SANEX and GANEX. The
SANEX process is undertaken after a PUREX-style process where only the trivalent minor
actinides and the lanthanides are present during the separation. Whereas, in the GANEX
process the organic phase contains the N-donor molecule and another extractant, such as
TBP, with the aqueous phase containing the entire An series in various oxidation states.
Speciation of the Ln3+ ions with the N-donor molecules has been shown to be dominated
by 1:2 (M:L) complexes in the bulk organic phase post extraction and coordination is
completed by a small ligand, either H O or NO -. Spectrophotometric titration yielded logβ
2 3
values for the 1:2 (M:L) complexes of Pr3+, Eu3+ and Tb3+ nitrate salts. In all cases it was
shown that the CyMe -BTPhen molecule has a greater affinity than the CyMe -BTBP
4 4
molecule for the Ln3+ ions, as expected given the ‘locked’ design of CyMe -BTPhen.
4
The uranyl ion was shown to only form 1:1 (M:L) complexes in solution with the N-donor
molecules but structural characterisation showed it to also form 2:1 (M:L) complexes with
the metal ions bridged by a peroxide anion. The formation of this species was found to
require a protic solvent, light and molecular dioxygen. Again, binding was shown, by
spectrophotometric titration, to be stronger with CyMe -BTPhen than CyMe -BTBP.
4 4
The speciation of the tetravalent An ions, Pu4+ and Th4+ was studied using 1H NMR and
X-ray absorption spectroscopy in GANEX-style conditions. When the organic phase
contains TBP and the N-donor extractants, complexation is completed by TBP in the post
extraction organic phase and the extraction of Th4+ is exclusively completed by TBP but by
both extractants for Pu4+. In both cases, the major bulk species was identified as
Pu/Th(NO ) .3TBP, although complexes of the N-donor extractants and the An4+ have
3 4
been observed in idealised conditions, in both 1:1 and 1:2 (M:L) stoichiometries,
depending on the solution composition. U4+ was shown to form a variety of complexes of a
myriad of M:L stoichiometries.
9
Declaration and Copyright Statement
Declaration

No portion of the work referred to in the thesis has been submitted in support of an
application for another degree or qualification of this or any other university or other
institute of learning.

Copyright Statement

i. The author of this thesis (including any appendices and/or schedules to this thesis) owns
certain copyright or related rights in it (the “Copyright”) and s/he has given The
University of Manchester certain rights to use such Copyright, including for
administrative purposes.
ii. Copies of this thesis, either in full or in extracts and whether in hard or electronic copy,
may be made only in accordance with the Copyright, Designs and Patents Act 1988 (as
amended) and regulations issued under it or, where appropriate, in accordance with
licensing agreements which the University has from time to time. This page must form
part of any such copies made.
iii. The ownership of certain Copyright, patents, designs, trade marks and other intellectual
property (the “Intellectual Property”) and any reproductions of copyright works in the
thesis, for example graphs and tables (“Reproductions”), which may be described in this
thesis, may not be owned by the author and may be owned by third parties. Such
Intellectual Property and Reproductions cannot and must not be made available for use
without the prior written permission of the owner(s) of the relevant Intellectual Property
and/or Reproductions.
iv. Further information on the conditions under which disclosure, publication and
commercialisation of this thesis, the Copyright and any Intellectual Property and/or
Reproductions described in it may take place is available in the University IP Policy
(see http://documents.manchester.ac.uk/DocuInfo.aspx?DocID=487), in any relevant
Thesis restriction declarations deposited in the University Library, The University
Library’s regulations (see http://www.manchester.ac.uk/library/aboutus/regulations) and
in The University’s policy on Presentation of Theses.

10