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Quantum chemistry and raman spectroscopy studies of anion hydration /Craig, J. D. C., January 2000 (has links)
Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. / Restricted until November 2001. Bibliography: leaves 100-105.
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The thermal conductivity of aqueous electrolyte solutions and polar liquidsBleazard, Joseph Gibson 12 1900 (has links)
No description available.
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Application of room temperature ionic liquids as electrochemical solventsEvans, Russell Griffith January 2005 (has links)
This thesis is concerned with investigating the suitability of room temperature ionic liquids as solvents in which to perform voltammetry, and in characterising electrochemical processes within these media. After providing a general introduction and a background to the ionic liquid field, the results of six original studies are presented, dealing in turn with the following subjects: • The oxidation of N,N,N',N'-tetraalkyl-para-phenylenediamine (TAPD) in five ionic liquids each incorporating the bis(trifluoromethylsulfonyl)imide anion. • The reduction of oxygen in four ionic liquids based on quaternary alkyl -onium cations and heavily fluorinated anions in which the central ion is either nitrogen or phosphorous. The simulation of double potential step chronoamperometry at a disk electrode for the case of unequal diffusion coefficients and its experimental validation using a variety of aqueous, traditional nonaqueous and ionic liquid solutions. • The rate of diffusion of N,N,N',N'-tetramethyl-para-phenylenediamme (TMPD), its radical cation and dication as a function of temperature and ionic liquid viscosity and four such solvents. • The temperature dependence of the viscosity of five ionic liquids along with the translational and rotational diffusion coefficients of dissolved 2,2,6,6- tetramethylpiperidine-N-oxyl (TEMPO). • The kinetics of the reaction between N,N-dimethyl-para-toluidine (DMT) and its electrogenerated radical cation in an ionic liquid solvent. The experimental strategy common to each report involves the application of cyclic voltammetry and chronoamperometry at disk electrodes immersed in uL-samples of ionic liquid solution. The data so measured is then analysed via the appropriate theoretical equations or, as is commonly necessary, by comparison with simulated voltammetry. Combined, these chosen redox systems provide access to information on various aspects of electrochemistry within ionic liquids, specifically (a) mass transport (b) the nature of the electron transfer process and (c) the rate of follow-up homogeneous reactions. It is the overall finding herein that while both diffusion and heterogeneous electron transfer are significantly slowed relative to the same processes in a conventional organic solvent, the rate of subsequent homogeneous chemistry remains largely unchanged.
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Electrolytic solution theory foundations of modern thermodynamical considerations /Drennan, Ollin J. January 1900 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1961. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 209-216).
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Contribution à l'étude conductimétrique de la composition ionique de l'eau de merPoisson, Alain. January 1970 (has links)
Thesis (Ph. D)--Université de Paris, Faculté des Sciences, 1970. / Includes bibliographical references (leaves [1-8] (at end)).
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Prediction of electrolyte solution properties using a combined Debye-Huckel, association and solvation modelKirby, Carl Scott 29 November 2012 (has links)
This paper presents a semi-theoretical computer model that estimates individual and mean ionic activity coefficients in the NaCl-NaOH-HCl-H₂O system at 25°C. This extra thermodynamic model incorporates long-range electrostatic ion-ion interaction (Debye- Hückel effects), short-range ion-ion interactions (ion association), and short-range ion-solvent interactions (hydration). The activity of water in NaCl, NaOH, and HCl solutions is fit with maximum deviations from experimental values of 0.78%, 0.79%, and 2.09%, respectively. Ion size parameters, å, were modified slightly from literature values. Hydration numbers for individual species were chosen on the basis of best fit. Ion pair dissociation constants of 15.0 were chosen for reactions involving NaCl(aq), NaOH(aq), and HCl(aq) ion pairs. The model predicts individual ionic activity coefficients for ions and ion pairs, and predicts mean molal ionic activity coefficients for NaCl, NaOH, and HCl for solutions up to 6.0 m with maximum deviations from experimental values of 0.73%, 1.77%, and 3.86%,respectively. The estimated degree of dissociation varies widely if the ion pair dissociation constants are varied between 5 and 1000. Calculated values for trace activity coefficients, saturation solubility, and vapor pressure compare favorably to experimental data. / Master of Science
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Evaluation of capillary electrophoresis as an analytical technique using bulk ionic composition of fluid inclusions in quartzMartin, Riana Theresa 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: This study was initialized to introduce capillary electrophoresis (CE) as a useful technique in
the analysis of fluid inclusions in quartz. lts advantages are low detection limits for the
dissolved ionic content of the fluid, the small amount of sample (1 g or less) for a detailed
qualitative and quantitative analysis, and the short time required to obtain results (one run for
either cations or anions take approximately 10 minutes).
The study area from which quartz veins were selected is situated within the Neoproterozoic
Saldania belt. Syn- and post-tectonic S-, 1- and A-type granitoids from the Cape Granite Suite
intruded the metamorphosed Malmesbury greywacke and pelites between 550 and 510 Ma.
Additional periods of tectonism and metamorphism occurred during Cape Supergroup
sedimentation (480 - 400 Ma) as well as Karoo sedimentation and the simultaneous Cape
Orogeny (280 -215 Ma).
The quartz-biotite±chlorite vems are hosted by Cape Granite as well as Malmesbury
sediments. These barren quartz veins are part of two vein sets, one dipping at an angle
between 15 and 500 to the S to SE and striking W, similar to Sn-mineralized quartz veins in
the SW-cape, while the other is near-vertical and striking W to NW. Except for their
orientation, no differences regarding associated minerals, inclusion characteristics or fluid
chemistry indicated a difference in origin.
Four fluid phases within a temperature range of 160 - 390 °C were identified as being largely
late-magmatic and released from the underlying Cape Granite plutons, namely an early 370-
390 °C population, followed by the 310 - 360, 230 - 300 and lastly the 160 - 200 °C
populations. Initiation of this fluid system occurred from at least SlOMa, after final granite
intrusion, but the age of the final stage is unknown. Renewed fluid circulation occurred during a later period of metamorphism, possibly during the Cape Orogeny. These fluids had
temperatures between 240 and 360°C and are of sedimentary origin, most likely released
from the Malmesbury metamorphites.
The technique of capillary electrophoresis has been evaluated for its application to bulk fluid
inclusion analysis, and the crush-leach fluid extraction procedure of Bottrell, et al., (1988)
optimized for CE analysis. Contamination factors were identified and minimized or
eliminated, where possible. Bulk fluid inclusion chemistry obtained by CE was therefore
proved to provide valuable information regarding the various fluid generations as long as
inclusion populations are investigated individually to explain and correlate bulk data. / AFRIKAANSE OPSOMMING: Die doel van die studie was om te toon dat die tegniek van kapillêre elektroforese bruikbaar is
in die analiese van vloeistofmsluitsels in kwarts. Die voordele van hierdie tegniek is lae
deteksie limiete vir die opgeloste ioon inhoud van die vloeistof, die klein monstergrootte
(< 1g) wat nodig is vir 'n omvattende kwalitatiewe en kwantitatiewe analise, en die kort
tydsduur waarin resultate verkry word ('n katioon of anioon analise vir een monster duur lO
minute).
Die studie gebied waar kwarts are gemonster is, is binne die Neoproterosoïese Saldania
Gordel geleë. Sin- en laat-tektoniese S-, I- en A-tipe graniete van die Kaapse Graniet Suite het
die gemetamorfiseerde Malmesbury grouwakke en peliete tussen 550 en 510 Ma
binnegedring. Latere periodes van tektonisme en metamorfose het tydens deponering van die
Kaap Supergroep (480 - 400 Ma), en die gelyktydige episodes van Karoo sedimentasie en
Kaapse Orogenese (280 - 215 Ma) plaasgevind.
Die gasheer gesteentes vir die kwarts-biotiet±chloriet are is Kaapse Graniet sowel as
Malmesbury sedimente. Hierdie ongemineraliseerde are is deel van twee aarstelsels, nl. een
met 'n duik hoek tussen 15 en 50° S tot SO en 'n westelike strekking, soortgelyk aan die Sn-
,.gemineraliseerde are in die SW-Kaap, terwyl die ander stel are feitlik vertikaal is en W tot
NW strek. Behalwe vir die verskil in oriëntasie was daar geen aanduiding, wat betref 'n
verskil in geassosieerde minerale, vloeistofinsluitsel kenmerke of vloeistof chemie, dat hierdie
twee aarstelsels van verskillende oorsprong is nie.
Vier vloeistof fases binne 'n temperatuur gebied van 160 - 390 °C en 'n vloeistof saliniteit
van 0 - 5.7 gewig % NaC1 ekw. is geïdentifiseer, met 'n laat-magmatiese assosiasie en
vrygestel deur die onderliggende Kaapse Graniete. Dit behels 'n vroeë 370 - 390 °C populasie, gevolg deur die 310 - 360, 230 - 300 en laastens die 160 - 200 °C populasies.
Inisiasie van hierdie sisteem kon moontlik rondom 510 Ma gelede plaasgevind het, maar die
ouderdom van die finale fase is onbekend. Hernude vloeistof sirkulasie het tydens 'n later
stadium van metamorfose onstaan, moontlik tydens die Kaapse Orogenese. Hierdie
vloeistowwe het temperature tussen 240 en 360 °C en is van sedimentêre oorsprong waar dit
moontlik deur metamorfose van die reeds gemetamorfiseerde Malmesbury gesteentes
vrygestel is.
Die tegniek van kapillêre elektroforese is vir die toepassing daarvan in die analise van
vloeistof insluitsels in kwarts geëvalueer, terwyl die vloeistof vrystellingsmetode van Bottrell
en Yardley (1988) vir hierdie tegniek geoptimaliseer is. Kontaminasie faktore is geïdentifiseer
en verminder of uitgeskakel waar moontlik. Daar is getoon dat die vloeistof chemie, wat
verteenwoordigend is van al die insluitsel populasies in 'n monster, wel bruikbaar is t.o.v.
afsonderlike vloeistof generasies, solank elke populasie individueel bestudeer is om die
omvattende chemiese data te verduidelik en met 'n enkele populasie te korrelleer.
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A high-resolution study of the structure and conformational stability of Pyrococcus horikoshii acylphosphatase in ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate by NMR spectroscopy. / CUHK electronic theses & dissertations collectionJanuary 2013 (has links)
近十年間,離子液體在生物催化和蛋白質化學方面的廣泛應用引起了鑒定蛋白質在離子液體中特性的研究興趣。本研究以古菌Pyrococcus horikoshii的酰基磷酸酶acylphosphatase (PhAcP) 和50% (v/v) 離子液體1-乙基-3-甲基咪唑四氟硼酸鹽 ([EMIM][BF₄]) 作為研究模型,首次利用多維核磁共振譜對蛋白質在離子液體中的結構和穩定性作高解析度的分析。我們首先通過蛋白質主鏈共振歸屬,得出PhAcP每個被歸屬的胺基酸在50% (v/v) [EMIM][BF₄] 中¹³C[superscript α]、¹³C[superscript β]、¹³CO、¹⁵N、H[superscript N]和H[superscript α]原子的化學位移。¹³C的化學位移相對無序纏捲狀態的¹³C化學位移的偏差分析 (¹³C secondary shift),以及二級結構之間的nuclear Overhauser effect (NOE) 連接顯示PhAcP在50% (v/v) [EMIM][BF₄] 中的二級結構與PhAcP的自然結構大致相同,其三級結構亦無顯著變化。此外,我們以二維的¹H-¹⁵N HSQC實驗觀察在318K、328K和338K這三個溫度下的硫氰酸胍 (GdnSCN) 誘導蛋白質變性,發現同一溫度下無論50% (v/v) [EMIM][BF₄]是否存在,PhAcP的變性曲線都互相重疊,得到的 [GdnSCN]₁[subscript /]₂值也相同,由此可推斷50% (v/v) [EMIM][BF₄] 對PhAcP的穩定性沒有影響。 / The extensive application of ionic liquid in biocatalysis and protein chemistry in the past decade arouses interest in the characterization of protein behavior in ionic liquid. This study demonstrates the use of multi-dimensional nuclear magnetic resonance (NMR) spectroscopy to investigate the structure and conformational stability of protein in ionic liquid at a high resolution for the first time, with Pyrococcus horikoshii acylphosphatase (PhAcP) and 50% (v/v) 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF₄]) as a study model. The backbone amide resonances of PhAcP in 50% (v/v) [EMIM][BF₄] were assigned in order to obtain the chemical shifts of ¹³C[superscript α], ¹³C[superscript β], ¹³CO, ¹⁵N, HN and H[superscript α] of each assigned residue. The estimation of secondary structure by the ¹³C secondary shift analysis and the nuclear Overhauser effect (NOE) connectivities observed within secondary structures together suggest that PhAcP has secondary structures arranged in native-like topology and there is no major alteration in the tertiary structure in 50% (v/v) [EMIM][BF₄]. Guanidine thiocyanate (GdnSCN)-induced denaturation was performed at 318K, 328K and 338K and monitored by 2D ¹H-¹⁵N HSQC experiments to study the conformational stability of PhAcP in 50% (v/v) [EMIM][BF₄]. The overlapping denaturation curves and consistent [GdnSCN]₁[subscript /]₂ values obtained at each temperature indicate no observable trend of stability alteration. / Detailed summary in vernacular field only. / Lee, Tsz Ying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 57-63). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgements --- p.iii / Contents --- p.iv / Abbreviations --- p.vii / List of Figures --- p.viii / List of Tables --- p.ix / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction to ionic liquid --- p.1 / Chapter 1.1.1 --- Ionic liquid as reaction medium, co-solvent and additive in biocatalysis and protein chemistry --- p.1 / Chapter 1.1.2 --- The impact of ionic liquid on protein structure and stability is poorly understood --- p.3 / Chapter 1.2 --- PhAcP in [EMIM][BF₄] as a model to study the structure and stability of protein in ionic liquid by NMR spectroscopy --- p.6 / Chapter 1.2.1 --- The application of [EMIM][BF₄] with protein --- p.6 / Chapter 1.2.2 --- The background of PhAcP --- p.9 / Chapter 1.2.3 --- Overview of the study --- p.10 / Chapter Chapter 2 --- Materials and Methods --- p.12 / Chapter 2.1 --- Expression and purification of PhAcP --- p.12 / Chapter 2.1.1 --- Expression of PhAcP in Escherichia coli system --- p.12 / Chapter 2.1.2 --- Purification of PhAcP --- p.14 / Chapter 2.2 --- Solubility determination --- p.15 / Chapter 2.3 --- NMR experiments --- p.17 / Chapter 2.3.1 --- General procedures and sample preparation --- p.17 / Chapter 2.3.2 --- ¹H-¹⁵N HSQC spectra in various concentrations of [EMIM][BF₄] --- p.18 / Chapter 2.3.3 --- Structural characterization --- p.18 / Chapter 2.3.4 --- Stability characterization --- p.19 / Chapter Chapter 3 --- Results --- p.21 / Chapter 3.1 --- Can the solubility of PhAcP in [EMIM][BF₄] reach the millimolar range required for NMR study? --- p.21 / Chapter 3.2 --- Determination of the [EMIM][BF₄] concentration for a feasible NMR study --- p.23 / Chapter 3.3 --- Backbone resonance assignment of PhAcP in 50% (v/v) [EMIM][BF₄] --- p.26 / Chapter 3.4 --- Structural characterization of PhAcP in 50% (v/v) [EMIM][BF₄] --- p.29 / Chapter 3.4.1 --- Secondary structure estimation by ¹³C secondary shifts --- p.29 / Chapter 3.4.2 --- NOE connectivities within secondary structures --- p.35 / Chapter 3.5 --- Characterization of the conformational stability of PhAcP in 50% (v/v) [EMIM][BF₄] by guanidine thiocyanate-induced denaturation --- p.40 / Chapter Chapter 4 --- Discussion --- p.46 / Chapter 4.1 --- The structure of PhAcP in 50% (v/v) [EMIM][BF₄] resembles the native conformation --- p.46 / Chapter 4.2 --- The conformational stability of PhAcP has no observable change in 50% (v/v) [EMIM][BF₄] --- p.47 / Chapter 4.3 --- Insight into the application of enzyme in ionic liquid --- p.48 / Chapter 4.4 --- Limitation of the study --- p.49 / Chapter 4.5 --- Insight into future studies --- p.50 / Chapter Chapter 5 --- Conclusions --- p.51 / Appendix --- p.53 / References --- p.57
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Structure and dynamics in solution – the core electron perspectiveJosefsson, Ida January 2015 (has links)
This thesis is based on theoretical studies of the molecular and electronic structure of solvated ions and molecules. Very detailed information of the system can be obtained from theoretical calculations, but a realistic model is dependent on an accurate computational method. Accurate calculations of core level electronic spectra, and evaluation of the modeling against experiments, are central parts of this work. The main tools used for characterization of the systems are high-level quantum chemistry and molecular dynamics simulations. Molecular components in solutions are involved in many key processes converting sunlight into chemical or electrical energy. Transition metal complexes, with their pronounced absorption in the visible light region of the electromagnetic spectrum, are core components in various energy conversion applications, and the iodide/triiodide redox couple is a commonly used electrolyte. The local structure of the electronic valence in transition metal complexes and the details of the solvation mechanisms of electrolyte solutions are investigated through the combination of computational modeling and core level spectroscopy. The studies of model systems show that interactions between the solute and solvent are important for the electronic structure, and knowledge of the details in model systems studied can be relevant for energy conversion applications. Furthermore, high-level quantum chemistry has been applied for interpreting time-resolved spectra, where the electronic structure of a metal complex is followed during a photoinduced chemical reaction in solution. With advanced modeling in combination with recent experimental developments, more complex problems than previously addressed can be dissected. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 8: Manuscript.</p>
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Electrodialysis in flow injection systems /Hattingh, Cornelius Johannes. January 2000 (has links)
Thesis (Ph.D.(Chemistry))--University of Pretoria, 2000. / Includes abstracts in English and Afrikaans. Includes bibliographical references. Also available online.
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