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Solvent and Ionic Complexes of the Calix[6]arenes

Description: One of the more attractive attributes of calixarenes is their wide variety of possible conformations and hence cavity shapes. However, the flexibility that allows this long-range benefit gives rise to major synthetic challenges when working with the larger members of the family. O-alkylations have proven to be the most widely employed synthetic routes to "functionalization" of the calixarenes, and these have shown a dependence upon both solvent and the metal ions present. Surprisingly, there have been no structural data presented concerning the complexes between the simple unsubstituted calix[6]arenes and the metal ions of groups 1 and 2. The structures of four complexes, containing cesium, rubidium, and calcium are reported as determined by X-ray crystallography. The solution behavior of the complexes for both representative groups is also discussed, in particular with regard to conformational stabilization of the calix[6]arenes and the role of solvent upon this stabilization. These complexes are also investigated as starting materials for the selective functionalization of the calix[6]arenes.
Date: December 1997
Creator: Wolfgong, William J.
Partner: UNT Libraries

Part I: Solid State Studies of Larger Calixarenes : Part II: Synthesis and Characterization of Metallocalixarenes

Description: Calixarenes are a class of macrocyclic compounds that have garnered interest in large part because of their ability to form host-guest complexes with various types of molecules. For all of the studies of complex formation by calixarenes, most of the work to date has concentrated upon the smaller calixarenes, and little is understood about the relationship between the complexes formed when in solution and that observed in the solid state. The first part of the study, presented in Chapter 3, is of the solid-state properties of two of the larger calixarenes, and in comparison to other reported structures reveals patterns to the observed conformations both in the solid state and in solution. The formation of metal complexes has also been investigated and has focused extensively upon the metals as guests. Thus, the ability of the calixarenes to act as ligands in inorganic complexes has been virtually untapped, despite the polyoxo binding site they can easily provide, and very few metallocalixarenes have been reported. The second part of this study goes beyond the simple solid-state properties of such compounds, and involves the synthesis of several metallocalixarenes as part of a project directed at the functionalization of calixarenes with the components of a class of catalysts known to polymerize various olefins. These catalysts, commonly referred to as Ziegler-Natta catalysts, are introduced in Chapter 4. The new compounds presented here--three new aluminocalixarenes in Chapter 5 and a new titanocalixarene in Chapter 6--were synthesized so as to contain some of the same components observed in several of the other catalysts. These new compounds have been characterized crystallographically as well as through proton and multinuclear NMR, and observed conformational patterns are discussed.
Date: May 1998
Creator: Smith, Janna Marie
Partner: UNT Libraries

Versatile assembly of p-carboxylatocalix[4]arene-O-alkyl ethers

Description: Crystallisation of lower-rim tetra-O-alkylated p-carboxylatocalix[4]arenes from pyridine results in the formation of both bi-layer and pillar type supramolecular motifs. Full alkylation at the calixarene lower rim has significant influence over the supramolecular self-assembly motif, including preclusion of pyridine guest molecules from the calixarene cavity in the solid state.
Date: July 8, 2009
Creator: Kennedy, Stuart; Teat, Simon J. & Dalgarno, Scott J.
Partner: UNT Libraries Government Documents Department

Development of a Selective Calixarene Sensor for Uranium

Description: Traditionally, measurements of uranium in wastewater have been obtained by laboratory based instrumentation, such as inductively coupled plasma spectroscopy, ion-chromatography and radiochemical methods. However, such methods and equipment, whilst offering excellent sensitivity and reproducibility, are far too large and heavy to be portable. Therefore, there has been a lot of interest in developing a portable sensor to carry out uranium measurements. This work describes how a class of molecule called calixarenes have been used to develop a sensing methodology for measuring uranium concentration at low levels. This has been achieved by taking the established coordinating properties of the calixarene molecule for uranium and then adding functionalities to the molecule to make it adhere to metal surfaces. This way, a layer of the uranophilic molecule has been prepared on electrode surfaces, one molecule thick. These electrodes have been shown to be sensitive to uranium between 5 and 300 parts per billion. Using these modified electrodes, a portable device has been developed, which potentially allows for measurement of uranium in the field. This sensor therefore presents a very significant advantage in that it allows for rapid determination of low levels of uranium in wastewater, whilst offering portability.
Date: February 26, 2002
Creator: Evans-Thompson, C.; Field, S. E.; Jones, A. H.; Kan, M. J.; Hall, C. W. & Nicholson, G. P.
Partner: UNT Libraries Government Documents Department

Calix 2007:9th International Conference on Calixarene Chemistry

Description: The DOE funds helped support an International Conference, Calix 2007, whose focus was on Supramolecular Chemistry. The conference was held at the University of Maryland from August 6-9, 2007 (Figure 1). The conference website is at www.chem.umd.edu/Conferences/Calix2007. This biannual conference had previously been held in the Czech Republic (2005), Canada (2003), Netherlands (2001), Australia (1999), Italy (1997), USA (Fort Worth, 1995) Japan (1993) and Germany (1991). Calixarenes are cup-shaped compounds that are a major part of Supramolecular Chemistry, for which Cram, Lehn and Pederson were awarded a Nobel Prize 20 years ago. Calixarene chemistry has expanded greatly in the last 2 decades, as these compounds are used in synthetic and mechanistic chemistry, separations science, materials science, nanoscience and biological chemistry. The organizing committee was quite happy that Calix 2007 encompassed the broad scope and interdisciplinary nature of the field. Our goal was to bring together leading scientists interested in calixarenes, molecular recognition, nanoscience and supramolecular chemistry. We believe that new research directions and collaborations resulted from an exchange of ideas between conferees. This grant from the DOE was crucial toward achieving that goal, as the funds helped cover some of the registration and accommodations costs for the speakers.
Date: September 9, 2011
Creator: Davis, Jeffery
Partner: UNT Libraries Government Documents Department

CSSX Radiolytic H2 Generation ("Thermolysis") -- Final Report

Description: The purpose of this work was to determine the radiolytic hydrogen gas yield of irradiated CSSX solvent at several temperatures. The active ingredient of this solvent is calix[4]arene-bis-(t-octylbenzo) crown-6, a calixarene crown ether used for cesium complexation. The solvent also contains 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol, a fluorinated alcoholic solvent modifer used to improve the solubility of the calixarene and its cesium complex in the Isopar L diluent. Isopar L is a branch-chain alkane and comprises most of the mixture. Samples of this solution were irradiated to various absorbed ?-ray doses in gas-tight sample containers, which were then sampled for hydrogen gas content. The methods are described below.
Date: January 1, 2009
Creator: Mincher, Bruce J.
Partner: UNT Libraries Government Documents Department


Description: Researchers successfully demonstrated the chemistry and process equipment of the Caustic-Side Solvent Extraction (CSSX) flowsheet using MaxCalix for the decontamination of high level waste (HLW). The demonstration was completed using a 12-stage, 2-cm centrifugal contactor apparatus at the Savannah River National Laboratory (SRNL). This represents the first CSSX process demonstration of the MaxCalix solvent system with Savannah River Site (SRS) HLW. Two tests lasting 24 and 27 hours processed non-radioactive simulated Tank 49H waste and actual Tank 49H HLW, respectively. A solvent extraction system for removal of cesium from alkaline solutions was developed utilizing a novel solvent invented at the Oak Ridge National Laboratory (ORNL). This solvent consists of a calix[4]arene-crown-6 extractant dissolved in an inert hydrocarbon matrix. A modifier is added to the solvent to enhance the extraction power of the calixarene and to prevent the formation of a third phase. An additional additive is used to improve stripping performance and to mitigate the effects of any surfactants present in the feed stream. The process that deploys this solvent system is known as Caustic Side Solvent Extraction (CSSX). The solvent system has been deployed at the Savannah River Site (SRS) in the Modular CSSX Unit (MCU) since 2008.
Date: November 29, 2011
Creator: Pierce, R.; Peters, T.; Crowder, M.; Pak, D.; Fink, S.; Blessing, R. et al.
Partner: UNT Libraries Government Documents Department

Caustic-Side Solvent Extraction: Chemical and Physical Properties of the Optimized Solvent

Description: This work was undertaken to optimize the solvent used in the Caustic Side Solvent Extraction (CSSX) process and to measure key chemical and physical properties related to its performance in the removal of cesium from the alkaline high-level salt waste stored in tanks at the Savannah River Site. The need to adjust the solvent composition arose from the prior discovery that the previous baseline solvent was supersaturated with respect to the calixarene extractant. The following solvent-component concentrations in Isopar{reg_sign} L diluent are recommended: 0.007 M calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) extractant, 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) phase modifier, and 0.003 M tri-n-octylamine (TOA) stripping aid. Criteria for this selection included BOBCalixC6 solubility, batch cesium distribution ratios (D{sub Cs}), calculated flowsheet robustness, third-phase formation, coalescence rate (dispersion numbers), and solvent density. Although minor compromises within acceptable limits were made in flowsheet robustness and solvent density, significant benefits were gained in lower risk of third-phase formation and lower solvent cost. Data are also reported for the optimized solvent regarding the temperature dependence of D{sub Cs} in extraction, scrubbing, and stripping (ESS); ESS performance on recycle; partitioning of BOBCalixC6, Cs-7SB, and TOA to aqueous process solutions; partitioning of organic anions; distribution of metals; solvent phase separation at low temperatures; solvent stability to elevated temperatures; and solvent density and viscosity. Overall, the technical risk of the CSSX process has been reduced by resolving previously identified issues and raising no new issues.
Date: October 8, 2002
Creator: Delmau, L.H.
Partner: UNT Libraries Government Documents Department

Demonstration of Caustic-Side Solvent Extraction with Optimized Solvent in the 2-cm Centrifugal Contactor Apparatus Using Dissolved Salt Cake from Tank 37H

Description: A solvent extraction process for removal of cesium from alkaline solutions has been developed utilizing a novel solvent invented at the Oak Ridge National Laboratory (ORNL). This solvent consists of a calix[4]arene-crown-6 extractant (BOBCalix) dissolved in an inert hydrocarbon matrix (Isopar(R) L). An alkylphenoxy alcohol modifier added to the solvent enhances the extraction power of the calixarene and prevents the formation of a third phase. An additional additive, trioctylamine (TOA), improves stripping performance and mitigates the effects of any surfactants present in the feed stream. The solvent extraction process was successfully demonstrated with actual SRS HLW supernate during testing performed at SRTC in FY-2001. However, the solvent system has recently been optimized to enhance extractant solubility in the diluent and increase suppressor concentration. The results of the optimized solvent performance in tests using the same SRS composite waste supernate as was used FY-20 01 are described in another report.
Date: October 21, 2002
Creator: Norato, M.A.
Partner: UNT Libraries Government Documents Department

Perforated monolayers. Final report

Description: This STI is a final report for a DOE-supported program, ''Perforated Monolayers,'' which focused on the fabrication of ultrathin membranes for gas separations based on Langmuir-Blodgett chemistry.
Date: June 1, 2000
Creator: L., Regen. Steven
Partner: UNT Libraries Government Documents Department

Evaluation of the Hydraulic Capacity and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-cm-Diameter Centrifugal Contactor

Description: The Caustic-Side Solvent Extraction (CSSX) process has been selected for the separation of cesium from Savannah River Site high-level waste. The solvent composition used in the CSSX process was recently optimized so that the solvent is no longer supersaturated with respect to the calixarene crown ether extractant. Hydraulic performance and mass transfer efficiency testing of a single stage of 5.5-cm ORNL-designed centrifugal contactor has been performed for the CSSX process with the optimized solvent. Maximum throughputs of the 5.5-cm centrifugal contactor, as a function of contactor rotor speed, have been measured for the extraction, scrub, strip, and wash sections of the CSSX flowsheet at the baseline organic/aqueous flow ratios (O/A) of the process, as well as at O/A’s 20% higher and 20% lower than the baseline. Maximum throughputs are comparable to the design throughput of the contactor, as well as with throughputs obtained previously in a 5-cm centrifugal contactor with the non-optimized CSSX solvent formulation. The 20% variation in O/A had minimal effect on contactor throughput. Additionally, mass transfer efficiencies have been determined for the extraction and strip sections of the flowsheet. Efficiencies were lower than the process goal of greater than or equal to 80%, ranging from 72 to 75% for the extraction section and from 36 to 60% in the strip section. Increasing the mixing intensity and/or the solution level in the mixing zone of the centrifugal contactor (residence time) could potentially increase efficiencies. Several methods are available to accomplish this including (1) increasing the size of the opening in the bottom of the rotor, resulting in a contactor which is partially pumping instead of fully pumping, (2) decreasing the number of vanes in the contactor, (3) increasing the vane height, or (4) adding vanes on the rotor and baffles on the housing of the contactor. The low ...
Date: September 1, 2002
Creator: Law, Jack Douglas; Tillotson, Richard Dean & Todd, Terry Allen
Partner: UNT Libraries Government Documents Department

Gamma Ray Radiolysis of the FPEX Solvent

Description: Slide presentation. FPEX contains a calixarene for Cs extraction, a crown ether for Sr extraction, Cs7SB modifier, and TOA to aid in stripping, in Isopar L diluent. The radiation stability FPEX must be evaluated prior to process use. Radiolytic degradation of species in solution are due to reaction with the direct radiolysis products of the diluent. In Isopar L, the reactive species produced include e-, •H and alkane radicals, resulting in a reducing environment. However, in nitric acid, oxidizing hydroxyl (•OH) and nitro (•NO2) radicals dominate system chemistry. Thus, the nature of diluent and the presence of radical scavengers affect the results of irradiation. We report the preliminary results of a new program to investigate the radiolysis of FPEX using the 60Co irradiation of FPEX neat solvent, acid pre-equilibrated solvent and mixed aerated phases. The Cs and Sr distribution ratios were used as metrics.
Date: September 1, 2006
Creator: Mincher, B. J.; Mezyk, S. P. & Peterman, D. R.
Partner: UNT Libraries Government Documents Department

Solution Effects on Cesium Complexation with Calixarene - Crown Ethers from Liquid to Supercritical Fluids

Description: Supercritical fluid CO2 is an alternative solvent for extraction of metals. The solubility parameter of supercritical CO2 varies with density resembling that of liquid hexane at moderate pressures in the supercritical region to those of chlorinated solvents at very high pressures. By changing density of supercritical CO2, the solvation environment of a metal chelate system can vary continuously and resembles over a wide range of solvents. Thus, supercritical CO2 provides a unique system for studying solvation effects on metal chelation. This project is designed to investigate the solvation effects on cesium complexation with macrocyclic compounds including crown ethers and calixarene-crown ethers in CO2 from liquid to supercritical region at high pressures. A powerful spectroscopic technique for studying cesium chelation is nuclear magnetic resonance (NMR). Cesium has only one isotope, 133Cs, with a nuclear spin I = 7/2. Popov et al. used NMR to study cesium complexation with crown ethers and cryptand.
Date: June 1, 1999
Creator: Wai, Chien M. & Yonker, Clem
Partner: UNT Libraries Government Documents Department

Solvent Extraction External Radiation Stability Testing

Description: Personnel irradiated a number of samples of calixarene-based solvent. Analysis of these samples indicated that measurable loss of the calixarene occurred at very high doses (-16 Mrad). No measurable loss of the Cs-7SB modifier occurred at equivalent doses. The primary degradation product, 4-sec-butylphenol, observed during analysis of the samples came from degradation of the modifier. Also, TOA proved more susceptible to damage than the other components of the solvent. The total degradation of the solvent proved relatively minor. The consistent solvent performance, as indicated by the measured D Cs values, after exposure at high total doses serves as evidence of the relatively low degree of degradation of the solvent components. Additional tests employing internal irradiation of solvents with both simulants and SRS tank waste will be completed by the end of March 2001 to provide confirmation of the results presented herein.
Date: January 5, 2001
Creator: Peterson, R.A.
Partner: UNT Libraries Government Documents Department

81929 - Fission-Product Separation Based on Room - Temperature Ionic Liquids

Description: This project has demonstrated that Sr2+ and Cs+ can be selectively extracted from aqueous solutions into ionic liquids using crown ethers and that unprecedented large distribution coefficients can be achieved for these fission products. The volume of secondary wastes can be significantly minimized with this new separation technology. Through the current EMSP funding, the solvent extraction technology based on ionic liquids has been shown to be viable and can potentially provide the most efficient separation of problematic fission products from high level wastes. The key results from the current funding period are the development of highly selective extraction process for cesium ions based on crown ethers and calixarenes, optimization of selectivities of extractants via systematic change of ionic liquids, and investigation of task-specific ionic liquids incorporating both complexant and solvent characteristics.
Date: December 9, 2004
Creator: Rogers, Robin D.
Partner: UNT Libraries Government Documents Department


Description: The DoE/NE underground storage tanks at Hanford, SRS, and INEEL contain liquid wastes with high concentrations of radioactive species, mainly 137Cs and 90Sr. Because the other components of the liquid waste are mainly sodium nitrate and sodium hydroxide, most of this tank waste can be treated inexpensively as low-level waste if 137Cs and 90Sr can be selectively removed. Many ionophores (crown ether and calixarene compounds) have been synthesized for the purpose of selectively extracting Cs+ and Sr2+ from an aqueous phase into an immiscible organic phase. Recent studies conducted at ORNL1,2 reveal that hydrophobic ionic liquids might be better solvents for extracting metal ions from aqueous solutions with these ionophores than conventional immiscible organic solvents, such as benzene, toluene, and dichloromethane, because both Cs+ and Sr2+ exhibit larger distribution coefficients in the ionic liquids. In addition, the vapor pressures of these ionic liquids are insignificant. Thus, there is little or no vaporization loss of these solvents. Most of the ionic liquids under investigation are relatively nontoxic compared to the hydrocarbon solvents that they replace, classifying them as ''green'' solvents.
Date: June 1, 2004
Creator: Hussey, Charles L.
Partner: UNT Libraries Government Documents Department


Description: A solvent extraction system for removal of cesium (Cs) from alkaline solutions was developed utilizing a novel solvent invented at the Oak Ridge National Laboratory (ORNL). This solvent consists of a calix[4]arene-crown-6 extractant dissolved in an inert hydrocarbon matrix. A Modifier is added to the solvent to enhance the extraction power of the calixarene and to prevent the formation of a third phase. An additional additive, called a suppressor, is used to improve stripping performance. The process that deploys this solvent system is known as Caustic Side Solvent Extraction (CSSX). The solvent system has been deployed at the Savannah River Site (SRS) in the Modular CSSX Unit (MCU) since 2008. Subsequent development efforts by ORNL identified an improved solvent system that can raise the expected decontamination factor (DF) in MCU from {approx}200 to more than 40,000. The improved DF is attributed to an improved distribution ratio for cesium [D(Cs)] in extraction from {approx}15 to {approx}60, an increased solubility of the calixarene in the solvent from 0.007 M to >0.050 M, and use of boric acid (H{sub 3}BO{sub 3}) stripping that also yields improved D(Cs) values. Additionally, the changes incorporated into the Next Generation CSSX Solvent (NGS) are intended to reduce solvent entrainment by virtue of more favorable physical properties. The MCU and Salt Waste Processing Facility (SWPF) facilities are actively pursuing the changeover from the current CSSX solvent to the NGS solvent. To support this integration of the NGS into the MCU and SWPF facilities, the Savannah River Remediation (SRR)/ARP/MCU Life Extension Project requested that the Savannah River National Laboratory (SRNL) perform testing of the new solvent for the removal of Cs from the liquid salt waste stream. Additionally, SRNL was tasked with characterizing both strip (20-in long, 10 micron pore size) and extraction (40-in long, 20 micron pore size) ...
Date: January 17, 2012
Creator: Restivo, M.; Peters, T.; Pierce, R.; Fondeur, F.; Steeper, T.; Williams, M. et al.
Partner: UNT Libraries Government Documents Department