Synthesis and screening of modified 6,6′-Bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenzo[e][1,2,4]triazin-3-yl)-2,2′-bipyridine ligands for actinide and lanthanide separation in nuclear waste treatment

Effects of chloro and bromo substitution at the 4-position of the pyridine ring of 6,6′-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenzo[e][1,2,4]triazin-3-yl)-2,2′-bipyridine (CyMe4-BTBP) have been studied with regard to the extraction of Am(III) from Eu(III) and Cm(III) from 0.1–3 M HNO3. Similarly to CyMe4-BTBP, a highly efficient (DAm > 10 at 3 M HNO3) and selective (SFAm/Eu > 100 at 3 M HNO3) extraction was observed for Cl-CyMe4-BTBP and Br-CyMe4-BTBP in 1-octanol but in the absence of a phase-transfer agent

Extraction of minor actinides, lanthanides and other fission products by silica-immobilized BTBP/BTPhen ligands

Novel BTBP [bis-(1,2,4-triazin-3-yl)-2,2’-bipyridine] / BTPhen [bis-(1,2,4-triazin-3-yl)-1,10-phenanthroline] functionalized silica gels have been developed to extract minor actinides, lanthanides and other fission products. BTPhen functionalized silica gel is capable of near-quantitative removal of Am(III) in the presence of Eu(III) from aqueous HNO3, while BTBP functionalized silica gel is able to remove problematic corrosion and fission products that are found in PUREX raffinates

Synthesis of novel BTPhen-functionalized silica-coated magnetic nanoparticles for separating trivalent actinides and lanthanides

BTPhen [bis-(1,2,4-triazin-3-yl)-1,10-phenanthroline] functionalized magnetic nanoparticles (MNPs), which selectively extracts Am(III) over Eu(III) from 0.1 M HNO3 with fast kinetics and a separation factor of 30 have been synthesized. These MNPs also show a small but significant selectivity for Am(III) over Cm(III) with a separation factor of around 3 in 0.1 M HNO3. We report also the synthesis of these BTPhen and related ligands via an improved synthetic route by-passing the problematic benzylic oxidation with stoichiometric SeO2

Neocuproine-functionalized silica-coated magnetic nanoparticles for extraction of copper(II) from aqueous solution

Neocuproine has been covalently bound to silica-coated maghemite(c-Fe2O3) magnetic nanoparticles (MNPs) by a phenyl ether linkage. The resulting MNPs are able to remove Cu(II) from 12 ppm aqueous solution with an extraction efficiency of up to 99% at pH 2

Separation of Am(III) from Cm(III) and Eu(III) by electro-spun polystyrene- immobilized CyMe4-BTPhen

The synthesis of a novel 5-(4-vinylphenyl)-CyMe4-BTPhen actinide selective ligand using selenium free synthetic procedures is reported. For the first time, we report the electrospinning of this actinide selective ligand into a polystyrene fiber and investigate its selective removal of Am(III) from Eu(III) and Am(III) from Cm(III). The functionalized fibres demonstrated a separation factor of SFAm/Eu ∼ 57 and a small, but significant separation of SFAm/Cm ∼ 2.9 at 4 M HNO3

Evaluation of thermal and oxidative stability of three generations of phenolic based novel dendritic fuel and lubricant additives

Antioxidants, particularly those designed for use in hydrocarbon media, suffer from a variety of limitations including high volatility and poor solubility. Using 2,2-bis(hydroxymethyl)propionic acid as the branching unit, a series of novel dendrons featuring 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic ester chain ends have been synthesised to provide improved solubility of such hindered phenolic antioxidants. The thermal stability, assessed by thermogravimetric analysis, revealed that all the functionalised dendrons have enhanced thermal stability when compared to commercial antioxidants (BHT, Irganox L135 and Irganox L57). Antioxidant ability was evaluated using pressurised differential scanning calorimetry and when blended with a lubricant base oil, at 0.5% w/w, an increase in antioxidant performance was observed when compared to the commercial antioxidants

Synthesis, characterisation, and performance evaluation of tri-armed phenolic antioxidants

In this study, a series of core units (glycerol, triethanolamine and triisopropanolamine derivatives) were investigated for their use in tri-armed phenolic antioxidants. The antioxidant ability of these tri-armed phenolic compounds featuring different core units were then evaluated in a hydrocarbon lubricant using differential scanning calorimetry (DSC) and compared to the commercially available antioxidants Irganox L135 and Irganox L57. An impressive oxidation induction time of ca. 9-12 minutes was observed for the glycerol based antioxidants when compared to the commercial antioxidants (ca. 4-6 minutes), whereas in contrast in the case of triethanolamine and triisopropanolamine derived antioxidants, a solubilising unit was incorporated in order to provide appropriate solubility within the hydrocarbon medium and revealed an excellent oxidation induction time of ca. 11-12 minutes

Separation of minor actinides from lanthanides using immobilized ligand systems: the role of the counterion

A CyMe4-BTPhen functionalized silica gel that selectively extracts Am(III) over Eu(III) from 4 M HNO3 with a separation factor > 154 has been developed. Evidence is presented that the counterion surrounding the M(III) in the proposed 1:1 [BTPhen:M(III)] complex plays an important role in the complexation of Am(III) and Eu(III)

Tuning the solubilities of bis-triazinylphenanthroline ligands (BTPhens) and their complexes

A series of bis-triazinylphenanthroline ligands (BTPhens) was synthesized by modifying the triazine substituents. It was found that varying these substituents altered the solubilities of the ligands in a number of non-polar solvents. Thus C5-BTPhen showed significantly higher solubility in octanol than C1-BTPhen. The high solubility of C5-BTPhen and its complexes was exploited to facilitate the NMR titration experiments. These experiments shown that the dominant species in solution were the 1:2 complexes [Ln(III)(BTPhen)2], even at high Ln concentrations, and that the relative stability of the 2:1 to 1:1 BTPhen-Ln complexes varied with different lanthanides. C5-BTPhen therefore shows considerable promise for a once-through selective actinide separation process

From food to mobility: investigating a screening assay for new automotive antioxidants using the stable radical DPPH

By taking inspiration from the food industry, an assay was investigated as a potential screening tool to test the efficiency of new phenolic antioxidants. The method was based on the spectrophotometric measurement of the stable free radical 1,1-diphenyl-2-picryl hydrazyl (DPPH) which, in its radical form, has an absorbance maxima at 515 nm. The disappearance of this absorbance band, upon reaction with an antioxidant, was monitored to reveal the kinetic pathway of the reaction, which was defined simply as either fast, medium or slow. Adaptation of the assay was attempted for application to biofuels and oil-based automotive fluids whereby the effect of polar and non-polar solvents on the kinetics of the reaction was investigated. In addition, the stoichiometry of the radical scavenging reaction was also analysed to give an insight into the structure-activity relationships of phenolic antioxidants