Determination of N,N’, N’’-tris(3,7-dimethyloctyl)guanidine (TiDG) in Cesium Extraction Solvent

Several analytical methods were evaluated for determining the concentration of N,N’,N”-tris(3,7-dimethyloctyl)guanidine (TiDG) in a cesium extraction solvent. Of the methods evaluated, non-aqueous titration and ¹H NMR were shown to be successful at quantifying the amount of TiDG present in both a pure solvent extraction system, and a blended system containing an additional base, trioctylamine.     

Evaluation of the Hydrophilic Complexant N,N,N’,N’-tetraethyldiglycolamide (TEDGA) and its Methyl-substituted Analogues in the Selective Am(III) Separation

ABSTRACT

N,N,N’,N’-tetraethyldiglycolamide (TEDGA) is used in the French EXAm (extraction of americium) process to separate Am(III) from Cm(III) and Ln(III). In this study, the complexation behavior of TEDGA towards actinides(III) and lanthanides(III) was compared to its methyl-substituted derivatives Me-TEDGA and Me₂-TEDGA under experimental conditions applying to the EXAm process. Using the EXAm solvent, 0.6 mol/L N,N’-dimethyl-N,N’-dioctyl-hexylethoxymalonamide (DMDOHEMA) and 0.45 mol/L bis(2-ethylhexyl)-phosphoric acid (HDEHP), An(III) and Ln(III) distribution ratios increase in the order TEDGA < Me-TEDGA < Me₂-TEDGA. This is explained by differences in the strength of complexation in the aqueous phase: Conditional stability constants for the formation of [Cm(DGA)_x]³⁺ complexes decrease in the order TEDGA > Me-TEDGA > Me₂-TEDGA, as shown by time-resolved laser fluorescence spectroscopy (TRLFS). TRLFS measurements verified the exclusive existence of [Cm(DGA)₃]³⁺ complexes in the aqueous phase. Both the homoleptic [Cm(DMDOHEMA)_n]³⁺ and the heteroleptic [Cm(DGA)_x(DMDOHEMA)_y]³⁺ complexes were detected in the organic phase, as postulated in the literature.^[14]     

Synthesis and Thermal Decomposition Studies of Silicon (IV) Compounds with N,N’-Bis(Salicylidene)Ethylenediimine

The silicon (IV) compounds possessing SiN₄O₂ (6), SiN₂O₂C₂ (7, 8), SiN₂O₂CCl (9) and SiN₄O₄ (10) coordinating frameworks have been synthesized in high yield by the reaction of the O,N,N,O- donor salen-type ligand N,N’-bis(salicylidene)ethylenediimine L with different silanes i.e. diethoxydiisocyanatosilane-(C₂H₅O)₂Si(NCO)₂ 1, dichlorodiphenylsilane-Ph₂SiCl₂ 2, dichloromethyl- phenylsilane-MePhSiCl₂ 3, trichlorophenylsilane-PhSiCl₃ 4 and silicon tetrachloride-SiCl₄ 5. The compounds 6–10 have been characterized by elemental analysis, IR, ¹H, ¹³C and ²⁹Si NMR and mass spectrometry. The decomposition reactivity of these compounds has been studied using a Thermal Gravimetric Analyzer (TGA) at a heating rate of 10°C/minute in an inert atmosphere.     

Non-Dispersive Solvent Extraction of Neodymium using N,N,N’,N’-Tetraoctyl Diglycolamide (TODGA)

Hollow fiber contactor was used to study non-dispersive extraction (NDSX) of Nd³⁺ ions from aqueous solutions. N,N,N′,N′-tetraoctyl diglycolamide (TODGA) diluted with n-dodecane was used as the organic phase with di-n-hexyl octanamide (DHOA) as the phase modifier. The role of cations (H⁺/Na⁺) on the transport of Nd³⁺ ions has been investigated for this system. It was observed that H⁺ ion has a significant role to play in the Nd³⁺/TODGA complexation reaction. A mathematical model has also been developed to simulate the NDSX process in a hollow fiber contactor. A comparison has also been made between extraction profiles from the NDSX process and the hollow fiber supported liquid membrane (HFSLM) process. It was observed that NDSX gave comparatively faster rates of extraction in the presence of H⁺ ions but slower in the absence of H⁺ ions.     

Insight into nitric acid extraction and aggregation of N,N, N’, N’-Tetraoctyl diglycolamide (TODGA) in organic solutions by molecular dynamics simulation

The molecular dynamics (MD) simulation of TODGA in n-dodecane shows formation of nanostructures of TODGA aggregates with nitric acid and water. These aggregates are dispersed in dodecane phase or form well defined reverse micelles grown sufficient in size depending on the acid concentration. With increasing nitric acid concentration, aggregation number of TODGA in reverse micelles also increases which, however, is independent of TODGA concentration. Aggregation number rises from 2 to 8 in presence of 0–3.5 M nitric acid in corresponding aqueous phase. The formation of the aggregates explains remarkable acid co-extraction from aqueous phase to organic dodecane phase by TODGA.     

Preparation and Characterization of New Optically Active Poly(amide imide)s Derived from N,N’-(4,4’-Sulphonediphthaloyl)-bis-(s)-(+)-valine Diacid Chloride and Aromatic Diamines under Microwave Irradiation

Summary The present paper is an extension of microwave method describing the synthesis of the new optically active poly(amide-imide)s. The main focus of this work is the design of new effective microwave method for preparing optically active poly(amide-imide)s. Imide-acid (3) was synthesized by the reaction of 3,3,4,4-diphenylsulfonetetracarboxylic dianhydride (1) with (s)-(+)-valine (2) in acetic acid. The compound 3 was coverted to diacid chloride 4 by reaction with excess amount of thionyl chloride. Polycondensetion reaction of diacid chloride 4 with several aromatic diamines such as 4,4-sulfonyldianiline (5a), 4,4-diaminodiphenyl methane (5b), 4,4-diaminodiphenylether (5c), p-phenylenediamine (5d), m-phenylenediamine (5e), 2,4-diaminotoluene (5f) and 4,4-diaminobiphenyl (5g) was carried out in the presence of small amount of o-cresol under microwave irradiation as well as conventional heating method. We obtained a series of optically active poly(amide-imide)s with high yield and inherent viscosity ranging from 0.22-0.35 dL/g. These new polymers were characterized by FT IR, ¹H NMR, elemental analyses and specific rotation techniques.     

Extraction of Uranium(VI) and Thorium(IV) from Nitric Acid Solution by N,N,N′,N′ – Tetraoctylglutaricamide

Synthesis and characterization of N,N,N′,N′-tetraoctylglutaricamide (TOGA) was carried out and used for extraction of U(VI) and Th(IV) from nitric acid solutions. The processes of extraction were determined by the slope analysis and by analyzing a function that allows the simultaneous treatment of all the experimental points obtained in different conditions. The different factors affecting the extraction distribution ratio(D) of U(VI) and Th(IV) (extraction concentration, concentrations of nitric acid, salting-out agent NaNO₃ concentration, equilibration time, temperature, and types of diluents) were investigated. The results obtained indicated that the extraction species of U(VI) and Th(IV) are mainly extracted as UO₂(NO₃)₂·1.0TOGA and Th(NO₃)₄·1.5TOGA. The apparent equilibrium constant of U(VI) and Th(IV) extraction determined are 3.35 ± 0.03 L³/mol³ and 1.87 ± 0.01 L⁵/mol⁵ at 298 ± 1 K. Thermodynamic parameters such as the free energy(ΔG), enthalpy(ΔH), and entropy(ΔS) changes associated with the extraction processes could be evaluated. Back-extraction of U(VI) and Th(IV) from organic phases was also studied.     

Synthesis and characterization of 4,4’–(dimethylsilylene) bis( phenyl chloroformate) and 4,4’–(dimethylgermylene)bis(phenyl chloroformate) and their use in the synthesis of poly(urethanes)

Summary The synthesis of 4,4–(dimethylsilylene)bis(phenyl chloroformate) and 4,4–(dimethylgermylene)bis(phenyl chloroformate) is described according to the same route for the synthesis of bisphenol–A bischloroformate. These compounds were characterized using elemental analysis, FT–IR and NMR spectroscopy. Poly(urethanes) derived from these bischlororformates containing silicon or germane in the main chain, were obtained in benzene solution by reaction with 4,4–methylenedianiline in the presence of pyridine. Poly(urethanes) were characterised by spectroscopic methods and the thermal properties (Tg and thermal stability) were compared with the homologue poly(urethane) obtained from bisphenol–A chloroformate.     

N,N,N’,N’-四丁基-3-氧戊二酰胺萃取铁(Ⅲ)的研究

在两种稀释剂体系中研究了N,N,N’,N’-四丁基-3-氧戊二酰胺(TBOPDA)从盐酸介质中萃取铁离子的性能和反应机理。考察了水相盐酸浓度、萃取剂浓度及温度对其萃取性能的影响。实验结果表明分配比随盐酸浓度的增加而增加;随萃取剂浓度的增加而增大;萃取过程为放热过程,升高温度不利于萃取。     

Synthesis and properties of polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane

A new kind of polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane was prepared by the anionic polymerization with a “seed solution” as initiator. The synthesis of monomers N,N′-bis(hydroxydiphenylsilyl)tetraphenylcyclodisilazane (BHPTPC), N,N′-bis(chlorodiphenylsilyl)tetraphenylcyclodisilazane (BCPTPC), and 1,3-dichloro-1,1,3,3-tetraphenyldisilazane (DCTPS) are all reported in this study. The synthesized polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane was characterized by ¹H–NMR, ²⁹Si–NMR, gel permeation chromatography (GPC), and intrinsic viscosity. The thermal stability of the polysiloxane was studied by isothermal gravimetric analysis (IGA). The results demonstrated that the synthesized polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane had excellent thermal stability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 929–933, 2001     

New optically active poly(amide-imide)s based on N,N′-(pyromellitoyl)-bis-L-amino acid and 1,3-bis(4-aminophenoxy) propane: Synthesis and characterization

Five new poly(amide-imide)s 8a–e were synthesized through the direct polycondensation reaction of five chiral N,N′-(pyromellitoyl)-bis-L -amino acids 3a–e with 1,3-bis(4-aminophenoxy) propane 7 in a medium consisting of N-methyl-2-pyrrolidone, triphenyl phosfite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel poly(amide-imide)s containing trimethylene moiety in the main chain in high yield with inherent viscosities between 0.34 and 0.65 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA) and differential thermal gravimetric (DTG). All of the polymers were soluble at room temperature in polar solvents such as N,N-dimethyl acetamide, N,N-dimethyl formamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. N,N′-(pyromellitoyl)-bis-L -amino acids 3a–e were prepared in quantitative yields by the condensation reaction of pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydide) 1 with L -alanine 2a , L -valine 2b , L -leucine 2c , L -isoleucine 2d , and L -phenyl alanine 2e in acetic acid. Also 1,3-bis(4-aminophenoxy) propane 7 was synthesized by using a two-step reaction. At first 1,3-bis(4-nitrophenoxy) propane 6 was prepared from the reaction of 4-nitrophenol 4 with 1,3-dibromoprapane 5 in NaOH solution. Then, dinitro compound 6 was reduced by using Na₂S. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

N,N’-双(4-甲基苄基)脲的简易合成及晶体结构

以对甲基苄胺和苄胺为原料,四氯化碳为溶剂,在光照条件下回流,分别合成了对应的N,N’-二取代脲的产物1,3-双(4-甲基苄基)脲和1,3-双苄基脲,它们的结构经过了核磁共振氢谱、质谱、红外和元素分析的表征,其中1,3-双(4-甲基苄基)脲还获得了晶体结构的进一步证实。     

Extraction of Copper(II) with N′,N′-Dialkylhydrazides of Benzoic and Phenylacetic Acids

This article is concerned with the study of the extraction of Cu(II), Co(II), Ni(II), and Zn(II) with N′,N′-dialkylhydrazides of benzoic and phenylacetic acids. The applied reagents are able to extract Cu(II) from ammoniac media efficiently. The influence of the length and structure of alkyl chains on the extraction of Cu(II) has been analyzed. It is shown that N′,N′-dibytil- and N′,N′-dihexylhydrazides of benzoic acid exhibit the most promise for extracting Cu(II) from ammoniac media, and N′,N′-dihexylhydrazide of phenylacetic acid as an extractant is worse than the analogous benzoic acid derivative. Copper stripping has been studied for various concentrations of H₂SO₄, and the copper extraction constants have been calculated. The data obtained indicate that the degree of Cu(II) extraction decreases with increasing concentration of ammonium salts.     

Synthesis and Structure of 1D Copper(II) Polymers with Dissymmetrical N,N′-Bis(substituted)oxamide Ligands: Cytotoxicity and DNA-Binding Property

Two one-dimensional copper(II) coordination polymers with different dissymmetrical N,N′-bis(substituted)oxamide ligands were synthesized, namely {[Cu₂(dmaepox)(dabt)]pic·H₂O}_n (1) and {[Cu₂(dmapob)(dabt)]NO₃·0.6H₂O}_n (2), where H₃dmaepox and H₃dmapob stand for N-(2-carboxylatophenyl)-N′-[3-(methylamino)propyl]oxamidate and N-(2-carboxylatophenyl)-N′-[3-(dimethylamino)propyl]oxamidate, respectively, and dabt is 2?2′-diamino-4?4′-bithiazole. Polymer 1 was characterized by elemental analyses, IR and electronic spectra and single-crystal X-ray diffraction. The crystal structure reveals that polymer 1 consists of many binuclear copper(II) units bridged by cis-oxamide and carboxylate groups. The two copper(II) ions are located in square-planar and square-pyramidal coordination environments, respectively. The separations of the Cu(II) atoms bridged by oxamide and carboxylate groups are 5.2035(7) and 5.1196(7) Å, respectively. The crystal structure of polymer 2 has been reported in our previous paper. However, its relative properties were not studied. In order to compare the influence of different bridging ligands on the cytotoxicities and DNA-binding properties, the cytotoxicities and reactivities towards DNA of polymers 1 and 2 were investigated. The results suggest that the two polymers can interact with herring sperm DNA in the mode of intercalation with binding affinities following the order of 1 > 2, and this is consistent with their in vitro cytotoxicities.     

Nitrogen (N) management in the ‘De Marke’ dairy farming system

In the sandy regions of The Netherlands, high losses of N from intensified dairy farms are threatening the environment. Therefore, government defined decreasing maximum levy-free N surplusses for the period 1998–2008. On most dairy farms, the current N surplus has to be reduced by half at least. Farmers fear that realizing these surplusses will be expensive, because it limits application of animal manure, which then has to be exported or additional land has to be bought. Moreover, farmers are worried about the impact on soil fertility. To explore the possibilities for reducing surplusses of average intensive farms by improved nutrient management, farming systems research is carried out at prototype farm De Marke. Results are compared with results of a commercial farm in the mid-1980s, the moment that systems research started and introduction of the milk quota system put a halt to further intensification. Results indicate that average intensive farms can realise a reduction in N surplus to a level below the defined final maximum, without the need to buy land or to export slurry. Inputs of N in purchased feeds and fertilisers decreased by 56 and 78%, respectively. Important factors are reduced feed intake per unit milk, as a result of a higher milk yield per cow, less young stock and judicious feeding, an improved utilization of home-made manure and a considered balance between the grassland and maize area. Changed soil fertility status did not constrain crop production. Nitrate concentration in the upper groundwater decreased from 200 to 50 mg l^-1, within a few years.     

N,N,N′,N′-Tetra(2-Ethylhexyl) Thiodiglycolamide T(2EH)TDGA: A Promising Ligand for Separation and Recovery of Palladium from High Level Liquid Waste (HLLW) Solutions

The extraction properties of N,N,N′,N′-tetra(2-ethylhexyl)thiodiglycolamide T(2EH)TDGA have been evaluated for the separation and recovery of palladium from simulated high-level liquid waste (SHLW). T(2EH)TDGA has shown very high selectivity for Pd (II) over other metal ions present in SHLW. The separation factor (SF) for Pd (II) over other metal ions was found to be more than 10⁵. Reusability studies of the extractant indicate that D_Pd remained almost constant even after five successive cycles of extraction and stripping. Palladium was quantitatively recovered from thiourea strip solution by treating it with ammonia and filtering the precipitate of palladium sulphide. The acid uptake constant (K_H) was found to be 0.62 which could be due to the presence of two carbonyl groups of amidic moiety. To account for very high extractability of palladium with T(2EH)TDGA over other ‘S’ donor extractants, namely Bis-(2-ethylhexyl)sulphoxide (BESO), FTIR, as well as Raman studies were carried out. FTIR and Raman studies suggested the ligation through carbonyl as well as the thio-ether group. Conditional extraction constants (log K′_ex) were determined and the thermodynamic parameters were calculated from the dependence of the conditional extraction constant (log K′_ex) on temperature. The calculated values of ΔG_ex, ΔH_ex, and ΔS_ex were ?41.78 kJmol^?1, ?55.12 kJmol^?1 and ?44.04 JK^?1 mol^?1 respectively. The extraction process is indicated to be enthalpy driven with the entropy factor counteracting it.     

Synthesis,characterization, thermal constant and relaxation of gadolinium(III), iron(III) and manganese(II) chelates of diethylenetriamine-bis-inositol-N,N′,N″-triacetic acid

The reaction of the bicyclic anhydride of diethylenetraiamine-pentaacetic acid (DTPAA) with inositol gave diethylenetriamine-inositol-biester-N,N^′,N″-triacetic acid (DTPA-BI) (1). (1) was characterized by FAB-MS, ¹HNMR, IR and elemental analysis. Its chelates of Gd(III), Fe(III) and Mn(II) holding promise of magnetic resonance imaging (MRI) were synthesized. Gd(III) complex was obtained from Gd₂O₃ and the acid form of (1). Thermodynamic stability constant and relaxation of Gd(III) complex with DTPA-BI were determined. The spin–lattice relaxivity (R₁=5.6 l mmol⁻¹ s⁻¹) of chelate was slightly larger than that of [GdDTPA]²⁻. The results showed that the complex is a prospective MRI agent, although thermodynamic stability constant of DTPA-BI K_[GdDTPA-BI]⁻=10^18.2 was a little less than that of [GdDTPA]²⁻ (K_[GdDTPA]²⁻=10^20.73).     

Manufacture and Characterization of Biodegradable Nanocomposites Based on Nanoscale MgAl-Layered Double Hydroxide Modified with N,N′-(Pyromellitoyl)-bis-L-Isoleucine Diacid and Poly(vinyl alcohol)

Bionanocomposite films of poly(vinyl alcohol) (PVA) with Mg-Al LDHs were prepared with different compositions by solution-intercalation method. N,N′-(Pyromellitoyl)-bis-L-isoleucine diacid was synthesized and it was used for organo-modification of chiral MgAl-LDH in distilled water. Hybrid films of PVA and modified chiral LDH were prepared under ultrasonic irradiation technique. The effect of LDH contents on thermal, physicomechanical, and morphological properties of PVA films were investigated by using X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, field emission scanning electron microscopy and transmission electron microscopy techniques. Mechanical data indicated improvement in the tensile strength and modulus with increasing of the LDH loading until 4%.     

N,N′-乙撑双(硬脂酰胺)

分了C:7H。。一e一NH一CH:CH:一NH一C一Ci:Ha。 C:.H,eN,O: 分子量593 l英文名IN,N‘一Ethylene bis(s-tearanl记e) l国外商品名1 Chemetronwa、一100(Chemetron);Armowax EBS(Armak)书H佣ehst WaxC(Hoechst);AerawaxC(Glyeo),Kemam溉w 20(枷mko);Lubro/EA(ICI)。 l性状】白色至淡黄色粉末或粒状物。熔点130一145℃,闪点约285℃,比重0.98。不溶于水,常温下不溶于乙醇、丙酮等大多数溶剂,可溶于混合二甲苯、菇烯、丁醇、甲基溶纤素及大多数氯代烃类。游离脂肪酸含量低于4%,水份低于。.5%。 【制法】乙撑双硬脂酞胺的制备是…