Search results for "Diamine"
showing 10 items of 447 documents
Calorimetric study of the solubilization of ethylenediamine, N,N-dimethylaminoethylamine and N,N,N?,N?-tetramethylethylenediamine by reversed AOT mic…
1993
Distribution constants and standard enthalpies of transfer of ethylenediamine (en), N,N-dimethylaminoethylamine (dmen) and N,N,N′,N′-tetramethylethylenediamine (tmen) partitioned between n-heptane and water containing reversed sodium bis(2-ethylhexyl) sulfosuccinate (AOT) micelles as a function of the molar concentration ratio R (R=[water]/[AOT]) were evaluated by a calorimetric method. The results show that en, dmen and tmen molecules, solubilized in the reversed micelles, are distributed between the micellar aqueous core and the micellar palisade layer. An analysis of the thermodynamic parameters of the partition process demonstrates the peculiar solvent properties of the water containing…
Mixed aggregates based on tetronic-fluorinated surfactants for selective oils capture
2015
Abstract An aqueous star-like copolymer solution was titrated with perfluoro carboxylic acids at various compositions to prepare a polymeric surfactant composed of fluorinated nano-domains. The copolymer is X-shaped where each arm contains ethylene oxide and propylene oxide repetitive units linked to a central ethylenediamine group. The aggregation behavior of the hybrid macromolecule was studied from the physico-chemical point of view by changing parameters like temperature and composition. The solubilization of perfluorinated and hydrogenated alcohols in mixed self-assembled structure revealed that a selectivity toward the fluorinated moiety can be done. The self-assembled structures are …
Speciation of low molecular weight ligands in natural fluids: protonation constants and association of open chain polyamines with the major component…
2000
Abstract The interaction of five open chain polyamines (ethylenediamine (en), diethylenetriamine (dien), trietylenetetramine (trien), tetraethylenepentamine (tetren), spermine (sper)) with the major components of seawater was studied potentiometrically at 25°C, in an artificial seawater (containing Na+, K+, Mg2+, Ca2+, Cl− and SO42−) at different salinities (5–45‰). Potentiometric data were interpreted in terms of both the apparent protonation constants of polyamines and the formation constants of complexes formed by unprotonated or protonated amines and the cation and the anion of seawater (the inorganic content of seawater being considered as a single 1:1 salt). Some empirical relationshi…
Evaluation of biosorbents for Cu removal from wastewater in the presence of EDTA
2007
BACKGROUND: This paper evaluates the use of several biosorbents for Cu removal from aqueous solutions in the absence and presence of ethylenediaminetetraacetic acid (EDTA). The objective was to determine the applicability of the sorption process after conventional physicochemical wastewater treatment, or as primary treatment, replacing the physicochemical process. RESULTS: Fixed-bed experiments were performed at Cu influent concentrations of 2 and 20 mg dm−3 and EDTA doses between 0 and 10 mg dm−3. At low Cu concentration without EDTA, Cu uptake capacity followed the order Posidonia oceanica > chitosan > chitin > Scharlau AC > Darco AC, with a maximum, at C/C0 = 0.2, of 23.2 mg g−1. In the …
Mononuclear and tetranuclear Fe(III) complexes with two different types of N, O donor Schiff base ligands
2013
Abstract A mononuclear Fe(III) complex of a tetradentate N 2 O 2 donor Schiff base ligand derived from 3-ethoxysalicaldehyde and ethylenediamine has been reported. In addition two tetranuclear Fe(III) complexes with discrete Fe 4 III (μ 4 -O) cores have been synthesized and characterized using two Schiff base ligands (H 2 L 1–2 ) derived from two different aromatic acid hydrazides and diacetyl monoxime. The mononuclear Fe(III) and one of the tetranuclear Fe(III) complexes have been structurally characterized by single-crystal X-ray crystallography. The mononuclear complex has a highly distorted octahedral geometry. The tetranuclear Fe(III) complexes are found to be rare examples with discre…
Muscarine receptor types mediating autoinhibition of acetylcholine release and sphincter contraction in the guinea-pig iris.
1990
The potencies of several muscarine receptor antagonists in blocking either the autoinhibition of acetylcholine release or the muscarinic contraction of the sphincter muscle upon acetylcholine release were investigated in the guinea-pig iris. The agonist at pre- or postjunctional muscarine receptors was acetylcholine released upon field stimulation (5.5 Hz, 2 min) of the irides preloaded with 14C-choline. The stimulation-evoked 14C-overflow was doubled in the presence of atropine 0.1 mumol/l but unaffected by the agonist (+/-)-methacholine (50 mumol/l). Thus, under the present stimulation conditions, the autoinhibition of acetylcholine release on the guinea-pig iris cholinergic nerves was ne…
Electrical power production from low-grade waste heat using a thermally regenerative ethylenediamine battery
2017
Abstract Thermally regenerative ammonia-based batteries (TRABs) have been developed to harvest low-grade waste heat as electricity. To improve the power production and anodic coulombic efficiency, the use of ethylenediamine as an alternative ligand to ammonia was explored here. The power density of the ethylenediamine-based battery (TRENB) was 85 ± 3 W m−2-electrode area with 2 M ethylenediamine, and 119 ± 4 W m−2 with 3 M ethylenediamine. This power density was 68% higher than that of TRAB. The energy density was 478 Wh m−3-anolyte, which was ∼50% higher than that produced by TRAB. The anodic coulombic efficiency of the TRENB was 77 ± 2%, which was more than twice that obtained using ammon…
Synthesis and Redox Behaviour of the Chalcogenocarbonyl Dianions, [(E)C(PPh2S)2]2−: Formation and Structures of Chalcogen−Chalcogen Bonded Dimers and…
2010
The lithium salts of the chalcogenocarbonyl dianions [(E)C(PPh(2)S)(2)](2-) (E=S (4 b), Se (4 c)) were produced through the reactions between Li(2)[C(PPh(2)S)(2)] and elemental chalcogens in the presence of tetramethylethylenediamine (TMEDA). The solid-state structure of {[Li(TMEDA)](2)[(Se)C(PPh(2)S)(2)]}-[{Li(TMEDA)}(2)4 c]-was shown to be bicyclic with the Li(+) cations bis-S,Se-chelated by the dianionic ligand. One-electron oxidation of the dianions 4 b and 4 c with iodine afforded the diamagnetic complexes {[Li(TMEDA)](2)[(SPh(2)P)(2)CEEC(PPh(2)S)(2)]} ([Li(TMEDA)](2)7 b (E=S), [Li(TMEDA)](2)7 c (E=Se)), which are formally dimers of the radical anions [(E)C(PPh(2)S)(2)](-) (.) (E=S (5 …
Systematic study of SYBR green chromophore reveals major improvement with one heteroatom difference
2021
Five nucleic acid binding cyanine dyes were synthesized and their photophysical properties were evaluated. Changing a single heteroatom in the chromophore causes major differences both in brightness and photostability between the dyes. With such alteration, the brightness of the chromophore increased two-fold compared to the one found in SYBR Green I.
Improving sensitivity in simultaneous determination of copper carboxylates by nonaqueous capillary electrophoresis
2005
Abstract A new method of nonaqueous capillary electrophoresis (NACE) with UV spectrophotometric detection was developed and optimized for the simultaneous determination of seven carboxylates (trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA), nitrilotriacetic acid (NTA), 1,3-diaminopropane-N,N,N′,N′-tetraacetic acid (PDTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes. The method development was carried out by using a fused silica capillary. Background electrolyte (BGE) was optimized and the best separation a…