A Selective Colorimetric and Fluorescent Chemodosimeter for Fe(III) Ion Based on Hydrolysis of Schiff Base

2015 ◽  
Vol 62 (4) ◽  
pp. 316-320 ◽  
Author(s):  
Haw-Tyng Tsai ◽  
Yeshwant Ramchandra Bhorge ◽  
Albert J. Pape ◽  
Sudhakar Narasimha Janaki ◽  
Yao-Pin Yen
1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.


2020 ◽  
Vol 44 (19) ◽  
pp. 7954-7961
Author(s):  
Sanchita Mondal ◽  
Saikat Kumar Manna ◽  
Sudipta Pathak ◽  
Aritri Ghosh ◽  
Pallab Datta ◽  
...  

A chromogenic and “off–on” fluorogenic chemodosimeter (L) based on a naphthalene–rhodamine B derivative was designed, synthesized and characterized for the selective and sensitive detection of Au3+ ions in mixed acetonitrile aqueous media.


Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 293 ◽  
Author(s):  
Van-Dung Mai ◽  
Se-Ra Shin ◽  
Dai-Soo Lee ◽  
Ilho Kang

A bio-derived dihydroxylimine hardener, Van2HMDA, for the curing of epoxy resin was prepared from vanillin (Van) and hexamethylene-1,6-diamine (HMDA) by Schiff base formation. The epoxy resin of diglycidyl ether of bisphenol A was cured with Van2HMDA in the presence of the catalyst, 2-ethyl-4-methylimidazole (EMI). The crosslinked epoxy resin showed thermal-healing properties at elevated temperatures. Moreover, the crosslinked epoxy resin can be reshaped by heating via imine metathesis of the hardener units. The imine metathesis of Van2HMDA was confirmed experimentally. Stress-relaxation properties of the epoxy resin crosslinked with Van2HMDA were investigated, and the activation energy obtained from Arrhenius plots of the relaxation times was 44 kJ/mol. The imine bonds in the epoxy polymer matrix did not undergo hydrolysis after immersing in water at room temperature for one week. However, in the presence of acid, the crosslinked polymer was easily decomposed due to the hydrolysis of imine bonds. The hydrolysis of imine bonds was used for the ecofriendly recycling of crosslinked polymer. It is inferred that thermal-healing, reshaping, and reprocessing properties can be implemented in the various crosslinked epoxy resins with the bio-derived dihydroxylimine hardener, albeit the recycled epoxy resin is of inevitably lower quality than the original material.


2014 ◽  
Vol 84 (10) ◽  
pp. 2037-2042 ◽  
Author(s):  
Ali M. Shaker ◽  
Lobna A. E. Nassr ◽  
Mohamed S. S. Adam ◽  
Ibrahim M. A. Mohamed

1972 ◽  
Vol 8 (1-2) ◽  
pp. 55 ◽  
Author(s):  
E.C. Lingafelter ◽  
L.C. Andrews ◽  
R.M. Kirchner ◽  
N.J. Rose ◽  
L.J. Wilson

2013 ◽  
Vol 67 (4) ◽  
Author(s):  
Ahmad Mohamad ◽  
Mohamed Adam

AbstractThree ligands of 2-pyridinylmethylene-8-quinolinyl (L1), methyl-2-pyridinylmethylene-8-quinolinyl (L2), and phenyl-2-pyridinylmethylene-8-quinolinyl (L3), Schiff bases were synthesised by direct condensation of 8-aminoquinoline with 2-pyridinecarboxaldehyde, 2-acetylpyridine, or 2-benzoylpyridine. They coordinated to Fe(II) ion in a 1: 2 mole ratio followed by treatment with iodide ions affording complexes with a general formula [Fe(L)2]I2·2H2O, (L = L1, L2, or L3). Spectrophotometric evaluation of the kinetics of base catalysed hydrolysis of these complex cations was carried out with an aqueous solution of NaOH in different ratios of water/methanol binary mixtures. Kinetics of the hydrolysis followed the rate law (k 2[OH−] + k 3[OH−]2)[complex]. Reactivity trends and their rate constants were compared and discussed in terms of ligand structure and solvation parameters. The methanol ratio affects the hydrolysis as a co-solvent which was analysed into initial and transition state components. The increase in the rate constant of the base hydrolysis of Fe(II) complexes, as the ratio of methanol increases, is predominantly caused by the strong effect of the organic co-solvent on the transition states.


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