Investigations of kinetics and mechanism of chloropinnoite in boric acid aqueous solution at 303 K by Raman spectroscopy

2004 ◽  
Vol 60 (12) ◽  
pp. 2725-2728 ◽  
Author(s):  
Li Xiaoping ◽  
Gao Shiyang ◽  
Xia Shuping
1990 ◽  
Vol 55 (8) ◽  
pp. 1984-1990 ◽  
Author(s):  
José M. Hernando ◽  
Olimpio Montero ◽  
Carlos Blanco

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.


1994 ◽  
Vol 48 (7) ◽  
pp. 875-883 ◽  
Author(s):  
Daniel R. Lombardi ◽  
Chao Wang ◽  
Bin Sun ◽  
Augustus W. Fountain ◽  
Thomas J. Vickers ◽  
...  

Raman spectra have been measured for a number of nitrates, nitrites, sulfates, ferrocyanides, and ferricyanides, both in the solid phase and in aqueous solution. Accurate locations of peak maxima are given. Limits of detection for some of the compounds are given for solutions and for solid mixtures in NaNO3. Preliminary measurements have been made on core material recovered from the storage tanks on the Hanford site in Richland, Washington. Representative spectra are presented, showing that it is possible to observe responses of individual components from measurements made directly on untreated cores, with the use of a fiberoptic sampling probe.


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.


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