Chemical Transformations of Aqueous Solutions Activated by Remote Plasma Spark Discharge in Air, Nitrogen, or Oxygen

2021 ◽  
Vol 55 (2) ◽  
pp. 145-149
Author(s):  
I. M. Piskarev
Keyword(s):  
Aqueous Solutions ◽  
Spark Discharge ◽  
Chemical Transformations ◽  
Remote Plasma

scholarly journals The Study of the Reaction of Pectin-Ag(0) Nanocomposites Formation

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Nadezhda Viktorovna Ivanova ◽  
Natalya Nikolaevna Trofimova ◽  
Lydmila Alexandrovna Es'kova ◽  
Vasilyi Anatolievich Babkin
Keyword(s):  
Aqueous Solutions ◽  
Larix Sibirica ◽  
Side Chains ◽  
Chemical Transformations ◽  
Reaction Conditions ◽  
Rhamnogalacturonan I ◽  
Spectroscopic Analyses ◽  
Furanose Form ◽  
Branched Structure ◽  
C Nmr

Pectin polysaccharides (PSs) were isolated from a bark of Larix sibirica Ledeb. Structure of PS fragments determined by chemical transformations, chromatography, and spectroscopic analyses was found to be a linear galacturonane comprising 1,4-linked α-D-GalpA residues and a rhamnogalacturonan I (RG-I). The fifth part of galacturonane residues was methyl esterified at at C-2 and/or C-3 and C-6 atoms. Some of RG-I side chains were identified as arabinogalactan subunits with highly branched structure consisting of linear backbone with3,6)-β-D-Galp-(1residues, substituted at C-6 by neutral side chains. This side chains contained2,5)-α-L-Araf-(1and3,5)-α-L-Araf-(1residues and terminal arabinose in the pyranose and furanose form. It was found that “pectin-Ag(0)” nanobiocomposites were formed via the interaction between PS aqueous solutions and silver nitrate, with PS playing both reducing and stabilizing functions. It was shown that the content of Ag(0) particles in “pectin-Ag(0)” depended on the reaction conditions and can range from 0.1 to 72 %, the size of Ag(0) particles being 3–27 nm. Using 13C NMR technique, it was revealed that PS underwent destructive changes and they they were more considerable, more than the lot of Ag(I) that was inputed into the reactionary medium.

scholarly journals Chemical transformations initiated by gas discharges in aqueous solutions

2019 ◽  
Vol 1393 ◽  
pp. 012132
Author(s):  
D A Shutov ◽  
A V Sungurova ◽  
A C Manukyan ◽  
A N Ivanov ◽  
V V Rybkin
Keyword(s):  
Aqueous Solutions ◽  
Chemical Transformations ◽  
Gas Discharges

scholarly journals Hydrogels Obtained via γ-Irradiation Based on Poly(Acrylic Acid) and Its Copolymers with 2-Hydroxyethyl Methacrylate

2020 ◽  
Vol 10 (14) ◽  
pp. 4960 ◽  
Author(s):  
Marin Micutz ◽  
Rodica Mihaela Lungu ◽  
Viorel Circu ◽  
Monica Ilis ◽  
Teodora Staicu
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Acrylic Acid ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Chemical Transformations ◽  
Hydroxyethyl Methacrylate ◽  
Γ Irradiation ◽  
Crosslinking Degree

Hydrogels containing both carboxyl and hydroxyl functional groups have been prepared by γ-irradiation of either aqueous solutions of acrylic acid (AA) and mixtures of AA and 2-hydroxyethyl methacrylate (HEMA) in different ratios, or aqueous solutions of poly(AA), PAA, and poly(AA-co-HEMA) obtained via solution polymerization. A higher absorbed dose is required in order to prepare hydrogels from monomer solutions, compared with those from polymer solutions. The range for the absorbed doses was chosen so that the probability of crosslinking reactions is higher than that of degradation ones. As the radiation energy deposited in a sample increases, the equilibrium swelling degree and the average molar mass between crosslinks diminishes. Chemical transformations induced by radiation were investigated by means of FTIR spectroscopy and thermal analysis of polymers before and after irradiation. For all these systems, the formation of a three-dimensional network enhances the glass transition temperature and thermal stability, but a further increase in the crosslinking degree may have the reverse effect on the glass transition temperature. Depending on the preparation protocol and/or hydrogel composition, superabsorbent materials that can bind different compounds throughout side functional groups may be obtained.

scholarly journals Decomposition of Dimethoate and Omethoate in Aqueous Solutions – Half-Life, Neurotoxicity and Mechanism of Hydrolysis

2021 ◽  
Author(s):  
Vladan J. Anićijević ◽  
Milena Petković ◽  
Igor A Pašti ◽  
Tamara Lazarević-Pašti
Keyword(s):  
Aqueous Solutions ◽  
Alkaline Hydrolysis ◽  
Quantum Chemical ◽  
Contaminated Water ◽  
Organophosphate Pesticides ◽  
Chemical Transformations ◽  
Acidic Solutions ◽  
Mechanism Of Hydrolysis ◽  
Hydrolysis Of ◽  
Over Time

Organophosphate pesticides are used in large quantities. However, they exhibit toxic effects on non-target organisms. Dimethoate and its oxo-analog omethoate inhibit acetylcholinesterase and are toxic for mammals. Moreover, they show extreme toxicity for bees. Once in the environment, they undergo chemical transformations and decomposition. We show that dime-thoate and omethoate decompose rapidly in alkaline aqueous solutions (half-lives 5.7 and 0.89 days) but are highly stable in acidic solutions (half-lives 124 and 104 days). These differences are explained using quantum chemical calculations, indicating that a weaker P–S bond in omethoate is more susceptible to hydrolysis, particularly at a high pH. The toxicity of these pesticides solutions decreases over time, indicating that no or very little highly toxic omethoate is formed during hydrolysis. Presented data can be used to predict dimethoate and omethoate concentrations in contaminated water depending on pH. Presented results suggest that alkaline hydrolysis of organophosphates has an advantage over other techniques for their removal since there is no risk of omethoate accumulation and increased toxicity of contaminated water.

Radiation-chemical transformations of humic acid in aqueous solutions

2006 ◽  
Vol 40 (6) ◽  
pp. 370-374 ◽  
Author(s):  
A. V. Bludenko ◽  
T. P. Zhestkova ◽  
T. N. Zhukova ◽  
A. V. Ponomarev
Keyword(s):  
Humic Acid ◽  
Aqueous Solutions ◽  
Chemical Transformations ◽  
Radiation Chemical

Simulation of the radiation-chemical transformations of acetic acid in aqueous solutions

2007 ◽  
Vol 41 (4) ◽  
pp. 233-238 ◽  
Author(s):  
A. V. Gordeev ◽  
I. M. Kosareva ◽  
G. L. Bykov ◽  
B. G. Ershov
Keyword(s):  
Acetic Acid ◽  
Aqueous Solutions ◽  
Chemical Transformations ◽  
Radiation Chemical

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

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