scholarly journals Silent Discharge Reactions in Aqueous Solutions. VIII. Effects of Discharge Gap Distance and Discharge Current on the Yield of Decomposition Products Formed from Water in Argon Atmosphere

1968 ◽  
Vol 41 (10) ◽  
pp. 2292-2297 ◽  
Author(s):  
Akira Yokohata ◽  
Katsuyuki Harakon ◽  
Satoru Tsuda
Keyword(s):  
Aqueous Solutions ◽  
Discharge Current ◽  
Argon Atmosphere ◽  
Silent Discharge ◽  
Decomposition Products ◽  
Discharge Gap

Effects of Ultrasounds on Neat nitrobenzene

2019 ◽  
Vol 70 (8) ◽  
pp. 3085-3088
Author(s):  
Carmen Eugenia Stavarache ◽  
Yasuaki Maeda ◽  
Mircea Vinatoru
Keyword(s):  
Nitro Group ◽  
Radical Cation ◽  
Reaction Mechanisms ◽  
Diphenyl Ether ◽  
Argon Atmosphere ◽  
Phenyl Radical ◽  
Dissolved Gas ◽  
Decomposition Products ◽  
Oxygenated Compounds ◽  
Phenyl Cation

Neat nitrobenzene was continuously irradiated at two ultrasonic frequencies: 40 and 200 kHz, under air and argon atmosphere, respectively. Samples taken at intervals of 1, 5, 10 and 24 h were analyzed by GC-MS and decomposition products were identified. Possible reaction mechanisms are discussed. Presence of air as dissolved gas leads to oxygenated compounds such as 1,4-benzoquinone, 2,4-dinitrophenol, m-dinitrobenzene while argon inhibits the decomposition of nitrobenzene, especially at sonication times under 5 h. Based on the nature of the compounds identified we advanced a mechanism, involving a divergent splitting of unstable radical cation of NB in air and argon respectively. Thus, under air, the phenyl cation formation is preferred leading to 1,4-benzoquinone nitro-biphenyls and dinitrobenzene, while under argon, the phenyl radical formation seems to be favored, leading to phenol and diphenyl ether. The oxygenated compounds detected under argon clearly are a consequence of the nitro group splitting.

scholarly journals Formation of Nanostructured Carbon from [Ni(NH3)6]3[Fe(CN)6]2

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 389 ◽  
Author(s):  
Denis P. Domonov ◽  
Sophiya I. Pechenyuk ◽  
Alexander T. Belyaevskii ◽  
Kirill V. Yusenko
Keyword(s):  
Thermal Decomposition ◽  
Water Solution ◽  
Argon Atmosphere ◽  
Nanostructured Carbon ◽  
Decomposition Products ◽  
Small Admixture ◽  
Coordination Bonds ◽  
High Degree ◽  
Degree Of Graphitization ◽  
Elementary Carbon

The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800 °C. Above 600 °C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500 °C and is completely oxidized above 700 °C.

Creepage of Estrogens vs. Loss by Sorption on Glassware

1974 ◽  
Vol 20 (12) ◽  
pp. 1528-1534 ◽  
Author(s):  
Stanley Kushinsky ◽  
Marilyn Anderson
Keyword(s):  
Aqueous Solutions ◽  
Organic Solvents ◽  
Atmospheric Pollutants ◽  
Decomposition Products ◽  
Cleaning Solution

Abstract Creepage and decomposition by atmospheric pollutants account for many if not all of the losses that have been attributed previously by others to sorption on glassware. Significant creepage occurs only in uncovered (or incompletely closed) vessels, in the presence of salts and in the absence of proteins (such as gelatin). More creepage occurs in vessels that have been freshly cleaned by treatment with heat, cleaning solution, or organic solvents, when the volume of solution is relatively small compared with the capacity of the vessel and at higher dilutions. In addition, the rate of creepage of intact estrogens is greater than that of the decomposition products. We have found no evidence for sorption of estrogens onto glass from buffered aqueous solutions or decomposition in tightly closed containers in the absence of proteins. Under the conditions we used for silanization, creepage was reduced drastically but not eliminated totally.

scholarly journals THE THE EFFECT OF THERMAL STERILIZATION AND EXCIPIENTS ON THE STABILITY OF ASCORBIC ACID IN AQUEOUS SOLUTIONS

2019 ◽  
pp. 313-316
Author(s):  
A. V. SYROESHKIN ◽  
T. V. PLETENEVA ◽  
E. V. USPENSKAYA ◽  
O. V. LEVITSKAYA ◽  
S. S. BARSEGYUN ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Ascorbic Acid ◽  
Biological Activity ◽  
Aqueous Solutions ◽  
Radiation Treatment ◽  
Ph Value ◽  
Optical Rotation ◽  
Active Pharmaceutical Ingredient ◽  
Thermal Method ◽  
Decomposition Products

Objective: To investigate the thermal stability of aqueous solutions of L-ascorbic acid (AA) and its reactions with excipients for the improvement of the injection forms technology. Methods: Solutions of L-ascorbic acid were prepared using deuterium depleted water (DDW-«light» water, D/H=4 ppm) and natural deionized high-ohmic water (BD, D/H=140 ppm). The optical rotation was observed using an automatic polarimeter Atago POL-1/2. Electrospray tandem mass spectra were recorded by Sciex X500R QTOF. Electronic spectra were recorded by UV-spectrometer Cary 60 (Agilent). Unicellular biosensor (Spirotox-test) was used for investigation of excipients influence on the AA biological activity. The statistical analysis was carried out using the OriginPro®9 packages. Results: The results demonstrate the thermal instability of AA. The optical activity of injection forms of AA differs from model solutions with the same concentration and pH value but without heat treatment. Monitoring of solutions by the LC-ESI-MS/MS method made it possible to characterize the nature of some thermal decomposition products. Thermodynamic calculations and evaluation of biological activity (Spirotox-test) indicate that AA interacts with sulfite-ion by redox mechanisms. Excipients in AA aqueous solutions decrease, but DDW increases the biological object lifetime. Conclusion: The use of the set of physicochemical and biological methods to study the effect of heat treatment of L-ascorbic acid solutions in the presence of sulfur (IV) compounds as excipients made it possible to identify decomposition products of the active pharmaceutical ingredient. The results indicate the need to exclude sterilization of the AA injection form by the thermal method and replace it with an alternative one, for example, with gamma radiation treatment.

scholarly journals Экспериментальные исследования таунсендовского разряда с многоострийным катодом на динамической платформе из магнитоуправляемых частиц Fe и Fe-Al

2021 ◽  
Vol 91 (8) ◽  
pp. 1276
Author(s):  
И.А. Шорсткий ◽  
N. Yakovlev
Keyword(s):  
Field Strength ◽  
Discharge Current ◽  
Atmospheric Pressure ◽  
Cathode Surface ◽  
Electrode Gap ◽  
Current Voltage ◽  
Average Electric Field ◽  
Current Voltage Characteristics ◽  
Townsend Discharge ◽  
Discharge Gap

Experimental results of the Townsend discharge in the air gap and atmospheric pressure from a multi-pin cathode based on a dynamic platform of magnetically controlled Fe and Fe-Al particles presented. Dynamic platform method formation from magnetically controlled particles for cathode surface presented. The current-voltage characteristics are obtained for various configurations of the cathode design (with a flat electrode without magnetically controlled particles, with a multi-pin cathode with magnetically controlled Fe or Fe-Al particles), as well as with the presence of a heated spiral in the electrode gap. The use of a multi-pin cathode based on the dynamic platform of magnetically controlled Fe and Fe-Al particles allows to maintain the average electric field strength in the discharge gap and to increase the spark discharge current.

Reactions of ozone and intermediate products of its decomposition with actinides, lanthanides and transition metals in aqueous solutions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Boris G. Ershov ◽  
Bladimir P. Shilov
Keyword(s):  
Transition Metals ◽  
Aqueous Solutions ◽  
Redox Reactions ◽  
Outer Sphere ◽  
Ozone Decomposition ◽  
Decomposition Products ◽  
Coordination Spheres ◽  
Anions And Cations ◽  
The Stability ◽  
Mechanisms Of Reactions

Abstract The properties and stability of ozone in aqueous solutions of various compositions in the рН range of 0–14 were considered. The effect of anions and cations, which are involved in the redox reactions of actinides, on the stability of ozone and its reactivity has been studied. The reactions of О3 with ions of d- and f-elements were analyzed. Depending on the solution composition and рН value, the reaction can occur directly with the O3 molecule (direct mechanism) and/or with short-lived ion-radical products (•OH, HO 2 • / O 2 − • ${\text{HO}}_{2}^{{\bullet}}/{\text{O}}_{2}^{-{\bullet}}$ , H2O2/ HO 2 − ${\text{HO}}_{2}^{-}$ , O 3 − • ${\text{O}}_{3}^{-{\bullet}}$ ) formed upon ozone decomposition in water (indirect mechanism). Ions with inert coordination sphere react with О3 in the outer-sphere fashion with electron transfer. Polyvalent ions with labile coordination spheres are oxidized in acidic medium via О atom transfer, possibly, with intermediate peroxy addition (H2O2, HNO4, H2SO5, etc.). In alkaline medium, О3 is converted to the O 3 − • ${\text{O}}_{3}^{-{\bullet}}$ radical ion, which is the key oxidant for actinides. The results of studies and the mechanisms of reactions of ozone and its intermediates decomposition products with U, Np, Pu, and Am in various oxidation states and with some transition metals (Fe, Mn, Ag, Co, etc.) in aqueous solutions are presented and discussed.

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