Synthesis of 3(2-haloethyl)aryltriazenes and study of their reactions in aqueous solution

1981 ◽  
Vol 59 (9) ◽  
pp. 1347-1356 ◽  
Author(s):  
J. William Lown ◽  
Ranjit Singh
Keyword(s):  
Aqueous Solution ◽  
Structural Changes ◽  
Aqueous Media ◽  
Antitumor Effects ◽  
Electrochemically Active ◽  
Decomposition Increase

Several 1-aryl-3-(2-haloethyl)triazenes have been synthesized and characterized spectroscopically as well as by their esterification of 3,5-dinitrobenzoic acid. Their rates of decomposition in aqueous media at pH7 were determined polarographically employing the electrochemically active triazene moiety. In two selected cases the rates of decomposition increase markedly with lowered pH in the range 9.3 to 4.65. The products of aqueous decomposition, both volatile and involatile, were identified and quantitated by gc and gc–ms. Discrimination between alternative decomposition pathways was possible by the preparation and use of selectively deuterated triazenes. The data are consistent with initial protonation of the triazene and generation therefrom of a 2-haloethyl cation (or its kinetic equivalent) which is subject to rearrangements detected by deuterium scrambling. A second competing pathway involves cyclization of the triazene to a 1-aryl-1,2,3-triazoline intermediate which is then subject to nucleophilic opening at two sites with attendant loss of nitrogen. The effects of structural changes in the triazenes on their modes of decomposition and generation of electrophiles should assist in the interpretation of their antitumor effects.

Highly efficient and selective photocatalytic CO2 to CO conversion in aqueous solution

2020 ◽  
Vol 56 (27) ◽  
pp. 3851-3854 ◽  
Author(s):  
Xiaomin Chai ◽  
Hai-Hua Huang ◽  
Huiping Liu ◽  
Zhuofeng Ke ◽  
Wen-Wen Yong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Performance ◽  
Aqueous Media ◽  
Highly Efficient ◽  
Co Conversion

A Co-based complex displayed the highest photocatalytic performance for CO2 to CO conversion in aqueous media.

Roughened gold electrode for in situ SERS analysis of structural changes accompanying the doping process of polyaniline in acidic aqueous media

2021 ◽  
Vol 882 ◽  
pp. 115034
Author(s):  
A. El Guerraf ◽  
M. Bouabdallaoui ◽  
Z. Aouzal ◽  
S. Ben Jadi ◽  
N.K. Bakirhan ◽  
...  
Keyword(s):  
Gold Electrode ◽  
Structural Changes ◽  
Aqueous Media

scholarly journals Double-Cross-Linked Networks Based on Methacryloyl Mucin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Modification ◽  
Structural Modification ◽  
Aqueous Media ◽  
Cross Linking ◽  
Ph Values ◽  
Acid Aqueous Solution ◽  
Reaction Media ◽  
Double Cross

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.

scholarly journals Phosphorylated cellulose nanofibers exhibit exceptional capacity for uranium capture

Cellulose ◽  
2020 ◽  
Vol 27 (18) ◽  
pp. 10719-10732
Author(s):  
Janika Lehtonen ◽  
Jukka Hassinen ◽  
Avula Anil Kumar ◽  
Leena-Sisko Johansson ◽  
Roni Mäenpää ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Cellulose Nanofibers ◽  
Aqueous Media ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Electron Microscopies ◽  
Network Scanning ◽  
Aqueous Matrices

AbstractWe investigate the adsorption of hexavalent uranium, U(VI), on phosphorylated cellulose nanofibers (PHO-CNF) and compare the results with those for native and TEMPO-oxidized nanocelluloses. Batch adsorption experiments in aqueous media show that PHO-CNF is highly efficient in removing U(VI) in the pH range between 3 and 6. Gelling of nanofiber hydrogels is observed at U(VI) concentration of 500 mg/L. Structural changes in the nanofiber network (scanning and transmission electron microscopies) and the surface chemical composition (X-ray photoelectron spectroscopy) gave insights on the mechanism of adsorption. The results from batch adsorption experiments are fitted to Langmuir, Freundlich, and Sips isotherm models, which indicate a maximum adsorption capacity of 1550 mg/g, the highest value reported so far for any bioadsorbent. Compared to other metals (Zn, Mn, and Cu) and typical ions present in natural aqueous matrices the phosphorylated nanofibers are shown to be remarkably selective to U(VI). The results suggest a solution for the capture of uranium, which is of interest given its health and toxic impacts when present in aqueous matrices.

scholarly journals A Carbon Nanotube Packed Bed Electrode for Small Molecule Electrosorption: An Electrochemical and Chromatographic Approach for Process Description

2020 ◽  
Vol 10 (3) ◽  
pp. 1133
Author(s):  
Tatjana Trunzer ◽  
Timothy Stummvoll ◽  
Melanie Porzenheim ◽  
Paula Fraga-García ◽  
Sonja Berensmeier
Keyword(s):  
Structural Changes ◽  
Aqueous Media ◽  
Electrical Potential ◽  
Packed Bed ◽  
Electrical Potentials ◽  
Packed Bed Electrode ◽  
Through Flow ◽  
Multi Walled Carbon Nanotubes ◽  
Electrochemical Double Layer ◽  
Walled Carbon Nanotubes

Triggering the interaction of nanomaterials with molecules by means of electrical potentials in aqueous media remains challenging, especially if 3D through-flow systems are used as electrodes, as in potential-controlled liquid chromatography (PCC). In this paper, multi-walled carbon nanotubes (MWCNTs) function as a particulate packed bed electrode in order to study the system’s response to various applied potentials and electrolyte compositions. The process principle was analyzed using chronoamperometry and cyclic voltammetry. Applying an electrical potential to the hydrophilic MWCNTs induces the presence of both capacitive and faradaic currents. This leads, over time, to a degradation of the electrode due to structural changes of the MWCNT matrix and an increase in redox reactions on the surface. The role of the electrochemical double layer (EDL) is highlighted as a main player in the process, directly influencing the adsorption capability of the electrode. The EDL rearrangement time and coverage radius depend on the composition of the mobile phase and on the potential applied. The capacity of the electrode for the target (maleic acid) increases at high positive potentials (+800 mV vs. Ag/AgCl), while the presence of electrolytes leads to a capacity decrease. Our research enhances the understanding of capacitive through-flow cells.

scholarly journals The Equilibrium, Kinetics, and Thermodynamics Studies of the Sorption of Methylene Blue from Aqueous Solution Using Pulverized Raw Macadamia Nut Shells

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Joshua N. Edokpayi ◽  
Samson O. Alayande ◽  
Ahmed Adetoro ◽  
John O. Odiyo
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Surface Area ◽  
Low Cost ◽  
Aqueous Media ◽  
Group Analysis ◽  
Second Order ◽  
Isotherm Models ◽  
Macadamia Nut ◽  
Pseudo Second Order

In this study, the potential for pulverized raw macadamia nut shell (MNS) for the sequestration of methylene blue from aqueous media was assessed. The sorbent was characterized using scanning electron microscopy for surface morphology, functional group analysis was performed with a Fourier-transform infrared spectrometer (FT-IR), and Brunauer–Emmett–Teller (BET) isotherm was used for surface area elucidation. The effects of contact time, sorbent dosage, particle size, pH, and change in a solution matrix were studied. Equilibrium data were fitted using Temkin, Langmuir, and Freundlich adsorption isotherm models. The sorption kinetics was studied using the Lagergren pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The feasibility of the study was established from the thermodynamic studies. A surface area of 2.763 m2/g was obtained. The equilibrium and kinetics of sorption was best described by the Langmuir and the pseudo-second-order models, respectively. The sorption process was spontaneous (−ΔG0=28.72−31.77 kJ/mol) and endothermic in nature (ΔH0=17.45 kJ/mol). The positive value of ΔS0 (0.15 kJ/molK) implies increased randomness of the sorbate molecules at the surface of the sorbent. This study presents sustainable management of wastewater using MNS as a potential low-cost sorbent for dye decontamination from aqueous solution.

scholarly journals Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography–Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5985
Author(s):  
Meei-Ju Yang ◽  
Shwu-Yuan Lee ◽  
Chieh-I Liu ◽  
Shih-Hsuan Chen ◽  
Iou-Zen Chen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Aluminum Chloride ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Structural Changes ◽  
Liquid Chromatography Mass Spectrometry ◽  
Relative Percentage ◽  
Alkaline Conditions

Tea is rich in catechins and aluminum. In this study, the process of catechin photolysis was applied as a model for examining the effects of aluminum chloride (AlCl3) on the structural changes of catechin and the alteration of aluminum complexes under blue light irradiation (BLI) at pH 8 using liquid chromatography and mass spectrometry techniques. Additionally, the effects of anions on catechin upon the addition of AlCl3 and treatment with BLI were also studied. In this study, when 1 mM catechin was treated with BLI, a superoxide anion radical (O2•−) was generated in an air-saturated aqueous solution, in addition to forming a dimeric catechin (proanthocyanidin) via a photon-induced redox reaction. The relative percentage of catechin was found to be 59.0 and 95.7 for catechin treated with BLI and catechin upon the addition of 1 mM AlCl3 treated with BLI, respectively. It suggested that catechin treated with BLI could be suppressed by AlCl3, while AlCl3 did not form a complex with catechin in the photolytic system. However, under the same conditions, it was also found that the addition of AlCl3 inhibited the photolytic formation of O2•−, and reduced the generation of proanthocyanidin, suggesting that the disconnection of proanthocyanidin was achieved by AlCl3 acting as a catalyst under treatment with BLI. The influence of 1 mM fluoride (F−) and 1 mM oxalate (C2O42−) ions on the photolysis of 1 mM catechin upon the addition of 1 mM AlCl3 and treatment with BLI was found to be insignificant, implying that, during the photolysis of catechin, the Al species were either neutral or negatively charged and the aluminum species did not form a complex with anions in the photolytic system. Therefore, aluminum, which is an amphoteric species, has an inherent potential to stabilize the photolysis of catechin in an alkaline conditions, while suppressing the O2•− and proanthocyanidin generation via aluminum ion catalysis in the catechin/Al system under treatment with BLI.

A reversible fluorescent-colorimetric chemosensor based on a novel Schiff base for visual detection of CO32− in aqueous solution

RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72185-72192 ◽  
Author(s):  
Anupam Ghorai ◽  
Jahangir Mondal ◽  
Rukmani Chandra ◽  
Goutam K. Patra
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Visual Detection ◽  
Colorimetric Detection ◽  
Aqueous Media ◽  
Rapid Response ◽  
Colorimetric Chemosensor ◽  
Excellent Selectivity

A novel Schiff base receptor L has been fabricated for fluorescent-colorimetric detection of CO32− in aqueous media. L shows an excellent selectivity, rapid response and reversibility and its sensitivity for CO32− is the lowest ever found (96 nM).

A Co(ii) complex of a vitamer of vitamin B6acts as a sensor for Hg2+and pH in aqueous media

2016 ◽  
Vol 40 (7) ◽  
pp. 6396-6404 ◽  
Author(s):  
Nilam Sing ◽  
Sanjay Roy ◽  
Partha Sarathi Guin ◽  
Kalachand Mahali ◽  
Prakash Majee ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Fluorescent Sensor ◽  
Aqueous Media ◽  
Template Reaction

A new Co(ii) complex was prepared by template reaction, acting as a dual fluorescent sensor for Hg2+ions and pH in aqueous solution.

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