Reactions of Chloramines with Ag(0) and Ag(I) States

1972 ◽  
Vol 50 (8) ◽  
pp. 1167-1180 ◽  
Author(s):  
O. E. Edwards ◽  
D. Vocelle ◽  
J. W. ApSimon
Keyword(s):  
Silver Oxide ◽  
Silver Ions ◽  
Silver Ion ◽  
Short Chain ◽  
Ferrous Ion ◽  
Metallic Silver ◽  
Nitrenium Ions ◽  
Homolytic Decomposition ◽  
Nitrogen Radicals ◽  
Silver Metal

Reactions of N-chloroazacyclooctane and N-chloroazacyclononane are described which give good yields of bicyclic amines. These are: (a) short chain homolytic reactions involving neutral nitrogen radicals initiated by ferrous ion or metallic silver; (b) apparent homogeneous reactions involving silver ion and bases; (c) reactions using silver oxide suspension which also require added bases.Both rate and product composition for (b) and (c) are sensitive to oxygen indicating that they are homolytic processes, probably initiated by traces of silver metal. No evidence for involvement of discrete nitrenium ions was found. However, reaction of N-chloroisoquinuclidine with silver ions has the character of a heterolytic process, giving products completely distinct from those from its homolytic decomposition. The addition of neutral piperidino radicals to styrene is described.

Reactions of Tertiary Hypohalites

1971 ◽  
Vol 49 (16) ◽  
pp. 2664-2671 ◽  
Author(s):  
V. Boido ◽  
O. E. Edwards
Keyword(s):  
Silver Oxide ◽  
Short Chain ◽  
Metallic Silver ◽  
Mercuric Oxide ◽  
Tertiary Alcohols ◽  
Convenient Synthesis ◽  
Homolytic Decomposition ◽  
Tertiary Alkyl

Metallic silver initiates short-chain homolytic decomposition of tertiary alkyl hypochlorites and hypobromites. Evidence is presented that the reaction of tertiary alcohols with silver oxide – mercuric oxide – bromine involves formation and homolytic decomposition of alkyl hypobromite followed by cyclization of γ-bromo alcohols. A convenient synthesis of tricyclo[4.3.1.03,8]decan-4-one (4-proto-adamantanone) is described.

Various Applications of Silver Nano-Particles by Ultrasonic Eco-Fabrication

2005 ◽  
Vol 486-487 ◽  
pp. 530-533 ◽  
Author(s):  
Yamato Hayashi ◽  
Hirotsugu Takizawa ◽  
Yoshitaka Saijo ◽  
Tohru Sekino ◽  
Katsuaki Suganuma ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Noble Metal ◽  
Room Temperature ◽  
Silver Oxide ◽  
Nano Particles ◽  
Metal Particles ◽  
Noble Metal Oxides ◽  
Alcohol System ◽  
Silver Metal ◽  
Suitable Process

Applications of silver nano-sized metal particles were investigated for a new, ecologically friendly and economical liquid-solid (silver oxide-alcohol) system. Silver metal oxides as starting materials have merits in metal particles fabrication because these materials are decomposed only by heating in air. That is, noble metal oxide does not use thestrong reduction atmosphere. This reduction is ecologically clean because many noble metal oxides are not toxic, and because O2 is evolved during decomposition. We reduced silver metal oxides by ultrasound and fabricated silver nano metal nanoparticles at room temperature, and various applications were investigated. By choosing a suitable process and conditions, it is reasonable to expect that ultrasonic eco-fabrications can be extended to obtain various silver nano-particles containing materials.

Controlling over the ligands of CdZnTe quantum dots to design a super simple ratiometric fluorescence nanosensor for silver ions detection†

The Analyst ◽  
2021 ◽  
Author(s):  
Haining Cui ◽  
Chengquan Wang ◽  
Suli Jia ◽  
Jing Qian ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Silver Ions ◽  
Silver Ion ◽  
Ratiometric Fluorescence

A super simple ratiometric fluorescence nanosensor has been fabricated by controlling over the ligands of CdZnTe quantum dots (QDs) allowing sensitive and visual detecting silver ion (Ag+). The green-emitting L-cysteine...

Immobilization of Silver Nanoparticles on Chitosan-Coated Silica-Gel-Beads and the Antibacterial Activity

2021 ◽  
Vol 892 ◽  
pp. 36-42
Author(s):  
Muhammad Iqbal Hidayat ◽  
Muhammad Adlim ◽  
Ilham Maulana ◽  
Muhammad Zulfajri
Keyword(s):  
Silver Nanoparticles ◽  
Silica Gel ◽  
Low Cost ◽  
Antibacterial Properties ◽  
Chitosan Film ◽  
Silver Ions ◽  
Filter Material ◽  
Silver Ion ◽  
Gel Beads ◽  
Metal Colloid

Silver nanoparticles (Ag0) have attracted the most attention due to their broad antimicrobial application and outstanding activity. The silver nanoparticles are usually in colloidal form, then immobilization the colloid onto solid support is still interesting to explore. In this work, a new method for silver colloidal nanoparticle immobilization on silica gel beads (SiG), which was then symbolized as Ag0-[chi-SiG] was conducted and characterized successfully. The finding proved that SiG must be coated with three chitosan film layers to give stable support for silver nanoparticles. This coating method caused the chitosan completely covered SiG, and the chitosan film provides coordination bonding for silver ions. The most appropriate solvent for silver ion impregnation on the surface of chi-SiG is methanol compared to other solvents. Tungsten lamp as the photo-irradiation, which is low cost and environmentally friendly has been proven effective for silver ion reduction, as shown by silver metal colloid UV-Vis surface plasmon resonance at 400-700 nm. Ag0-[chi-SiG] showed the antibacterial properties of inhibiting the growth Staphylococcus aureus and Escherichia coli; then it provides the potential application for antibacterial filter material. According to the weight comparison between antibacterial standard and Ag content, then Ag0-[chi-SiG] has two and five times higher of exhibiting zone for each bacteria.

ChemInform Abstract: Silver Ion Exchanged Zeolite Modified Electrodes: Observation of Electrochemically Distinct Silver Ions.

ChemInform ◽  
2010 ◽  
Vol 22 (10) ◽  
pp. no-no
Author(s):  
M. D. BAKER ◽  
J. ZHANG
Keyword(s):  
Modified Electrodes ◽  
Silver Ions ◽  
Silver Ion

scholarly journals Fabric with silver thread role in the control of bacterial contamination in critically ill patients

2017 ◽  
Vol 68 (01) ◽  
pp. 54-57
Author(s):  
Peneș Ovidiu N. ◽  
Neagu Andrei Mihai ◽  
Plața Flavius ◽  
Păun Silviu Dumitru
Keyword(s):  
Human Body ◽  
Cell Membranes ◽  
Wound Care ◽  
Silver Ion ◽  
Biologically Active ◽  
Personal Hygiene ◽  
Minimal Risk ◽  
Fungal Cell ◽  
Cardiac Devices ◽  
Silver Metal

Silver has an intriguing, long history used for its antibiotic properties in human health care. It has been used in water purification, wound care, bone prostheses, reconstructive orthopaedic surgery, cardiac devices, catheters and surgical appliances, dressings and textiles. Advancing biotechnology has enabled incorporation of ionizable silver into fabrics, textiles and dressings for clinical use to reduce the risk of nosocomial infections and for personal hygiene. The antimicrobial action of silver is proportional to the bioactive silver ion (Ag(+)) released and its availability to interact with bacterial or fungal cell membranes. Silver metal and inorganic silver compounds ionize in the presence of water, body fluids or tissue exudates. The silver ion is biologically active and interacts with proteins, amino acid residues, free anions and receptors on mammalian and eukaryotic cell membranes. Bacterial sensitivity to silver is genetically determined and relates to the levels of intracellular silver uptake and its ability to interact and irreversibly denature key enzyme systems. Silver exhibits low toxicity in the human body. Minimal risk is expected due to clinical exposure by inhalation, ingestion, dermal application or through the urological or haematogenous route. Chronic ingestion or inhalation of silver preparations (especially colloidal silver) can lead to deposition of silver metal/silver sulphide particles in the skin (argyria), eye (argyrosis) and other organs. These are not life-threatening conditions but cosmetically undesirable. Silver is absorbed into the human body and enters the systemic circulation as a protein complex to be eliminated by the liver and kidneys. This complex mitigates the cellular toxicity of silver and contributes to tissue repair. Silver allergy is a known contraindication for using silver in medical devices or antibiotic textiles.

scholarly journals Transport and Separation of the Silver Ion with n–decanol Liquid Membranes Based on 10–undecylenic Acid, 10–undecen–1–ol and Magnetic Nanoparticles

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 936
Author(s):  
Gheorghe Nechifor ◽  
Florentina Mihaela Păncescu ◽  
Paul Constantin Albu ◽  
Alexandra Raluca Grosu ◽  
Ovidiu Oprea ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Membrane Separation ◽  
Silver Ions ◽  
Silver Ion ◽  
Bulk Liquid ◽  
Liquid Membranes ◽  
Gravimetric Analysis ◽  
Undecylenic Acid ◽  
Scanning Calorimetry ◽  
Source Phase

This paper presents a transport and recovery of silver ions through bulk liquid membranes based on n–decanol using as carriers 10–undecylenic acid and 10–undecylenyl alcohol. The transport of silver ions across membranes has been studied in the presence of two types of magnetic oxide nanoparticles obtained by the electrochemical method with iron electrodes in the electrolyte with and without silver ions, which act as promoters of turbulence in the membrane. Separation of silver ions by bulk liquid membranes using 10–undecylenic acid and 10–undecylenyl alcohol as carriers were performed by comparison with lead ions. The configuration of the separation module has been specially designed for the chosen separation process. Convective-generating magnetic nanoparticles were characterized in terms of the morphological and structural points of view: scanning electron microscopy (SEM), high-resolution SEM (HR–SEM), energy dispersive spectroscopy analysis (EDAX), Fourier Transform InfraRed (FTIR) spectroscopy, thermal gravimetric analysis (TGA), differential scanning calorimetry and magnetization. The process performance (flux and selectivity) was tested were tested for silver ion transport and separation through n–decanol liquid membranes with selected carriers. Under the conditions of the optimized experimental results (pH = 7 of the source phase, pH = 1 of the receiving phase, flow rate of 30 mL/min for the source phase and 9 mL/min for the receiving phase, 150 rot/min agitation of magnetic nanoparticles) separation efficiencies of silver ions of over 90% were obtained for the transport of undecenoic acid and about 80% for undecylenyl alcohol.

scholarly journals The catalytic combination of hydrogen and oxygen at the surface of platinum

1936 ◽  
Vol 156 (888) ◽  
pp. 284-306 ◽  
Keyword(s):  
Room Temperature ◽  
Quantitative Measurement ◽  
Silver Oxide ◽  
Catalytic Properties ◽  
Metallic Surface ◽  
Metallic Silver ◽  
Mercury Vapour ◽  
Platinum Surface ◽  
Gaseous Oxygen ◽  
Low Pressures

Research on the catalysis by metals of the combination of hydrogen and oxygen at low pressures was commenced in these laboratories by Cooper in 1923. Investigating the catalytic properties of a short platinum filament subjected to various pre-treatments by heating it electrically in hydrogen or oxygen or in vacuo , he found that the metallic surface thus cleaned became so active at room temperature as to render the quantitative measurement of the catalysed reaction impossible. It was discovered also that mercury vapour is a very potent poison of the surface, the enormously active clean platinum surface being rendered completely inactive by exposure to mercury vapour for a few minutes: a fact noted but apparently insufficiently emphasized in a paper published by Chapman and Hall in 1929. Owing to the difficulties involved in wording with a catalyst of such high activity, the research was discontinued in favour of an investigation of the same reaction using silver instead of platinum, a clean surface of this metal having been found to catalyse the reaction at a convenient rate at room temperature. The following facts were established:— (1) At the temperature of the laboratory a surface of metallic silver adsorbs completely a quantity of gaseous oxygen sufficient to form a complete unimolecular layer of silver oxide. This adsorbed oxygen cannot, of course, be removed by evacuation.

scholarly journals Effect of Chloride Ions on the Point-of-Use Drinking Water Disinfection Performance of Porous Ceramic Media Embedded with Metallic Silver and Copper

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1625
Author(s):  
Rekha Singh ◽  
Woohang Kim ◽  
James A. Smith
Keyword(s):  
Drinking Water ◽  
Porous Ceramic ◽  
Chloride Ion ◽  
Silver Ions ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Metallic Silver ◽  
E Coli ◽  
Ion Concentrations ◽  
Copper Release

This study quantifies the effects of chloride ions on silver and copper release from porous ceramic cubes embedded with silver and copper and its effect on E. coli disinfection in drinking water. Log-reduction of E. coli by silver ions decreased after 4 h of contact time as the chloride ion concentration increased from 0 to 250 mg/L but, it was not changed by copper ions under the same conditions. For silver addition by silver-ceramic cubes, log reductions of E. coli decreased sharply from 7.2 to 1.6 after 12 h as the chloride concentration increased from 0 to 250 mg/L. For the silver-ceramic cube experiments, chloride ion also reduced the total silver concentration in solution. After 24 h, total silver concentrations in solution decreased from 61 µg/L to 20 µg/L for corresponding chloride ion concentrations. According to the MINTEQ equilibrium model analysis, the decrease in disinfection ability with silver embedded ceramic cubes could be the result of precipitation of silver ions as silver chloride. This suggests that AgCl was precipitating within the pore space of the ceramic. These results indicate that, although ionic silver is a highly effective disinfectant for E. coli, the presence of chloride ions can significantly reduce disinfection efficacy. For copper-ceramic cubes, log reductions of E. coli by copper embedded cubes increased from 1.2 to 1.5 when chloride ion concentration increased from 0 to 250 mg/L. Total copper concentrations in solution increased from 4 µg/L to 14 µg/L for corresponding chloride ion concentrations. These results point towards the synergistic effect of chloride ions on copper oxidation as an increased concentration of chloride enhances copper release.

scholarly journals HISTOCHEMICAL INVESTIGATIONS OF A SILVER METHOD FOR AXONS

1959 ◽  
Vol 7 (2) ◽  
pp. 86-92 ◽  
Author(s):  
R. K. WINKELMANN ◽  
ROBERT W. SCHMIT
Keyword(s):  
Silver Oxide ◽  
Dark Field ◽  
Reducing Agent ◽  
Water Soluble ◽  
Silver Ion ◽  
General Distribution ◽  
Amine Groups ◽  
Solubility Studies ◽  
Sulfite Ion

Silver ion is not specific either in location or in action in the present silver method. Studies with radioactive silver, with the dark-field microscope, and with simple reducing solutions demonstrate a general distribution of silver ion in the impregnated tissue. Copper and mercury may be substituted for silver in the impregnating solution. A water-soluble aldehyde is necessary as a fixative. The substrate for staining appears to require the presence of protein-bound amine groups. The product-forming solution does not require the presence of a reducing agent. Sulfite ion is not necessary. All controllable sources of base that were utilized produced the histologic results. The product appears to be silver oxide in terms of the present solubility studies.

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