STABILIZATION OF COPPER(I) WITH ORGANIC LIGANDS FOR TRACE LEVEL ANALYSIS IN AQUEOUS SOLUTIONS (KINETICS, CORROSION, CYANIDE, DETERMINATION).

Persistent Link:
http://hdl.handle.net/10150/187866
Title:
STABILIZATION OF COPPER(I) WITH ORGANIC LIGANDS FOR TRACE LEVEL ANALYSIS IN AQUEOUS SOLUTIONS (KINETICS, CORROSION, CYANIDE, DETERMINATION).
Author:
SCOTT, NELSON.
Issue Date:
1984
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The dissolution of copper metal in the presence of copper(II) ions and allyl alcohol in aqueous solution is found to be pseudo-first order with respect to both copper(II) ions and allyl alcohol. The reaction is inhibited by acid. The rate determining step is not the formation of copper(I) but the transfer of electrons from the surface of copper metal to the copper(II) ions in solution. The reaction rate has been monitored spectrophotometrically by complexing the copper(I) formed with 2,9-dimethylphenanthroline (neocuproin) and measuring the absorbance of the solution at the wavelength of maximum absorption of the complex, 450 nm. Other factors that affect the reaction are the presence of anions, the solvent composition, the nature of the unsaturated ligand used to stabilize the copper(I) and the rate of stirring. The reduction of copper(II)-neocuproin by allylamine and allyl alcohol has been studied in basic solution. A method has been developed for the rapid, sensitive determination of CN⁻ based on a spectrophotometric technique using copper(I)-neocuproin as a reagent. SCN⁻ does not interfere but S²⁻ appears to be a very powerful source of interference. By appropriate choice of the concentration of copper(I)-neocuproin reagent the range of response can be adjusted to be in the range 1-10 ppm. The theoretical detection limit of the method is as low as 19 ppb at the 95% confidence limit and the precision, measured as the relative standard deviation, is better than 1.5%. The disturbance of the equilibrium between the bis ligand and mono ligand complexes of copper(I) appears to be the reason for the observed decrease in absorbance on the addition of cyanide to a solution of copper(II)-neocuproin. The problems associated with using the commercially available ion selective electrode for cupric determination have been highlighted. The possibility of developing a PVC matrix membrane electrode for the determination of CN⁻ has been explored. The main difficulty is the instability of the copper(I)-neocuproin complex at pH values as high as 11 that are required to stabilize CN⁻.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Copper -- Reactivity.; Copper -- Analysis.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Fernando, Quintus

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleSTABILIZATION OF COPPER(I) WITH ORGANIC LIGANDS FOR TRACE LEVEL ANALYSIS IN AQUEOUS SOLUTIONS (KINETICS, CORROSION, CYANIDE, DETERMINATION).en_US
dc.creatorSCOTT, NELSON.en_US
dc.contributor.authorSCOTT, NELSON.en_US
dc.date.issued1984en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe dissolution of copper metal in the presence of copper(II) ions and allyl alcohol in aqueous solution is found to be pseudo-first order with respect to both copper(II) ions and allyl alcohol. The reaction is inhibited by acid. The rate determining step is not the formation of copper(I) but the transfer of electrons from the surface of copper metal to the copper(II) ions in solution. The reaction rate has been monitored spectrophotometrically by complexing the copper(I) formed with 2,9-dimethylphenanthroline (neocuproin) and measuring the absorbance of the solution at the wavelength of maximum absorption of the complex, 450 nm. Other factors that affect the reaction are the presence of anions, the solvent composition, the nature of the unsaturated ligand used to stabilize the copper(I) and the rate of stirring. The reduction of copper(II)-neocuproin by allylamine and allyl alcohol has been studied in basic solution. A method has been developed for the rapid, sensitive determination of CN⁻ based on a spectrophotometric technique using copper(I)-neocuproin as a reagent. SCN⁻ does not interfere but S²⁻ appears to be a very powerful source of interference. By appropriate choice of the concentration of copper(I)-neocuproin reagent the range of response can be adjusted to be in the range 1-10 ppm. The theoretical detection limit of the method is as low as 19 ppb at the 95% confidence limit and the precision, measured as the relative standard deviation, is better than 1.5%. The disturbance of the equilibrium between the bis ligand and mono ligand complexes of copper(I) appears to be the reason for the observed decrease in absorbance on the addition of cyanide to a solution of copper(II)-neocuproin. The problems associated with using the commercially available ion selective electrode for cupric determination have been highlighted. The possibility of developing a PVC matrix membrane electrode for the determination of CN⁻ has been explored. The main difficulty is the instability of the copper(I)-neocuproin complex at pH values as high as 11 that are required to stabilize CN⁻.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectCopper -- Reactivity.en_US
dc.subjectCopper -- Analysis.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorFernando, Quintusen_US
dc.identifier.proquest8504759en_US
dc.identifier.oclc693584798en_US
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