Étude cinétique de la N-chloration de la diméthylamine et de la diéthylamine en phase aqueuse

1989 ◽  
Vol 67 (5) ◽  
pp. 786-791 ◽  
Author(s):  
Denise Matte ◽  
Bernard Solastiouk ◽  
André Merlin ◽  
Xavier Deglise
Keyword(s):  
Kinetic Study ◽  
Aqueous Medium ◽  
Acid Medium ◽  
Spectrophotometric Method ◽  
Hypochlorous Acid ◽  
Chloride Ions ◽  
Proton Exchange ◽  
Basic Medium ◽  
Protonated Amine ◽  
Phase Aqueuse

A complete kinetic study of the N-chlorination, in aqueous medium, of dimethylamine and diethylamine by a stopflow spectrophotometric method is presented. In neutral or basic medium our experimental results can be interpreted by two kinetically indistinguishable mechanisms; the reactions between protonated amine (R2NH2+) and hypochlorite ion (ClO−) and the reaction between R2NH and hypochlorous acid (ClOH) are equivalent because of the fast equilibrium of proton exchange existing between the two groups of possible reactants [Formula: see text]. In acid medium, in the presence of chloride ions, we observed a reaction by aqueous chlorine (Cl2) on the amine (Cl2 + R2NH → chloramine).Keywords: kinetics, N-chlorination, amines, aqueous medium.

Kinetic Study of the Oxidation of Glycine by Permanganate Ions in Acid Medium

1996 ◽  
Vol 61 (2) ◽  
pp. 232-241 ◽  
Author(s):  
Maria J. Insausti ◽  
Fernando Mata-Pérez ◽  
Maria P. Alvarez-Macho
Keyword(s):  
Kinetic Study ◽  
Acid Medium ◽  
Spectrophotometric Method ◽  
Inflection Point ◽  
Autocatalytic Reaction ◽  
Soluble Form ◽  
Kinetic Curves

The oxidation of glycine by permanganate ions was studied in a buffered solution at pH 2.2. An autocatalytic reaction was observed, autocatalyzed by a soluble form of Mn(IV). Autocatalytic S-shaped kinetic curves were obtained by the spectrophotometric method and characterized by the time ti vs concentration in the inflection point.

Étude cinétique de la N-chloration de la succinimide en phase aqueuse

1992 ◽  
Vol 70 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Denise Matte ◽  
Bernard Solastiouk ◽  
André Merlin ◽  
Xavier Deglise
Keyword(s):  
Aqueous Medium ◽  
Rate Constants ◽  
Low Ph ◽  
Chloride Ions ◽  
Nucleophilic Attack ◽  
Stopped Flow ◽  
Molecular Chlorine ◽  
Kinetics Of ◽  
Limiting Values ◽  
Phase Aqueuse

A kinetic study of the N-chlorination, in aqueous medium, of succinimide (SH) at low pH (<5) and at high pH (>9) is presented. We have derived the rate constants and activation energies of the processes involved. A stopped-flow spectrophotometric technique was used to study the kinetics. Without chloride ions, our experimental results can be interpreted by two kinetically indistinguishable mechanisms:[Formula: see text]The limiting values of the rate constants for the case in which only one process is involved in the kinetics of chlorination were evaluated: [Formula: see text]; [Formula: see text].In acid medium, in the presence of chloride ions, we observe a nucleophilic attack of the S− ion on molecular chlorine Cl2. This process is added to the two former processes. Keywords: kinetics, N-chlorination, succinimide, aqueous medium, stopped flow.

Collaborative Study of the Spectrophotometric Determination of Procainamide Hydrochloride

1976 ◽  
Vol 59 (4) ◽  
pp. 807-810
Author(s):  
Jeffrey C Hamm
Keyword(s):  
Sodium Hydroxide ◽  
Acid Medium ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Dosage Forms ◽  
Standard Deviations

Abstract The USP analysis for procainamide HCl is titrimetric and relatively nonspecific, capsule and tablet dyes may interfere, and the method is not applicable to coated tablets. In the spectrophotofluorometric method the sample deteriorates when exposed to a xenon source. In the ultraviolet spectrophotometric method reported here, the sample is dispersed in acid medium, possible interferences are extracted in chloroform, base is added, procainamide is extracted in chloroform, the residue is dissolved in sodium hydroxide, and the compound is measured by absorption at 272 nm and comparison with a standard. Recoveries of standards added to capsule, tablet, and injection composites ranged from 99.3 to 102%. Twelve collaborators reported duplicate assay results for all 3 dosage forms with per cent standard deviations for 5 samples ranging from 1.01 to 1.27%. The method has been adopted as official first action.

An equilibrium and kinetic study of the methylene blue-ferrocyanide reaction in acid medium

1990 ◽  
Vol 94 (10) ◽  
pp. 4116-4119 ◽  
Author(s):  
John R. Sutter ◽  
Wynetta. Spencer
Keyword(s):  
Methylene Blue ◽  
Kinetic Study ◽  
Acid Medium

scholarly journals New Spectrophotometric Method for Determination of Cadmium

2009 ◽  
Vol 6 (s1) ◽  
pp. S496-S500
Author(s):  
K. S. Parikh ◽  
R. M. Patel ◽  
K. N. Patel
Keyword(s):  
Stability Constant ◽  
Spectrophotometric Method ◽  
Basic Medium ◽  
Buffer Solution ◽  
Solution Ph ◽  
Yellow Colour ◽  
Maximum Absorbance ◽  
The Stability

The reagent 2-hydroxy-4-n-butoxy-5-bromopropiophenone thiosemicarbazone (HBBrPT) has been used for the determination of Cd(II) by using spectrophotometric method. The reagent HBBrPT gave an intense yellow colour with Cd(II) solution in basic medium. The maximum absorbance was observed at 440 nm, in basic buffer solution (pH 10.00). The molor absorptivity and Sandell’s sensitivity of Cd(II)-HBBrPT complex were 4035 mol-1cm-1and 0.02765 μg cm-2respectively. The stability constant of 1:2 Cd(II)-HBBrPT complex was 8.46×106. The effect of various iron was also studied.

scholarly journals Spectrophotometric determination of phosphorus in coal and coal ash using bismuth-phosphomobybdate complex

2003 ◽  
Vol 68 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Randjel Mihajlovic ◽  
Natasa Ignjatovic ◽  
Marija Todorovic ◽  
Ivanka Holclajtner-Antunovic ◽  
Vesna Kaljevic
Keyword(s):  
Aqueous Solution ◽  
Ascorbic Acid ◽  
Acid Medium ◽  
Spectrophotometric Method ◽  
Methyl Ketone ◽  
Coal Ash ◽  
Molar Absorptivity ◽  
Stable Complex ◽  
Tolerance Limits

A modified spectrophotometric method using the bismuth phosphomolybdate complex for the determination of phosphorus in coal and coal ash is suggested. Bismuth together with phosphate and molybdate forms a very stable complex in acid medium which turns blue ("molibdenum blue") by reduction with ascorbic acid. The apparent molar absorptivity of PBiMo is 1.66x104 dm3 mol-1cm-1 at 720 nm and 2.10x104 dm3 mol-1cm-1 at 670 nm isobutyl methyl ketone (MIBK). Interference caused by the ions present are within the tolerance limits (?2 %). Beer?s law is obeyed in the for concentration range to 0.6 ?g/mL (aqueous solution) and to 1.2 ?g/mL P (MIBK). The sensitivity of the proposed method is 0.0078 ?g/mL (aqueous solution) and 0.0066 ?g/mL (MIBK).

Nonspecific Chlorination of Organics: a Chemistry Unique to Human Industry? (Putting Kraft Mill AOX Emissions into Perspective)

1998 ◽  
Vol 33 (3) ◽  
pp. 347-362
Author(s):  
Frederick Archibald ◽  
Loredana Valeanu ◽  
Gunther Leichtle ◽  
Benoit Guilbault
Keyword(s):  
Hypochlorous Acid ◽  
Higher Plants ◽  
Chloride Ions ◽  
Soil Extracts ◽  
Wide Range ◽  
Mammalian Blood ◽  
Kraft Mill ◽  
Natural Result ◽  
Living Organisms ◽  
Work Done

Abstract To counter the claim that all biotreated organochlorine (AOX) emissions from modern kraft mills are unnatural and inherently hazardous, it has been argued that over 2400 different AOX compounds are now known to be produced by living organisms. This is an invalid rationale. These 2400 natural compounds are mostly specific halometabolites — each is produced as a large number of identical molecules by a specific enzyme-mediated mechanism. In contrast, in a kraft mill bleachery, heterogeneous wood derivatives are non-specifically chlorinated by hypochlorous acid (HOCl) or hypochlorite ion (OCl-) to produce mixtures containing hundreds of different AOX species. It is therefore much more reasonable to compare mill-derived AOX to other human and natural sources of OCl-/HOCl-generated non-specific AOX. Chloroperoxidase (CPO)-type enzymes naturally produce HOCl and OCl-from common chloride ions and hydrogen peroxide (H2O2). They have now been demonstrated in bacteria, fungi, algae, lichens, higher plants and animals. We demonstrate that a common fungal CPO can, when applied to soil extracts, lignins, cellulosics, tannins and natural lake water organics, rapidly generate nonspecific AOX. In agreement with earlier work done in other geographic areas, AOX was found in all of a wide range of samples from the Montreal region, both from urban and relatively remote pristine lakes and woodlands. Much of it is almost certainly produced via nonspecific HOCl/OCl- chlorination. Finally, we demonstrate that nonspecific AOX is produced by a CPO in mammalian blood as the natural result of the body's immune system fighting infections. Thus, HOCl/OCl- based production of AOX from mixtures of organic molecules is seen to be a common occurrence in nature as well as a product of human technology.

scholarly journals Investigation of the extraction equilibrium of ion-association complexes of molybdenum (VI) with some polyphenols and thiazolyl blue. extraction-spectrophotometric determination of molybdenum

2005 ◽  
Vol 3 (4) ◽  
pp. 747-755 ◽  
Author(s):  
Atanas Dimitrov ◽  
Vania Lekova ◽  
Kiril Gavazov ◽  
Boyan Boyanov
Keyword(s):  
Organic Solvent ◽  
Aqueous Medium ◽  
Spectrophotometric Method ◽  
Ion Association ◽  
Extraction Process ◽  
Association Constants ◽  
Optimum Conditions ◽  
Extraction Equilibrium ◽  
Simple Extraction

AbstractThe extraction process of ternary ion-association complexes of molybdenum (VI) with some polyphenols (4-nitrocatechol, 2,3-dihydroxy naphthalene) and thiazolyl blue has been investigated by using an extraction-spectrophotometric method. The optimum conditions for their quantitative preparation in aqueous medium and subsequent extraction into an organic solvent have been found. The extraction, distribution and association constants, and the recovery factors have been calculated. The composition of the complexes has been determined. A precise, sensitive and simple extraction-spectrophotometric method for determination of molybdenum in products from ferrous metallurgy has been developed.

Sign in / Sign up

Export Citation Format

Share Document