Catalytic and Induced Reactions in Microchemistry

Kolthoff, I. M.; Livingston, Robert S.

doi:10.1021/ac50096a003

Cited by 15 publications

(4 citation statements)

References 24 publications

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“…For a simple discussion of induced reactions, see Bray(5) orKolthoff and Livingston(8) 8. This conclusion is in interesting agreement with the results of Lipmann (18) on the corresponding system containing ferric ion and pyruvic acid.…”

supporting

confidence: 78%

The Photochemical Oxidation of Oxalic Acid Sensitized by Ferric Ion.

Livingston¹

1940

J. Phys. Chem.

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It has been shown by Allmand and Webb (2) that the photochemical oxidation of oxalic acid by ferric ion, 2Fe+++ + C2O4--= 2Fe++ + 2CO¡> requires approximately two quanta for each molecule of oxalic acid oxidized. It was also shown qualitatively by the same authors2 that carbon SUMMARY 1. The results of Allmand and Webb (2) and of Allmand and Young (3) on the photolysis of ferric oxalate by monochromatic light at room temperature have been confirmed quantitatively.2. The corresponding iron-sensitized oxidation has been shown to have a quantum yield of approximately unity, twice as great as the yield of the photolysis.3. These results have been checked by an independent experimental method.4. It has been shown that the absorption of red light by the system does not induce the reaction.5. A series of semi-quantitative experiments, performed in the dark, has demonstrated that the thermal oxidation of ferrous ion by oxygen does not induce the oxidation of oxalate ion.6. A brief discussion of the more probable mechanisms is included.In conclusion I should like to express my thanks to Mr. William Horowitz and Mr. George Rashka, who performed the majority of the experiments reported here, and to Dr. Foster Riecke for his kindness in reading and criticising the manuscript.

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confidence: 78%

The Photochemical Oxidation of Oxalic Acid Sensitized by Ferric Ion.

Livingston¹

1940

J. Phys. Chem.

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“…The analytical utility of kinetics has been recognized for some time in inorganic analytical chemistry, and micro-chemical applications have been discussed in detail (6,9,24). Catalytic activity has found considerable qualitative application, allowing the detection of minute quantities of various elements.…”

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confidence: 99%

Chemical Analysis by Measurement of Reaction Rate. Determination of Acetylacetone

Blaedel¹,

Petitjean²

1958

Anal. Chem.

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“…cells, while known for many years, and these reactions have found a place in the analytical chemistry of several elements, including manganese (17) and cerium (21). Kolthoff and Livingston (13) proposed that catalysis of the persulfate oxidation of manganous ion to permanganate be used for the detection of silver. The present study w'as undertaken to examine its applicability to the determination of very small quantities of silver.…”

mentioning

confidence: 99%

“…Persulfate oxidations of this type have been extensively studied from the standpoint of kinetics (1,3,4,11,13,23,24), and a mechanism seems fairly well established involving oxidation of silver to a higher valence by persulfate, follow-ed by oxidation of manganous ion to permanganate w'ith return of the silver to its normal valence. Despite these previous reports, it was found necessary in the present study to seek optimal conditions empiri- Because of the growing importance of trace methods of analysis and the need, in particular, for procedures for carrier-free preparations containing only millimicrogram amounts of silver, a quantitative method has been developed using the catalytic action of silver on the persulfate oxidation of manganous ion to permanganate.…”

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Catalytic Determination of Submicrogram Quantities of Silver

Underwood¹,

Burrill²,

Rogers³

1952

Anal. Chem.

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against a solution of the bleached reagent. The point of maximum absorption was found to be 525 mp.While cells with either 20or 50-mm. light paths can be used, it was found that the 50-mm. cells greatly increased the sensitivity of the method and produced a much more readable curve. The curve is essentially linear from 0 to 100 micrograms of fluoride per 50 ml. of sample when per cent transmittancy is plotted against concentration on semilog paper. This is illustrated in Figure 2. Curve 1 was obtained using the 50-mm. cells, while curve 2 was obtained using the same reagent but with 20-mm. cells. Curve 1 is a typical example of the numerous standardization curves which have been run during the past year using this method.The standardization curves are slightly shifted because of variations in developing time, temperature during development, and slight variations in reagent concentration. The effect of the development time on the color intensity is shown in Figure 3. The four curves shown are of different fluoride ion concentrations. From these data i t is evident that in the first 90 minutes of color development there is a rather rapid change in the color intensity. Bfter 120 minutes the rate of change is much lower. The 2-hour development time was chosen for this reason. Because of the many factors affecting the rate of color development, it has become standard procedure in this laboratory to run a series of standards with each group of fluoride ion determinations.Some workers (7, 10) using the zirconium-alizarin method have recommended that, after the addition of the reagent, the samples be heated to boiling on a hot plate. This procedure was investigated and it was found that after heating, 3 to 4 hours were required for the color to reach the same intensity as could be obtained in 2 hours without heating.This method does not overcome the well-known interferences of phosphate, sulfate, and chloride ions. Consequently, samples suspected of containing interfering amounts of these ions must be distilled to isolate the fluoride ion. Careful attention must be paid to the cleanliness of the glassware, as many present-day detergents contain phosphates or polyphosphates to which the zirconium-alizarin reagent is sensitive. 1597When it becomes necessary to analyze routinely samples containing more fluoride ion than can be handled conveniently by the method, the reagent is modified in the follotying manner: Composition of Modified Reagent Zirconium oxychloride Alizarin sodium sulfonate Sulfuric acid (concd.) 40 ml. Hydrochloric acid (concd.) 120 ml. 0.70 0.60 gram gram Diluted t o 1000 ml. with distilled waterThis reagent is prepared in the same manner as the initial reagent. Standards having a volume of 50 ml. and containing from 0 to 200 micrograms of fluoride ion and one containing 500 micrograms of fluoride ion are repared. To the 50-ml. aliquots of the samples and to the stancfards are added 5 ml. of the modified zirconium-alizarin reagent which has been diluted 1 to 1 with distilled water. The colors are allowed t...

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Catalytic and Induced Reactions in Microchemistry

Abstract: ALTHOUGH catalytic andinduced reactions are widely used in the detection and quantitative estimation of certain ions or compounds, not much theoretical work has been done on the mechanism of most of these reactions. It is rather deplorable

Cited by 15 publications

References 24 publications

The Photochemical Oxidation of Oxalic Acid Sensitized by Ferric Ion.

The Photochemical Oxidation of Oxalic Acid Sensitized by Ferric Ion.

Chemical Analysis by Measurement of Reaction Rate. Determination of Acetylacetone

Catalytic Determination of Submicrogram Quantities of Silver

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