Determination of Sulfur by Wet Combustion with Perchloric Acid

1956 ◽  
Vol 29 (3) ◽  
pp. 1107-1116 ◽  
Author(s):  
Per Olof Bethge
Keyword(s):  
Hydrogen Sulfide ◽  
Organic Compounds ◽  
Conventional Method ◽  
Perchloric Acid ◽  
Sample Weights ◽  
Combustion Technique ◽  
Cent Sample

Abstract Difficulties in the determination of sulfur in wood and pulp samples by the conventional method of Grote and Krekeler have been overcome by applying a wet combustion technique, using perchloric and nitric acids. The sulfur is reduced to hydrogen sulfide by boiling with a reduction mixture, and determined iodometrically. The method gives quantitative yields for pure organic compounds, and is suitable for a great variety of samples with sulfur contents from 0.01 to 100 per cent. Sample weights can be varied from 9 mg. to 5 grams.

Sealed-Tube Combustion Technique for Determination of Deuterium in Organic Compounds

1956 ◽  
Vol 28 (4) ◽  
pp. 530-531 ◽  
Author(s):  
N. R. Trenner ◽  
B. H. Arisen ◽  
R. W. Walker
Keyword(s):  
Organic Compounds ◽  
Combustion Technique

The Determination of Free Sulfur in Soft Vulcanized Rubber by a Volumetric Method

1932 ◽  
Vol 5 (3) ◽  
pp. 360-362 ◽  
Author(s):  
W. D. Guppy
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfuric Acid ◽  
Organic Compounds ◽  
Subsequent Oxidation ◽  
Vulcanized Rubber ◽  
Elementary State ◽  
Previously Treated ◽  
Mineral Sulfides ◽  
Free Sulfur

Abstract The methods so far proposed for the determination of the free sulfur in vulcanized rubber depend upon the removal of the sulfur by extraction of the rubber with hot acetone, and subsequent oxidation to sulfuric acid of the sulfur in the extract. The extract is liable however to contain, in addition to sulfur in the elementary state, organic compounds containing sulfur derived from the rubber resins, accelerator, or antioxidant. In the subsequent oxidation this sulfur will be oxidized to sulfuric acid to an extent which depends on the method of oxidation used. In the present work, a method of analysis has been developed which is more rapid than the existing methods, and in which it is considered that the determination of the sulfur present in the elementary state is less likely to be affected by organic compounds containing sulfur. It has been found that when vulcanized rubber placed in contact with a metal, such as tin or aluminum, is boiled in hydrochloric acid, hydrogen sulfide is generated by the action of the nascent hydrogen produced. This reaction occurred with rubber which had been previously treated with acid alone to decompose metallic sulfides, but no hydrogen sulfide was obtained from rubber which had been previously extracted with acetone and was free from metallic sulfides. As these results showed that the reactions were not due to the presence of mineral sulfides, or of sulfur combined with the rubber, it was concluded that the hydrogen sulfide was formed by the reduction of the free sulfur.

The Determination of Free Sulfur by a Volumetric Method Part II

1933 ◽  
Vol 6 (4) ◽  
pp. 512-517
Author(s):  
W. D. Guppy
Keyword(s):  
Hydrogen Sulfide ◽  
Organic Compounds ◽  
Sulfur Compounds ◽  
Acetone Extract ◽  
Volumetric Method ◽  
Organic Sulfur Compounds ◽  
Vulcanized Rubber ◽  
Volumetric Determination ◽  
Free Sulfur

Abstract 1. The method previously described for the volumetric determination of free sulfur in vulcanized rubber has been compared with the older gravimetric methods in cases where other organic compounds containing sulfur are present in the vulcanizate. 2. The volumetric method gave lower results than the methods involving oxidation of the acetone extract in the case of vulcanized rubber containing aldehydeamine condensation products of thiouram disulfide compounds. This indicated that the sulfur combined with some organic compounds was not reduced by the reagents used. 3. The results with the accelerator tetraethylthiouram disulfide showed that in some cases part of the sulfur in organic compounds was reduced under the conditions of the reaction. 4. The acetone-soluble and the acetone-insoluble portions of brown substitute contain organic sulfur compounds. Part of the sulfur in these compounds was reduced to hydrogen sulfide by the action of nascent hydrogen. 5. The sulfur compounds present in white substitute were stable toward the reducing agents used in the estimation of free sulfur. 6. The sulfur compounds formed by the vulcanization of ebonite were in part reduced to hydrogen sulfide with tin and acid. Variations in the composition of the mixing and in the vulcanizing conditions altered the amount of these reducible compounds. 7. The volumetric method previously described cannot be used for the determination of the free sulfur in ebonite, brown substitute or in vulcanized rubber containing brown substitute. In the case of vulcanized rubber containing brown substitute or of ebonite the method can be used to determine the amount of sulfur in the acetone extract. 8. The volumetric method can be employed for the determination of the free sulfur in soft vulcanized rubber containing white substitute and in reclaimed rubber.

Sign in / Sign up

Export Citation Format

Share Document