Determination of Sulfur in Rubber. Use of Tetrahydroxyquinone as a Titration Indicator

Abstract

The determination of sulfur in rubber by the precipitation of oxidized sulfur as sulfate by means of barium chloride and the back-titration of the excess barium has been shown to be as accurate as the gravimetric procedure in solutions of the characteristics described above, for the determination of sulfur, with the use of tetrahydroxyquinone as the indicator. The method is very rapid compared to the gravimetric procedure and after oxidation to the sulfate form in solution, a determination can be made on a single sample in 20 to 30 minutes; with groups of analyses this time can be greatly reduced when compared to the time required for a single analysis.

Microdetermination of Sulfate Obtained from Combustion of Organic Compounds

“…Recent studies (6,(8)(9)(10)(11)18) on the use of tetrahydroxyquinone as an indicator in the direct titration of the sulfate ion led the authors to study its use in a micromethod for the direct titration of sulfur as sulfate, following burning of the sulfur-containing compound in oxygen in the regular manner. Sheen and Kahler (10) used 0.025 N barium chloride, but this is too high a concentration for microwork.…”

Direct Titration Method for Determination of Barium

“…A considerable amount of experimental work on the direct titration of sulfate with standard barium chloride has been carried out (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Schroeder (6) first proposed direct titration for the determination of sulfate using tetrahydroxyquinone as an internal indicator.…”