4.1 Sulfenamides can degrade in chemical purity and functional performance, usually characterized by a drop in assay, a release of free amine, and an increase in insolubles. This test method may be used as an indication of such degradation.

4.2 Since MBTS (mercaptobenzothiazole disulfide) is a primary degradation product of sulfenamides, the determination of MBTS is a means of assessing possible degradation of sulfenamides. Insolubles are a means of mercaptobenzothiazyl disulfide (MBTS) content of the sulfenamide; MBTS is a primary degradation product of sulfenamides. Amine salts of mercaptobenzothiazole (MBT) may also be insoluble. However, certain soluble species may also be generated during sulfenamide degradation. Consequently, insolubles are not an absolute measure of purity and can actually decrease with sulfenamide degradation.

1.1 This test method covers a general procedure for the determination of insoluble impurities of sulfenamides in suitable organic solvents.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.