Process for preparing storage-stable benzothiazolyl sulfenamides
OwnerStefan Grabowski, Leon Felix +3inventors
InventorsStefan Grabowski, Leon Felix, Domien Sluyts, Patrick Missiaen, Reinhard Preuss
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Abstract
The present invention provides a process for preparing benzothiazolyl sulfenamides by reacting primary amines with alkali metal salts of mercaptobenzthiazole in the presence of hydrogen peroxide and alkali metal hypochlorite. The process according to the present invention is characterized by high rates of conversion, wherein the benzothiazolyl sulfenamides obtained are obtained with high purity, in high yields and with high storage-stability, even at elevated temperatures and high humidity.
Claims8
A process for preparing benzothiazolyl sulfenamides comprising:
- reacting an aqueous solution of a metal salt of mercaptobenzthiazole with a primary amine(s) in the presence of ≦90 mol. % of hydrogen peroxide, with respect to the alkali metal salt of the mercaptobenzthiazole used, at a pH in the range 10.0 to 11.0,
- wherein the amount of hydrogen peroxide is added over a period of ≧2 hours,
- adding, within a period of ≧10 minutes, an alkali metal hypochlorite increasing the pH of the reaction mixture to 11.5 to 12,
- wherein the amount of primary amine used is 100 to 500 mol. % and the sum of the hydrogen peroxide used and alkali metal hypochlorite used is ≦130 mol. %, with respect to the amount of alkali metal salt of the mercaptobenzthiazole.
A process according to claim, wherein the pH is increased to range 11.6 to 11.8.
Dependencies are inferred from the claim text.