Journal of Molecular Catalysis A: Chemical 172 (2001) 165–173 Reaction of N-alkyl-2-benzothiazolesulphenamide with acetic anhydride in the presence of acids I. Technological aspects Magdaléna Štolcová ∗ , Alexander Kaszonyi, Milan Hronec Department of Organic Technology, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava 1, Slovak Republic Received 15 November 2000; accepted 5 March 2001 Abstract The reaction of N-alkyl-2-benzothiazolesulphenamide with acetic anhydride in a non-polar solvent and in the presence of carboxylic or mineral acids at temperatures of 50–90 ◦ C has been studied. At low initial concentration of an acid or in its absence a typical autocatalytic behavior of the reaction is observed. However, at higher concentration of acetic acid (>3 mol dm -3 ), phosphoric or sulphuric acid (>0.2 mol dm -3 ) the autocatalytic course of the reaction disappeared and higher rate of an N-alkyl-2-benzothiazolesulphenamide conversion was observed. The molar ratio of formation of the desired prod- uct, alkylbis(2-benzothiazolylsulphen)amide, to the main by-product, alkylamide of acetic acid, is up to 1.6 in the acid catalyzed reaction. The type of alkyl derivatives of 2-benzothiazolesulphenamide has a strong effect on the rate of formation of the corresponding alkylbis(2-benzothiazolylsulphen)amide. The yield of alkylbis(2-benzothiazolylsulphen)amides varies between 80–20 mol% at total conversion of the corresponding sulphenamides in the following order: IPbisBS > CHbisBS > TBbisBS > TAbisBS. © 2001 Elsevier Science B.V. All rights reserved. Keywords: N-alkyl-2-benzothiazolesulphenamides; alkylbis(2-benzothiazolylsulphen)amide; Acetic anhydride; Acid catalysis 1. Introduction Benzothiazolesulphenamides belong to the class of compounds widely used in the rubber industry as cross-linking agents. Specific properties of these materials have stimulated scientists to study these derivatives in various reactions with potential appli- cation in agriculture, pharmacy, as protecting groups in syntheses and in other applications [1,2]. The reaction of N-alkyl-2-benzothiazolesulphen- amides (alkylBS) with anhydrides of carboxylic acids leads to the formation of corresponding alkylbis(2-ben ∗ Corresponding author. Fax: +421-7-52493198. E-mail address: stolcova@chtf.stuba.sk (M. Štolcov´ a). zothiazolylsulphen)amides (alkylbisBS) [3,4]. In the literature is described the use of two types of anhy- drides of carboxylic acids. Conly [3] used anhydrides of monocarboxylic acids, e.g. acetic, propionic, buty- ric acid in the presence or absence of a solvent at 25–75 ◦ C (Eq. (1)): (1) 1381-1169/01/$ – see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S1381-1169(01)00141-8