Bis(2,3-dimethylbutenyl)sulfanes, the products of sulfane addition to 2,3-dimethyl-1,3-butadiene and of the reaction of sulfur with 2,3-dimethyl-2-butene.

Abstract

The reaction of sulfanes (H 2S n, n > 1) with 2,3-dimethyl-1,3-butadiene (DMBD) yields 3 sets of products; bis(2,3-dimethyl-2-buten-1-yl)sulfanes 1 as the main product, and two minor products (2,3-dimethyl-2-buten-1-yl) (2,3-dimcthyl-1-buten-4-yl)sulfanes 2 and (2,3-dimethyl-2-buten-1-yl)(2,3-dimethyl-1-buten-3-yl)sulfanes 3. The raction of sulfur with 2,3-dimethyl-2-butene (a low molecular weight model for unsaturated rubber), in the presence of zinc oxide and an accelerator yields also 1 as the major product and 3 as a minor product, but not product 2. The mechanisms of both reactions, i.e. addition in the first case and substitution in the second case, are discussed.