Tetraphenylphosphonium Allyldithiocarbimates: A Novel Safe Amine Class of Morita–Baylis–Hillman-Derived NBR Vulcanization Accelerators

Eliminating N-nitrosamines from rubber products, which are introduced by common vulcanization accelerators, is a significant challenge faced by the industry. The class of tetraphenylphosphonium allyldithiocarbimate salts offers a green and operationally simple alternative to traditional accelerators. This study describes the synthesis of four novel compounds and their application as accelerators for nitrile-butadiene rubber (NBR) vulcanization. The compounds were synthesized from easily accessible Morita–Baylis–Hillman acetates and potassium dithiocarbimate salts using acetone:water (1:1, v:v) as the solvent, which produced a precipitate that was washable with water. Compared to vulcanizates with tetramethyl thiuram disulfide (TMTD), those with the allyldithiocarbimate compounds showed longer t90 times, faster ts1 times, comparable tensile strength, and better tear resistance, indicating that these compounds can be a viable alternative for producing good-quality rubber artifacts.