SYNTHESIS AND INITIATION TRANSFER PROPERTIES OF CARBAMOYL DISULFIDES

Three model tetraalkylcarbamoyl disulfides were prepared and their ini tiation/transfer capabilities tested. The compounds studied were: bis( 1-piperidinecarbonyl) disulfide (1), bis(4-(2-hydroxyethyl)piperazine- 1-carbonyl) disulfide (2), bis[N-ethyl-N-(2-(trimethylsiloxyethyl)carb amoyl] disulfide (3). It was found that, in contrast to tetraalkylthiu ram disulfides, the carbamoyl disulfides were not able to initiate fre e radical polymerization of methyl methacrylate (MMA) and styrene (ST) , even at the highest temperatures applicable to these monomers. Appar ently the central S-S bond in carbamoyl disulfides is much stronger th an the corresponding S-S bond in thiuram disulfides. Moreover, the car bamoyl disulfides are rather poor transfer agents. The transfer consta nts were estimated to be 2,5 . 10(-3), 18 . 10(-3) and 2,8 . 10(-3) fo r 1, 2 and 3 in thermal polymerization of MMA at 110, 110 and 100-degr ees-C, respectively, and 2,1 . 10(-3) for 3 in polymerization of MMA i nitiated with AIBN at 70-degrees-C. Chemistry aspects of synthesis and stability of hydroxy-functionalized carbamoyl disulfides are discusse d.