Atom transfer radical polymerization through N-chlorosulfonamides

Controlled polymerizations of vinyl monomers such as methyl methacrylate and styrene are achieved using N-chloro,N-propyl-p-toluenesulfonamide (NCPT) together with a cuprous bromide/hexahexyl triethylenetetramine (CuBr/H-TETA) complex. Although N-halosulfonamides are known to decompose radically to give free chlorine, NCPT alone (without a cuprous complex) does not initiate any polymerization even in prolonged reaction times. Instead these add to the double bonds to give 2-chloroethylsulfonamides. In the present polymerization system a good chlorine donator (NCPT) is combined with an organic soluble complex (CuBr/H-TETA) to perform atom transfer radical polymerizations (ATRPs) in homogenous conditions. The linear proportionality of the molecular weights to the conversions and straight lines observed in ln(M₀/M) (where M₀ and M are the monomer contents at the beginning and at any time, respectively) versus time plots indicate typical controlled polymerization characteristics. The use of freshly prepared NCPT is advisable due to its slow and spontaneous decomposition when standing at room temperatures. Because of their easy preparation, N-chlorosulfonamides can be used and are preferred instead of special halogen compounds commonly used in copper mediated ATRP.