Ring-opening Cationic Copolymerization of Liquid SO<SUB>2</SUB> with Cyclohexene Oxide

Sulfur-containing polymers derived from SO2: synthesis, properties, and applications

“…Based on the gas–liquid partition chromatographic analysis results of the copolymers hydrolyzed with NaOH, Schafer proposed that monomer distribution in the copolymers obeyed or disobeyed the Markovian statistics depending on the nature of a given catalyst. 128 Similar results were provided by Matsuda et al 134 who investigated the copolymerization of cyclohexene oxide (CHO) and SO 2 mediated by similar catalysts, such as SnCl 4 , FeCl 3 , SbCl 5 , and TiCl 4 . The resultant copolymers consisted of only around 20 mol% sulfite linkages, suggesting the lower reactivity of SO 2 compared with epoxides.…”

On the Ionic Species Formed in Reactions of Sulfur Dioxide with Cyclic Ethers and Propylene Sulfide

“…It is known that some oxiranes, e.g. PO or CHO, undergo cationic copolymerization with SO 2 in the presence of Lewis acids 1,6,7 forming poly(ether sulfites) of an average molecular weight M n 1500-2000. They contain oxirane homosequences composed of 1-12 m.u.…”

“…The ionic copolymerization of SO 2 has not been hitherto systematically studied. There are only scarce reports on the copolymerization of SO 2 with certain oxiranes in the presence of an initiator characterized by nucleophilic or electrophilic properties, but in a majority of systems the reaction mechanism has not been explained. − The SO 2 copolymerization with ethylene oxide (EO) initiated by strong organic Lewis bases 8,10−12 such as amines, phosphines, alkyl sulfides, or salts of various inorganic or organic acids is relatively best known.…”

Copolymerization Involving Sulfur-Containing Monomers

“…Also, the copolymerization of SO 2 with EO is achievable in the absence of a catalyst wherein one electron donor (epoxide) and one electron acceptor (strongly electrophilic S atom in SO 2 ) are involved (Scheme b). , The copolymerization of SO 2 with various epoxides was achieved with a high-polyether-sequence content, of which the highest SO 2 insertion content attained 31.5% when EO was employed. The steric hindrance of the substituents of the epoxide has a significant influence on the SO 2 insertion . The nucleophilicity of the epoxide, which is determined by both the steric and inductive effects of the substituent, significantly affects the alternating degree of the copolymerization .…”

“…The steric hindrance of the substituents of the epoxide has a significant influence on the SO 2 insertion. 234 The nucleophilicity of the epoxide, which is determined by both the steric and inductive effects of the substituent, significantly affects the alternating degree of the copolymerization. 236 This phenomenon likely accounts for the differences observed in the SO 2 insertion during copolymerization with various epoxides.…”