Synthesis of Tosyl- and Nosyl-Ended Polyisobutylenes with High Extent of Functionalities: The Effect of Reaction Conditions

Abstract

Endfunctional polymers possess significant industrial and scientific importance. Sulfonyl endgroups, such as tosyl and nosyl endfunctionalities, due their ease of substitution are highly desired for a variety of polymer structures. The sulfonylation of hydroxyl-terminated polyisobutylene (PIB-OH), a chemically and thermally stable, biocompatible, fully saturated polymer, with tosyl chloride (TsCl) and nosyl chloride (NsCl) is presented in this study. PIB-OHs derived from commercial exo-olefin-ended PIB (PIBexo-OH) and allyl-terminated polymer made via quasiliving carbocationic polymerization of isobutylene (PIBall-OH) were tosylated and nosylated in the presence of 4-dimethylaminopyridine (DMAP), pyridine and 1-methylimidazole (1-MI) catalysts and triethylamine (TEA). Our systematic investigations revealed that the end product distribution strongly depends on the relative amount of the components, especially that of TEA. While PIBexo-OTs with quantitative endfunctionality is readily formed from PIBexo-OH, its nosylation is not as straightforward. During sulfonylation of PIBall-OH, the formed tosyl and nosyl endgroups are easily substituted with chloride ions, formed in the first step of sulfonylation, leading to chloride termini. We found that decreased amounts of TEA afford the synthesis of PIBall-OTs and PIBall-ONs with higher than 90% endfunctionalities. These sulfonyl-ended PIBs open new ways for utilizing PIB in various fields and in the synthesis of novel PIB-containing macromolecular architectures.

Polyisobutylenes with Controlled Molecular Weight and Chain-End Structure: Synthesis and Actual Applications

“…Polymers 2023, 15, x FOR PEER REVIEW Scheme 19. Synthesis of arenesulfonyl-ended PIBs derived from exo-olefin-ended and all nated polymers [153].…”

“…PIB exo OH was obtained in a similar way, using 9-borabicyclo[3.3.1]nonane (9-BBN) as a hydroboration reagent [ 153 ]. In addition, termination of quasiliving carbocationic polymerization of IB ( t BuCH 2 CMe 2 Cl/TiCl 4 /N,N,N′,N′-tetramethylethylenediamine) by Me 3 SiCH 2 CH=CH 2 , followed by hydroboration/oxidation afforded PIB all OH.…”

“…In addition, termination of quasiliving carbocationic polymerization of IB ( t BuCH 2 CMe 2 Cl/TiCl 4 /N,N,N′,N′-tetramethylethylenediamine) by Me 3 SiCH 2 CH=CH 2 , followed by hydroboration/oxidation afforded PIB all OH. PIB exo OH and PIB all OH was further converted into PIB-OSO 2 Ar (Ar = p -tolyl and 4-nitrophenyl, respectively) ( Scheme 19 ) [ 153 ]. A significant difference in the reactivity was found, i.e., PIB all OH reacted faster than PIB exo OH, presumably because of the steric reasons.…”

Synthesis of linear and star-shaped telechelic polyisobutylene by cationic polymerization

“…Thus, to achieve liquid PIB rubber, functionalized telechelic structure is the only possible method so far. 16–32…”

“…Thus, to achieve liquid PIB rubber, functionalized telechelic structure is the only possible method so far. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Kennedy is the rst researcher to report the synthesis of hydroxyl-terminated PIB liquid rubber. 33,34 Firstly, PIB with the end of tertiary chlorine was synthesized by using the difunctional initiator/BCl 3 as the initiator system.…”