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Alkyl chloride‐boron trichloride initiated polymerizations of isobutylene: Detailed analysis of the initial propagation steps
Author(s) -
Mayr Herbert,
Roth Michael
Publication year - 1998
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19981320112
Subject(s) - isobutylene , boron trichloride , chloride , adduct , chemistry , hydrochloride , polymerization , polymer chemistry , degree of polymerization , alkyl , cationic polymerization , boron , medicinal chemistry , organic chemistry , polymer , copolymer
Living oligomerizations of isobutylene initiated either by cumyl chloride, the [1:1]‐adduct of cumyl chloride to isobutylene ( P ), the [1:2]‐adduct of cumyl chloride to isobutylene ( P2 ), diisobutylene hydrochloride ( P1 '), or triisobutylene hydrochloride ( P2 ') have been studied in presence of BCl 3 and benzyltriethylammonium tetrachloroborate. In contrast to common opinion, the gross propagation rates of the various telechelics depended significantly on the degree of polymerization with k rel = 0.07, 1.8, 2.3, 1.3, 1.1, 1.0, 1.0 for Ph‐C(CH 3 ) 2 ‐[CH 2 ‐C(CH 3 ) 2 ] n ‐Cl with n = 1, 2, 3, 4, 5, 6, 7, respectively. These results are compared with the initiation efficiencies of (CH 3 ) 3 C‐(CH 2 ‐C(CH 3 ) 2 ] n ‐Cl ( K rel = 0.3 and 0.8 for n = 1 and 2, respectively). The consequences for the synthesis of telechelics with very narrow molecular weight distribution are discussed.