CATIONIC POLYMERIZATION OF CYCLIC OLEFINS
CATIONIC POLYMERIZATION OF CYCLIC OLEFINS
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DOI：
10.1002/pol.1966.150040413
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发表时间：
1966-01-01
期刊：
影响因子：
--
通讯作者：
OKAMURA, S
中科院分区：
文献类型：
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作者：
MIZOTE, A;TANAKA, T;OKAMURA, S
从环应变、环稳定性和过渡态位阻的角度讨论了茚、苯并呋喃和1,2‐二氢萘的聚合和可聚合性。通过与苯乙烯的共聚反应和溴化碘在乙酸中的加成速率估计了这些烯烃的单体反应活性。将聚合速率和聚合度与茚、1,2‐二氢萘和苯并呋喃的单体反应性和共振能进行比较，以此作为环应变和稳定性的度量。结果表明，它的反应性是苯乙烯的1.5 ~ 2.0倍。这种高反应活性归因于单体状态下的环应变和共面五元环烯烃过渡状态下的低空间位阻。1,2‐二氢萘是应变的，因此具有反应性，但由于位阻阻碍了向高分子量产物的传播。反应部位C - <s:1> - C双键的共轭稳定降低了苯并呋喃的反应活性。
The polymerization and the polymerizabilities of indene, benzofuran, and 1,2‐dihydronaphthalene are discussed from the point of view of ring strain, ring stabilization, and steric hindrance in the transition state. Monomer reactivities of these olefins were estimated from copolymerization with styrene and from the rate of addition of iodine bromide in acetic acid. Rates and degrees of polymerization are compared with monomer reactivities and resonance energies of indene, 1,2‐dihydronaphthalene, and benzofuran as a measure of ring strain and stabilization. It is found that indence is 1.5–2.0 times more reactive than styrene. This high reactivity of indene is attributed to the ring strain in the monomer state and to the low amount of steric hindrance in the transition state of the coplanar five‐membered cyclic olefin. 1,2‐Dihydronaphthalene is strained and therefore reactive, but propagation to higher molecular weight products is impeded due to the steric hindrance. The reactivity of benzofuran is decreased by conjugative stabilization of CC double bonds at the reaction site.