引用本文:
周广滨, 许国津, 李晶洁. 丁二烯/甲苯/叔丁氧基钾-正丁基锂体系聚合反应的研究Ⅲ.链转移[J]. 应用化学,
1988, 5(2): 23-28.
Citation: Zhou Guangbin, Xu Guojin, Li Jingjie. A STUDY OF THE BUTADIENE/TOLUENE/POTASSIUM BUTOXIDE-N-BUTYLLITHIUM POLYMERIZATION SYSTEM Ⅲ.CHAIN TRANSFER[J]. Chinese Journal of Applied Chemistry, 1988, 5(2): 23-28.
Citation: Zhou Guangbin, Xu Guojin, Li Jingjie. A STUDY OF THE BUTADIENE/TOLUENE/POTASSIUM BUTOXIDE-N-BUTYLLITHIUM POLYMERIZATION SYSTEM Ⅲ.CHAIN TRANSFER[J]. Chinese Journal of Applied Chemistry, 1988, 5(2): 23-28.
丁二烯/甲苯/叔丁氧基钾-正丁基锂体系聚合反应的研究Ⅲ.链转移
摘要:
本文以叔丁氧基钾-正丁基锂作引发剂,甲苯作溶剂及链转移剂,研究了丁二烯阴离子链转移反应若干影响因素。含不同反离子引发剂的聚合体系中,向甲苯的链转移常数Cs分别为:Cs(Li)=0.11×10-3,Cs(Na)=0.40×10-3,Cs(K)=1.43×103-(K/Li=1.1),Cs(K)=1.26×10-3(K/Li=0.5)。温度每升高10℃,增长速率常数增加1.7倍左右,而转移速率常数则增大2.1倍,表观转移活化能为62.8kJ/mol。随着K/Li的增大,链转移常数相应增大,当K/Li从0增加到0.5时,Cs增大约10倍,当K/Li从0.5增加到1.1时,Cs的变化很小。体系中可能存在向单体的链转移反应。
English
A STUDY OF THE BUTADIENE/TOLUENE/POTASSIUM BUTOXIDE-N-BUTYLLITHIUM POLYMERIZATION SYSTEM Ⅲ.CHAIN TRANSFER
Abstract:
The chain transfer of butadiene polymerization was studied with n-butyl lithium and potassium butoxide as catalyst, toluene as solvent and chain transfer agent. The chain transfer constants to toluene with different counterions were found to be:Cs(Li)=0.11×10-3, Cs(Na)=0.40x10-3, Cs(K)=1.43x10-3, (K/Li=1.1), Cs(K)=1.26×10-3K/Li=0.5) respectively. The propagation rate constant increased 1.7 times for every 10℃ increase in temperature, and the chain transfer rate constant increased 2.1 times. The apparent activation energy of chain transfer was 62.8 kJ/mol. When increeasing K/Li from 0 to 0.5, Cs increased about 10 times, but when K/Li increased from 0.5 to 1.1, Cs changed scantly. Probably there existed certain chain transfer to monomer in this system.
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Key words:
- Butadiene
- / Anionic initiation polymerization
- / Toluene
- / Chain transfer
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