|本期目录/Table of Contents|

[1]李 欣,董 静,韩卓凌,等.外加含氮给电子体对钕系顺丁橡胶聚合行为的影响[J].合成橡胶工业,2024,5:438.
　LI Xin,DONG Jing,HAN Zhuo-ling,et al.Influence of external nitrogen-containing donors on polymerization behavior of neodymium-based cis-1,4-polybutadiene rubber[J].China synthetic rubber industy,2024,5:438.
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外加含氮给电子体对钕系顺丁橡胶聚合行为的影响(PDF)

《合成橡胶工业》[ISSN:1000-1255/CN:62-1036/TQ]

期数:
2024年5期
页码:
438
栏目:
出版日期:
2024-09-15

文章信息/Info

Title:
Influence of external nitrogen-containing donors on polymerization behavior of neodymium-based cis-1,4-polybutadiene rubber
文章编号:
1000-1255（2024）05-0432-05
作者:
李 欣1; 董 静2; 韩卓凌1; 王 凤1; 张学全1; 刘 恒1
（1. 青岛科技大学 高分子科学与工程学院/山东省橡胶材料科学与工程高校实验室，山东 青岛266042； 2.中国石油石油化工研究院 兰州化工研究中心，兰州730060）
Author(s):
LI Xin1;  DONG Jing2;  HAN Zhuo-ling1;  WANG Feng1;  ZHANG Xue-quan1;  LIU Heng1*
（1. Shandong Provincial College Laboratory of Rubber Material and Engineering/School of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China; 2. Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina, Lanzhou 730060, China）
关键词:
外加含氮给电子体; 稀土钕催化剂; 丁二烯; 顺式-1; 4-结构含量; 聚合机理
Keywords:
-
分类号:
-
DOI:
DOI:10.19908/j.cnki.ISSN1000-1255.2024.05.0438
文献标识码:
-
摘要:
考察了外加含氮给电子体对新癸酸钕/三乙基铝/氢化二异丁基铝/乙基倍半铝氯化物催化体系制备顺丁橡胶聚合行为的影响。结果表明，外加1~5份（质量）三辛基胺对聚合物的收率、分子量及其分布等影响不大，但能够明显提高催化剂的顺式-1,4-结构的选择性，聚合物的顺式-1,4-结构摩尔分数由93.66%提高至96.18%。改变外加含氮给电子体种类也能够得到类似效果。
Abstract:
Neodymium(Nd)-based catalyst in butadiene (Bd) polymerization has drawn interests due to its availability in affording higher cis-1,4-unit selectivity than transition metal (Ti, Co, Ni, etc.)-based catalysts［1-2］. Such outstanding high cis-1,4-unit selecti-vity is hypothetically originated from the presence of 4 f orbitals, that can participate in monomer coordination and thereby govern subsequent enchainment manners. This unique characteristic also renders the active species highly susceptible to Lewis bases, and may impact the overall selectivity as well as polyme-rization behavior after coordination. Nevertheless, it is still a virgin area in such a field, and the influence of Lewis bases on Nd-based diene polymerizations is still a black box. Based on this consideration, how nitrogen-containing donors (D) impacts the overall behaviors of Nd-mediated Bd polymerizations is disclosed.　Systematic evaluation was commenced by incorporation different amounts of trioctylamine(TOA) into neodymium neodecanoate［Nd(vers)3］/triethylaluminum (AlEt3) /diisobutyl aluminum hydride ［Al(i-Bu)2H］/ethyl sesquialuminum chloride (Al2Et3Cl3) mediated Bd polymerization. As shown in Table 1, with the increase of the n(TOA)/n(Nd) ratio from 0 to 5, the polymerization performances was negligible influenced, giving polybutadiene rubber with similar yields, molecular weights (■■) and polydispersity indexes. Nevertheless, it was astonishingly found that cis-1,4-unit stereoselectivity of the system was remarkably enhanced from 93.66% to 96.18%, with simultaneously decreasing of trans-1,4-unit selectivity from 6.00% to 3.48%. Further increa-sing n(TOA)/n(Nd) to 8 witnessed an even higher cis-1,4-unit selectivity up to 99.29%. Such a result was solidly confirmed from carbon nuclear magnetic ersonance (13C-NMR) spectra (Fig 1) that one predominant peak was observed that assigned to cis-1,4-unit of polybutadiene rubber sample. These positive results were hypothetically originated from the changes in monomer enchainment fashion after the Nd metal was coordinated by TOA. After the vacant site on Nd metal was occupied by TOA, a sterically congested active species would be resulted, which then forced Bd monomer coordinating the Nd atom in a cis-1,4-η4 manner because such a conformation required much smaller space than trans-1,4-η4 manner. The cis-1,4-η4 coordinated monomer was more favo-rable to be inserted to form anti-structured π-allyl propagation species, with which a cis-1,4-unit was concurrently generated. For the present system, changing the addition order of different components during the aging process by selecting (Nd, D, Bd, Al, Cl), or (Nd, Bd, Al, D, Cl), or (Nd, Bd, Al+D, Cl), or (Nd, Bd, Al, Cl, D) resulted in little influence on the selectivities, all of them gave cis-1,4-unit selectivities higher than 96%, implying the similar structured active species formed therein. Besides TOA, other types of nitrogen-containing donors could also give parallel results. For instance, incorporation of N,N,N’,N’-tetramethylethylenediamine, 2,6-dimethylpyrdine and 2,6-dichloropyridine could enhance the cis-1,4-unit selectivities to 97.79%-98.94%, suggesting the universal influence of nitrogen-donors.

参考文献/References

［1］ Fan Changliang, Bai Chenxi, Cai hongguang, et al. Preparation of high cis-1,4 polyisoprene with narrow molecular weight distribution via coordinative chain transfer polymerization[J]. Journal of Polymer Science (Part A): Polymer Chemistry, 2010, 48(21): 4768-4774.［2］ Wang Feng, Zhang Chunyu, Hu Yanming, et al. Reversible coordinative chain transfer polymerization of isoprene and copolymerization with ε-caprolactone by neodymium-based catalyst[J]. Polymer, 2012, 53(26)： 6027-6032.

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更新日期/Last Update: 1900-01-01