大量酸盐控制环氧化物,无水化物和CO2的化学选择性聚合:从明确定义的块到真正随机的共聚物
Yukun Ma1, Zehao Wang1, Lihang Jiang1
1Key Laboratory of Biobased Polymer Materials, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China.
Angewandte Chemie (International ed. in English)
|October 1, 2024
概括
本研究介绍了一种无金属催化剂系统,用于合成精确序列的聚碳酸共聚合物. 催化剂使氧化物,无水化物和二氧化碳的块和随机共聚合物的受控合成成为可能.
科学领域:
- 聚合物化学 聚合物化学
- 材料科学 材料科学 材料科学
- 有机合成 有机合成
背景情况:
- 合成具有可控组成和序列的共聚合物对于高性能材料至关重要,但仍然具有挑战性.
- 现有的方法通常需要金属催化剂,限制了应用,并引发了环境问题.
研究的目的:
- 开发一种无金属的催化系统,用于精确定义的块和真正随机的聚碳酸共聚合物的单/单步合成.
- 为了研究二元催化剂系统的化学选择性,用于环氧化物,无水化物和二氧化碳的聚合.
主要方法:
- 使用了四基[tris(dimethylamino) phosphoranylidenamino]化 (P5Cl) 和三甲基 (TEB) 作为一种二元,无金属的催化剂系统.
- 采用环开环交替共聚化 (ROAC) 的环氧化物 (CHO),甲酸盐 (PA) 和二氧化碳.
- 调整了催化剂的摩尔比率 (P5Cl/TEB),以控制化学选择性,并实现块或随机共聚合物形成.
主要成果:
- 通过使用1/0.5的P5Cl/TEB比率,实现了明确区块聚碳酸共聚合物的合成,有利于顺序ROAC.
- 使用1/2的P5Cl/TEB比率制造出真正随机的聚碳酸共聚合物,从而实现同时的ROAC.
- 证明了P5Cl/TEB催化剂系统对各种单体和启动剂的多功能性,产生多样化的共聚物结构.
结论:
- P5Cl/TEB催化剂系统提供了一种强大而通用的无金属方法,用于合成可调节序列和组合的聚碳酸共聚合物.
- 控制化学选择性的能力为访问块和随机共聚合物架构提供了强大的策略.
- 这种方法显著推进了用于扩展应用的功能聚合物材料的合成.
相关概念视频
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
2.5K
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
2.5K
Preparation of Epoxides
7.5K
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...
7.5K
Cationic Chain-Growth Polymerization: Mechanism
2.3K
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the...
2.3K
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
1.9K
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
1.9K
Acid-Catalyzed Ring-Opening of Epoxides
7.1K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
7.1K
Olefin Metathesis Polymerization: Overview
2.0K
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
2.0K


