2 - -2-与1 - 环-1-离开组:在RAFT聚合过程中比较对称三碳酸盐的活性
Oleksandr Ivanchenko1, Maksym Odnoroh1, Faustine Rolle1
1Laboratoire SOFTMAT, Université Toulouse 3 - Paul Sabatier, CNRS UMR 5623, 118 route de Narbonne, Toulouse, 31062, France.
Macromolecular rapid communications
|June 5, 2024
概括
一种新的RAFT药物, bis{1-cyanocyclohex-1-yl) trithiocarbonate (TTC-bCCH),可以有效控制聚合物. 与甲基甲酸盐相比,它与二二二二三碳酸盐 (TTC-bCP) 呈现出明显的反应性,影响了区块共聚物的特性.
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:
- 可逆添加碎片链转移 (RAFT) 聚合是一种控制聚合物合成的关键技术.
- 三碳酸盐剂对RAFT至关重要,但需要新的结构来定制聚合物特性.
- 了解链传递剂 (CTA) 反应性对于预测和控制聚合物架构至关重要.
研究的目的:
- 介绍和描述 bis ((1-cyanocyclohex-1-yl) trithiocarbonate (TTC-bCCH) 作为一个新的 RAFT CTA.
- 比较TTC-bCCH的聚合行为和动力学与二-2-烯-2-) 三碳酸盐 (TTC-bCP).
- 研究这些CTA对 (甲基) 烯酸ABA块共聚合物的特性的影响.
主要方法:
- 合成并对TTC-bCCH进行了表征.
- 使用TTC-bCCH和TTC-bCP进行了烯,n-丁烯酸和甲基甲烯酸的RAFT聚合.
- 使用密度函数理论 (DFT) 计算来理解反应率差异.
- 使用rheological分析进行了ABA阻断共聚物的特征.
主要成果:
- 无论是TTC-bCCH还是TTC-bCP,都证明了对 styrene 和 n-butyl acrylate 的分子量和分散性的有效控制.
- 与TTC-bCP相比,TTC-bCCH表现出甲基甲酸甲基低链转移常数的四倍.
- DFT计算支持观察到的反应性趋势.
- 与TTC-bCCH合成的块共聚物显示了变化的热力学特性,表明相分离的变化.
结论:
- TTC-bCCH是一种可行的RAFT CTA,具有可调节的反应能力,特别是对于甲基甲酸盐.
- 选择三碳酸盐CTA显著影响由此产生的块共聚合物的特性.
- 对TTC-bCCH的进一步研究可能会导致具有定制热力学反应的先进材料.
相关概念视频
Relative Reactivity of Carboxylic Acid Derivatives
2.6K
Carboxylic acid derivatives such as acid halides, anhydrides, esters, and amides undergo nucleophilic acyl substitution reactions with varying degrees of reactivity.
A key factor in assessing the reactivity of the acid derivatives is the basicity of the substituent or the leaving group. The lower the basicity of the leaving group, the higher the reactivity of the derivative. The basicity of the leaving group follows this order:
Halide ions < Acyloxy ions < Alkoxy ions < Amine ions
A key factor in assessing the reactivity of the acid derivatives is the basicity of the substituent or the leaving group. The lower the basicity of the leaving group, the higher the reactivity of the derivative. The basicity of the leaving group follows this order:
Halide ions < Acyloxy ions < Alkoxy ions < Amine ions
2.6K
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
8.4K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
8.4K
Radical Reactivity: Electrophilic Radicals
1.9K
Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For example, the malonate radical, in which the radical center is flanked by two electron‐withdrawing groups, reacts readily with butyl vinyl ether, which consists of an electron‐donating oxygen substituent. The reaction between electrophilic malonate radical and nucleophilic vinyl ether is favored because the radical has a...
1.9K
Radical Reactivity: Intramolecular vs Intermolecular
1.7K
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak...
1.7K
Radical Reactivity: Concentration Effects
1.5K
In a radical reaction, the concentration of starting materials governs the selectivity of a radical. For example, the reaction between an alkyl halide and an alkene, in the presence of tin hydride and AIBN, begins with the generation of a tin radical. The generated radical then abstracts halogen from the alkyl halide, producing an alkyl radical. This alkyl radical can either react with tin hydride, yielding an alkane, or add to an alkene, generating a nitrile-stabilized radical, eventually...
1.5K
Radical Substitution: Allylic Bromination
5.1K
In organic synthesis, the formation of products can be altered by changing the reaction conditions. For example, a dibromo addition product is formed when propene is treated with bromine at room temperature. In contrast, propene undergoes allylic substitution in non-polar solvents at high temperatures to give 3-bromopropene. In order to avoid the addition reaction, the bromine concentration must be kept as low as possible throughout the reaction. This can be achieved using N-bromosuccinimide...
5.1K


