环氧树脂和复合材料中C-O键的催化断开
Alexander Ahrens1, Andreas Bonde2, Hongwei Sun2
1Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark. aahrens@inano.au.dk.
Nature
|April 26, 2023
概括
研究人员开发了一种化学回收热复合材料的新方法. 这种工艺可以回收有价值的建材,如双A和完整的纤维,为塑料废物提供可持续的解决方案.
科学领域:
- 材料科学
- 化学工程
- 环境科学
背景情况:
- 纤维增强的环氧复合材料在航空,汽车和风力发电中非常重要,因为它们的强度和轻量级.
- 目前废弃复合材料的处理方法,如风力轮机叶片,主要涉及垃圾填埋,导致环境污染.
- 环氧树脂的耐热性对传统的回收方法构成重大挑战,需要创新的方法.
研究的目的:
- 开发一个热环氧复合材料的化学回收协议.
- 能够回收有价值的聚合物构件和完整的钢筋纤维.
- 解决与塑料废物相关的环境问题,并促进复合材料管理中的循环经济原则.
主要方法:
- 采用过渡金属催化协议,具体使用 (Ru) 催化剂.
- 该方法涉及级联反应,包括脱,键裂和还原,以破坏环氧聚合物中的C ((alkyl) -O键.
- 该协议在未经修改的氨基固化环氧树脂和商业复合材料上进行了测试,包括风力轮机叶片外.
主要成果:
- 该研究成功地证明了从环氧复合材料中回收双A,这是一个关键的聚合物构件.
- 完整的钢筋纤维 (玻璃或碳) 也被回收,保持其结构完整性.
- 化学回收方法在实验室制备的树脂和现实世界复合材料应用上都证明有效.
结论:
- 已经建立了一个新型的过渡金属催化化学回收工艺,用于耐热环氧复合材料.
- 这种方法为复合废物的可持续管理提供了可行的途径,回收有价值的材料.
- 这些发现突显了塑料和复合材料行业循环经济的潜力,减轻了对环境的影响.
更多相关视频
相关概念视频
02:24Acid-Catalyzed Ring-Opening of Epoxides
7.5K
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...
7.5K
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
6.0K
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
6.0K
02:26Base-Catalyzed Ring-Opening of Epoxides
8.7K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
8.7K
02:50Catalysis
27.1K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
27.1K
01:13Esters to Carboxylic Acids: Acid-Catalyzed Hydrolysis
3.0K
Hydrolysis of esters under acidic conditions proceeds through a nucleophilic acyl substitution. In the presence of excess water, the reaction proceeds in a reversible manner, forming carboxylic acids and alcohols.
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...
During hydrolysis, the ester is first activated towards nucleophilic attack through the protonation of the carboxyl oxygen atom by the acid catalyst. The protonation makes the ester carbonyl carbon more electrophilic. In the next step, water acts as a nucleophile and adds to the...
3.0K
03:00Preparation of Epoxides
7.9K
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...
7.9K