Iron-Catalysed Oxygenation with O2

铁催化 O2 氧化

• 批准号: EP/R009694/1
• 负责人: Jianliang Xiao
• 金额: $ 44.52万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FR009694%2F1
• 关键词: Iron; Catalysed; Oxygenation; O2

Being used in the catalytic production of more than half of all the commercial chemicals, oxidation is one of the most significant industrial reactions, second only to polymerisation. Not surprisingly, the U.S. Department of Energy identified selective oxidation of organic chemicals to be the most important research area to impact the future chemical industry. However, it remains "one of the reactions with the greatest potential for improvement", primarily because of the low selectivity encountered in the vast majority of oxidation reactions and the widespread use of stoichiometric, toxic and hazardous oxidants, such as CrO3, H2S2O8, PhIO, HNO3. Using catalysts and environmentally benign oxidants is undoubtedly the most realistic way to address these issues. In this regard, developing iron-catalysed aerobic oxidation is most appealing, due to the unrivalled advantage of abundance, low cost and benign nature of Fe and O2. However, although iron-containing metalloenzymes are capable of selectively oxidizing various substrates with O2 under mild conditions, few man-made iron catalysts are known that can catalyse efficient, selective aerobic oxidation.We recently uncovered a novel class of well-defined iron complexes bearing pyridine bisimidazoline (PyBisulidine) ligands, which allow for highly chemoselective oxygenation of ethers and olefins. Building on this success, this project seeks to develop the next generation of more active iron catalysts for selective oxygenation of more challenging substrates. In particular, we will concentrate on two reactions, depolymerisation of lignin and cleavage of aliphatic C=C double bonds, under aerobic conditions. These reactions, which are vastly different in nature and can thus demonstrate the wide scope of the iron catalysts, are of both fundamental and commercial significance. Lignin is the only natural polymers made of aromatic units and could be used to produce a wide range of platform aromatic compounds. However, this requires the depolymerisation of the lignin ether linkage in the first place. Considering the huge scale of any possible processes toward this end, the catalyst to be used should ideally be based on a cheap metal such as iron. Oxidative cleavage of alkenes into carbonyls is a widely used transformation. However, ozone is most often used in industrial operations, and this comes with the well-known safety issues of explosivity, the cost of special equipment, and the large amount of waste generated. Thus, there has been a strong incentive to develop catalytic methods to replace ozone. Iron-based catalysts are particularly interesting, considering not only the environmental benefit of iron but also the ability of iron oxygenases to oxidize olefins to carbonyl compounds with exquisite selectivity. For both of these reactions, few iron catalysts are known that can make use of O2 as oxidant. The Fe-PyBisulidine complexes are expected to bring about a step change in addressing these challenges. The new catalysts will find applications in other reactions as well. The ether linkage is one of the most ubiquitous bonds found in nature and manmade chemicals, ranging from pharmaceuticals and agrochemicals through household products to lignin and coal. Thus, using the new catalysts and O2, compounds containing an ether bond may be transferred into highly value-added products, and polluting plastics, agrochemicals and detergents may be degraded in air. To further demonstrate the value of the iron catalyst, collaboration with a SME to produce, via acylation of arenes, compounds of direct business interest will be implemented.

氧化反应是最重要的工业反应之一，仅次于聚合反应，用于催化生产超过一半的商业化学品。毫不奇怪，美国能源部将有机化学品的选择性氧化确定为影响未来化学工业的最重要研究领域。然而，它仍然是“具有最大改进潜力的反应之一”，主要是因为在绝大多数氧化反应中遇到的低选择性和化学计量的、有毒和有害的氧化剂如CrO 3、H2 S2 O 8、PhIO、HNO 3的广泛使用。使用催化剂和环境友好的氧化剂无疑是解决这些问题的最现实的方法。在这方面，发展铁催化好氧氧化是最有吸引力的，由于铁和O2的丰富，低成本和良性的性质无与伦比的优势。然而，虽然含铁的金属酶是能够选择性地氧化各种底物与O2在温和的条件下，很少有人人造的铁催化剂是已知的，可以催化有效的，选择性好氧oxidation.We最近发现了一类新的定义明确的铁配合物轴承吡啶bisimidazoline（PyBisulidine）配体，这允许高度化学选择性氧化的醚和烯烃。在这一成功的基础上，该项目旨在开发下一代更具活性的铁催化剂，用于更具挑战性的底物的选择性氧化。特别是，我们将集中在两个反应，木质素的解聚和脂肪族C=C双键的裂解，在有氧条件下。这些反应在性质上有很大的不同，因此可以证明铁催化剂的广泛范围，具有基础和商业意义。木质素是唯一由芳香族单元组成的天然聚合物，可用于生产各种平台芳香族化合物。然而，这首先需要木质素醚键的解聚。考虑到为此目的的任何可能的方法的巨大规模，所使用的催化剂理想地应该基于廉价的金属，例如铁。烯烃氧化裂解为羰基化合物是一种广泛应用的转化反应。然而，臭氧最常用于工业操作，这伴随着众所周知的爆炸性安全问题，特殊设备的成本以及产生的大量废物。因此，开发催化方法来取代臭氧具有很强的激励作用。铁基催化剂是特别令人感兴趣的，不仅考虑到铁的环境效益，而且考虑到铁加氧酶以精确的选择性将烯烃氧化成羰基化合物的能力。对于这两种反应，已知很少有铁催化剂可以利用O2作为氧化剂。预计Fe-PyBisulidine络合物将在解决这些挑战方面带来一步变化。新的催化剂也将在其他反应中得到应用。醚键是在自然界和人造化学品中发现的最普遍的键之一，从药品和农用化学品到家用产品，再到木质素和煤炭。因此，使用新的催化剂和O2，含有醚键的化合物可以转化为高附加值的产品，污染塑料，农用化学品和洗涤剂可以在空气中降解。为了进一步证明铁催化剂的价值，将与中小企业合作，通过芳烃酰化生产具有直接商业利益的化合物。

项目成果

Chemoselective Oxyfunctionalization of Functionalized Benzylic Compounds with a Manganese Catalyst.

• DOI: 10.1002/anie.202205983
• 发表时间: 2022-07-25
• 期刊: Angewandte Chemie (International ed. in English)

Chemoselective Decarboxylative Oxygenation of Carboxylic Acids To Access Ketones, Aldehydes, and Peroxides.

• DOI: 10.1021/acs.orglett.3c00649
• 发表时间: 2023-04-14
• 期刊: ORGANIC LETTERS
• 影响因子: 5.2
• 作者: Guan, Renpeng;Chen, Guanhong;Bennett, Elliot L.;Huang, Zhiliang;Xiao, Jianliang
• 通讯作者: Xiao, Jianliang

Chemical Recycling of Polystyrene to Valuable Chemicals via Selective Acid-Catalyzed Aerobic Oxidation under Visible Light.

• DOI: 10.1021/jacs.2c01410
• 发表时间: 2022-04-13
• 期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
• 影响因子: 15
• 作者: Huang, Zhiliang;Shanmugam, Muralidharan;Liu, Zhao;Brookfield, Adam;Bennett, Elliot L.;Guan, Renpeng;Herrera, David E. Vega;Lopez-Sanchez, Jose A.;Slater, Anna G.;McInnes, Eric J. L.;Qi, Xiaotian;Xiao, Jianliang
• 通讯作者: Xiao, Jianliang