Nitrogen In the Circular Economy (NICE): The valorisation of nitrogenous waste

循环经济中的氮 (NICE)：含氮废物的增值

• 批准号: 2602586
• 金额: --
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2602586
• 关键词: Nitrogen; Circular; Economy; NICE; valorisation

Project background (identification of the problem and its importance and relevance to sustainability) Nitrogen containing molecules are ubiquitous and form the basis of many essential agrochemicals, pharmaceuticals, additives, textiles, and performance materials. The synthesis of nearly all nitrogen containing molecules requires ammonia, which is derived from the Haber-Bosch (HB) process. The HB process has a large detrimental environmental impact: it uses around 2% of global energy and contributes an estimated 2% to global carbon dioxide emissions. Consequently, the production of nitrogen containing compounds comes at a high environmental cost. Additionally, these resources are overconsumed and then discarded as waste once their initial purpose has been fulfilled. This is a symptom of our linear economy; fortunately, the circular economy provides a solution. To transition from a linear to a circular economy, processes need to be developed that enable waste to be transformed into useful, high value products and materials. Protein-rich biomass waste streams are abundant, yet the nitrogenous fraction remains undervalued and underused. The valorisation of such protein-rich waste streams into useful, high value, nitrogenous chemicals is one approach to improve the sustainability of their synthesis. The development of chemoselective disconnections for unactivated C-N bonds, particularly in underexplored transformations will enable the synthesis of small nitrogen containing compounds from nitrogenous waste, reducing both our dependence on the HB process and the environmental cost of producing such chemicals. Proposed solution and methodology This research project strives to develop methods to valorise nitrogenous waste streams that are abundant, currently underused, and for which valorisation into fine chemicals will not disrupt the food chain or require the growth of more crops. Through research into selective C-N sigma bond cleavage of various nitrogenous substrates, this project is envisioned to develop methods to valorise these waste streams to improve the flow of nitrogen containing compounds through the nitrogen cycle and to enable the transition towards a more circular economy. The current state of the art for selective C-N sigma bond cleavage requires incredibly forcing conditions and/ or activated substrates which limit the current applications of these methods. There is also a lack of mechanistic understanding in the literature, which can impede the development of novel approaches. This project seeks to address these issues by developing novel catalytic systems for selective C-N bond cleavage. Catalyst screening will be performed to find catalysts which can facilitate C-N sigma bond activation and cleavage using model N-compounds to explore and compare catalyst reactivities and selectivities, selected according to their activity towards C-N bond cleavage, commercial availability, ease of synthesis, and their scale-up potential. In particular, complexes of first row transition metals will be prioritised due to their sustainable credentials, low cost, and research group expertise. Upon the identification of a suitable catalyst system, optimisation will be carried out focusing on delivering high product yield and selectivity, whilst considering reaction sustainability in accordance with the 12 Principles of Green Chemistry. Substrate scope will be expanded by testing a large range of substrates with a variety of properties to gain insight into the limitations of the catalyst system. Data collected throughout this project will be continually analysed to gain insight into the catalyst mechanism of action, including isolation of potential reaction intermediates, along with detailed kinetic investigations; together this insight will enable a plausible catalytic cycle to be proposed.

项目背景（确定问题及其重要性和与可持续性的相关性）含氮分子无处不在，是许多重要农用化学品、药品、添加剂、纺织品和性能材料的基础。几乎所有含氮分子的合成都需要氨，而氨来源于哈伯-博世（HB）过程。HB过程对环境有很大的有害影响：它使用了全球约2%的能源，估计占全球二氧化碳排放量的2%。因此，含氮化合物的生产带来了很高的环境成本。此外，这些资源被过度消耗，一旦达到最初的目的，就被当作废物丢弃。这是我们线性经济的一个症状；幸运的是，循环经济提供了一个解决方案。为了从线性经济过渡到循环经济，需要开发能够将废物转化为有用的高价值产品和材料的工艺。富含蛋白质的生物质废物流丰富，但含氮部分仍然被低估和未充分利用。将这种富含蛋白质的废物流转化为有用的、高价值的、含氮的化学品是提高其合成可持续性的一种方法。非活化C-N键的化学选择性断开的发展，特别是在未充分探索的转化中，将使含氮废物合成含氮小化合物成为可能，减少我们对HB过程的依赖和生产此类化学品的环境成本。建议的解决方案和方法本研究项目致力于开发方法，使目前未充分利用的丰富的含氮废物流增值，并将其增值为精细化学品，而不会破坏食物链或需要种植更多作物。通过对各种含氮基质的选择性C-N sigma键裂解的研究，该项目设想开发方法来评估这些废物流，以改善含氮化合物在氮循环中的流动，并使向更循环的经济过渡。选择性C-N - sigma键裂解目前的技术状况需要令人难以置信的强制条件和/或活化底物，这限制了这些方法的当前应用。文献中也缺乏对机制的理解，这可能会阻碍新方法的发展。该项目旨在通过开发新的选择性C-N键裂解催化系统来解决这些问题。催化剂筛选将进行，以找到催化剂，可以促进C-N sigma键的活化和裂解使用模型n化合物探索和比较催化剂的反应性和选择性，选择根据他们的活性，对C-N键的裂解，商业可用性，容易合成，和扩大规模的潜力。特别是，第一排过渡金属的配合物将优先考虑，因为它们具有可持续性，低成本和研究小组的专业知识。在确定合适的催化剂体系后，将进行优化，重点是提供高产品收率和选择性，同时根据绿色化学的12条原则考虑反应的可持续性。通过测试具有各种特性的大范围底物，以深入了解催化剂系统的局限性，将扩大底物范围。在整个项目中收集的数据将不断进行分析，以深入了解催化剂的作用机制，包括分离潜在的反应中间体，以及详细的动力学研究；总之，这一见解将使我们能够提出一个合理的催化循环。