Improving Catalysis Sustainability

在过去的5年中，主要研究者（PI）团队的研究开发了Pd（钯）N-杂环卡宾（NHC）催化剂，以解决C-C，C-S和C-N键形成中的合成问题。有了这些创新，只能在恶劣条件下工作的工艺（例如，强碱、高温）。这些Pd催化剂已经全部商业化并在世界范围内的实验室中使用。虽然催化本身被视为绿色化学的十二项原则之一，但要使这种化学真正可持续，还必须做更多的工作。钯是一种受欢迎的金属催化剂，因为其无与伦比的广谱反应性和选择性。然而，钯也是最稀缺的元素之一，从集中在采矿矿床中到广泛分布到废物流中，这些废物流确实允许金属被回收和再循环，从而基本上永远失去了它。此外，为了寻找稀有金属而必须移动的地球剪切体积会造成大规模的环境破坏。 该研究提案的首要目标是按照以下四个概念提高催化的可持续性：1）制造更长寿命的高反应性催化剂，从而显著减少催化所需的金属和相关配体的量，2）适应更丰富的金属（例如，钴）通过配体设计用于更广泛的合成应用，3）设计催化剂以在更环境友好的溶剂（包括水和醇）中有效地工作，以及4）使用酶（其是天然催化剂）进行共催化。 在实现上述目标的过程中，将为催化工具箱开发四种新工具，这将有助于使合成化学这一领域更具可持续性。重要的是，拟议的研究从一开始就针对大规模的化学生产，因此结果应该更直接地适用于当前的制造实践。具体来说，新的配体设计将提高催化剂的寿命，允许使用更少的贵金属（和非贵金属），我们将通过使现有的催化过程适合在水中进行，使催化远离大规模使用有机溶剂。许多化学品制造商的白色文件突出强调催化和生物催化是实现合成零碳足迹的关键技术，因此预计本提案的成果将产生重大影响和应用。 使用这种方法正在追求的重要应用包括追求新的药物和诊断剂来对抗疾病，电子工业的新材料，以及新的农用化学品，以帮助确保可靠的食品供应。PI与这些领域的公司有着良好的联系，这将简化这些发现转化为商品和服务的过程，从而造福社会。

Over the last 5 years, research in the Principal Investigator's (PI) group has developed Pd (palladium) N-heterocyclic carbene (NHC) catalysts to solve synthetic problems in the formation of C-C, C-S, and C-N bonds. With these innovations, processes that only worked under harsh conditions (e.g., strong base, high temperatures) can now be done routinely with mild base at RT. These Pd catalysts have all been commercialized and are being used in laboratories worldwide. While catalysis itself is viewed as one of the Twelve Principals of Green Chemistry, more must be done to make such chemistry truly sustainable. Pd is a popular metal for catalysis because of its unsurpassed broad-spectrum reactivity and selectivity. However, Pd is also among the most scarce elements and goes from being concentrated in mining deposits to being distributed widely into waste streams that do allow the metal to be recovered and recycled, thus essentially losing it forever. Further, the shear volume of earth that has to be moved to find rare metals causes large-scale environmental damage. The overriding objective of this research proposal is to improve catalysis sustainability following four concepts: 1) making longer-living, high reactivity catalysts thereby significantly reducing the amount of metal and associated ligand necessary for catalysis, 2) adapting more abundant metals (e.g., cobalt) for wider synthetic applications through ligand design, 3) devising catalysts to work effectively in more environmentally friendly solvents including water and alcohol, and 4) performing co-catalysis employing enzymes, which are nature's catalysts. In approaching the above objectives four new tools will be developed for the catalysis toolbox that will help make this area of synthetic chemistry more sustainable. Importantly, proposed research targets large-scale chemical production from the outset, so results should be more directly applicable to current manufacturing practices. Specifically, new ligand designs will improve catalyst lifetime allowing far less precious (and non-precious) metals to be used and we will move catalysis away from large-scale organic solvent use by making existing catalytic processes amenable to being conducted in water. White papers of many chemical manufacturers prominently highlight catalysis and biocatalysis as key technologies for achieving a zero-carbon footprint in synthesis, thus significant impact and application of the outcomes in this proposal are anticipated. Important applications being pursued using this methodology include the pursuit of new pharmaceutical and diagnostics agents to battle disease, new materials for the electronics industry, and new agrochemicals to help ensure a reliable food supply. The PI is well connected with companies in these sectors, which will streamline the transformation of these discoveries into goods and services to benefit society.