New ligand technology for solving challenging environmental problems

拟议的研究计划的长期主题是开发化学转化，这将导致更节能和负担得起的工业过程的发展。下面概述的目标涉及选择配体设计，以形成新的复合物，重点是解决主要的环境挑战。 黄金问题：氰化法是从低品位金矿石中提取和回收金的主要方法，这是由于该方法的高浸出效率和成熟技术。大量氰化钠的使用仍然存在争议，并且引起了极大的环境问题，但是迄今为止，还没有开发出可以在工业规模上实施的氰化物的可行替代品。我们正在开发一种适用于黄金开采行业的硫基配体系统的黄金提取工艺，我们预计该工艺将（i）完全消除氰化物的使用，并且在该工艺中（ii）比现有的氰化物技术更快、更便宜，（iii）更环保、更安全，以及（iv）简单、易于实施。这项研究的关键是研究金提取的机制，以便我们能够更好地了解发生的化学反应，从而在我们彻底改变黄金行业的同时进一步改进我们的设计。 塑料问题：全球塑料产量目前每年超过2亿吨，其中绝大多数直接来自化石燃料。传统的聚合物，如聚乙烯和聚丙烯（仅占全球塑料产量的1.25亿吨），可以在环境中存在100多年，并在垃圾场和海洋中积累。超过35%的聚乙烯（PE）和聚丙烯（PP）生产用于产品包装，在这些应用中，塑料被短期使用，然后被处理。可模仿PE特性的生物降解聚合物的开发为生产传统塑料的环保替代品提供了机会。PE模拟物的高度有前途的候选者是从大环内酯获得的聚合物。我们正在开发用于大环脂肪族环酯开环聚合的高效单组分催化剂，并打算将该技术开发为化石燃料衍生聚合物的可行替代品。由此产生的聚合物将模仿化石燃料塑料的特性，但将是可生物降解的，并来自可再生资源。

The long term theme of the proposed research program is to develop chemical transformations which will result in the development of more energy efficient and affordable industrial processes. The goals outlined below involve selected ligand designs for the formation of new complexes with a focus on solving major environmental challenges. The gold problem: cyanidation is the dominant process for extraction and recovery of gold from low-grade gold ore due to the high leaching efficiency and mature technology of the process. The use of large amounts of sodium cyanide remains controversial and is of great environmental concern, however no viable alternative to cyanide that can be implemented at an industrial scale has been developed… until now. We are developing a gold extraction process using a sulfur-based ligand system applicable to the gold mining industry that we anticipate will (i) completely eliminate use of cyanide and in the process be (ii) faster and cheaper than existing cyanide technology, (iii) be more environmentally friendly and safer and (iv) be simple and easy to implement. Essential to this research will be an investigation into the mechanism of gold extraction so that we can better understand the chemistry taking place and thus further improve on our designs as we revolutionize the gold industry. The plastic problem: global plastic production is currently exceeding 200 million tonnes per year, the vast majority of which is derived directly from fossil fuels. Conventional polymers such as polyethylene and polypropylene (which alone account for 125 million tonnes of global plastic production) can persist in the environment for over 100 years and accumulate in waste dumps and in oceans. Over 35% of polyethylene (PE) and polypropylene (PP) production goes to product packaging, applications in which the plastics are used on a short term basis and then disposed. The development of biodegradable polymers that can mimic the properties of PE presents the opportunity to produce environmentally friendly alternatives to conventional plastics. Highly promising candidates for PE mimics are polymers obtained from macrolactones. We are developing efficient, single-component catalysts for the ring-opening polymerization of large-ring aliphatic cyclic esters and intend to develop this technology as a viable alternative to polymers derived from fossil fuels. The resulting polymers would mimic the properties of fossil fuel-based plastics but would be biodegradable and be derived from renewable resources.