DANIEL ARNOLD1, ROBERT HIGGINS2, DUNCAN HOLDSWORTH3
1. Senior Technical Product Specialist, Johnson Matthey, West Deptford, United States
2. Process Safety Chemist, Johnson Matthey, West Deptford, United States
3. Projects Director, Mastermelt Ltd., Redcar, United Kingdom

Abstract

In this article, we explore the importance of metal extraction and refinement when using platinum group metal (PGM) catalysts in API synthesis. We detail the wide range of treatment options that R&D teams can integrate into their chemical processes, including metal scavenging and complex chemical treatments, and emphasise the challenges associated with each of them. We also discuss the importance and potential cost-savings involved in considering one’s waste stream early in process development. By embracing extraction and refinement, chemists can reduce their carbon emissions and capital expenditure, especially during scale-up, and forge a more sustainable pharmaceutical value chain.

Introduction
Platinum group metal (PGM) catalysts, referring to platinum, palladium, ruthenium, rhodium and iridium complexes, have become a staple of active pharmaceutical ingredient (API) synthesis. Favoured for their high activity and selectivity, they have found routine application as homogeneous catalysts. With stringent regulatory guidelines in place to limit residual metal levels within APIs, process chemists are often presented with challenges of identifying and implementing techniques to remove contaminant metals from synthetic products during process development.

In addition to this, the high value of PGMs and a greater focus on sustainability have led to a heightened interest in the extraction and refining of waste streams that contain these metals for reuse in catalysis. This has been further driven by a growing demand for homogeneous catalysts across the pharma, agrochemical, and fine chemicals industries. By taking a circular approach, chemists can significantly reduce carbon emissions and capital expenditure associated with PGM catalysis in industrial processes.

Effective metal extraction and ...