Project Outline

The solid (crystal) form of agrochemicals has enormous impact on their efficacy.¹ However, this same feature also determines their longevity in the environment. It is therefore essential to design the solid form of agrochemicals that simultaneously maximises their potency whilst minimising their long-term effect on soil and pollinators. Controlling solid form is a difficult task and often requires ‘trial and error’ methods that consume large quantities of solvent and time. This is harmful to the environment and has significant negative economic impact. The agrochemical industry therefore urgently needs new strategies to manufacture its chemicals in a more sustainable and targeted fashion.

Mechanochemical methods (i.e., driving chemistry using mechanical force) are emerging as technologies with immense potential to simultaneously synthesise new molecules and control their solid form without need for solvent.² However, it is not well understood exactly how to design a mechanochemical process to target a specific solid form. Such an understanding is essential if we hope to realise the full potential of this transformative technology.

This project will explore, for the first time, the ability to synthesise agrochemicals with a high degree of solid form control, using mechanochemical methods. In doing so the project will lay foundations for new directions in agrochemical design and manufacture. Following the successful preparation of the targeted agrochemicals, the project will investigate their associated agrotoxicity, with the primary aim to link solid form to behaviour. The link between solid form and behaviour, as well as solid form stability in environmental conditions, will be guided by quantum chemical atomistic modelling.

The project will explore fundamental insights into the mechanisms of the mechanochemical synthesis of agrochemicals. This will be achieved through a combination of laboratory analysis and advanced time-resolved in situ analytics³ such as X-ray diffraction and X-ray spectroscopy, making use of large international synchrotron facilities. The experimental methods will be streamlined with aid of AI and computational modelling, ensuring the project is at the forefront of research and technology. The fundamental insights will be supplemented by studies of material application, including studies into chemical toxicity, biodegradation, and their efficacy in real-world applications. Hence, the student will gain a true appreciation for sustainable science from fundamentals to applications.

Overall, the project will set out to establish a cradle-to-grave life cycle for advanced agrochemical manufacture using state-of-the-art sustainable mechanochemical methods. This promises to change the face of agrochemical manufacture. The principles developed in this project are readily transferrable to other industries, including pharmaceutical manufacture and food sciences. In addition to broad interdisciplinary scientific training, the student will be therefore well placed to translate their skills into diverse career paths in academia or industry.

References

1. Y. Xiao, C. Wu, P. Cui, L. Zhou and Q. Yin, Pursuing Green and Efficient Agriculture from Molecular Assembly: A Review of Solid-State Forms on Agrochemicals, J. Agric. Food Chem., 2023, 71, 10500–10524.
2. D. E. Crawford and J. Casaban, Recent Developments in Mechanochemical Materials Synthesis by Extrusion, Adv. Mater., 2016, 28, 5747–5754.
3. A. A. L. Michalchuk and F. Emmerling, Time‐Resolved In Situ Monitoring of Mechanochemical Reactions, Angew. Chem. Int. Ed., 2022, 61, anie.202117270.

Techniques

• Mechanochemistry (twin-screw extrusion, ball milling, resonant acoustic mixing)
• Single crystal and powder X-ray diffraction
• Solution NMR spectroscopy
• Solid state NMR spectroscopy
• Mass Spectrometry
• Raman spectroscopy (microscope and on-line probe)
• ICP-MS
• Density Functional Theory simulations (High Performance Computing)
• Design of Experiments (DoE) statistical analysis (JMP)
• Life cycle assessment (SimaPro)
• Time-resolved in situ synchrotron X-ray diffraction and X-ray absorption spectroscopy