Advancing the synthesis of electronically functional materials in flow reactors

Abstract

Conventional synthetic methods often give poor control over reaction conditions especially when applied to large quantity synthesis. Flow chemistry has been reported to provide a more con- trolled environment for synthesis and is particularly beneficial for the synthesis of functional ma- terials with properties that are sensitive to the reaction conditions. This thesis describes the development of several flow systems for the synthesis of electronically functional materials. An integrated flow system was developed for the preparation of the non-fullerene acceptor FBR is described. In addition to translating the two reaction steps to flow, the system also carries out in-line separation and solvent change in between the steps. In contrast to conventional batch conditions, the flow process dramatically reduced the reaction time from >12 hours down to 10 – 20 minutes. A separation procedure after the first step was able to isolate THF from aqueous base and simultaneously swapped the solvent from THF to toluene in preparation for carrying out the second reaction step. A complete flow system for synthesising P3HT polymer was also reported, including both monomer activation step and polymerisation. The system was able to produce P3HT polymer with high molecular weight (50.3 kDa) and low dispersity (1.20). The effect of changing the Grignard to monomer ratio on the polymer properties was investigated in detail. Additionally, in-line NMR spectroscopy analysis was employed in the flow system to provide near real-time analysis of the monomer activation step. Finally, the post-polymerisation functionalisation of the conjugated polymer F8BT-F with 4-methoxylthiophenol group was trans- lated to a flow reactor. The substitution reaction time was cut down to 30 minutes from >12 hours in batch.