The dying of fabric using azo dyes in a continuous process is often performed by treating fabric (soaked in a phenolate solution) with an aryl diazonium compound. This method circumvents the need for dissolving the dye, but suffers from the instability of the diazonium species. However, in a continuous process it is advantageous to synthesise the diazonium compound in a continuous matter as well, without having to store the diazonium solution under freezing conditions to prevent denitrogenation.

Synthesis of Sudan I

To avoid decomposition of the diazonium compound while keeping a high throughput at the same time, FutureChemistry has translated this reaction from a batch process to a continuous flow process. FutureChemistry’s typical three-tier approach led to a protocol which can be adapted to any viable
substrate:

      1) Translation of batch process to continuous flow process:
           a) Stock solutions approach, yielding a homogeneous reaction mixture.
           b) Quenching solution to follow the reaction in time.
           c) Flow markers approach to accurately assess reaction parameters.
      2) Automated reaction optimisation.
      2) Automated reaction optimisation.
      3) Out scaling to preparative synthesis

Log in to the FutureChemistry Portal to download the application notes.