Batch reactors are versatile and have decades’ worth of process development, however, they suffer from low-labour efficiency and low space time yields due to discontinuous operation and slow mass transfer rates.
Continuous flow operation allows for enhanced mass and heat transfer offering an opportunity for higher cost efficiency and intensified production scales. Smaller intensified reactors are safer reactors.
Why is it a challenge?
Although hydrogenation reactions make up around 10% of reactions in the fine chemicals industry, the requirement of a heterogeneous catalyst presents challenges due to complex gas-liquid-solid hydrodynamics. One of the most challenging reactions of these is the semi-hydrogenation of alkynes to alkenes, widely used in the synthesis of vitamins.
What did we do?
We have developed novel catalyst-coated tube-based reactors for hydrogenation processes. StoliFlow reactors are 5m long tube reactors with an internal diameter of 1.5 mm coated with a thin layer of an active metal catalyst. The StoliFlow tube reactors are highly selective towards intermediate hydrogenation reactions such as the semi-hydrogenation of 2-methyl-3-butyn-2-ol (MBY). We tested the operation at an elevated temperature (up to 175 °C compared to around 70 °C used in industry).
StoliFlow reactors provided excellent selectivity in the alkyne semi-hydrogenation reaction towards the desired alkene, reaching a maximum yield of 95% under solvent free conditions at ambient H2 pressure and metal leaching below 1 part per billion (ppb).
The flow reactors enabled high conversion with short reaction time (seconds) and high temperature – this combination is neither practical nor possible in batch. Such conditions allow 8 fold higher specific reaction rates compared to batch with the same 1% substrate decomposition rates.
Raman Spectroscopy for online analysis: effect of gases, solids, laser power, aquisition time, signal/noise and more….
We investigated Raman spectroscopy for online analysis by monitoring hydrogenation reactions through relative peak intensities, subsequently, determine the concentration of components.
We manufactured 10 kg catalyst using characterisation to validate the scale-up procedure from lab to manufacturing processes.
Stoli cascaded imine formation and hydrogenation; intensified process to maximise rate, and catalyst utilisation.
We have developed a monolith-based fuel cell catalyst for sustainable remote energy generation.
After 100 long-term runs and building a bespoke reactor system to manage safety risks, we developed a stable catalyst with months at least 2 month lifetime.
With Stoli proprietary coating technology, we developed a novel catalyst coating for an intensified reactor for a more efficient and sustainable process.