The gas/liquid reactor fits into the standard glass manifold just like any other, so is compatible with all existing systems. Liquid is fed through the coil just like other reactors, but there is also a connection for gas which is fed at the desired pressure from a regulated supply.
With the Vapourtec platform, all tube reactor coils are contained within an insulated glass manifold and the temperature is controlled by rapidly circulating gas. Coils can easily and rapidly interchanged and up to four separate manifolds can be used in sequence.
The reactor can be used in two ways:
- Pre-dissolving the gas into the liquid before the reaction
- Performing the reaction in the new reactor, feeding gas as it is consumed by the reaction
The reactor specification is as follows:
- The working (liquid) volume of the standard reactor is 15ml
- The gas volume is approximately 4ml.
- The maximum gas supply pressure is 30 bar
- The maximum liquid reaction pressure is 30 bar
- The maximum operating temperature is 150°C
The gas reactor has the following restrictions:
- It is not acid resistant (the liquid wetted parts of the reactor include 316 stainless steel).
- The differential between the gas and liquid pressures should not exceed 8 bar except when the temperature is < 60°C.
- Compatible gases include (but are not limited to) CO, H2, O2 . Slower diffusion will be experienced with gas with much larger molecules.
Pre-dissolving the gas in the reagent stream
This method involves saturating one reagent stream with gas before the reaction itself. It is limited by the solubility of the gas in the reagent and solvent liquid stream, which for some gases will impose quite a significant limitation on the concentration at which the reaction can be run with useful conversion.
Feeding the gas into the reaction as it is consumed
Because the new Vapourtec reactor is compatible with the existing R4 reactor heater, it is possible to use it for the main reaction, controlling the reaction temperature as required while feeding in gas. Therefore the solubility of the gas in the solvent/reagent is no longer the limiting factor. As gas is consumed by the reaction, more is fed into it.
This is where the Vapourtec reactor is unique. Hydrogenations, for example, have to be performed in a very dilute solution of if the solubility of hydrogen is the limiting factor, but with this new reactor hydrogenation at 1M is easily achieved.
The rate at which gas diffuses into the liquid stream is determined by the pressure of the gas, the temperature at the membrane, and the gas molecule in question.