The new Gas Module works seamlessly with the new H-Cube® Pro allowing a further 13 gases to be used at up to 100 bar using the same touch screen intuitive controls. Reactions such as carbonylation or oxidation can now be performed on the H-Cube® Pro at the same high pressure and ease of use, extending the reactor’s chemistry capacity significantly.
GAS-LIQUID REACTIONS INCONTINUOUS FLOW
The use of continuous flow tri-phasic, gas-liquid-solid reactions employing immobilized metal catalysts has increased significantly over the past few years. For heterogeneous catalytic gas-liquid reactions the primary advantages of flow result from the high specific interfacial area. The power of this technique is particularly obvious in gas-liquid-solid triphasic reactions involving various gases, a substrate dissolved in a solvent, and an immobilized solid precious metal catalyst. Owing to the large interfacial areas and the short path required for molecular diffusion in the very narrow microchannel space, very efficient gas-liquid-solid interaction occurs. In microreactors, reactions could take place which are not attainable in normal batch systems in minutes instead of hours. An additional advantage of flow reactors is that the small volume reduces the damage potential of explosions and therefore conforms with the 12th principle of green chemistry. Another green advantage: using gaseous reagents over chemicals reduces work-up and purification .
H-Cube® Pro - Gas Module™ platform provides you:
- 13 gases in one device·Fast reactions
- chemistry in minutes
- Powerful: Up to 100 bar capability
- Intuitive User Interface
- Fast: Just like with hydrogenation on H-Cube® Pro Reactions with other gases can complete in less than 10 minutes
- Robust: All high-quality stainless steel parts
- Simple: 3 button stand-alone control or via simple touch screen control on H-Cube® Pro
Table 1. Available gas flow rates
1. OXIDATION OF INDOLINE TO INDOLE
Table 2. Conditions and results of oxidation reaction
The H-Cube® Pro was coupled with the Gas Module™ and an oxygen cylinder. The following reaction parameters were set before starting the experiment using pure acetone; temperature: 150 ºC; liquid flow rate: 0.5 mL/min; gas flow rate: 50 mL/min; catalyst applied: Au/TiO<sub>2</sub> (length of catalyst cartridge: 70 mm, Order No. THS 01639); system pressure: 10 bar. Reactant solution was prepared by dissolving 82 mg 5-nitroindoline (0.5 mmol) in 10 mL acetone. When the “Stable” sign appeared in the status line of the H-Cube® Pro, the inlet valve was switched from “Solvent“ to “Reactant“, and the solution of 5-nitroin-doline passed through the catalyst cartridge. Collection of the product was started at the “Product” outlet after switching the outlet valve to Product. When all the 10 mL reactant solution was used up, the inlet valve was switched back to Solvent. Product collection was continued for an additional 10 min, in order to recover the total amount of product from the catalyst cartridge. The product solution was analyzed by GC-MS without any further dilution.
Batch reference: Oxidative aromatization using activated carbon molecular oxygen system . Yield: 63 %, 120 ºC, 9 h
2. AMINOCARBONYLATION OF IODO BENZOICACID WITH PYRROLIDINE
Table 3. Results at various CO flow rates
The H-Cube® Pro was coupled with the Gas Module™ and a carbon monoxide cylinder. The following reaction parameters were set before starting the experiment using pure acetone; temperature: 100 ºC; liquid flow rate: 0.5 mL/min; gas flow rate: 10, 30, 60 mL/min; catalyst applied: Pd(PPh<sub>3</sub>)<sub>4</sub> polymer-bound (length of catalyst cartridge: 70 mm, Order No. THS 05134); system pressure: 30 bar. Reactant solution was prepared by dissolving 496 mg 2-iodo benzoic acid (2 mmol), 213 mg pyrrolidine (3 mmol), and 607 mg triethylamine (6 mmol) in 200 mL tetrahydrofuran. When the Stable sign appeared in the status line of the H-Cube® Pro, the inlet valve was switched from Solvent to Reactant, and the reaction mixture passed through the catalyst cartridge. Collection of the product was started at the Product outlet after switching the outlet valve to Product. When the 10 mL reactant solution was used up, the inlet valve was switched back to Solvent. Product collection was continued for an additional 10 min, in order to recover the total amount of product from the catalyst cartridge. The product solution was analyzed by LC-MS without any further dilution.
The H-Cube® Pro - Gas Module™ platform shows several advantages: the gas insertion is very well regulated for high reproducibility; it could generate high capacity gas flow of various gases with excellent gas mixing which allows the user to perform many gas-liquid-solid reactions in flow that are normally difficult to carry out in batch. The H-Cube® Pro - Gas Module™ readily increases the chemistry and parameter space making it available for the organic chemistry laboratories.
 Irfan, M; Glasnov, T; Kappe, C O; ChemSusChem, 4, 3, 300–316, (2011)
 Nomura, Y; Kawashita, Y; Hayashi, M; Heterocycles, 74, 629 - 635,(2007)