Oxidation reactions are of fundamental importance in nature, and are key transformations in organic synthesis. The oxidation reactions are widely utilized in the chemical industry using various oxidizers from the molecular oxygen through the Hydrogen peroxide to the osmium tetroxide. Employing traceless gaseous reagents over chemicals allows the ability to develop greener processes by reducing the waste from purification because excess gas is easily removed from a reaction. Oxidation reactions are important in the synthesis of organic compounds because these reactions create new functional groups or modify existing functional groups in molecules. However, autooxidations and other reactions with radical intermediates frequently exhibit low chemo- and regioselectivity. Stoichiometric metal oxidants, such as KMnO4 or K2CrO4 generate large quantities of waste.
Oxidation with molecular oxygen
The use of molecular oxygen minimizes chemical waste producing water as the sole final by-product and the process has very high atom-economy. The direct oxidation of organic substrates by O2 is rare as the energy barrier for electron transfer from the organic substrate to the oxidant is usually high. For molecular oxygen, which has a triplet ground state, this high energy barrier is nature-s way of protecting organic compounds from destructive oxidation. One of the disadvantages of using molecular oxygen is the difficulty to protect the starting material from the over oxidation. The flow technology’s accurate residence time control let the chemist to manage selective oxidation reaction by using the cheapest oxidizing agent. The ThalesNano’s H-Cube Pro with a Gas Module gives the tool to manage heterogeneous catalyzed oxidation reactions up to 100 bar and 100 ml/min Oxygen flow rate.
|Oxidation with molecular oxygen using the H-Cube Pro™ with the Gas Module|
Ozonolysis is the cleavage of an alkene or alkyne with ozone to form organic compounds in which the multiple carbon–carbon bonds have been replaced by a carbon – oxygen bond. Ozonolysis is a process capable of producing aldehydes, dialdehydes, carboxylic acids, dicarboxylic acids, alcohols, and dialcohols depending on the used quench reagent. Reactions are typically highly selective, hydroxyl groups, for instance, remain untouched in this process. Ozonolysis is the only oxidative process which does not require addition of water. However the reaction is highly exothermic, and therefore it should be carried out at -78°C. The ozonides produced during the reaction can decompose at temperatures as low as room temperature causing explosions. Using ThalesNano’s IceCube reduces the risks of the reaction because the explosive ozonide is produced and quenched continuously in µg quantities. The flow technology guarantees less chance for run-away reaction, easier temperature control. Easy to set up and all parameters are controlled by user.
|Oxidation with ozone using the IceCube™ Reactor|