Microreactor hydrogen peroxide synthesis

A few fundamental studies have also been reported on the topic of hydrogen peroxide synthesis by direct combination of H2 and 02 in a microreactor. A recent contribution ofVoloshin et al. [86] from the Stevens Institute ofTechnology shows the first results on the role of reaction conditions. A maximum concentration of 1.3 wt% H202 was achieved. Further studies are necessary, but this interesting direction warrants further investigation. 

Voloshin Y, Haider R, Lawal A (2007) Kinetics of hydrogen peroxide synthesis by direct combination of H2 and 02 in a microreactor. Catal Today 125(l-2) 40 7... 

Hessel V, Hofmann C, Lob P, Lohndorf J, Lowe H, Ziogas A (2005) Aqueous Kolbe-Schmitt synthesis using resorcinol in a microreactor laboratory rig under high-P,T conditions. Org Process Res Dev 9 479-489 Inoue T, Schmidt MA, Jensen KF (2007) Microfabricated multiphase reactors for the direct synthesis of hydrogen peroxide from hydrogen and oxygen. Ind Eng Chem Res 46 1153-1160... 

Compared to the bateh synthesis, higher eonversion was obtained using a prepacked microreactor with a residence time of 0.5 min. However, after 2h reaction time the yield of benzodiols decreased, but catalyst could be regenerated using hydrogen peroxide. 

Recently, a new microreactor for the direct synthesis of hydrogen peroxide has been designed at the AIST, Tsukuba, and Mitsubishi Gas Chemical Inc., Tokyo. It operates at room temperature and IMPa. The reactor is made of glass and the catalyst is palladium on titania. The yield of 40% was reached, based on hydrogen, and the concentration was 10% [56]. 

An example of direct one-step synthesis is the direct fluorination employing elemental fluorine (see above) [42,43]. Another example involves the direct synthesis of hydrogen peroxide starting from H2 and O2 over a palladium catalyst. Although this is an environmentally benign and atom-efficient method, it involves the handling of an explosive gas mixture. Such reaction conditions can be safely performed with microreactor technology [45]. 

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