Direct synthesis of hydrogen peroxide

Hydrogen peroxide is a large-scale manufactured chemical compound due to its application as a disinfectant and in bleaching, although it also has an important use as a reactant in many minor-scale fine-chemical productions. 

At present, its synthesis requires a sequential hydrogenation and subsequent oxidation of alkyl anthraquinone [248]. One of the main problems of this process is the high cost of the quinine solvent and the need for continuous anthraquinone replacement. The manufacturing process is also hindered by frequent storage and transport problems. In view of these obstacles, the development of a new synthetic method is of great interest from a commercial standpoint. 

Although much research over the last century has focused on a direct synthetic process, at present no commercial route is known. For many years, the catalysts used were based on Pd [249-251]. 

Hutchings et al. initially showed that Au/Al203 catalysts could promote direct reactions and results were subsequently drastically improved with the use of Au/Pd alloys supported on alumina [23, 252]. 

However, selectivity continued to be a problem in the process due to the hard conditions required by the method. Thus, in parallel research, Haruta et al. [253] and Ishihara and coworkers [254] achieved the reaction at only 10 °C. These studies compared the activity of Au/Si02 and Au-Pd/Si02 catalysts and the authors concluded that the enhancement observed when Pd was added to Au was directly related to the activation of hydrogen. However, excess Pd also induced rapid decomposition of H202. 

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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... 

J. Van Weynbergh, J.-P. Schoebrichts, and J.- C. Colery, Direct synthesis of hydrogen peroxide by heterogeneous catalysis, catalyst for the said synthesis and method of preparation of the said catalyst, US Pat. 5447706 (1995). 

R. Meiers, and W. F. Holderich, Epoxidation of propylene and direct synthesis of hydrogen peroxide by hydrogen and oxygen, Catal. Lett. 59, 161-163 (1999). 

In 2002, Hutchings began working on the direct synthesis of hydrogen peroxide, a process with well-known problems of selectivity, where the efficiency of gold made it possible to manage safe conditions [23]. 

Direct Synthesis of Hydrogen Peroxide Recent Advances... 

Direct synthesis of hydrogen peroxide from its elements is thermodynamically feasible and it is a known reaction from the beginning of the last century [11], However, intense research activity in many companies on the direct synthesis of H202 only began in 1980. Some 100 patents were issued in the 1980s and 1990s from companies such as Air Products, BASF, Dow Chemicals, Du Pont, ENI, Eka Nobel, FMC, Solvay Interox, Mitsubishi Gas Chemical and Shell. Table 8.2 summarizes some selected comparative results. 

In principle, process integration applies even more to direct synthesis of hydrogen peroxide, further improving the advantages over the anthraquinone route. Methanol can be used to replace water as the solvent and the dilute methanol solution obtained fed into the epoxidation reactor. Minimal purification may be required, for example for the removal of hydrogen bromide and other additives that may have been needed to increase the selectivity. 

Solsona, B. E. Edwards, J. K. Landon, P. Carley, A. F. Herzing, C., Direct synthesis of hydrogen peroxide from H2 and 02 using A1203 supported Au-Pd catalysts, Chem. Mater. 2006, 18(11), 2689-2695... 

Centi, G., Perathoner, S. and Abate, S. (2009) Direct synthesis of hydrogen peroxide recent advances, in Modem Heterogeneous Oxidation Catalysis ... 

G. Li, J. Edwards, A. E. Carley, G. J. Hutchings, Direct synthesis of hydrogen peroxide from H2 and O2 using zeolite-supported Au-Pd catalysts, Catal Today 122 (2007) 361. 

New routes to hydrogen peroxide new methods for direct synthesis of hydrogen peroxide (from hydrogen and oxygen) in a controlled, safe manner could provide a lower cost oxidant that reduces the use of chlorine. For example, in situ generation of hydrogen peroxide can be used to produce propylene oxide in place of the chlorohydrin route and... 

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