Overall kinetics of hydrogen peroxide formation by direct combination of H2 and O2 in a microreactor

Voloshin, Yury; Lawal, Adeniyi

doi:10.1016/j.ces.2009.09.056

Cited by 60 publications

(52 citation statements)

References 25 publications

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“…To increase selectivity, H 2 O 2 production needs to increase, or the rate of water formation to decrease, or both of them together. It is reported [19,20] that stabilizers and small H 2 conversion can increase selectivity up to 100%. In our case reagents conversion was rather low due to the short contact time between the liquid phase and the catalytic bed.…”

Section: Production Rate and Selectivity Optimizationmentioning

confidence: 99%

“…Selectivity in most of the cases is enhanced by adding some stabilizers, like alogens (NaBr, HBr) or acids (H 2 SO 4 ) [9,10,12,20,23], to the reaction medium (e.g. methanol, water, ethanol), to support H 2 O 2 production by suppressing water formation and H 2 O 2 decomposition.…”

Section: Introductionmentioning

confidence: 99%

“…The possibility of using microreactors is further limited by the low conversion of the reagents inside the reactor (e.g. when H 2 conversion is around 35% selectivity is around 30% and when H 2 conversion is around 2% selectivity is 100%) [19,20] and their cost, still high to be scaled up for industrial purpose [17][18][19][20][21] reactors is an alternative for direct synthesis [15,16,22]. The catalyst is deposited into the pores of a fine-porous surface layer, while O 2 and H 2 are kept separated by a membrane [15].…”

Section: Introductionmentioning

confidence: 99%

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Continuous H2O2 direct synthesis over PdAu catalysts

Biasi¹,

Menegazzo²,

Pinna³

et al. 2011

Chemical Engineering Journal

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a b s t r a c t H 2 O 2 direct synthesis over two bimetallic, palladium-gold catalysts based on sulfated ceria (PdAu-CeS) and on sulfated zirconia (PdAu-ZS) has been studied in a continuous, trickle-bed reactor, at −10• C and 10 bar. Three different liquid flow rates and seven different gas flow rates were used. The combined effect of liquid and gas flow rates, with two different H 2 /O 2 ratio (2/18 and 4/16) in the gas feed, has been studied, by independent variations. The highest H 2 /O 2 ratio always increases production rate and selectivity. In the case of 4/16 ratio, PdAu-CeS catalyst shows an enhancement in selectivity only, while the increase in H 2 O 2 production rate is not significant compared to the 2/18 ratio case. PdAu-ZS catalyst shows a remarkable gain in both selectivity and production rate when the 4/16 ratio in gas feeding is used, outperforming the PdAu-CeS catalyst. The enhancement of the catalytic activity is more pronounced in the case of PdAu-ZS, compared to PdAu-CeS, when the highest H 2 /O 2 ratio is used. A selectivity up to 90% has been measured on PdAu-ZS with the higher H 2 /O 2 ratio and larger liquid flow rates. The maximum production rate measured is 6 mol/min (i.e. a productivity 0.18 mol H 2 O 2 g Pd −1 h −1 ) with 1 ml/min liquid flow rate and 2.7 ml/min gas flow rate again on PdAu-ZS.

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Section: Production Rate and Selectivity Optimizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Continuous H2O2 direct synthesis over PdAu catalysts

Biasi¹,

Menegazzo²,

Pinna³

et al. 2011

Chemical Engineering Journal

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“…Furthermore, alternative reaction systems such as microreactors [19][20][21][22][23] and catalytic membranes [24][25][26] have been successfully employed in direct synthesis of hydrogen peroxide during the last few years. There are also other systems, such as fuel cells for electrochemical synthesis, [27][28][29][30][31][32][33][34] which strictly speaking can be considered as "direct synthesis" because they only use hydrogen and oxygen, but they are beyond the scope of this review.…”

Section: Tapio O Salmimentioning

confidence: 99%

“…They also observed and increase in the selectivity between 0.35 and 0.7 MPa but they did not observe a significant increase in selectivity between 0.7 and 2.1 MPa. 23 Most of the patents indicated ranges of pressure up to more than 20.0 MPa. At industrial scale, the pressure will be a compromise between expensive equipment and an intensive lowvolumetric process.…”

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confidence: 99%

Engineering in direct synthesis of hydrogen peroxide: targets, reactors and guidelines for operational conditions

et al. 2014

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The demand for hydrogen peroxide is booming since it is considered as one of the most environmentally friendly and versatile chemical oxidants available and has a wide range of applications. The annual market, close to 3000 kt per year being produced via the auto-oxidation process (with 2-ethyl anthraquinone (traditional) or amyl anthraquinone for mega-plants), is mostly supplied by the company Solvay (30%), followed by Evonik (20%) and Arkema (13%). Nevertheless, the dream of a direct synthesis process is close to a century old and it has gained momentum in research efforts during the last decade with more than 15 groups active in the world. In this review, we focus the discussion on the targets, e.g. plant tonnage, the reactors and the most feasible industrial operational conditions, based on our experience and point of view using the chemical engineering tools available. Thus, direct synthesis can be competitive when on-site production is required and capacities less than 10 kt per year are He has led and participated in 3 EU, 6 national/regional projects and 10+ SME contracts and has published 30+ research papers. Teresa MorenoTeresa Moreno obtained her degree in Chemical Engineering from Complutense University (Madrid, Spain) and later completed her PhD in Chemical Engineering at the University of Valladolid (Spain, 2011) studying the catalytic direct synthesis of hydrogen peroxide in supercritical CO 2 and the online determination of the product using Raman spectroscopy. She is currently a Research Scientist in the Industrial Bioactive Technologies Group at Callaghan Innovation (New Zealand) working on the development of processes for adding value to natural materials toward high value products and applications, including the development of sustainable technologies using supercritical fluids. View Article OnlineView Journal | View Issue and semi-continuous modes of operation. However, at the moment, demonstrations of continuous operations as well as carefully determined kinetics are needed in order to scale up the process. Finally, operational conditions, including the catalyst composition (active metal, oxidation state and support), promoters (halides and acids-pH-isoelectric point), solvents, pressure and temperature need to be carefully analysed. In our opinion, as we try to show here, H 2 O 2 direct synthesis is a competitive process and is ready for larger scale demonstration. Also, more than a hundred patents within the area support this claim, although the barriers of technology demonstration and further licensing are still pending.

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