Direct production of H2O2 from H2 and O2 in a biphasic H2O/scCO2 system over a Pd/C catalyst: Optimization of reaction conditions

Moreno, Teresa; Serna, Juan García; Alonso, Manuel García

doi:10.1016/j.supflu.2011.09.013

Cited by 7 publications

(24 citation statements)

References 33 publications

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“…First of all it can be seen that adding the acid to the reaction medium containing a fixed amount of NaBr has a beneficial effect on the direct synthesis (Runs #1 to #5 and #11, #12), second, that using different acids resulted in a different pH but a similar production of H 2 O 2 (Runs #8 and #9), and that the increase in NaBr concentration resulted in a higher H 2 O 2 production (Runs #1, #6 and #7). The optimal pH for the production of H 2 O 2 seems to be 2.5, as already reported in literature …”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Hydrogen peroxide obtained via direct synthesis as alternative raw material for ultrapurification process to produce electronic grade chemical

Abejón

Biasi

et al. 2015

J of Chemical Tech & Biotech

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BACKGROUND:The catalytic direct synthesis of hydrogen peroxide is a highly interesting alternative process to avoid the current anthraquinone route because implies significant sustainability improvements. Among all the peroxide applications, its use as electronic chemical requires very low metallic content. The employment of direct synthesis peroxide as raw material for ultrapurification process has not been investigated before, so its viability is still pending of evaluation. RESULTS:Although the improvements of the catalyst or reactor performances of the direct synthesis process were not defined as objectives of the work, a maximal peroxide concentration of 2.3% was obtained, which is a very good result considering the low pressure used. Some relationships between the measured metallic concentrations in the obtained chemical and the operation conditions have been very useful to identify the most important conditions (selection of appropriate quality for the chemicals and proper materials for the installation) to promote the production of hydrogen peroxide with low metallic content. The technical competitiveness of this alternative ultrapurification process was clearly demonstrated as the number of required membrane stages (from 1 to 6 depending on the product quality) is lower than the required one by the traditional case. Besides, the process can be considered economically viable if the direct synthesis peroxide can be produced with a total cost below 36.5 $/m 3 . CONCLUSION:Further investigation, specifically focused to holistic approaches, is still necessary in order to assess the total costs of hydrogen peroxide production by direct synthesis. This way, the current available information could be complemented and the competitiveness of this direct route to obtain hydrogen peroxide for electronic grade chemical production could be more clearly defined.

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Section: Resultsmentioning

confidence: 99%

“…The addition of promoters such as halide salts and inorganic acids in the medium solution seems to increase the selectivity, thus reducing the occurrence of undesired reactions: numerous studies have been carried out, in which the effect of these enhancers have been evaluated …”

Section: Introductionmentioning

confidence: 99%

Hydrogen peroxide obtained via direct synthesis as alternative raw material for ultrapurification process to produce electronic grade chemical

Abejón

Biasi

et al. 2015

J of Chemical Tech & Biotech

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“…The decrease in selectivity, productivity, and H 2 conversion at the higher acid concentrations may be attributed to a notable leaching of Pd from the catalyst but also to a decrease in the solubility of both the gaseous reactants (H 2 and O 2 ). 26,27,29,30 As acid can favor the solubilization of Pd, reducing the metallic Pd (not soluble) to Pd 2+ (soluble in solvents), 31 it is easy to deduce that the presence of acid may increase the leaching of Pd. Acid and bromide play a synergic role in the formation of H 2 O 2 : protons (acid) in fact, when added to the reaction medium, facilitate the adsorption of Br − anions on the catalyst surface and thus allow the change of electronic properties of Pd.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Bromide and Acids: A Comprehensive Study on Their Role on the Hydrogen Peroxide Direct Synthesis

Gallina

García-Serna

Salmi

et al. 2017

Ind. Eng. Chem. Res.

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Hydrogen peroxide direct synthesis was studied using different concentrations of NaBr and H3PO4 (promoters) with a commercial Pd/C catalyst. The aim of the study was to understand the role of the acids and bromide on the catalyst and thus the effect on the direct synthesis. The experimental work was done in a continuous trickle bed reactor (TBR) using different concentrations of promoters. The effect of the promoters on the catalyst (Pd leaching and bromide adsorption) was monitored by inductively coupled plasma (ICP) on the solution obtained from the reaction environment. ICP analysis coupled with the monitoring of conversion, selectivity, and productivity helped to understand the effect of the promoters and to check the possibility to discriminate better the reaction network mechanism with different reaction conditions. Pd leaching was correlated to catalyst activity and bromide/phosphoric acid ratio. This work provides new and original evidence on the role of promoters, allowing one to understand better how to push the direct synthesis and how to control the catalyst ability to produce H2O2 rather than H2O.

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“…When CO 2 is selected as the SCF in conjunction with water, both solvents in the biphasic system are environmentally benign, non-toxic, inexpensive, and abundant. In fact, scCO 2 -water mixtures as both emulsions [22][23][24][25][26][27][28][29][30][31] and microemulsions [32] have been used for a wide variety of chemical reactions including Diels-Alder cycloaddition [33], olefin epoxidation [34], hydrolysis reactions [35][36][37], polymerization reactions [38], Barbier reaction [39], oxidation [40], hydrogenation [41,42], hydroformylation [43], biomass pretreatment [44], hydrogen peroxide synthesis [45,46], and particle and materials synthesis [47]. Beyond the chemical process industries, scCO 2 /water mixtures -including emulsions -are likely important in geological systems and potentially of interest for geological CO 2 sequestration and CO 2 enhanced oil recovery [48].…”

Section: Introductionmentioning

confidence: 99%

Formation and characterization of emulsions consisting of dense carbon dioxide and water: Ultrasound

Timko

Marre

Maag

2016

The Journal of Supercritical Fluids

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International audienceIn this work, we studied ultrasound formation of surfactant-free emulsions consisting of water and dense carbon dioxide (CO2). Emulsions with limited kinetic stability were formed after approximately 2 min of pulsed ultrasound at 20 kHz and above a critical power density of at least 0.05 W cm−3. Emulsion stability and formation were studied using a variety of techniques. In situ microscopy using a high-pressure microfluidic reactor indicated that the water/CO2 emulsion consisted of finer droplets of about 5 μm compared to the CO2/water emulsion which consisted of droplets with average diameters of about 12 μm. A partially miscible tracer technique was used to measure the dispersed phase content of the two emulsions to be about 4 vol% and up to 9 vol% for the CO2/water and water/CO2 emulsions, respectively. Engineering analysis and complementary experiments indicated that the water/CO2 emulsions formed via a two-step mechanism consisting of surface wave break-up to form a coarse emulsion followed by cavitation to form a fine emulsion. We use KI oxidation as a probe reaction to examine ultrasound-induced chemistry in the dense CO2/water system, finding that KI oxidation was suppressed by the presence of a high pressure CO2 phase. Through the combination of formation, stability, and KI oxidation experiments and analyses, we suggest that the dense CO2 cushioned cavitation bubble collapse, damping ultrasound chemical effects while permitting physical effects such as emulsification. Engineering analysis suggests energy efficient scale-up might be achieved in a carefully designed flow reactor

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Direct production of H2O2 from H2 and O2 in a biphasic H2O/scCO2 system over a Pd/C catalyst: Optimization of reaction conditions

Cited by 7 publications

References 33 publications

Hydrogen peroxide obtained via direct synthesis as alternative raw material for ultrapurification process to produce electronic grade chemical

Hydrogen peroxide obtained via direct synthesis as alternative raw material for ultrapurification process to produce electronic grade chemical

Bromide and Acids: A Comprehensive Study on Their Role on the Hydrogen Peroxide Direct Synthesis

Formation and characterization of emulsions consisting of dense carbon dioxide and water: Ultrasound

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