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Sandri F, De Boni F, Marelli M, Sedona F, Causin V, Centomo P, Zecca M. The role of acetonitrile in the direct synthesis of hydrogen peroxide over palladium supported by ion-exchange resins. CATAL COMMUN 2022. [DOI: 10.1016/j.catcom.2022.106585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Silica Bifunctional Supports for the Direct Synthesis of H2O2: Optimization of Br/Acid Sites and Pd/Br Ratio. Catalysts 2022. [DOI: 10.3390/catal12070796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have studied the direct synthesis of hydrogen peroxide using a catalytic system consisting of palladium supported on silica bifunctionalized with sulfonic acid groups and bromide in the absence of acid and halide promoters in solution. Catalysts with several bromide substituents were employed in the catalyst synthesis. The prepared samples were characterized by TXRF, XPS, and hydrogen peroxide decomposition. Catalysts characterization indicated the presence of only palladium (II) species in all of the samples, with similar values for surface and bulk of Pd/Br atomic ratio. The catalysts were tested via direct synthesis, and all samples were able to produce hydrogen peroxide at 313 K and 5.0 MPa. The hydrogen peroxide yield and selectivity changed with the Pd/Br ratio. A decrease in the Pd/Br ratio increases the final hydrogen peroxide concentration, and the selectivity for H2O2 reaches a maximum at a Pd/Br ratio around 0.16 and then decreases. However, the maximum hydrogen peroxide concentration and selectivity occur at slightly different Pd/Br ratios, i.e., resp. 0.4 vs. 0.16.
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Sandri F, Danieli M, Zecca M, Centomo P. Comparing Catalysts of the Direct Synthesis of Hydrogen Peroxide in Organic Solvent: is the Measure of the Product an Issue? ChemCatChem 2021. [DOI: 10.1002/cctc.202100306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Francesco Sandri
- Dipartimento di Scienze Chimiche Università degli Studi di Padova Via Marzolo 1 35131 Padova Italy
| | - Mattia Danieli
- Dipartimento di Scienze Chimiche Università degli Studi di Padova Via Marzolo 1 35131 Padova Italy
| | - Marco Zecca
- Dipartimento di Scienze Chimiche Università degli Studi di Padova Via Marzolo 1 35131 Padova Italy
| | - Paolo Centomo
- Dipartimento di Scienze Chimiche Università degli Studi di Padova Via Marzolo 1 35131 Padova Italy
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Yao Z, Zhao J, Zhao C, Deng S, Zhuang G, Zhong X, Wei Z, Li Y, Wang S, Wang J. A first-principles study of reaction mechanism over carbon decorated oxygen-deficient TiO2 supported Pd catalyst in direct synthesis of H2O2. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2020.11.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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The Direct Synthesis of H2O2 and Selective Oxidation of Methane to Methanol Using HZSM-5 Supported AuPd Catalysts. Catal Letters 2019. [DOI: 10.1007/s10562-019-02876-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Direct Synthesis of Hydrogen Peroxide under Semi-Batch Conditions over Un-Promoted Palladium Catalysts Supported by Ion-Exchange Sulfonated Resins: Effects of the Support Morphology. Catalysts 2019. [DOI: 10.3390/catal9020124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Palladium catalysts supported by a mesoporous form of sulfonated poly-divinylbenzene, Pd/µS-pDVB10 (1%, w/w) and Pd/µS-pDVB35 (3.6% w/w), were applied to the direct synthesis of hydrogen peroxide from dihydrogen and dioxygen. The reaction was carried for 4 h out in a semibatch reactor with continuous feed of the gas mixture (H2/O2 = 1/24, v/v; total flow rate 25 mL·min−1), at 25 °C and 101 kPa. The catalytic performances were compared with those of a commercial egg-shell Pd/C catalyst (1%, w/w) and of a palladium catalyst supported by a macroreticular sulfonated ion-exchange resin, Pd/mS-pSDVB10 (1%, w/w). Pd/µS-pDVB10 and Pd/C showed the highest specific activity (H2 consumption rate of about 75–80 h−1), but the resin supported catalyst was much more selective (ca 50% with no promoters). The nanoparticles (NP) size was somewhat larger in Pd/µS-pDVB10, showing that either the reaction was structure insensitive or diffusion limited to some extent over Pd/C, in which the support is microporous. The open pore structure of Pd/µS-pDVB10, possibly ensuring the fast removal of H2O2 from the catalyst, could also be the cause of the relatively high selectivity of this catalyst. In summary, Pd/µS-pDVB10 was the most productive catalyst, forming ca 375 molH2O2·kgPd−1·h−1, also because it retained a constant selectivity, while the other ones underwent a more or less pronounced loss of selectivity after 80–90 min. Ageing experiments showed that for a palladium catalyst supported on sulfonated mesoporous poly-divinylbenzene storage under oxidative conditions implied some deactivation, but a lower drop in the selectivity; regeneration upon a reductive treatment or storage under strictly anaerobic conditions (dry-box) lead to an increase of the activity but to both a lower initial selectivity and a higher drop of selectivity with time.
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Tian P, Ding D, Sun Y, Xuan F, Xu X, Xu J, Han YF. Theoretical study of size effects on the direct synthesis of hydrogen peroxide over palladium catalysts. J Catal 2019. [DOI: 10.1016/j.jcat.2018.10.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Experimental Evaluation of a Membrane Micro Channel Reactor for Liquid Phase Direct Synthesis of Hydrogen Peroxide in Continuous Flow Using Nafion® Membranes for Safe Utilization of Undiluted Reactants. Catalysts 2018. [DOI: 10.3390/catal8110556] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In recent years, various modular micro channel reactors have been developed to overcome limitations in challenging chemical reactions. Direct synthesis of hydrogen peroxide from hydrogen and oxygen is a very interesting process in this regard. However, the complex triphasic process (gaseous reactants, reaction in liquid solvent, solid catalyst) still holds challenges regarding safety, selectivity and productivity. The membrane micro reactor system for continuous liquid phase H2O2 direct synthesis was designed to reduce safety issues by separate dosing of the gaseous reactants via a membrane into a liquid-flow channel filled with a catalyst. Productivity is increased by enhanced mass transport, attainable in micro channels and by multiple re-saturation of the liquid with the reactants over the length of the reaction channel. Lastly, selectivity is optimized by controlling the reactant distribution. The influence of crucial technical features of the design, such as micro channel geometry, were studied experimentally in relationship with varying reaction conditions such as residence time, pressure, reactant ratio and solvent flow rate. Successful continuous operation of the reactor at pressures up to 50 bars showed the feasibility of this system. During the experiments, control over the reactant ratio was found to be crucial in order to maximize product yield. Thereby, yields above 80% were achieved. The results obtained are the key elements for future development and optimization of this reactor system, which will hopefully lead to a breakthrough in decentralized H2O2 production.
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Selinsek M, Deschner BJ, Doronkin DE, Sheppard TL, Grunwaldt JD, Dittmeyer R. Revealing the Structure and Mechanism of Palladium during Direct Synthesis of Hydrogen Peroxide in Continuous Flow Using Operando Spectroscopy. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03514] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Dmitry E. Doronkin
- Institute
for Chemical Technology and Polymer Chemistry, KIT, Karlsruhe 76131, Germany
| | - Thomas L. Sheppard
- Institute
for Chemical Technology and Polymer Chemistry, KIT, Karlsruhe 76131, Germany
| | - Jan-Dierk Grunwaldt
- Institute
for Chemical Technology and Polymer Chemistry, KIT, Karlsruhe 76131, Germany
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