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Epoxidation of 1,5,9-cyclododecatriene with H2O2in the presence of tungstophosphoric acid (H3PW12O40)

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Wołosiak A., Lewandowski G.
Polish Journal of Chemical Technology
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2010
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vol. 12
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issue 3
40-44
EN
The influence of the technological parameters on the epoxidation of 1,5,9-cyclododecatriene (CDT) to 1,2-epoxy-5,9-cyclododecadiene (ECDD) by the phase-transfer catalysis method (PTC) in the presence of tungstophosphoric heteropolyacid (H3PW12O40) and hydrogen peroxide as the oxidizing agent has been presented. The phase-transfer catalyst was Aliquat® 336 (methyltrioctylammonium chloride). The epoxidation of CDT to ECDD in the PTC system proceed under the relatively mild condition: low temperature, lack of solvent, short reaction time.The effect of: the mixing velocity, the molar ratio of CDT:H2O2 and H2O2:H3PW12O40, the nature of the solvent and its concentration, was studied. The most advantageous technological parameters were: the mixing rate 400 - 600 rpm, the molar ratio of CDT:H2O2 = 3:1 - 1.5:1, the molar ratio of H2O2:H3PW12O40 = 200:1 - 400:1, the temperature 40 - 50°C, solvent: dichloromethane or lack of the solvent, dichloromethane concentration: 10 - 50 vol%, reaction time 35 - 50 min. The application of the above-mentioned parameters allows to achieve the yield of 44 - 47% ECDD in relation to introduced CDT.
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Oxidation of Cyclohexene with H₂O₂ Catalyzed by Vanadium Based Polyoxometalates Doped Modified Clays as Green Catalysts

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Boudjema S., Rabah H., Choukchou-Braham A.
Acta Physica Polonica A
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2017
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vol. 132
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issue 3
469-472
EN
The catalytic performance of supported heteropolyacids in various liquid-solid and gas-solid heterogeneous reactions may be affected by the choice of support and/or the method of heteropolyacid deposition. Vanadium substituted polyphosphomolybdate with the Keggin structure H₄[PVMo₁₁O₄₀]· 13H₂O (PVMo) was dispersed throughout acid activated bentonite (clay from Hammam Boughrara, Maghnia, Algeria). A series of catalysts were prepared via modified impregnation. Modified preparation method employed ultrasonication as a means of the dispersion homogenization, followed by freeze-drying. The catalysts were characterized by the Brunauer-Emmett-Teller, the Fourier transform infrared, and ³¹P solid-state magic angle spinning-NMR spectroscopy. The catalytic performance of PVMo/Hmont was evaluated in the oxidation of cyclohexene. Intact Keggin anions were preserved on Hmont after deposition aided by ultrasonication. The obtained results showed that a better catalytic activity can be obtained with PVMo/bentonite (98% of conversion and 89% of cyclohexene oxide), by drop addition of H₂O₂, for 3 h.
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