After the required time, the resulting mixture was cooled, sampled and analyzed. Reaction conditions: RT = 75 °C; P(CO2) = 0.55 MPa; (H2O2/ Cumene: 2.5) volume ratio; Rt = 7 h; m(cat) = 0.75 g and m(co-catalyst) = 0.25 g. a1, Ph = O; 2, Ph-PrOH; 3, PhOH; 4, Acet; 5, Toluene; 6, Benzene; 7, Ethylbenzene. P. Andrigo, A. Caimi, P. Cavalieri d'Oro, A. Fait, L. Roberti, M. Tampieri, V. Tartari. Besides the reflections assigned to AC, characteristic peaks of CoPW are also observed. Figure 5. The peak at around 1730 cm−1 correspond to the C=O strength vibration in the COOH group (Fanning and Vannice 1993, Zhuang et al 1994, Shanmugharaj et al 2007, Yang et al 2017). The kinetic modeling of cumene oxidation taking into account oxygen mass transfer. Express 7 025606. For this purpose, the effect of the oxidizing system composition, the reaction temperature, the H2O2/Cumene ratio, the amount of catalyst, the reaction time and the CO2 pressure on the oxidation of Cumene was examined. Unfortunately, when they are used in the liquid phase and in the polar medium, they have the disadvantages of homogeneous catalysts, that is to say, difficulties of recycling and purification of the products. Indeed, the x-ray diffractions for the keggin structure show peaks in each of the four ranges of 2θ, namely 7°–10°, 16 –23°, 25°–30° and 31°–38°. The reflections observed at 26.1°, 43.1°, 53.5° and 78.7° 2θ for AC-CoPW (figure 2(b)) correspond to (002), (100), (004) and (110) diffractions respectively of hexagonal graphite (Zhang et al 2002, Sun et al 2005, Delidovich and Palkovits 2016). Ana Ison, Cheng Xu, G. Ken Weakley, David E. Richardson.

To find out more, see our, Browse more than 70 science journal titles, Read the very best research published in IOP journals, Read open access proceedings from science conferences worldwide, © 2020 The Author(s). Heteropolyatungstates are among the most suitable catalysts for H2O2 oxidation reactions. Hydrogen peroxide produces water by decomposition, which contributes to the deactivation of several catalysts (Sundaravel et al 2013, Liu et al 2016). Reactions conditions: T = 75 °C; P (CO2) = 0.55 MPa; (H2O2/cumene: 2.5) volume ratio; tr = 7 h; m (cat) = 0.75 g and m (co-catalyst) = 0.3 g. The effect of co-catalyst amount on cumene oxidation was investigated in the mass fraction ranging from 0.16 to 0.34. Elemental analysis of CoPW was done by ICP and the results were reported in table 1(a). Ph-PrOH and Ph = O products are important intermediates. Cumene is formed in the gas-phase Friedel–Crafts alkylation of benzene by propylene.

Find more information about Crossref citation counts. XRD characterization were carried out employing an Ultima IV x-ray Rigaku diffractometer using Cu-Kα radiation. Vadim V. Krongauz, John F. O’Connell, Michael T. K. Ling. Influence of substituents on rate constants for recombination of tertiary peroxy radicals. Benzene and propylene are compressed together to a pressure of 30 standard atmospheres at 250 °C in presence of a catalytic Lewis acid. Kinetics and mechanism of the reaction of dimethyldioxirane with cumene. Etsuo Niki, Yoshio Kamiya, Nobuto Ohta. Materials Research Express, In fact, it has been reported that when hydrogen peroxide is used with carbon dioxide its efficiency increased (Hâncu et al 2002, Nolen et al 2002).

Therefore, their utilization as heterogeneous catalytic systems are promising ways. FRANK R. MAYO, MARTIN G. SYZ, THEODORE MILL, and JANE K. CASTLEMAN. The procedure is as follow: a given amount of catalyst and co-catalyst (TBABr) were added to the cumene and hydrogen peroxide (30% in aqueous solution) solution. Table 2. The term stems from cumene (isopropyl benzene), the intermediate material during the process. Reactivity of the C-H bond of organic molecules with various structures in hydrogen abstraction by peroxyl radicals. These results are confirmed by the surface area measurement. RIS.

The effect of CO2 on the course of the reaction was studied by varying the CO2 pressure from 0M Pa to 0.55 MPa. Cumene is formed in the gas-phase Friedel–Crafts alkylation of benzene by propylene. Cumene hydroperoxide was observed as trace because of it decomposition in acidic aqueous medium (H2O produced by H2O2 decomposition. Indeed, the unsupported CoPW catalyst has only Lewis type acid sites, whereas the supported catalyst ACA-CoPW has, in addition to these Lewis type acid sites, Brønsted type acid sites on the surface of the activated carbon. As for the selectivities of the reaction products, it can be noticed that increasing the concentration of H2O2 decreased, the selectivity of Ph-PrOH and PhOH in favor of Ph = O. Among the tungstate-based systems, the Peroxotungstate [PO4(WO(O2)2)4]3−, also called Venturelo complex has been postulated as being a catalytically active species in the oxidation of various reactions (Ishii et al 1988, Duncan et al 1995, Qi et al 2011). This is explained by the decrease in the concentration of H2O2, and therefore it is the effect of CO2 that remains predominant (constant CO2 pressure) thus leading to cracking reactions. It was noted that small concentrations of {{\rm{HCO}}}_{4}^{-} present in the mixtures are sufficient to significantly increase oxidation. Hubert Muchalski, Alexander J. Levonyak, Libin Xu, Keith U. Ingold, and Ned A. Porter .