Untitled

Characterization of bifunctional Pt/H[Ga]ZSM5 and Pt/H[Al]ZSM5 catalysts

“…6a and b). Thus, as a consequence of annulling the hydro-dehydrogenating function in these solids, carbonaceous residues formed in these catalysts are of the cyclic ketones type, such as isophorone and isoxylitones [12], substances having large molecular weight and volume, as well as high boiling point. This causes them to be retained inside the inner structure of the support, leading to a rapid deactivation of the catalysts, as can be seen in Fig.…”

“…In this regard, it is of great interest studying how these solids behave when the nature of the supported phase and the strength of the acidic sites in the zeolitic supports are changed, and also when promoting agents or a second supported metal, such as tin [10,11], copper [12], etc., are added. However, it must be considered that the presence of a second supported metal does not guarantee that a catalyst with the desired properties for a given process is obtained.…”

Vapor phase selective hydrogenation of acetone to methyl isobutyl ketone (MIBK) over Ni/CeO2 catalysts

“…To deal with the thermodynamic constraints and the more stringent environmental legislation, several catalytic systems have been investigated for the single-stage process wherein n-butyraldehyde and H 2 into 2-ethylhexanal or acetone and H 2 into MIBK are directly converted. The catalysts investigated so far in the gas phase conversion are based on molecular sieves as supports such as Pt/H-ZSM-5, 20 Pd/SAPO-11 and Pd/AlPO-11, 21 Ni/AlPON, 22 Pt/Cu/ H(Al)-ZSM-5, 23 and Pt/Cs-X and Pt/Na-X, 24 Pt/C, 25 or they are produced with oxidic supports such as Cu/M I (M II ) oxides, 26 Pd/Mg(Al)O, 27 Ni/CaO-C, 28 Cu/MgO, 29 Pd/Na-MgO, 30 Pd-polyoxometalates, 31 (Pd or Ni)/hydrotalcites, 32 Ni/MgO, 33 and Amberlyst. 34 The reactions were typically studied using fixed-bed tubular reactors at atmospheric pressure and at temperatures that rarely exceed 473 K. Obviously, platinum, palladium, nickel, and copper are the preferred metals for implementing a catalytic hydrogenation activity.…”

Stability Investigation of a Supported TiO2–Pd Bifunctional Catalyst over the One-Pot Liquid-Phase Synthesis of Methyl Isobutyl Ketone from Acetone and H2

“…Nicol et al and Mahajani et al reported that they obtained acetone conversions varying from 25 to 50% and MIBK selectivities varied between 70% and 90% by using a commercial catalyst Pd/Amberlyst CH28 at pressures of 1–10 MPa and temperatures of 120–200 °C. − Nevertheless, the disadvantages of high-pressure operation and poor thermal stability of the resin increase extra commercial costs and limit its lifetime. So, for several decades, other types of multifunctional catalysts with metal oxides as the support, such as Pd/CaO–MgO–SrO–Al 2 O 3 , Pd/Nb 2 O 5 , − Pd/ZnO–Cr 2 O 3 , , Pd/MgO/SiO 2 , Ni/CaO–C, Cu/MgO, and Pd/Ni–LDH–NO 3 , were extensively investigated for the gas-phase reaction in the atmospheric fixed-bed reactors or the liquid-phase reaction in the autoclave batch reactors. However, there are a few reports on the stability investigation of the catalyst for the liquid-phase reaction in the trickle-bed reactors, which are closer to the industry practice of MIBK mass production than other types of reactors.…”