Liquid phase hydrogenation of acethydrazone to N'-methyl acethydrazide over Pd/γ-Al2O3 catalyst

Abstract

Catalytic hydrogenation of acethydrazide (AH) is the main step in the production of N´-methyl acethydrazide (MAH). In this step, AH reacts with formaldehyde to produce acetylhydrazone (AOH). AOH is hydrogenated in the presence of 5% Pd/γ-Al 2 O 3 catalyst to MAH. In this paper, the effects of hydrogen pressure, catalyst loading and initial concentration of AOH on the initial rate of hydrogenation were studied in a batch slurry reactor within a temperature range of 303-333K. The hydrogenation rate was first order with respect to hydrogen concentration at lower hydrogen pressures. However, at higher pressures, the rate became independent of both hydrogen and initial AOH concentrations. A single site Langmuir-Hinshelwood type formulation was found to describe adequately the kinetic data. A good correlation was observed between the predicted concentration vs. time profiles and those determined experimentally. The apparent activation energy was calculated from the initial rates as 40.6 kJ/mol.

Optimization of Pd-B/γ-Al2O3 catalyst preparation for palm oil hydrogenation by response surface methodology (RSM)

“…The batch consisted of 250 g of fully refined palm oil. For each run, and prior to hydrogen injection, the reactor was flushed with nitrogen gas to remove the air and dissolved oxygen (Pakdehi et al, 2010). Hydrogenation was performed on the 0.12% Pd-B/γ-Al 2 O 3 catalyst at a temperature of 393 K, hydrogen pressure of 500 kPa and agitation of 500 rpm for 1h.…”

Liquid-Phase Hydrogenation of Maleic Acid over Pd/Al2O3 Catalysts Prepared via Deposition–Precipitation Method

“…Yuan et al reported achieving MA conversion of 98% and succinic anhydride selectivity of 99% using Pd/Al 2 O 3 catalyst under 1.0 MPa of H 2 pressure and 1,4-dioxane as solvent [5]. Among the various catalysts, the Pd/Al 2 O 3 catalyst has an advantage for the chemical industry due to the high thermal stability and high dispersion of Pd [10,11]. However, few studies have been performed on the optimization of reaction conditions for the hydrogenation of maleic acid (MA) on the optimization of reaction conditions for the hydrogenation of maleic acid (MA) to SA over a Pd/Al2O3 catalyst.…”