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

Brazilian Journal of Chemical Engineering

S. G. Pakdehi²  M. Sohrabi¹  A. S. Moghaddam¹ 

[1] ,University of Tehran Faculty of Chemical Engineering Tehran,Iran

关键词: Monomethyl hydrazine;    Hydrogenation;    Pd/γ-Al2O3 catalyst;    Kinetics;   

DOI  :  10.1590/S0104-66322010000100013

来源: SciELO

【 摘 要 】

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-Al2O3 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.

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