An experimental kinetic optimization of NDMA hydrogenation to UDMH and DMA on a Pd/C catalyst

Gorji, M ; Sharif University of Technology | 2006

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  1. Type of Document: Article
  2. Publisher: 2006
  3. Abstract:
  4. The Unsymmetrical dimethyl hydrazine (UDMH) apart from its use as a versatile rocket fuel, finds numerous industrial applications. Interest in UDMH for various applications in the missile and rocket industry has prompted the study of this member of hydrazine family to greater extent. It can be prepared in several ways but one of the most efficient ones which results in higher yields is the catalytic hydrogenation of Nitroso Dimethylamine (NDMA). In this work the kinetic of NDMA to UDMH hydrogenation on a 5% Pd/C in aqueous solution of NDMA was studied experimentally and optimum conditions of the reaction for maximum yield of UDMH in the presence of undesired dimethyl amine (DMA) product was investigated. Experiments carried out in a Semi-batch three phase CSTR reactor under constant pressure and temperature in the range of 40 to 70°C, pressures of up to 15 bar and NDMA concentration of 40 to 70 wt%. Effects of temperature, pressure and NDMA concentration on NDMA conversion and yield of UDMH product in presence of undesired dimethylamine (DMA) were studied. The study showed that at NDMA concentration of more than 50 wt%, yield of UDMH falls below 0.89 while the best NDMA concentration is between 40 to 50 wt%. Also at the temperature above 50°C, the UDMH yield falls below 0.91 and the best temperature range for this was found to be 40 to 50°C. Lower temperature and concentrations of NDMA lead to higher yields of UDMH. The optimum conditions for selective production of UDMH were sought to be concentration of 40 to 50 wt% and temperature of 40 to 50°C. For these optimum conditions, a kinetic scheme based upon Eley-Rideal(ER) model was proposed to predict UDMH and DMA production rates. Based on the selected ER model, the reaction parameters for UDMH and DMA rate equations were estimated through non linear method of Nelder and Mead and the activation energies of UDMH and DMA reactions were determined to be 15.97 and 64.98 KJ/mol, respectively
  5. Keywords:
  6. Aircraft fuels ; Catalyst activity ; Chemical reactors ; Hydrogenation ; Industrial applications ; Rockets ; Catalytic hydrogenation ; Nitroso Dimethylamine (NDMA) ; Unsymmetrical dimethyl hydrazine (UDMH) ; Versatile rocket fuels ; Hydrazine
  7. Source: CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN)