Fluid Phase Behavior from Molecular Simulation: Hydrazine, Monomethylhydrazine, Dimethylhydrazine and Binary Mixtures Containing These Compounds Ekaterina Elts1, Thorsten Windmann1, Daniel Staak2, Jadran Vrabec1 ∗ 1 Lehrstuhl f¨ur Thermodynamik und Energietechnik, Universit¨at Paderborn, Warburger Straße 100, 33098 Paderborn, Germany 2 Lonza AG, Chemical Research and Development, CH-3930 Visp, Switzerland Keywords: Molecular modeling and simulation; vapor-liquid equilibrium; Henry’s law constant; Hy- drazine; Monomethylhydrazine; Dimethylhydrazine; Argon; Nitrogen; Carbon Monoxide; Ammonia; Water Abstract New molecular models for Hydrazine and its two most important methylized derivatives (Monomethyl- hydrazine and Dimethylhydrazine) are proposed to study the fluid phase behavior of these hazardous compounds. A parameterization of the classical molecular interaction models is carried out by using quan- tum chemical calculations and subsequent fitting to experimental vapor pressure and saturated liquid density data. To validate the molecular models, vapor-liquid equilibria for the pure hydrazines and binary hydrazine mixtures with Water and Ammonia are calculated and compared with the available experimen- tal data. In addition, the Henry’s law constant for the physical solubility of Argon, Nitrogen and Carbon Monoxide in liquid Hydrazine, Monomethylhydrazine and Dimethylhydrazine is computed. In general, the simulation results are in very good agreement with the experimental data. ∗ corresponding author, tel.: +49-5251/60-2421, fax: +49-5251/60-3522, email:
[email protected] 1 1 Introduction On October 24, 1960, the greatest disaster in the history of rocketry, now also known as Nedelin disaster, occurred [1–3]. At that time, the Soviet newspapers published only a short communique informing that Marshall of Artillery Mitrofan Nedelin has died in an airplane crash.