Normal Boiling Point Prediction Of Carbocyclic Nitroaromatic Compounds

Physical CHEMISTRY INTRODUCTION The basis for any design and simulation of chemical and environmental systems is a reliable set of physical and chemical properties of reactants. Since it is not always possible to find experimental values in the literature as well as measurement is expensive and time consuming or sometimes even difficult or impossible, estimation methods are generally of great value. Empirical methods complemented the computer output for desk calculations of performance and physicochemical properties of energetic compounds would be needed because the expenditure connected with the development and synthesis of a new energetic material. One of the most comprehensive estimation procedures for boiling point, melting point, and vapor pressure is group contribution methods, where values assigned to atoms, bonds, and their placement in a molecule are used to estimate their contribution to the inherent physicochemical properties of that molecule[1]. Some of group contribution methods are Joback and Reid[2], Constantinou et al.[3,4], Prickett et al.[5], Constantinou and Gani[6]. Some new simple methods have been recently introduced for simple evaluation of thermochemical properties of energetic compounds, e.g. melting point[7,8] and heat of formation[9-11]. The normal boiling points reflect the strength of the intermolecular forces (among other forces present) that hold them together. However, the stronger the intermolecular forces, the more tightly the atoms will be held Mohammad Hossein Keshavarz*, Hamid Reza Pouretedal Department of Chemistry, Malek-Ashtar University of Technology, Shahin-Shahr P.O. Box-83145/115, (ISLAMIC REPUBLIC OF IRAN) Tell : (0098)-0312-522-5071; Fax : (0098)0312-522-5068 Received: 6 August, 2007 ; Accepted: 11 August, 2007 A new approach has been introduced to predict boiling point of carbocyclic nitroaromatic compounds. This method is based on the number of carbon, hydrogen and oxygen as well as the contribution of specific polar group para to nitro group in disubstituted benzene ring and the number of alkyl or aryl group ortho to nitro group. Thirteen experimental data were used to predict the suitable correlation. Optimized correlation can be used to dinitro aromatic compounds which belong to energetic compounds. Predicted boiling points using the method described herein have been tested for 26 nitroaromatic carbocyclic compounds and compared with group-contribution method of Joback-Reid[K.G.Joback, R.C.Reid, Chem. Eng.Comm., 57, 233(1987)]. Predicted boiling temperatures have the average deviations for new and Joback-Reid procedures 3.0% and 13.1%, respectively.  2007 Trade Science Inc. INDIA