Prediction of heat of formation and related parameters of high energy materials.

Heat of formation is one of the most important parameters in the performance prediction of explosive and propellant formulations and their individual ingredients. This paper reports the development of user-friendly computer code for the prediction of heat of formation based on two approaches. In first methodology, the logic of Benson's Group additivity method and in the second method, the logic of Pedley method was used for predicting the heats of formation of high energy materials (HEMs). The predicted heats of formation by Benson method for various classes of high energy materials gave deviation in the range of 2-10%, whereas nearly 10-15% deviation was observed using Pedley methodology in comparison to experimental values. The linear regression coefficient values (R(2)) of 0.9947 and 0.9637 are obtained for heat of formation values predicted by this code using methodologies I and II, respectively. The newly developed code LOTUSES (version 1.3) has been validated by calculating the heats of formation of standard explosives such as TNT, pentaerythritol tetranitrate (PETN), RDX, HMX, etc., To the best of our knowledge, no such code is reported in literature which can predict heats of formation values integrated with performance parameters of HEMs belonging to all categories of organic compounds viz. aliphatic, aromatic and heterocyclic materials. The code can also be used to obtain parameters such as velocity of detonation, C-J pressure, volume of explosion products, power index, temperature of explosion and oxygen balance of HEMs. The code has been developed in Visual Basic having enhanced Windows environment. This software namely LOTUSES 1.3 is an updated version of the earlier ones namely LOTUSES 1.1 and 1.2 which do not cater for the calculation of heat of formation and temperature of explosion of HEMs. LOTUSES 1.3 is, therefore, a totally integrated software for computing most of the vital parameters of HEMs requiring mainly the molecular structural information of an explosive under consideration.