Group Reciprocal Bond Topology Space Method

Data concerning the properties of organic compounds are very important in chemical and petroleum industries. It is not always available to find reliable experimental values of properties for the interesting compounds in the literature, nor is it practical to measure the properties as the need arise. Therefore, estimation of properties of organic compounds is required. To obtain the properties of pure compounds, simple group contribution methods, which can provide the important advantage of quickly estimating without requiring substantial computational resources, are widely used. However, many of these methods are of questionable accuracy and utility. To overcome this limitation, complex group contribution methods have been introduced into the relevant research.In this thesis, a new complex group contribution method was proposed, two improvements were achieved based on simple group contribution methods, and a concept of group reciprocal bond was proposed and classified in order to increase the environmental impact of bond's position in a molecule. In our theory, the molecule space was described by a space matrix,and the bond positions in the molecule were indicated by row vectors in the matrix, bond module index was defined to identify bond position in the molecule. 7 property data of 1228 substances were collected from "CRC Handbook of Data on Organic Compounds", "TRC Thermodynamic Table-Hydrocarbons" and"The Properties of Gases and Liquids". In view of simple group contribution and bond module index, a universal model was set up as the following:, and bond contribution data from 1228 substances were calculated by this equation. Expressions in the new method for Tm, Tb, Tc, Pc, Vc, △Hvb, △H0f, 298, Zc and △G0f, 298 were proposed, and the relative group parameters were presented. The average percent deviations in the model to estimate Tm, Tb, Tc, Pc, Vc, △Hvb and Zc are 7.53%, 1.58%, 0.76%, 2.17%, 1.56%, 1.26% and 1.76%, respectively. The average absolute deviations in the model for estimating △H0f, 298 and △G0f, 298 are 3.86 kJ/mol and 4.22 kJ/mol, respectively。Furthermore, some property data of 2, 3, 5-trimethylethane, 2, 4-diamethylphenol, 1-bromine-2, 4-diamethyl benzene and ethylbenzene were calculated from complex group contribution method and the results were obviously better than those of the others.