Group contribution analysis

An alternate approach makes use of a group contribution analysis (7.9j approach. The group contribution analysis method has proved useful for the determination of solubility parameters (12.13L and has provided an approach for a host of other chemical properties (14). In a group contribution analysis, each moiety in the chemical or polymer contributes additively to the property in question. 

Fig. 11. Group contribution analysis leads to the determination of the effective area under the loss modulus-temperature curve. As in any spectroscopic experiment, background must be subtracted, and the instrument calibrated.

The basic theory for the group contribution analysis is predicated on the assumption that the structural groups within the repeat unit contribute to the total loss area on an additive weight fraction basis (3 ). In a quantitative manner (15) ... 

Applications of neural networks are becoming more diverse in chemistry [31-40]. Some typical applications include predicting chemical reactivity, acid strength in oxides, protein structure determination, quantitative structure property relationship (QSPR), fluid property relationships, classification of molecular spectra, group contribution, spectroscopy analysis, etc. The results reported in these areas are very encouraging and are demonstrative of the wide spectrum of applications and interest in this area. 

The formation of these polar groups contributes increased adhesion. Observation of disappearing vinyl groups in the silane coupling agent and of the formation of polystyrene in the silica by FTIR analysis (Fig. 15) have confirmed the occurrence of a reaction between the polymer and the silane coupling agent [77]. 

From a comparative analysis of H NMR spectra of structurally similar pairs of nitroxyl radicals of 3-imidazoline and 3-imidazoline-3-oxide, it was concluded that the nitrone group contributes to a more efficient long-range spin density delocalization in the conjugated n -system of functional groups bonded with atom C-4 (404). 

The objective of this analysis was to gain knowledge from the R-group contributions as determined by the Free-Wilson methodology. Only R-groups for which a coefficient could be determined across the 45 kinases in the panel and the 2 PDE biochemical assays reported in this study were taken into account. For the Diaminopyrimidine series, this resulted in 36 R1 - and 26... 

Suzuki et al. (1992) used principal components analysis to develop a combined connectivity, group contribution method for 229 monofunctional compounds from the Hine and Mookerjee data set. The average error was 0.14 log units. 

Nikolova-Jeliazkova N, Jaworska J (2005) An approach to determining AD for QSAR group contribution models an analysis of SRC KOWWIN. Altern Lab Anim 33 461-470... 

The objective of this work is to develop a set of group contributions for estimating the specific chemical enthalpy, 8, and the specific chemical exergy, e, which are essential in carrying out the thermodynamic analysis and synthesis of a process system. This set of group contributions can be employed not only for known organic compounds, but also for new organic compounds which are yet to be synthesized or discovered. 

In this paper, methods to estimate the heat of formation AHj0 and the absolute entropy S° for coal and coal-derived liquids are proposed based on the group contribution method. By applying these methods and the Structured Process Energy-Exergy-flow Diagram (SPEED, 11), an exergy analysis for the H-Coal process is performed. 

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