Ab initio kinetic modeling

Ab Initio Kinetic Modeling of Free-Radical Polymerization... 

AB INITIO KINETIC MODELING OF FREE-RADICAL POLYMERIZATION... 

SCHEME 9.3 Schematic comparison of conventional and ab initio kinetic modeling. 

Through the ab initio approach, it is also much easier to build a more complete kinetic model in the first place. Not only can individual reactions/side reactions be ruled in or out of the reaction scheme on the basis of the ab initio calculations, but also the practical limits to model complexity are less demanding than those of conventional kinetic models. Whereas with conventional modeling it is necessary to restrict the number of unknown parameters according to the degrees of freedom in the data, for ab initio kinetic modeling this is not necessary. Certainly each additional reaction/side reaction in a kinetic scheme represents an extra kinetic parameter that needs to be calculated. However, as each calculation is independent, the inclusion of additional reactions does not increase the overall degree of difficulty—provided computer time is available, one can consider as many reactions... 

While the accuracy of quantum chemical-derived parameters depends instead on the assumptions and numerical approximations used to solve the Schrodinger equation, in this chapter we have shown that, with appropriate care, these errors can be minimized, at least for flie key steps in radical polymerization. Indeed, as shown in the case study provided, ab initio kinetic modeling can be used to make first-principles predictions of the concentration profiles of reagents, intermediates, and products in a complicated multistep process such as the RAFT process. In making... 

Within the radical polymer field, two broad areas of application for ab initio kinetic modeling are model development and process optimization. The RAFT case study presented in this chapter is an example of the former type of application we are currently using the same ab initio approach to conventional radical polymerization to develop better models for predicting copolymer composition and microstructure, structural defect formation as a result of side reactions, and the effect of solvent and additives on the stereochemistry of the resulting polymer. 

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