Chemical processing anticipating process chemistry effects

Through the use of a model for a batch reactor for a particularly complex reaction, we have demonstrated the value of modeling in optimization of process conditions and in evaluation of possible hazards. For a very complex system like the present one, it is most probably easier and more cost effective to do the modeling than to run the experiments needed for proper analysis. To save laboratory data acquisition time, it is always better to plan an experimental strategy based on the anticipated need in advance. This model has been successfully used in two scale-ups. Data from these scale-ups have been used to refine the model. These refinements included a better understanding of the chemistry of the process. Plots similar to the ones presented in Figures 6-10 were used in the Reactive Chemicals Review of the present process. 

Increasingly, the chemical structure is used by medicinal chemists, even in the library selection process, with anticipation of the question What chemistry can 1 do on this molecule if it turns out to be a lead In other words, are there sufficient handles in the structure to enable a trained chemist to prepare analog compounds and develop the lead Even thinking deeper beyond lead development, can such compounds be serious candidates for effective process development, survive clinical trials, and eventually be manufactured It may be dangerous to base these decisions on the chemical structure alone, but as better tools are developed, this basic information will increase in importance. Not to be forgotten is the fact that most of the time, the only information presented to the people who acquire compounds from third-party vendors is what the chemical structure is and how much (in weight) of the compound is available. The current trend in the better vendor companies is to add information and to help companies make better compound selections. 

For all except one of the chemical ionization studies reported so far, the reactants initiated an acid-base, even-electron chemistry. For such reactants there are several reasons to anticipate that the spectra produced by chemical ionization will differ significantly from the spectra produced by electron impact, photon impact, or field ionization. The chemical ionization is effected by the transfer of massive entities such as protons, hydride ions, or alkyl carbonium ions. Consequently the chemical ionization processes are not governed by Frank-Condon considerations, and the ions produced by the transfer of even-electron entities are, for even-electron molecules, even-electron ions. The amounts of energy which are involved in chemical ionization processes tend to be low by mass spectrometric standards, although the exact amount involved depends upon the identity of the reactant used. 

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