A Property Based Approach to Integrated Process and Molecular Design

Abstract

In this work, a new simple yet effective, systematic method to synthesize and design molecules is presented. Visualization of the problem is achieved by employing an annex to the recently developed property clustering techniques, which allows a high-dimensional problem to be visualized in two or three dimensions by employing the concepts of reverse problem formulation. Group contribution methods are used to predict the properties of the formulated molecule. For the molecular design problem the target properties as well as the molecular groups that make up the formulations are identified on a ternary diagram. The target properties are represented as individual points if given as discrete values or as a region if given as intervals. The formulation of the desired molecule is achieved via linear “mixing” of molecular groups in order to match the desired performance.

A significant advantage of the developed methodology is that for problems that can be satisfactorily described by just three properties, the process and molecular design problems can be simultaneously solved visually on ternary diagrams, irrespective of how many molecular fragments are included in the search space. The process design problem is solved for the desired target properties using property clusters. This is the solution of a reverse simulation problem, where the process design problem is solved in terms of constitutive variables and without having to commit to any component a priori. The target properties as well as a selection of molecular building blocks (groups) are used as input into the molecular design algorithm. The problem is now visualized on a molecular ternary cluster diagram. The structure and identity of candidate components is then identified by combining or “mixing” molecular fragments until the resulting properties match the targets. The designed candidate formulations are screened using the developed necessary and sufficient conditions for the synthesis of molecules. Finally, the feasible molecular formulations are mapped back to the process domain for verification.

Although, the molecular property clustering framework provides a property interface for the simultaneous consideration of process and molecular design problems, it should be emphasized that the developed tools can also be used to solve just molecular synthesis problems (e.g. solvent design). As a CAMD tool, this algorithm has the added feature of visual synthesis for those problems that can be described using three clusters or properties; and for those requiring more than three, an algebraic approach for the formulation and solution of molecular design problems is outlined.