A chemical process controller manages a 5-cycle refinement loop using formulations U, V, W, X. Formulation X is an unstable compound and is excluded. Cycle 1 must use formulation U or formulation W. Two reaction constraints apply: formulation V cannot immediately follow formulation U, and formulation W cannot immediately follow formulation W. Formulation U can transition to U or W; formulation V can transition to U, V, or W; and formulation W can transition to U or V.