“…It is not necessary in the modeling procedure to know the detailed reaction mechanism since the mathematical model is empirical. Generally, the CCD consists of a 2 n factorial runs with 2n axial runs and n c center runs [10]. These designs consist of a 2 n factorial or fractional (coded to the usual ±1 notation) augmented by 2n axial points (±α,0,0,..., 0), (0, ±α,0,...,0),..., (0, 0, ...,±α), and n c center points (0, 0, 0, ...,0) [11][12].…”