| Experiment | Experimental matrix | Experimental design | ||||||
| X1 | X2 | X3 | X4 | U1 | U2 | U3 | U4 | |
| 1 | +1 | +1 | +1 | −1 | 8 | 150 | 12 | CH3OH |
| 2 | −1 | +1 | +1 | +1 | 4 | 150 | 12 | H2O |
| 3 | −1 | −1 | +1 | +1 | 4 | 75 | 12 | H2O |
| 4 | +1 | −1 | −1 | +1 | 8 | 75 | 6 | H2O |
| 5 | −1 | +1 | −1 | −1 | 4 | 150 | 6 | CH3OH |
| 6 | +1 | −1 | +1 | −1 | 8 | 75 | 12 | CH3OH |
| 7 | +1 | +1 | −1 | +1 | 8 | 150 | 6 | H2O |
| 8 | −1 | −1 | −1 | −1 | 4 | 75 | 6 | CH3OH |