Table 2.
Central composite design for independent variables and their response
| Runs | A (Ethanol concentration (%)) |
B (Time (h)) |
C (Temperture (°C)) |
D (Liquid–solid ratio (mL/g) |
Yield (mg/g) |
|---|---|---|---|---|---|
| 1 | 1 | 0 | 0 | 1 | 13.950 |
| 2 | 0 | 1 | 0 | −1 | 17.746 |
| 3 | 0 | 0 | 0 | 0 | 18.649 |
| 4 | 1 | 1 | 0 | 0 | 15.243 |
| 5 | 0 | 1 | −1 | 0 | 15.488 |
| 6 | −1 | 1 | 0 | 0 | 17.984 |
| 7 | 1 | −1 | 0 | 0 | 14.842 |
| 8 | 0 | 0 | −1 | −1 | 15.583 |
| 9 | 1 | 0 | 0 | −1 | 13.494 |
| 10 | 0 | 0 | 1 | 1 | 17.147 |
| 11 | 0 | 0 | 0 | 0 | 18.354 |
| 12 | 0 | −1 | 0 | 1 | 16.689 |
| 13 | 0 | 0 | 0 | 0 | 19.180 |
| 14 | −1 | 0 | −1 | 0 | 17.899 |
| 15 | −1 | 0 | 0 | −1 | 15.466 |
| 16 | −1 | 0 | 1 | 0 | 18.354 |
| 17 | 0 | 1 | 1 | 0 | 17.329 |
| 18 | 0 | −1 | 0 | −1 | 17.104 |
| 19 | 0 | 0 | 0 | 0 | 19.90 |
| 20 | −1 | 0 | 0 | 1 | 20.396 |
| 21 | 0 | −1 | −1 | 0 | 15.618 |
| 22 | 0 | −1 | 1 | 0 | 17.289 |
| 23 | 0 | 0 | −1 | 1 | 16.727 |
| 24 | −1 | −1 | 0 | 0 | 15.688 |
| 25 | 1 | 0 | 1 | 0 | 14.892 |
| 26 | 0 | 0 | 0 | 0 | 16.733 |
| 27 | 0 | 0 | 1 | −1 | 18.951 |
| 28 | 1 | 0 | −1 | 0 | 14.962 |
| 29 | 0 | 1 | 0 | 1 | 16.542 |