Table 1.

Central composite rotatable design with the experimental values of the response variables (Methanol solvent)

Run order	Time (min)	Liquid/Solid ratios X2	Total phenol (mg/g) Y1	Yield (%)
	X1			Y2
1	6	17.5	43.55	14.50
2	4	10	37.6	12.52
3	2	10	32.8	12.81
4	4	17.5	42.99	14.31
5	2	25	33.19	12.96
6	4	17.5	42	13.98
7	4	17.5	42.43	14.10
8	4	17.5	43.15	14.30
9	4	17.5	43	14.35
10	6	25	37.41	14.61
11	4	25	36.88	13.85
12	2	17.5	38.64	12.86
13	6	10	41.89	16.36