Experimental scheme and results obtained from RSM for the oil yield.

Run	Independent variable			Oil yield (%)
	X 1 (temperature/pressure, °C/MPa)	X 2 (time, min)	X 3 (stirring speed, rpm)
1	−1 (30/0.60)	−1 (30)	0 (750)	14.39
2	+1 (50/0.93)	−1 (30)	0 (750)	14.91
3	−1 (30/0.60)	+1 (60)	0 (750)	16.12
4	+1 (50/0.93)	+1 (60)	0 (750)	16.65
5	−1 (30/0.60)	0 (45)	−1 (500)	13.34
6	+1 (50/0.93)	0 (45)	−1 (500)	14.12
7	−1 (30/0.60)	0 (45)	+1 (1000)	16.78
8	+1 (50/0.93)	0 (45)	+1 (1000)	17.04
9	0 (40/0.77)	−1 (30)	−1 (500)	12.25
10	0 (40/0.77)	+1 (60)	−1 (500)	14.04
11	0 (40/0.77)	−1 (30)	+1 (1000)	16.07
12	0 (40/0.77)	+1 (60)	+1 (1000)	17.02
13	0 (40/0.77)	0 (45)	0 (750)	16.80
14	0 (40/0.77)	0 (45)	0 (750)	16.90
15	0 (40/0.77)	0 (45)	0 (750)	16.96
16	0 (40/0.77)	0 (45)	0 (750)	16.76
17	0 (40/0.77)	0 (45)	0 (750)	16.84