Response Surface Methodology Process Optimization of Biodiesel Production from Castor Seed Oil

Table 1

The full factorial experimental design of biodiesel production with the four factors and three levels.

Factors	Unit	Levels of the factors
		Low (−1)	Medium (0)	High (+1)
Temperature (°C)	X1	30	40	60
The ratio of methanol: castor oil	X2	6 : 1	9 : 1	12 : 1
Time (min)	X3	30	60	90
Catalyst load (%)	X4	1	1.5	2