Optimization of Process Variables in the Synthesis of Tributyl Citrate Using a Polyvinylpolypyrrolidone-Supported Brønsted Acidic Ionic Liquid Catalyst

Table 4

Significance of the coefficient and the corresponding statistical analysis.

Source	Sum of squares	df	Mean square	value	value
Model	123.54	14	8.82	57.92	<0.0001
	14.94	1	14.94	98.03	<0.0001
	23.52	1	23.52	154.37	<0.0001
	1.95	1	1.95	12.79	0.0030
	1.41	1	1.41	9.27	0.0087
	2.67	1	2.67	17.55	0.0009
	0.14	1	0.14	0.92	0.3530
	0.14	1	0.14	0.95	0.3468
	0.11	1	0.11	0.71	0.4121
	0.096	1	0.096	0.63	0.4403
	1.10	1	1.10	7.24	0.0176
	14.63	1	14.63	96.05	<0.0001
	19.88	1	19.88	130.50	<0.0001
	20.34	1	20.34	133.50	<0.0001
	9.81	1	9.81	64.36	<0.0001
Residual	2.13	14	0.15
Lack of fit	1.85	10	0.19	2.66	0.1793
Pure error	0.28	4	0.070
Cor total	125.67	28