Process variables and experimental data for two factors, three levels response surface design^a.

Run	A (°C)	B (%)	R 1 (%)	R 2 (min)
1	62.50	50.00	80	7
2	35.98	85.36	50	5
3	89.02	14.64	77	5
4	62.50	50.00	83	6
5	25.00	50.00	45	11
6	62.50	50.00	84	5
7	100.00	50.00	77	5
8	62.50	0.00	90	5
9	62.50	50.00	84	5
10	89.02	85.36	62	6
11	62.50	100.00	37	11
12	62.50	50.00	82	5
13	35.98	14.64	64	5

^a A = temperature (°C), B = water content of aqueous ethanol (%), R₁ = yield of reaction, R₂ = reaction time.