Table 4.

Effect estimates for final regression model

The predictive equation of polynomial model with independent variables in terms of coded value; A = temperature, B = time, C = concentration of formic acid, D = proportion of ethyl acetate	R 2
Cellulose yield = 79.56100 + 5.64413A − 2.86408A2 + 1.44436B − 0.61022B2 + 1.71400C − 0.34961C2 − 0.68850D − 0.32527D2 − 0.89951AB − 0.40092AC + 0.62936AD + 0.39846BC − 0.57846BD − 0.51987CD	0.9269
Hemicellulose removal = 89.38847 + 10.73493A − 2.42983A2 + 3.99649B − 2.07151B2 + 2.71207C − 0.31563C2 − 3.83649D − 0.95184D2 − 1.65683AB + 0.85786AC + 1.73912AD − 1.24598BC + 0.80047BD + 1.57243CD	0.9711
Lignin removal = 81.44070 + 6.04246A − 6.06154A2 + 2.02353B − 0.61872B2 + 2.67628C − 0.37040C2 + 2.36608D − 0.45633D2 − 0.97931AB − 1.59158AC − 0.19203AD + 1.45194BC − 0.99416BD − 1.91678CD	0.8833
Released glucose = 771.37040 + 77.89330A − 70.17410A2 + 2.00700B − 28.53370B2 + 10.03920C − 34.43090C2 − 30.50870D − 17.06030D2 − 16.34580AB − 24.11710AC + 27.72490AD − 20.80220BC + 11.33870BD + 13.32820CD	0.9045
Glucose yield = 83.62166 − 0.62253A − 6.51073A2 − 2.58010B − 1.72853B2 − 1.62834C − 4.37388C2 − 2.02913D − 0.95523D2 − 1.39497AB − 1.76428AC + 2.88942AD − 1.96341BC + 1.21576BD + 1.53686CD	0.8237