Corn stover was pretreated with various chemical agents, including
sodium hydroxide,
sulfuric acid,
ethylenediamine,
n-butylamine (either alone or in
solution with
methanol), and
acetonitrile or
ethanol containing
hydrochloric acid. Of these chemicals,
n-butylamine was the best
reagent for pretreatment of corn stover, considering the degree of loss of total
carbohydrate, delignification, cumulative
weight loss, cumulative yield of reducing
sugars per original total
carbohydrate, and the potential ease of recovery and reuse of
reagent. In comparison to the other
reagents tested,
n-butylamine (n-BA) selectively delignified corn stover. The best conditions were as follows: a 12-h presoak of about a 155 g dry wt/L slurry (1 mm average particle size) in 100% n-BA at room temperature, followed by 30 min of refluxing (86.5 degrees C) with 40% (w/w) n-BA-distilled water
solution. The cumulative yield of reducing
sugars after enzymic hydrolysis was 44.5% of the original total
carbohydrate and the cumulative total
weight loss (dry basis) was 59%. Degradative loss of total
carbohydrate during pretreatment was not detected.