S. Lepeniotis et Bi. Feuer, SYNTHESIS OF STARCH ACETATE - STATISTICAL DESIGNED EXPERIMENTS TO OPTIMIZE THE REACTION CONDITIONS, Chemometrics and intelligent laboratory systems, 36(2), 1997, pp. 229-243
The synthesis conditions for Durabond A corn starch acetate (SA) were
varied by using statistical designed experiments with the aim to optim
ize the yield and solubility, and to minimize the color. The thirty ex
periments in the design vary the: (1) Percentage water in the starch (
0, 3, 6); (2) catalyst concentration (0.25, 0.60, 0.95 wt%); (3) total
amount of acetic anhydride (1.0, 1.25, 1.5 mol times the number of hy
droxyl groups on the starch); (4) starch concentration (15, 25, 35 wt%
); (5) reaction time (1, 2.5, or 4 h); and (6) reaction temperature (6
0, 80 or 100 degrees C). The major factors controlling the acetyl valu
e (AV), yield and the solubility are the reaction temperature (T) and
the T squared. Some two factor interactions that effect the process ar
e: (1) water percentage with T, (2) the reaction time with T, and (3)
the catalyst concentration with starch concentration. The optimal cond
itions are: (1) a T range from 84 degrees C to 92 degrees C; (2) a sul
furic acid catalyst concentration of 0.25 wt% with respect to the star
ch concentration, (3) an acetic anhydride ratio of 1.0; (4) a 35 wt% s
tarch concentration; (5) a 4 h reaction time, and (6) a percentage wat
er in the starch of(0-6%). There is a strong correlation between the 1
0% and 20% SA solution solubility in acetone:water (96:4) with the AV.
if the AV is > 55 then > 90% of the SA at a concentration of 10% is s
oluble in acetone:water (96:4).