Use of butanol-water mixtures for making wheat straw pulp

A central composite design was used to investigate the influence of the coo king conditions (time, temperature and butanol concentration) for wheat str aw with butanol-water mixtures on the properties of the pulp obtained (yiel d and holocellulose, alpha-cellulose, lignin and ethanol-benzene extractive s contents) and the pH of the resulting waste water. A second-order polynom ial model consisting of three independent process variables was found to ac curately describe the organosolv pulping of wheat straw. The equations deri ved predict the yield, the holocellulose, alpha-cellulose, lignin and ethan ol-benzene extractives contents of the pulp, and the pH of the waste water with multiple-R, R-2, adjusted-R-2 and Snedecor' F values of 0.99, 0.99, 0. 99 and 310.33; 0.98, 0.97, 0.95 and 56.63; 0.91, 0.84, 0.74 and 9.14; 0.99, 0.98, 0.96 and 70.52; 0.97, 0.94, 0.92 and 40.42; and 0.98, 0.95, 0.93 and 49.33, respectively. The process variables must be set at low values in order to ensure a high y ield and pH. On the other hand, if a high holocellulose content and low lig nin and ethanol-benzene extractives contents are to be obtained, then the p rocess variables must be set at high values. Finally, obtaining pulp with a high alpha-cellulose content entails using a long cooking time and a high temperature, as well as a low butanol concentration.