The preparation of D-glucaric acid by oxidation of molasses in packed beds

An attempt has been made to prepare glucaric acid by oxidation of sugar bee t molasses in packed beds. In the first part, a suitable oxidizing medium w as sought. Experiments were performed in a cylindrical Pyrex-glass reactor with air-molasses cocurrent downflow. Spherical glass and cylindrical vanad ium pentoxide particles were used as an inert packing and catalyst respecti vely. The addition of catalyst, sodium nitrite, nitric and sulfuric acids t o the medium resulted in an improvement in glucaric acid yield. The presenc e of nitric acid in the oxidizing medium and the use of vanadium pentoxide catalyst were the most effective factors as regards the yield. In the secon d part, the effects of temperature, molasses concentration, amount of catal yst and air flow rate on the yield were studied; each of these variables in creased the yield. The use of a longer catalyst bed, however, resulted in a decrease in the yield. The highest rate of conversion of glucose to glucar ic acid was 63.9% at optimum conditions. (C) 2001 Society of Chemical Indus try.