An attempt has been made to prepare glucaric acid by oxidation of sugar beet molasses in packed beds. In the first part, a suitable oxidizing medium was sought. Experiments were performed in a cylindrical Pyrex-glass reactor with air-molasses cocurrent downflow. Spherical glass and cylindrical vanadium pentoxide particles were used as an inert packing and catalyst respectively. The addition of catalyst, sodium nitrite, nitric and sulfuric acids to the medium resulted in an improvement in glucaric acid yield. The presence 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 second part, the effects of temperature, molasses concentration, amount of catalyst and air flow rate on the yield were studied; each of these variables increased 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 glucaric acid was 63.9% at optimum conditions. (C) 2001 Society of Chemical Industry.