sulfuric acid 12 h; Heating;

1: 84.5 percent / KOH / ethane-1,2-diol; H2O / 10 h / Heating 2: 87 percent / H2SO4 / 12 h / Heating View Scheme

1: 83 percent / CH3COONa, HCOOH, NH2OH.HCl / 1 h / Heating 2: 84.5 percent / KOH / ethane-1,2-diol; H2O / 10 h / Heating 3: 87 percent / H2SO4 / 12 h / Heating View Scheme