1: 5 percent / sodium dithionite / aq. NaOH / 1.) room temp., 2 h, 2.) 50 deg C, 14 h, 3.) 100 deg C, 15 min 2: 1.) conc. HCl, NaNO2, 2.) NaOH / 1.) H2O, 0 deg C, 2.) pH 10-11, 15 min 3: aq. NaOH / 72 h / 60 - 100 °C / pH 10 View Scheme

1: aq. NaOH / 1 h 2: 1.) P2O5, 85percent H3PO4 View Scheme

sodium hydroxide T=60 - 100°C; 72 h; pH 10;

in sodium hydroxide; water T=90°C; pH=10; 72 h;

1: 5 - 25 °C / pH 10 2: H2O; aq. NaOH / 72 h / 90 °C / pH 10 View Scheme

1: aq. NaOH / 72 h / 60 - 100 °C / pH 10 2: 1.) conc. HCl, NaNO2, 2.) NaOH / 1.) H2O, 0 deg C, 2.) pH 10-11, 15 min 3: aq. NaOH / 72 h / 60 - 100 °C / pH 10 View Scheme