trichlorophosphate T=95 - 100°C; 3 h;

1: 85 percent / 2N-aq. NaOH / 0.5 h / Heating 2: 60 percent / 280 °C View Scheme

Multi-step reaction with 2 steps 1: 1.) conc. HCl, NaNO2, 2.) sodium acetate / 1.) water, below 5 deg C, 2.) ethanol, water, 30 min2: 97 percent / 1,2-dichloro-benzene / 0.75 h / Heating  

With  sodium hydroxide 0.5 h;  Heating;