phosphorus pentoxide; toluene-4-sulfonic acid in toluene 1 h; Heating;

1: 45 percent / Triton-B / diethyl ether 2: 100 percent / 37percent aq. HCl / Heating 3: 80 percent / P2O5, p-toluenesulfonic acid / toluene / 1 h / Heating View Scheme

1: 100 percent / 37percent aq. HCl / Heating 2: 80 percent / P2O5, p-toluenesulfonic acid / toluene / 1 h / Heating View Scheme