The preparation process for 4-Piperazinophenol dihydrobromide is as follows:
Step 1: Synthesis of Dibromoethylamine hydrobromide: React diethylamine with 40% hydrogen bromide. The mixture is heated, dehydrated by fractional distillation, and excess hydrogen bromide is removed by distillation. Acetone is then added to precipitate the crystals.
Step 2: Synthesis of 4-Methoxyphenylpiperazine Dibromide: The product from Step 1 is refluxed with p-Toluidine in n-Butanol. Anhydrous sodium carbonate powder is added. Crystals are obtained upon cooling.
Step 3: Synthesis of 4-hydroxyphenylpiperazine dihydrobromide: Heat the product from Step 2 with recovered 40% hydrogen bromide solution under reflux conditions, then perform fractional distillation. Continue distillation after raising the temperature. Concentrate the distillate and add acetone to precipitate the crystals.
