Preparation process of bupivacaine hydrochloride

The invention discloses a preparation process of bupivacaine hydrochloride. According to the specific scheme, N-(2,6-xylyl)-2-piperidine formamide is adopted as a starting raw material and dissolved in methylbenzene, then a deacidification agent, a phase transfer catalyst and bromobutane are added, certain temperature is kept for reacting, and after the reaction is finished, filtering is carried out at room temperature, and a bupivacaine solution is obtained; the bupivacaine solution is acidized with an acidification agent, aftertreatment is carried out, and bupivacaine hydrochloride is obtained through drying. According to the preparation process, the solvent can be recycled, the production cost can be reduced, environmental pollution can be reduced, meanwhile, byproducts of other products of the company are fully utilized, refuse reclamation is achieved, and generated waste gas, waste water and industrial residues are reduced.