Studies And Improvement On The Technics Of The Racemination Of Dextromisole Hydrochoride

Levamisole hydrochloride, the ramification of imidazole, is a broad-spectrum medicine against wireworm. Compare to its racemate (DL-Tetramisole) , levamisole hydrochloride has more validity and less toxicity. In general, it can be got by disconnecting from DL-Tetramisole . Its dextrorotatory substant is an antidepressant which does not have the helminthic effect.Based on consulting the domestic and international reference documents, two totally different processes are discussed in my paper and a reasonable process is determined by the comparison of process available . In the first one , use dimethyl sulfoxide as the solvent and achieve the process of racemization of dextrorotatory imidazole in sodium hydroxide environment. And monofactor method and multifactor orthogonalizing design method are applied to get the optimum processing conditions in this racemization process. But because dimethyl sulfoxide is expensive and hard recovery in price and contaminate environment , based on the results of the first one, new technics is searched after, which can not be found in any documentation.By the technique contrast analyzes, put forward that the water, which is easy to get and lower price and free from the pollution to the environment, maybe the best one to replace the dimethyl sulfoxide as the menstruum. Then through controlling the acid and alkalinity and the time of reaction of the solution, the racemization process can be easily obtained. Meanwhile, we got the optimum processing conditions. This is exactly one of the innovations in my paper.The following have been obtained through lots of experiments.1. The optimum processing conditions by using dimethyl sulfoxide as the solvent in this racemization process: racemization time 12 hs; volume of dimethyl sulfoxide 110 mLs; the mass of sodium hydroxide 3.0 g. Under the process, the specific rotatory power of the D-Tetramisole can be successfully lower to 2? and a higher product yield is obtained.2. The optimum process of the new technics has been obtained based on a large number experiments: racemization time 9hs; the mass proportion of the NaOH and raw material 20 I 9; volume of water 60 mLs. This kind of new method is simple and have the good environmental protection and positive technique advance meaning, which be needed further proved.3. Even though obtain the stage results, the new technics still need the deeper theories support and more experiments proof.WANG Xue (Chemical Engineering) Directed by Professor HE Jianxun...