Trans Alkyl Cyclohexyl Benzoate And 3 - Fluoro-4 - Aminophenol Synthesis Research

This dissertation consists of two parts:Part One: The preparation of trans- alkylcyclohexylbenzoicThe synthesis of alkylcyclohexylbenzoic: Alkylcyclohexylbenzoic,an important intermediate of liquid crystals,can also be used in the fields of medicines and pesticides.Acetylcyclohexylbenzene was prepared from the reaction of acetylchloride,cyclohexene and benzene with the AlCl3 as the catalyst .Then,the alkylcyclohexylbenzene was obtained through the reducing reaction of wolf-huangminglong.Through Frieded-Crafts acylation of alkylcyclohexylbenzene and acetylchloride,the alkylcyclohexylacetophenone was prepared.Following by oxidizing,alkylcyclohexylbenzoic was obtained. Factors such as solution and temperature were discussed and the optimum process conditions were as follows:n(acetylchloride):n(cyclohexene):n(AlCl3):n(benzene)=1:1:2.5:10,at 0-5℃reacting for one hour ,then rising the temperature to 35-40℃for 4-5 hours, acetylcyclohexylbenzene was prepared,the yield was 85%. The temperature at 130℃for 1.5 hours and at 220℃for 5 hours, alkylcyclohexylbenzene was obtained, the yield was 53%. Through Frieded-Crafts acylation of alkylcyclohexylbenzene and acetylchloride in the solution of dichloromethane, the alkylcyclohexylacetophenone was prepared ,the yield was 76% after recrystallization. Ethylcyclohexylbenzoic was prepared after oxidition.A series of alkylcyclohexylbenzoics were obtained and the products were characterized by 1HNMR and IR.Transformation of cis-alkylcyclohexylbenzoic to trans- alkylcyclohexylbenzoic: Alkylcyclohexylbenzoic obtained contains cis-and trans-,but trans- alkylcyclohexylbenzoic is needed in the preparation of liquid crystals,so it is the key procedure of cis-alkylcyclohexylbenzoic transforming to trans- alkylcyclohexylbenzoic.The methods reported have many defects,a new method designed in the experiment: Alkylcyclohexylbenzoic ester was synthesized by reaction of alkylcyclohexylbenzoic and alcohol,then transformed in the aqueous slkali in use of the electron-withdrawing of ester.By hydrolysis,high productive rate of trans- alkylcyclohexylbenzoic was prepared. Factors such as the use level of base and temperature were discussed.Part Two:The preparation of 3-Fluoro-4-amino-phenol.Fluorophenylmethylether was synthesized by reaction of sodium methoxide and 2,4-difluoronitrobenzene which was prepared by the starting material 2,4-dichloronitrobenzene.By demethylation, 3-Fluoro-4-nitro-phenol and 5-Fluoro-2-nitro-phenol were yielded .Separate them to get the 3-Fluoro-4-nitro-phenol.By reducing with zinc powder, 3-Fluoro-4-amino-phenol was obtained. This way of the synthesis process made the reaction conditions moderate and the amount of material easily control, and greately enhanced the purification and yield of the products. Factors influening the reaction were discussed and the products were characterized by 1HNMR and IR.