Study On The Synthesis Technology Of 3,4-Diethoxyaniline

The 3,4-Diethoxyaniline is a kind of important fine organic chemical products, widely used in pharmaceuticals, pesticides, spices, food, rubber, electroplating and other fields, but also the fungicide carbendazim intermediates. Because of the extensive application of 3,4-Diethoxyaniliner, the product has high added value and high market demand., so its prices continue to rise.Reported in the literature synthesis of 3,4-Diethoxyaniliner method mainly has: ① Catechol and ethanol by etherification, nitrification after synthesis, the method need specific composition and shape of the catalyst and demanding of temperature and other reaction conditions, and low yield, the shortcomings of high cost point, were not reported in domestic industrialization; ②atechol and diethyl sulfate (DES) under the influence of the phase transfer catalyst after etherification, nitrification synthesis, the method has the advantages of high yield, less side reaction, but the toxicity of diethyl sulfate, serious pollution to the environment, does not meet the conditions for industrial production.The research work in this thesis is divided into three parts:The first part 1,2-Diethoxybenzene synthesis and process conditions to study as the goal, under the protection of nitrogen to with mixing son, filling funnel, condensing tube of three mouth flask with catechol, ethanol, ethyl bromide and polyethylene glycol 400, heating and stirring until the solution reflux, slowly dripping solution of sodium hydroxide, dripping is finished insulation reaction for a period of time, after the end of the reaction distillation out excessive ethanol and ethyl bromide, after the solution was poured into ice water to cool dilution, namely precipitate a large number of white crystal, filtering, washing, drying get products 1,2-Diethoxybenzene.In the second part, the synthesis and the optimum technological conditions of the 3,4-Diethoxynitrobenzene were finished. The 1,2-Diethoxybenzene join equipped with a stirrer, and funnel and a condensation tube of three mouth flasks, dissolved with ice acetic acid, mixing and cold water bath temperature control in 20+2℃, dropwise addition of concentrated nitric acid, insulation reaction for a period of time after injected water, a yellow solid precipitate, filtering, washing, drying, pale yellow to adjacent nitro diphenyl ether.The last part is about the synthesis and processing conditions of the target product 3,4-Diethoxyaniline. In a three mouth flask added a certain amount of adjacent nitro diphenyl ether, palladium carbon catalyst and anhydrous ethanol, stirring, with nitrogen replacement system in the air, to three times of hydrogen nitrogen replacement, and then heated to 90 ℃. After the reaction, cool to room temperature and empty. After the reaction is finished, the flask in the filtrate after moved to the distillation flask, under the protection of nitrogen, atmospheric distillation, solvent recovery, the 2-amino diphenyl ether. The product by ethanol recrystallization was the pink solid.