| About1%of crude benzene produced by coking is thiophene. Shanxi Province is our country coal big province and coking production base, which can provide many thiophenes. However, the low purity of thiophene and poor development of downstream products can lead to the overstocking of thiophene. The domestic enterprises in Shanxi have already begun to study on the purification of thiophene in recent year, therefore, the development of downstream products of thiophene have become feasible, which can optimize the industrial structure and make the enterprise profit maximization.At present,2.6million people died of cardio-cerebrovascular disease. The2-(2-thienyl) ethylamine are the downstream products of thiophene, which can be used as an important drug intermediate for the prevention and treatment of cardio-cerebrovascular disease. Based on the above facts, the synthesis of2-(2-thienyl) ethylamine has great significance.In this paper, based on the study of the synthetic route of2-(2-thienyl) ethylamine, we have investigated a synthetic route which has advantages of brief reaction steps, high yield and little pollution to environment. In this study, the traditional method for synthesis of2-thienyl formaldehyde has been optimized. Meanwhile, an innovation synthetic route of2-thiophenecarboxaldehyde has been used, in which triphosgene (BTC) is used to substitute phosphorus oxychloride for the synthesis of2-thiophenecarboxaldehyde. The conditions for synthesis of isopropyl chloroacetate have been optimized. The lithium aluminium hydride is used to reduce the2-thienylacetaldoxime, and the main results obtained are shown as follows:1. Thiophene reacts with N,N-dimethyl formamide (DMF) in the presence of phosphorus oxychloride, and the corresponding molar ratio is1:1.3:1.3When the optimal reaction time and temperature are4hours and86℃, respectively, the yield of2-thiophenecarboxaldehyde can reach88%.2. Thiophene reacts with DMF in presence of BTC, and the corresponding molar ratio is1:1.3:1.3in which the weight of thiophene is12.6g, and the dosage of1,2-dichloroethane is35ml. The yield of2-thiophenecarboxaldehyde can reach74.6%under the reaction temperature of50℃with1.5hours, then heat up to80℃for7hours.3. Monochloro acetic acid reacts with isopropyl alcohol, and the corresponding molar ratio is1:1.3. The sodium bisulfate is used as catalyst, and the amount is2%of monochloro acetic acid. When the amount of monochloro acetic acid and cyclohexane are0.5mol and30ml, respectively, the reaction time is3hours, the yield of isopropyl chloroacetate is86%.4. When the amount of2-thienylacetaldoxime, tetrahydrofuran and lithium aluminum hydride are0.013mol,100ml and0.039mol, respectively, the circumfluence time is3hours, the yield of2-(2-thienyl) ethylamine can reach 68.7%. |
