Synthesis Of Benzotriazole And Its Derivatives

Benzotriazole (BTA) is an important organic synthesis intermediates,it is mainly used in the field of water stabilizers, preservatives, optical stabilizers and so on. Its derivatives such as trifluoromethyl benzotriazole are widely used in biochemistry, medicine, pesticides and other areas. In recent years, the need of benzotriazole is growing bigger and bigger. However, in China, the existing production of benzotriazole is small in scale, backward in technology, far from being able to meet the needs of the community. Due to a variety of biological activity, benzotriazole derivatives receive wider and wider spread attention about their synthesis as well as the activity research. Therefore, it is important that we must make efforts to explore the research and development of benzotriazole and its derivatives.In this paper, firstly, synthesizing technology of benzotriazole was studied, using cheap and simple O-nitrochlorobenzene as material, the process contains two steps: the first step was that 1-hydroxy benzotriazole (HBTA) was obtained by O-nitrochlorobenzene reacted with hydrazine hydrate. Solvent method and phase-transfer catalysis method have been used, the synthesis conditions on the yield were studied by experiments, under the best conditions, the yield of products exceeded 98%, but the solvent method has some shortcomings: high price of solvent, high boiling point, difficult recovery, energy consumption, high cost and so on; the phase-transfer catalysis process has some advantages: the small mole ratio of raw materials, the reaction time is shorter, easy to operate, low energy consumption, and the phase transfer catalyst PEG-800 is abundant, low price, good stability, none toxicity and environmentally friendly. So phase-transfer catalysis process is the prospect industrial synthetic method of HBTA. The optimum reaction conditions of HBTA were as follows: the molar of O-chloronitrobenzene to hydrazine hydrate to PEG-800 was 1:4:0.03, the reaction time,the reaction temperature,the yield and the purity was 5h,110℃,98.1% and 99.3%.The second step of the process is HBTA reverted to benzotriazole, in the presence of electrolytes, HBTA as raw material, iron reduction is used in this step,The different factors affecting the reaction were investigated,the optimum reaction conditions of BTA were as follows: the molar of HBTA to Fe was 1:2.5, isooctyl alcohol as extracting agent, the reaction time,the reaction temperature,the yield and the purity was 4 h,85℃,88.7% and 96.4%.At the same time, the liquid chromatography analysis method of HBTA and BTA are established. In a certain concentration range, the linear correlation coefficient,the recovery and the accuracy of the method are measured: HBTA, the recovery was 98.0~103.0%,the coefficient of variation was 0.25%,the linear correlation coefficient was 0.9989. The corresponding coefficient of BTA were:98.0～100.4%,0.18%,0.9992. This method can rapidly and effectively detect HBTA and BTA.Finally, N-1-benzylbenzotriazole and bis(benzotriazol-1-yl)-a-w-propane are synthesized by dry method of microwave radiation from benzotriazole . Microwave radiation power, reaction time, ratio of raw materials, the type and amount of catalyst on the reaction yield were tested in the paper, the optimum conditions were obtained, their structures were determined by IR and 1HNMR.The results showed: microwave radiation technology for organic reactions significantly shorten the reaction time and greatly improve the reaction rate. It conforms to the energy conservation, the clean production, the green chemistry development tendency.