O-chlorobenzoic Acid Synthesis And Structural Analysis

O, p-chlorobenzoic acids are two important primary materials or intermediates and have extensive application in organic synthesis reactions of pesticide, medicine and dye etc. They have been synthesized from o, p-chlorotoluene in this paper.By the principle of diazotization and Sandmeyer reaction, p-chlorotoluene was obtained with the decomposition of the compound which was got after intermixing the diazo salt with cuprous chloride solution. It was reported that p-chlorotoluene was got after distillation with water vapor. In this paper, many reaction conditions have been improved, such as mixing the solution of CuSC? ?SHiO and the solution of NaCl instead of mixing CuSC>4 ?5H2O and NaCl to avoid the unsolvable white powder, adding a little of ice into the p-toluidine solution to control the temperature between 0-5 癈 during the diazotization, adding some hydrochloric acid to ensure the acidity of the solution and direct extraction of p-chlorotoluene with toluol. In a word, the improved method has a good effect.The PTC ?potassium permanganate oxidization method was applied in the experiment, in which potassium permanganate oxidized o, p-chlorotoluene to produce o, p-chlorobenzoic acids with quaternary ammonium salt A-l as phase transfer catalyst (PTC) under the neutral reaction conditions. Through a series of experiments, the effects of different factors such as different PTC activity, PTC reagent amount, reaction temperature, reaction time, potassium permanganate amount and water amount etc. were investigated.Under the optimal reaction conditions in which the reaction underwent for 2.5h at 93 癈 with A-l as PTC reagent, the yield of o, p-chlorobenzoic aicds were 76.4%, 76.9% respectively. The experiment results showed that this method had temperate reaction conditions, shorter reaction time, simple experiment operation and less cost of production expenses. Therefore, it has better competitive ability than the method with metal oxide as catalyst, and has a bright future in the industrial manufacture.The use of microwave irradiation in organic synthesis is a kind of new technology. In this paper, the microwave irradiation was applied with phase transfer catalysis in the oxidization of o, p-chlorotoluene to produce o, p-chlorobenzoic acids. Through a series of experiments, the effects of different factors such as the power of microwave irradiation, reaction time, different PTC activity, PTC reagent amount, potassium permanganate amount and water amount etc. were investigated. The experiment results showed that under the optimal reaction conditions in which the reaction underwent for 30min at 455W with A-l as PTC reagent, the yield of o, p-chlorobenzoic aicds were 70.8%, 72.5% respectively. The method has been proved to be successful in this experiment.