STEP Organic Synthesis:Thermal And Electrochemical Process For The Efficient Production Of Benzoic Acid

Benzoic acid,which is an important organic synthesis intermediate,has been widely used in food,medicine,dyes,chemical industry.The traditional production methods,such as toluene liquid phase air oxidation method,toluene chlorination hydrolysis method and so on,have caused serious pollution to the environment.Therefore,it is necessary to develop green ways to synthesize benzoic acid which have no pollution to the environment.Solar energy is the green pollution-free energy,the efficient use of solar energy can ease the shortage of energy and environmental pollution and other issues.Solar energy is only converted into heat or electrical energy generation in traditional technology,so the solar energy utilization efficiency is limited.In 2009,Licht and Wang proposed the theoretical model of STEP(solar thermal electrochemical process)using the solar energy to convert the stable and large molecules into energetic molecules.STEP use solar energy photo thermal effect and the photoelectric effect,providing energy for the chemical reaction,which improves the solar energy utilization efficiency,solar energy chemical reactant conversion and product selectivity greatly at the same time.In this paper,the STEP chemical theory was first applied to the study of direct oxidation of toluene into benzoic acid.Solar energy(solar heating and solar power generation)is used to drive the reaction to oxidize toluene into benzoic acid.The synthesis effect of benzoic acid is investigated under the solar thermal electric coupled mode through adjusting the proportion of solar heating and solar power generation in the coupled mode and best reaction conditions are determined.The effects of solar thermal-electric two under the coupled action of benzoic acid synthesis results and determine the reaction in the best conditions.The theoretical potential of oxidation of toluene under different temperature were calculated,the effects of electrode materials and the effects of experimental factors about the yield of benzoic acid are investigated,the products are detected by gas chromatography and ultraviolet visible spectrophotometer and infrared spectrometer.The results of the study show that when the temperature is 90℃ and reactive voltage is3 V,the yield of benzoic acid can reach 23.14% and the selectivity of benzoic acid was90.85% using platinum electrode as the anode to oxidize toluene into benzoic acid.When thetemperature is 90℃ and the reactive voltage is 2V,the yield of benzoic acid is 51.62% and the selectivity of benzoic acid was 89.27% using graphite as the anode to oxidize toluene into benzoic acid.In summary,the direct oxidation reaction of toluene into benzoic acid is feasible under the solar thermal-electric coupled mode.The toluene conversion and product selectivity are high using platinum plate and graphite as anode in the oxidation reactions respectively.STEP can be applied to efficient synthesis of benzoic acid.