Study On Adipic Acid Synthesized By Cyclohexene And Oxygen

This dissertation was financial supported by the Key Scientific and Technological Project Funds of Henan Province (523050300).Adipic acid is an important dicarboxylic acid, which mainly in making some of polymers, such as 6,6-nylon, polyurethane and so on. There is pollution problem in the traditional technology of synthesis adipic acid. And in recent years, hydrogen peroxide is used to synthesize adipic acid by oxidating cyclohexene directly. for higher price of H₂O₂, this new technology can not be applied in industry. It is well-known that olefin is easy to react with ozone, so this paper uses O₂ indirectly, some of the O₂ is transformed into O₃ in a ozonizer, this is a new way to synthesize adipic acid with cyclohexene, 30 wt% H₂O₂ and oxygen as raw materials. Main results obtained on research work are as follows:In the process of the ozonation reaction, the bubble column, whose ratio of column height to diameter was 10 : 1 and the gas distributer was G4 glass sand core, was adopted as the ozonation reaction column. Several factors which influence the ozonation reaction, such as, sorts and volumes of solvent, ozonolysis temperature had been investigated. The proper ozonolysis condition was confirmed, that is, V(C₆H₁₀) : V(C₂H₄O₂)=1:10 (based on 2.8 mmol of cyclohexene, approx 3 ml), ozonolysis time 1.5 h, flux of oxygen 200 mL/min, efficiency of zonator 100 %, ozonolysis temperature 5-10℃.In the process of synthesis adipic acid by oxygenolysis of the ozonized intermediate, firstly, 30 wt% H₂O₂ was used as oxidant. Effects of some factors were investigated in oxygenolysis of ozonized intermediate, such as, molar ratio of hydrogen proxide to cyclohexene, oxygenolysis temperature and time. The proper oxygenolysis condition was n(H₂O₂) : n(C₆H₁₀)=2.4 : 1 (based on 2.8 mmol of cyclohexene), oxygenolysis temperature 75℃, oxygenolysis time 3.5 h. Under this optimum condition, the average yield of adipic acid synthesized by three parallel tests was about 80.4 %. Although H₂O₂ is an important "green" oxidant, its price is higher than general oxidants. And then oxygen is natural, cheap and rich oxidant, therefore, O₂ was choosed as an oxidant from some oxygen sources in oxygenolysis of the ozonized intermediate. The main factors which influence the reaction, such as, oxygenolysis temperature and time, sorts and weights of catalysts and flux of oxygen. Twice orthognol test was adopted to optimize the reaction conditions, the optimal oxygenolysis condition was as follows: oxygenolysis temperature 75℃, oxygenolysis time 3.5 h, amount of molybdenum in molybdenum trioxydatum 1 mmol, flux of oxygen 40 mL/min. Under the condition, the yield of adipic acid was 79.5 %, the recovery rate of acetic acid was 70 %.Clean oxidant was used in this work to replace the traditional industry process, which would pollute the environment seriously. The results showed, in oxygenolysis of ozonized intermediate, the yield of adipic acid was synthesized by using O₂ as oxidant is a little lower than that of by using H₂O₂. Considering the cost of oxidants, it is sure that the former is better than the latter, and so technology of O₂ as oxidant possesses more potential foreground in application of industrial fields.