The Non-catalytic Oxidation Of Isobutane To Produce Tert-butyl Hydroperoxide

Tert-butyl peroxide(TBHP) is an important chemical products widely used as initiator of oxidant in free radical reaction, the oxidizing agent to manufacture propylene oxide from propylene. The production process used in domestic industry is tert-butyl alcohol-hydrogen peroxide method. The process is simple, but produces a large amount of waste sulfuric acid containing hydrogen peroxide and TBHP,thus brings serious pollution to environment. The significant problem domestic enterprises faced is to develop environment friendly TBHP production process. Isobutane resource is rich in domestic refinery, oxygen is cheap and clean as oxygents, non-catalytic oxidation of isobutane to produce TBHP meets the need for environment friendly. Isobutane is oxidized in Foreign industry at temperatures of 137℃and pressures of around 3.15MPa, at 36.9% conversion of isobutene, the selectivity to TBHP and TBA (mole fraction) is 53.4%, 40.2% .The equipment investment for the method is expensive, the technology is complex and the reaction requires high temperature and pressure conditions, due to instability of TBHP at 75℃or above, severe decomposition occur when temperature is higher than 90℃. It is still a hidden danger for safety. Rearch was carried out on isobutane non-catalytic oxidation to prepare TBHP in this paper, aimed to provide a TBHP production method for technical accumulation in domestic.Firstly, the conditions of isobutane non-catalytic oxidation were investigated. The oxidation reactor was passivated by sodium nitrite, citric acid and carbonatesodium to remove the metal oxide reaction with the wall. The influence of reaction time, reaction temperature, alkoxyl molar ratio and initiator concentration on the results of oxidation were investigated . The results show that :the introduction time is about 1-1.5h;Under the optimal conditions, temperature 120℃, reaction time4h, alkoxyl molar ratio 5.52, the concertration of initiator 0-2.5%(wt%), the conversion of isobutene is 18.09%, the selectivity to TBHP is 48.01%, the selectivity to TBA is 49.55%, the selectivity to PK is 2.44%.By gas chromatography-mass spectrometry technology, qualitative analysis on reaction products of isobutane non-catalytic oxidation and byproducts of tert-butyl hydrogen peroxide decomposition were proceeded . Referring to the reaction mechanism for non-catalytic isobutane oxidation in the literature, a dynamics network model is presented on the reaction of tert-butyl hydroperoxide decomposition by simplifing reasonably. The dynamic datas of TBHP decomposition at different temperature were measured by appriorate experiment methods. A TBHP decomposition dynamics model was build, the real number coding in genetic algorithmsa was chosed to get the decomposition dynamics parameters. It is found that the results calculated from dynamics model agree well with the experimental datas. From the TBHP decomposition reaction model parameters we can see, The activation energy value of TBHP decomposition to TBA is slightly greater than the other decomposition reaction ,but the pre-exponential factor of TBHP decomposition to TBA is far greater than the other decomposition reaction . The establishment of TBHP decomposition dynamics model provides foundation for model building of isobutane non-catalytic oxidation dynamic.