The New Process Study On The Mixed C₉ Aromatics Being Oxidized Into Methyl Carboxyl Phthalate Through Liquid Phase Oxidation With Air

This article is aimed at studying a new processing method of C9 aromatics tomake full use of C9 resources and to gain additional benefit. According to thismethod, the situation of C9 aromatics being mixed into gasoline will be changed,on which both chemical resources will be utilized uneconomically and airpollution will be severed. It's well known that the component of the mixed C9 aromatics are composedof 1,4,6 trimethyl benzene,1,2,4 trimethyl benzene and methyl and ethyl benzeneetc. the present method of their utilization is to make a separation of them toproduce 1,2,4 trimethyl benzene which will then be oxidized into their derivedanhydrides, the anhydrides will be esterified with the mixed alcohols to producethe plasticizers. This method seems hard to be industrialized for restrictoperational conditions and high cost to realize the process of separation. The newmethod will not only decrease the production cost of plasticizer but also improvethe utilization performance of the products as well as show their competitivenessthrough platforming the mixed C9 aromatics into respective mixed feedstock forproducing mixed phenyl carboxylic esters. More over, the technology will supplya domestic gap and create the necessary conditions for improving top gradeplasticizer. The main research included the new process of the mixed C9 aromaticsdirectly being oxidized into phenyl carboxylic acids and their derived esterswithout being separated from the mixed C9 aromatics.The technical key point is best choice of catalyzer, confirmation of optimizedprocess conditions and reactor' form, structure and material.The resolve routes are described as follows: 1. The choice of most suitable catalyzer The oxidation to alkyl benzene will commonly make choice of cobalt acetate,manganese acetate or vanadium oxide as main catalyzer with some auxiliarycatalyzer. The choice of C9 aromatics oxidation catalyzer will make use of thescreening mono component alkyl benzene oxidation catalyzer for the maturationoxidation of mono component alkyl benzene. According to overseas reports, asuitable proportional and a certain of structured cobalt acetate, manganese acetateand bromide as catalyzer can be chosen together with some paraldehyde aspromoter. 2. The confirmation of optimized processing conditions After the catalyzer is settled, another key point will be turned to the choiceof best suitable operational conditions. 72吉林大学硕士论文 The semi-continuous reaction will be adopted in the article, withlower-temperature oxidation method to realize the oxidation to the mixed C9aromatics. The method is described as follows: a proportional and a certain ofstructured cobalt acetate, manganese acetate and bromide will be utilized as maincatalyzer and paraldehyde as promoter, the mixed phenyl carbonates will beproduced through air-liquid phase oxidation at a certain of temperature andpressure, and via heating, scrubbing, crystalizing and drying steps etc. to producethe mixed phenyl carbonates for production of plasticizer, finally to be esterified. 3. The confirmation of optimized reactor's form, structure and materialMagnetic stirrer, spot heating and semi-continuous reactor with Mo2Ti stainlesssteel and at design pressure of 2.0 MPa are utilized, the usable capacity of thereactor is 1500 ml, within which are composed of gas-liquid separator, gas-liquiddistributor, pressure regulator, indicator, temp-regulator and respective indicators.The mono-component aromatics oxidation technologies are utilized in this studyto realize the choice of the processed equipment materials, mass balancecalculation and heat balance calculation, more over, an experimental unit with 5ldosing capacity composed of titanium are built up to oxidize the mixed C9aromatics into the derived mixed carboxylic acids. The main research is reportedas follows: (1) The confirmation of the p...