Preparation Of P-nitrobenzoic By Nitration-oxidation Of Waste Polystyrene Foam

Polystyrene is a kind of High polymer materials polymerized by styrene, it has manyvirtues such as good machinability, low density, light weight, and nice stability. Its productionlike foam can be used as packaging materials and heat insulation material, etc. It is a widelyused material. Waste polystyrene foam is very difficult to degrade under natural conditions,intensifying the white pollution, seriously effects ecological environment.This paper mainly studies recycling of waste polystyrene foam. After certain pre-treatment,the Recycled polystyrene foam used as raw materials will undergo two reaction steps nitrationand oxidation, and produce p-nitrobenzoic acid. Main contents and conclusions aresummarized as below:1Pretreatment of experimental raw material: including the selection of solvents and the tryand confirm of processing method. The polystyrene foam we used is new waste packingmaterial of experimental instruments. We analyst the IR-spectrum of polystyrene aftertreatment, the result is that it is pure enough to be used as raw materials. So there no treatmentto the additives that maybe contained in the foam.2Nitration reaction of polystyrene: nitration reaction is an important intermediate step, itsproducts poly-Nitrostyrene will directly influence the next reaction. In this step, we studyevery factors include temperature, reaction time, material proportion and metal ions that caneffects the production. And the production of different reaction conditions is analyst byUV-vis absorption spectrum and IR-spectrum.3Oxidation reaction: oxidation reaction is the last step of the experiment and also is the mostimportant step, in order to explore the feasibility of poly-Nitrostyrene translate intop-nitrobenzoic acid. We did a lot of experiments and read a lot of documents. We triedmicrowave oxidation, sodium permanganate oxidation and potassium dichromate oxidation,because of the limitations of former two methods, our experiments mainly using sodiumdichromate oxidation method. After research we found the relatively better reaction conditionis100℃,24h and the rate of water to concentrated sulphuric acid is1:1, poly-Nitrostyreneto potassium dichromate is1:1.5, used zinc ions as catalyst, the yield may reach30%. Theproduction under different reaction conditions is analyst by UV-vis absorption spectrum andIR-spectrum.We can degrade polystyrene under a more peace reaction condition by nitration and oxidation. But there is still a lot deficiencies, the reaction conditions still need to beoptimized.