利用回收聚苯乙烯裂解制苯乙烯单体

研究了废聚苯乙烯在硫酸铈、氯化稀土和复合催化剂等10种不同催化剂催化下的裂解情况。通过气相色谱/质谱分析可知,裂解产物为苯、甲苯、苯乙烯和α-甲基苯乙烯。结果表明,各种催化剂的活性顺序为:复合催化剂Ⅰ>复合催化剂Ⅱ>Ba(NO3)2>Fe2O3>CeSO4>CuO>氯化稀土>ZnO>CaO>Al2O3。通过正交实验对实验条件进行了优化。当复合催化剂Ⅰ用量为0.80％、390℃、常压条件下裂解28～53 min时,平均裂解产率为95.O％,裂解产物中苯乙烯质量分数为96.8％,苯乙烯的产率为91.9％。粗产物经简单蒸馏,苯乙烯的总回收率为82.3％,苯乙烯纯度可达99.9％。

Study on Recovery of Styrene Monomer from Pyrolysis of Waste Polystyrene

Disposal of polymer wastes has become one of the main issues in area of treatment of environmental pollution. Process of pyrolysis of waste polystyrene (WPS) was investigated in detail. 10 kinds of catalysts such as cerous sulfate, rare earth chlorides, composite catalyst were used. Pyrolytic products of WPS were benzene, toluene, styrene and a - methylstyrene, and were identified by GC/MS. Activity order of catalyst were as follows: composite catalyst( I) >composite catalyst(II) >Ba(NO3)2 >Fe2O3 >CeSO4 >CuO>rare earth chloride > ZnO > CaO > A12O3. Optimum conditions of degradation over composite catalyst (I) were selected by orthogonal experiments. Average yields of pyrolytic products, styrene content and total yields of styrene were 95.0% ,96.8% and 91.9% respectively under degradation conditions of 28 to 53 min at 390 ℃ .atmospheric pressure, and catalyst mass fraction 0.80% . Output of styrene monomer was 82.3 % . Purity was 99.9 % , obtained by simple distillation.