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ZnO催化尿素与乙二醇醇解反应制备碳酸乙烯酯
The Synthesis of Ethylene Carbonate from Urea and Ethylene Glycol Catalyzed by Zinc Oxide Catalyst
【摘要】 通过尿素沉淀法制备了ZnO催化剂,并应用于催化尿素和乙二醇(EG)醇解制备碳酸乙烯酯(EC)的反应。通过对催化剂前驱体的沉淀条件、前驱体焙烧温度以及催化剂回收与再生对产物EC收率的影响规律进行考察,并结合X射线衍射(XRD)、扫描电镜(SEM)、N2吸附–脱附及粒度分析对催化剂进行了表征。研究结果表明,制备催化剂前驱体的沉淀液配比、pH值和前驱体焙烧温度对催化剂催化性能影响较大,控制沉淀液尿素(urea)与Zn(NO3)2物质的量之比为4:1,前驱体焙烧温度为450℃时,可制得颗粒均匀、孔隙丰富的ZnO催化剂,其催化尿素与乙二醇醇解反应具有良好的反应活性。催化剂重复使用时活性一定程度下降,这与催化剂活性组分的流失有关,回收的催化剂经焙烧再生是恢复催化活性的关键途径。
【Abstract】 Zinc oxide(ZnO) catalysts were prepared by precipitation method with urea acting as precipitant and were applied in alcoholysis of urea and ethylene glycol(EG) to prepare ethylene carbonate(EC). Effects of precipitation conditions, calcination temperature of precursor and regeneration condition of catalyst on EC yield were studied, and the as-prepared catalysts were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), N2 asorption-desorption and laser particle size analyzer. The result showed that urea consumption, pH value in precipitation process and calcination temperature were critical to the catalytic performance of ZnO. Porous ZnO with uniform particles and high EG yield was prepared by molar ratio of urea and Zn(NO3)2 was 4:1 and the precursor calcination temperature was 450 ℃, and the catalyst showed excellent activity. The reused catalysts exhibited lower EG yield than the fresh one due to the loss of ZnO in catalyst recycling process and the reused catalyst need to be calcinated at 450 ℃ to restore catalytic activity.
【Key words】 ethylene glycol; urea; ZnO; ethylene carbonate; 2-oxazolidinone;
- 【文献出处】 化学反应工程与工艺 ,Chemical Reaction Engineering and Technology , 编辑部邮箱 ,2020年06期
- 【分类号】TQ225.52
- 【下载频次】240