Zn-Al-C03LDHs催化碳酸二苯酯与1,4-丁二醇酯交换合成聚碳酸酯二醇

摘要

采用共沉淀法制备了不同n(Zn)/n(Al)比的锌铝类水滑石(Zn-A1-CO3 LDHs),并用XRD、FT-IR和TG-DTA等方法对它们进行了表征.研究了不同n(Zn)/n(Al)比的Zn-Al-CO3 LDHs对碳酸二苯酯(DPC)与l,4-丁二醇(1,4-BD)酯交换反应合成聚碳酸酯二醇(PCDL)的催化活性,并与镁铝水滑石(Mg-Al-CO3 LDHs)、乙醇钠和三乙烯二胺等催化剂进行了比较.在酯交换过程中,以苯酚的收率表征催化剂的活性；在缩聚过程中,以产品的数均分子量Mn、羟基值表征催化剂的活性.结果显示,n(Zn)/n(Al)比为2.0的Zn-Al-CO3 LDH的催化活性较好.在优化反应条件下,获得了分子量分布较窄的PCDL,其数均分子量为1610,羟基值为69.7 mg KOH·g-1.%Zn-Al-CO3 layered double hydroxides (Zn-Al-CO3 LDHs) with different molar ratios of Zn to Al were prepared by co-precipitation method and characterized through XRD, FT-IR and TG-DTA. The catalytic activities of Zn-Al-CO3 LDHs for the synthesis of polycarbonate diols (PCDL) via the transesterification between diphenyl carbonate (DPC) and 1,4-butanediol (1,4-BD) were investigated, and were compared with those of catalysts reported, such as Mg-Al-CO3 layered double hydroxides (Mg-Al-CO3 LDHs), sodium ethylate and triethlenediamine. The yield of phenol was used to evaluate the catalytic activity in the transesterification process, and the numerical mean molecular weight Mn and hydroxyl value of the product were used to evaluate the catalytic activity in the polycondensation process. The results show that the Zn-Al-CO3 LDH with the molar ratio of Zn to Al of 2.0 has a higher catalytic activity. Under optimal reaction conditions, PCDL with the Mn of 1610 and hydroxyl value of 69.7 mg KOHg-1 was synthesized, and its molecular weight distribution is relatively narrower.