锂基催化剂在酯交换合成碳酸二甲酯方面的性能研究

Study on performance of lithium-based catalysts in synthesis of dimethyl carbonate by transesterification

以Li为主要活性组分,采用沉淀法制备了LiAl催化剂,通过引入不同的金属元素(Mg、La、Ce和Y)对LiAl催化剂进行改性,同时对催化剂进行了XRD、TG-DTG、CO_(2)-TPD和BET表征,考察LiAl摩尔比、焙烧温度对甲醇和碳酸丙烯酯(PC)酯交换合成碳酸二甲酯(DMC)反应活性的影响。结果表明,催化剂Li/Al摩尔比为3∶1,焙烧温度为500℃时,催化剂具有最高的反应活性。其中,LiYAl催化剂在反应条件为65℃,甲醇和PC的醇酯摩尔比为10∶1,催化剂用量为2%的条件下反应2 h,DMC的产率为59.2%,重复使用4次后,仍具有较高的产率。

LiAl Catalysts were prepared by precipitation method using Li as the main active component.The LiAl catalysts were modified by introducing different metal elements(Mg,La,Ce and Y),and the catalysts were also characterised by XRD,TG-DTG,CO_(2)-TPD and BET.The effects of LiAl molar ratio and roasting temperature on the reaction activity of methanol and propylene carbonate(PC)ester exchange for the synthesis of dimethyl carbonate(DMC)were investigated.The results showed that the catalysts had the highest reactivity when the catalyst LiAl molar ratio was 3∶1 and the roasting temperature was 500℃.In particular,the LiYAl catalyst reacted for 2 h at a reaction condition of 65℃,an alcohol-ester molar ratio of 10∶1 between methanol and PC and a catalyst dosage of 2%,and the yield of DMC was 59.2%,which was still high after four times of reuse.