双(1-烷氧基-2,2,6,6-四甲基哌啶-4-基)癸二酸酯的合成及其热稳定性

Synthesis and Thermal Stability of Bis(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)Sebacate

以1-烷氧基-2,2,6,6-四甲基哌啶-4-醇、癸二酸二甲酯为原料,LiOH和四丁基溴化铵(TBAB)为催化剂,正庚烷为溶剂,在反应过程中采用分水器不断地分出甲醇的酯交换方法,制备了系列双(1-烷氧基-2,2,6,6-四甲基哌啶-4-基)癸二酸酯,并通过红外光谱、核磁共振氢谱、核磁共振碳谱和质谱表征了其结构。结果表明:其较佳合成条件为n(癸二酸二甲酯)∶n(1-烷氧基-2,2,6,6-四甲基哌啶-4-醇)∶n(LiOH)∶n(TBAB)=1∶2.2∶1.6∶0.024,在回流状态下反应6~8 h,粗产品通过m(甲醇)∶m(水)=1∶1的混合溶剂洗涤提纯。在以上条件下,产品的产率大于80%,质量分数大于95%。热重分析表明,以上合成的目标产物热稳定性良好。该方法具有反应条件温和,催化剂便宜,反应设备简单,产品产率及纯度高等优点。

Bis(1-alkoxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacates(NORSs)were synthesized through transesterification by using dimethyl sebacate and 1-alkoxy-2,2,6,6-tetramethylpiperidin-4-ol as raw materials,LiOH and tetrabutyl ammonium bromide as catalysts,n-heptane as a solvent,and constantly separating methanol from the reaction system with a water konckout vessel,and their structures were characterized by IR,1H NMR,13C NMR and MS.The results revealed that their optimal conditions were as follows:n(dimethyl sebacate)∶n(1-alkoxy-2,2,6,6-tetramethylpiperidine-4-ol)∶n(LiOH)∶n(TBAB)=1∶2.2∶1.6∶0.024,the transesterification time being 6-8 h at the reflux temperature,and the crude products were purified by washing using the mixture of water and methanol with weight ratio of 1∶1.Under the above conditions,the mass fraction of the target products was more than 95%,the yield was more than 80%.The thermogravimetric analysis showed that the above NORSs had good thermal stability.The method has some advantages such as mild reaction conditions,cheap catalyst,simple apparatus and the high yield and purity.