癸二酸二甲酯与1,2,2,6,6-五甲基哌啶醇的酯交换反应

Transesterification Between Dimethyl Sebacate and 1,2,2,6,6-Pentamethyl-4-Piperidinol

对癸二酸二甲酯与1,2,2,6,6-五甲基哌啶醇的酯交换反应进行了研究;分别考察了四异丙基钛酸酯、氨基锂、氧化二辛基锡3种催化剂的性能;采用氢核磁共振确定了产物的结构;考察了以四异丙基钛酸酯为催化剂时反应温度、反应时间、原料配比和催化剂用量对反应的影响。实验结果表明,四异丙基钛酸酯催化剂的催化效果最好;在癸二酸二甲酯与1,2,2,6,6-五甲基哌啶醇摩尔比1∶1.79、四异丙基钛酸酯催化剂的用量为反应物总质量的0.31%、反应温度180℃、反应时间6h的条件下,所得产物中单(1,2,2,6,6-五甲基-4-哌啶基)癸二酸甲酯(简称单酯)质量分数为23%和双(1,2,2,6,6-五甲基-4-哌啶基)癸二酸酯(简称双酯)质量分数为73%,单双酯质量比为1∶3.17,产物收率为93.3%。该方法可得到理想的单双酯比例及产物收率,具有很好的工业应用前景。

Transesterification between dimethyl sebacate and 1,2,2,6,6-pentamethyl-4-piperidinol was studied with tetraisopropyl orthotitanate, lithium amide and di-n-octyltin oxide used separately as catalysts. Catalytic activity of tetraisopropyl orthotitanate was the highest. Effects of reaction temperature, reaction time, n （ dimethyl sebacate ） ： n （ 1,2,2,6,6-pentamethyl- 4-piperidiol ） and catalyst dosage on the transesterification were investigated. Under optimal reaction conditions： reaction time 6 h, reaction temperature 180℃, n （ dimethyl sebacate ） ： n （1,2,2,6,6-pentamethyl-4-piperidiol） 1 ： 1.79 and mass fraction of tetraisopropyl orthotitanate to total reactants 0.31%, contents of mono（ 1,2,2,6,6-pentamethyl-4-piperidinyl） monomethyl sebacate and bis-（ 1,2, 2,6,6-pentamethyl-4-piperidinyl） sebacate in products can reach 23% （mass fraction）and 73% respectively, and yield of products 93.3%. The products were characterized by means of ^1H NMR.