Abstract:

Dendertic hindered amine light stabilizers with lower basicity were prepared via Michael addition and transesterification reactions with dimethyl malonate，methyl acrylate，2,2,6,6-tetramethyl- piperidine-4-ol and 1,2,2,6,6-pentamethyl-piperidine-4-ol as the main starting materials，the product yields were 89.3% and 78.0% respectively based on dimethyl malonate. The optimum conditions for Michael addition were found as 1∶2.2 molar ratio of dimethyl malonate with methyl acrylate，2.2eq NaOMe as catalyst for 4 h reaction；and those for the transesterification were found as，1∶4.8 molar ratio of the addition product with 2,2,6,6-tetramethyl-piperidine-4-ol or 1,2,2,6,6- pentamethyl-piperidine-4-ol，2% tetraisopropyl orthotitanate of the addition product as catalyst for 24h reaction. The pH values of the synthesized compounds were 8.7 and 6.6，respectively.

摘要：

以丙二酸二甲酯、丙烯酸甲酯、2,2,6,6-四甲基哌啶醇、1,2,2,6,6-五甲基哌啶醇等为主要原料，经Michael加成、酯交换反应合成了低碱性树枝状受阻胺光稳定剂，目标产物总收率分别为89.3%和78.0%（以丙二酸二甲酯计）。优化的合成条件为：Michael加成反应中，n(丙二酸二甲酯)︰n(丙烯酸甲酯) =1︰2.2，以NaOMe为催化剂，与丙二酸二甲酯的摩尔比为2.2，反应温度为20 ℃；酯交换反应中，n(加成产物)︰n(2,2,6,6-四甲基哌啶醇/1,2,2,6,6-五甲基哌啶醇)=1︰4.8，以四异丙基钛酸酯为催化剂，用量为加成产物质量的2%，反应时间24 h。所合成的化合物pH值分别为8.7和6.6。