常压高效合成双（烷基聚氧乙烯基）仲胺

Efficient synthesis of bis(alkyl polyoxyethylene) secondary amine via one-pot method under ambient pressure

摘要:

仲胺基聚醚由聚氧乙烯醚和长链烷基组成，具有结构可调、低毒、分散性好等优点，已被广泛用作颜料分散剂。目前，仲胺基聚醚主要通过聚醚多元醇和液氨合成，然而存在产率低、反应条件苛刻等问题。本研究以端伯胺基C12-14烷基聚乙二醇醚（A/C12-14E5）为原料，通过伯胺在常压条件的分子间脱氨耦合，成功地高效合成了双（C12-14烷基聚氧乙烯基）仲胺（S/C12-14E5），探究了耦合温度、催化剂用量、氢气流量及反应时间对S/C12-14E5选择性的影响。结果表明，当反应温度为200 ℃，催化剂用量为原料总质量的2.5%，氢气流量为200 mL/min，反应时间为5 h时，仲胺含量达到97.3%。在此基础上，进行了底物拓展、放大实验，并提出了可能的反应机理。

Abstract:

Polyether secondary amines with polyoxyethylene ether and long-chain alkyl, have been widely used as pigment dispersing agents due to their adjustable structure, low toxicity, and good dispersibility. At present, polyether secondary amines are mainly synthesized via the reaction between polyether polyol and liquid ammonia with low yield and harsh condition. Herein, bis(C12-14 alkyl polyoxyethylene) secondary amine (S/C12-14E5) was successfully synthesized via the intermolecular deamination coupling of amine-terminated polyether with C12-C14 alkyl group (A/C12-14E5) under ambient pressure. The influences of coupling temperature, catalyst dosage, hydrogen flow rate and reaction time on the selectivity of S/C12-14E5 were systematic studied. The results showed that the average secondary amine content reached up to 97.3% when the conditions of reaction temperature was 200 ℃, the amount of catalyst was 2.5% based on the total mass of raw material, the hydrogen flow was 200 mL/min, and reaction time was 5 h. On this basis, we studied the substrate scope and scale-up reaction to demonstrate the utility of our protocol. A possible reaction mechanism was also proposed.