Catalytic behavior of melamine glyoxal resin towards consecutive oxidation and oxy-Michael addition
作者:Mohd. Bismillah Ansari、Eko Adi Prasetyanto、Jun Lee、Sang-Eon Park
DOI:10.1007/s11164-010-0169-7
日期:2010.11
Synthesis of melamine glyoxal resin involves a catalyst-free, one pot reaction between melamine and glyoxal in DMF. The synthesized resins have a similar morphological arrangement to that of layered materials as depicted by their XRD pattern and Raman spectra. The catalytic behavior of melamine glyoxal resin (MGR) have been studied in allylic oxidation of cyclohexene and simultaneous Michael addition. The MGR/solvent/O2 oxidant system can be regarded as a metal-free, additive-free, cost-effective and environmentally benign catalytic system. The oxidative behavior of MGR is attributed to its ability to generate in situ organic peroxide species during the course of reaction. Generation of peroxide species is confirmed by the KI/starch test and further confirmed by the complete suppression effect of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) over oxidation. The activity for Michael addition can be attributed to the presence of a higher content of nitrogen atoms, which serves as the active site. In oxidation, 28.1% conversion of cyclohexene with 37.19 and 62.81% selectivities for cyclohexenol and cyclohexenone were observed, respectively. In consecutive oxidation and oxy-Michael addition, 31.5% conversion of cyclohexene was observed with selectivities of 61.6% for cyclohexenone and 38.4% for alkoxy product.
美菱氨乙醛树脂的合成涉及在DMF中进行无催化剂的一锅反应,反应物为美菱氨和乙醛。合成的树脂在形态上与分层材料相似,这一点可以通过其XRD图谱和拉曼光谱得到印证。美菱氨乙醛树脂(MGR)的催化行为在环己烯的烯丙氧化和同时的迈克尔加成反应中得到了研究。MGR/溶剂/O2氧化剂体系可视为一种无金属、无添加剂、经济有效且对环境友好的催化体系。MGR的氧化性行为归因于其在反应过程中生成原位有机过氧化物的能力。过氧化物的生成通过KI/淀粉试验得到了确认,并且通过TEMPO(2,2,6,6-四甲基哌啶-1-氧基)对氧化的完全抑制效果进一步确认。迈克尔加成的活性可归因于氮原子的含量较高,这些氮原子作为活性位点。在氧化反应中,观察到环己烯转化率为28.1%,其对环己醇和环己酮的选择性分别为37.19%和62.81%。在连续的氧化和氧-迈克尔加成反应中,观察到环己烯的转化率为31.5%,其对环己酮的选择性为61.6%,对烷氧产物的选择性为38.4%。