Cui Shaoying, Arza Carlos R, Froimowicz Pablo, Ishida Hatsuo
State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute of Sichuan University, Chengdu 610065, China.
Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106-7202, USA.
Polymers (Basel). 2020 Mar 20;12(3):694. doi: 10.3390/polym12030694.
In this study, 2-(aminomethyl)phenol and its derivatives, the reactants for 2-substituted 1,3-benzoxazines, are synthesized by HCl hydrolysis from the typical benzoxazines. The phenol/aniline-based mono-oxazine benzoxazine, PH-a, and the bisphenol A/aniline-based bis-oxazine benzoxazine, BA-a, are used as examples to demonstrate the feasibility of this new approach. Their chemical structures are characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) and Raman spectroscopies, and are further verified by elementary analysis. Their thermal properties are studied by differential scanning calorimetry (DSC). These two 2-(aminomethyl) phenolic derivatives are reacted with paraformaldehyde to close the oxazine rings. A benzoxazine with a phenyl substituent at the 2-position of the oxazine ring is obtained from the 2-((phenylamino)methyl)phenol (PH-a) and benzaldehyde. All these results highlight the success of the HCl hydrolysis and the formation of stable intermediates, namely 2-(aminomethyl) phenolic derivatives, from readily available benzoxazine monomers. This further demonstrates the feasibility of using these intermediates as reactants for a novel benzoxazine synthesis.
在本研究中，2-（氨甲基）苯酚及其衍生物（2-取代1,3-苯并恶嗪的反应物）由典型的苯并恶嗪通过盐酸水解合成。以苯酚/苯胺基单恶嗪苯并恶嗪PH-a和双酚A/苯胺基双恶嗪苯并恶嗪BA-a为例，证明了这种新方法的可行性。通过核磁共振（NMR）、傅里叶变换红外光谱（FTIR）和拉曼光谱对其化学结构进行了表征，并通过元素分析进一步验证。通过差示扫描量热法（DSC）研究了它们的热性能。这两种2-（氨甲基）酚类衍生物与多聚甲醛反应以闭合恶嗪环。由2-（（苯基氨基）甲基）苯酚（PH-a）和苯甲醛制得在恶嗪环2-位带有苯基取代基的苯并恶嗪。所有这些结果都突出了盐酸水解的成功以及由易得的苯并恶嗪单体形成稳定的中间体，即2-（氨甲基）酚类衍生物。这进一步证明了使用这些中间体作为新型苯并恶嗪合成反应物的可行性。
