Catalysts screening, optimization and mechanism studies of dimethylhexane-1,6-dicarbamate synthesis from 1,6-hexanediamine and dimethyl carbonate over Mn(OAc)2catalyst
Catalysts screening, optimization and mechanism studies of dimethylhexane-1,6-dicarbamate synthesis from 1,6-hexanediamine and dimethyl carbonate over Mn(OAc)2catalyst
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Mn(OAc)2催化剂上1,6-己二胺与碳酸二甲酯合成1,6-二氨基甲酸二甲酯的催化剂筛选、优化及机理研究
DOI：
10.1016/j.cattod.2016.02.059
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发表时间：
2017
期刊：
影响因子：
5.3
通讯作者：
Li Huiquan
中科院分区：
文献类型：
--
作者：
Zhao Liyan;He Peng;Wang Liguo;Ammar Muhammad;Cao Yan;Li Huiquan
以碳酸二甲酯（DMC）和1，6-己二胺（HDA）为原料，采用均相催化剂（如，金属硝酸盐和乙酸盐）。研究发现，Mn（OAM）2是该反应最有效的催化剂。在最佳反应条件下（反应温度为363 K，DMC与HDA摩尔比为4：1，催化剂浓度为HDA质量的7%，反应时间为5 h），HDA完全转化，HDC收率可达98.0%。采用在线原位傅里叶变换红外光谱（FTIR）和密度泛函理论（DFT）研究了Mn（OAc）2与基质的相互作用.结果表明，HDA和DMC均与Mn（OAc）2发生了相互作用，但DMC的过渡态（DMC-TS）的能垒高于HDA的过渡态（HDA-TS），表明HDA比DMC更容易与Mn（OAc）2形成新的配合物。整个反应过程可以认为是HDA与Mn（OAc）2相互作用形成的新物种Ⅱ进攻DMC的羰基碳生成中间体HMC，最终生成HDC。实验数据与计算结果吻合较好。
The catalytic synthesis of dimethylhexane-1,6-dicarbamate (HDC) from 1,6-hexanediamine (HDA) and dimethyl carbonate (DMC) over a series of homogeneous catalysts (e.g., metallic nitrates and acetates) were investigated. Mn(OAc)2was found to be the most effective catalyst for this reaction. Under the optimum reaction conditions (reaction temperature of 363 K, DMC-to-HDA molar ratio of 4:1, catalyst concentration of 7 wt% (based on HDA), and reaction time of 5 h), HDC yield can reach as high as 98.0% with HDA totally converted. Online in-situ Fourier Transform Infrared (FTIR) and Density Functional Theory (DFT) calculations were used together to investigate the interactions between Mn(OAc)2and substrates. The results indicated that both of HDA and DMC had interactions with Mn(OAc)2, but the energy barriers of the transition states (TS) of DMC (DMC-TS) was higher than that of HDA (HDA-TS), which meant that HDA was easier to interact with Mn(OAc)2to form new complex than DMC. The whole process can be proposed that, the new speciesII, which was formed by the interaction of HDA and Mn(OAc)2, attacked carbonyl carbon of DMC to generate intermediate HMC and finally to HDC. The experimental data and calculation results are in good agreement with each other.