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首页> 外文期刊>Catalysis science & technology >Highly efficient synthesis of novel bio-based pentamethylene dicarbamate via carbonylation of pentanediamine with ethyl carbamate over well-defined titanium oxide catalysts
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Highly efficient synthesis of novel bio-based pentamethylene dicarbamate via carbonylation of pentanediamine with ethyl carbamate over well-defined titanium oxide catalysts

机译：高效合成新型生物基五甲基二甲苯二氨甲酸酯通过五烷二胺与乙基甲酯的羰基化在氧化钛催化剂上的明确定义

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摘要

Carbonylation of pentanediamine (PDA) is a green and effective route for the synthesis of pentamethylene dicarbamate (PDC), an important intermediate compound for the preparation of polyurethanes (PUs) and other chemicals. In this work, TiO2-101 and TiO2-110 catalysts with preferential exposure of (101) and (110) facets, respectively, were prepared and studied for the carbonylation of PDA with ethyl carbamate (EC). The catalysts were characterized by various techniques, including XRD, BET, SEM, TEM, XPS, NH3-TPD, and in situ FTIR. The characterization results indicated that TiO2 catalysts with exposed (110) and (101) facets were synthesized successfully. The overall results suggested that the (101) facets on the TiO2 surface provide high amounts of surface Lewis acid sites that played a pivotal role in PDC formation, which gave a conversion and yield both up to 99% under optimized conditions. In situ FTIR spectroscopy clearly revealed that polyurea as an intermediate was formed in the reaction and subsequently converted to PDC catalyzed by the TiO2 catalyst. Furthermore, the DFT results showed that the conversion of polyurea to PDC over the (101) facets was more prone to occur than the (110) facets due to the lower reaction energy barrier. In addition, the TiO2-101 catalyst displayed excellent stability without an obvious activity decline after five cycles. Furthermore, this strategy also could be successfully expanded to the efficient syntheses of a series of N-substituted carbamates.
机译：五烷二胺（PDA）的羰基化是合成五甲基二甲苯甲酸酯（PDC）的绿色和有效途径，这是用于制备聚氨酯（PUS）和其他化学物质的重要中间化合物。在这项工作中，准备并研究了（101）和（110）片面的TiO2-101和TiO2-110催化剂，并研究了用乙基氨基甲酸乙酯（EC）的PDA羰基化制备和研究。催化剂的特征是各种技术，包括XRD，BET，SEM，TEM，XPS，NH3-TPD和原位FTIR。表征结果表明，成功合成了暴露（110）和（101）面的TIO2催化剂。总体结果表明，TiO2表面上的（101）面提供了大量的表面刘易斯酸位点，在PDC形成中起着关键作用，在优化条件下，这给出了转化率并产生高达99％的表面。原位FTIR光谱清楚地表明，在反应中形成了中间体，然后转化为TIO2催化剂催化的PDC。此外，DFT的结果表明，由于反应能屏障较低，多脲对PDC在（101）面上的转化更容易出现。此外，TIO2-101催化剂在五个周期后表现出极好的稳定性，没有明显的活性下降。此外，该策略也可以成功扩展到一系列N溶解氨基甲酸酯的有效合成。

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