负载型Zn(OAc)2催化合成1,6-六亚甲基二氨基甲酸甲酯

Synthesis of Dimethylhexane-1,6-dicarbamate over Supported Zinc Acetate Catalyst

摘要:

采用等体积浸渍法制备了一系列不同载体负载Zn(OAc)2催化剂，用于1,6-己二胺（HDA）与碳酸二甲酯（DMC）反应制备1,6-六亚甲基二氨基甲酸甲酯（HDC）。通过X射线粉末衍射（XRD），N2物理吸附（BET），NH3程序升温脱附（NH3-TPD），热重分析（TG-DTG），傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）分析手段对催化剂进行了表征，结果表明硅胶负载Zn(OAc)2催化剂上Si—O—Zn键的形成有利于DMC的活化，表面酸性位促进了碱性HDA的活化，从而使其具有最佳催化活性。在反应温度80 oC 、反应时间6 h、DMC/HDA摩尔比2:1、催化剂用量Zn(OAc)2/HDA摩尔比0.02:1的条件下，HDA转化率为96.0%，HDC收率可达68.5%，催化剂具有良好的稳定性，循环利用5次后活性无明显下降。

Abstract:

A series of supported Zn(OAc)2 catalysts were prepared by incipient impregnation and used for synthesis of dimethylhexane-1,6-dicarbamate(HDC) by methoxycarbonylation of 1,6-hexanediamine (HDA) with dimethyl carbonate (DMC). The catalysts were characterized by XRD, BET, NH3-TPD, TG-DTG, FTIR, XPS and the results confirmed that the SiO2 supported Zn(OAc)2 catalyst showed the best activity owing to the formation of Si-O-Zn and the surface acidity which facilitated the activation of DMC and HDA. Under the optimum reaction conditions of 0.02 mmol Zn(OAc)2/mmol HDA, DMC to HDA molar ratio=2, 80 °C and 6 h, the conversion of HDA was 96.0%, the yield of HDC was 68.5%. The used catalyst can be recycled by simply separation and wash, and no obvious deactivation was found even after 5 cycles.