壳聚糖接枝苯并18-冠-6负载氯化钯催化氢化对硝基苯胺的研究

Study on Chitosan Grafting Benzo-18-Crown-6 Supported Palladium Chloride for the Hydrogenation of p-Nitroaniline

用苯并18 冠6 与壳聚糖接枝,再负载氯化钯,制成非均相负载型钯催化剂(CCTS B 18 C 6 Pd),并对该催化剂进行了X 射线光电子能谱(XPS)表征.将其用于对硝基苯胺的催化氢化反应,实验结果表明,催化剂表现出较好的催化活性,对苯二胺的产率较高,且催化剂易与产物分离.同时研究了反应时间及催化剂中钯含量、温度、底物浓度等因素对催化氢化对硝基苯胺的影响,考查了催化剂的稳定性.在甲醇溶剂中,温度20 ℃,催化剂中钯的含量为0.004 g,底物浓度为0.025 g·mL-1时,对苯二胺的产率达到99.9%.

Palladium chloride was supported on the chitosan grafting benzo-18-crown-6 to obtain the heterogeneous supported palladium catalyst (abbreviated as CCTS-B-18-C-6-Pd). The constitution of catalyst was characterized with X-ray photoelectron spectrometry(XPS). The catalyst was used to catalyze the p-nitroaniline. The experiment results indicate the catalyst showed a good activity, and the yield of p-phenylenediamine was high during the course of hydrogenation. The catalyst was easily separated from the product. The influence of experimental parameters on reaction such as the reaction time, the amount of palladium in catalyst, temperature, the concentration of substrate was discussed and the catalyst stability was examined. The yield of p-phenylenediamine reached (99.9%) when the temperature was 20 ℃,the (amount) of palladium was 0.004 g and the concentration of substrate was 0.025 g·mL^(-1) in the solvent of methanol.