【作者】 石丽丽；

【导师】 孙琪；

【作者基本信息】 辽宁师范大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 本文主要采用水热合成法,使用聚乙烯吡咯烷酮（PVP）为保护剂,制备出了一系列不同比例的FeCl₃/PVP胶体催化剂,考察了该催化剂的制备条件（水热时间、PVP与FeCl₃摩尔比）和反应条件（反应温度、水合肼用量和催化剂用量）对苯胺产率的影响。运用XRD、TEM等手段对催化剂的形貌和结构进行了表征。结果表明,不同的水热处理时间和PVP与FeCl₃摩尔比制备出的催化剂,在粒径大小、胶粒形貌以及稳定性等方面均有明显的差异。在PVP与FeCl₃摩尔比1:40、100℃下水热2 h制得的胶体稳定性好、分散度高,其胶粒大小为70⁹0 nm的棒状结构。该胶体催化剂在催化水合肼还原硝基苯的反应中表现出很高的催化活性,以水合肼为还原剂,在反应温度80℃、反应时间80 min、硝基苯用量4.89 mmol、无水乙醇用量5 mL、FeCl₃/PVP胶体催化剂用量2.0 mL （nFe= 0.1500 mmol）、n（水合肼）∶n（硝基苯）= 2.5的条件下,苯胺收率可达到100.00%.另采用同样的制备方法,用水合肼作还原剂制备了PVP修饰下的Fe3O₄,着重探索了在催化剂的制备过程中还原剂的用量、还原剂的加入方式以及对催化剂进行去除PVP的处理对硝基苯还原的影响,结果表明,PVP的保护作用明显,它的存在,大大提高了Fe3O₄的催化活性, Fe₃O₄/PVP对硝基苯的还原有很高的活性。在尝试将FeCl₃/PVP胶体负载到活性炭上时,发现未负载过渡金属的活性炭对硝基苯还原也有一定的催化作用,尤其是经盐酸处理的活性炭,在氮气氛高温焙烧的条件下,可使苯胺的收率在2.5h达到100.00%。更多还原

【Abstract】 In this paper, a series of different proportions of FeCl₃/PVP colloid nanoparticles catalyst has been successfully synthesized through the hydrothermal process using polyvinyllpyrroh -done （PVP） as protective agent. Effects of hydrothermal time and protective agent dosage on the performance of FeCl₃/PVP colloidal catalyst for the reduction of nitrobenzene were investigated. The yield of aniline was studied by reaction temperature, hydrazine hydrate dosage, and catalyst dosage. The structure and morphology of the colloidal catalysts were characterized by means of X-ray diffraction （XRD） and transmission electron microscopy （TEM）. The results showed that the hydrothermal treatment time,PVP and FeCl₃ molar ratio made the catalyst particles size, morphology and the stability different. Under hydrothermal treatment conditions, n（PVP）:n（FeCl₃）=1:40, temperature 100℃, time 2 h, the high-stability, high-dispersion, club-shaped colloidal catalyst with a size of 70⁹0 nm were prepared. The FeCl3/PVP colloidal catalyst exhibits high catalytic activity for reduction of nitrobenzene reduced by hydrazine hydrate under the conditions: nitrobenzene 4.89 mmol, absolute alcohol 5 mL, 2.0 mL FeCl3/PVP colloidal catalyst（nFe=0.1500mmol）, n（hydrazine hydrate）:n（nitrobenzene） =2.5, 80℃for 80 min, the yield of aniline could reach 100.00%.Meanwhile, we prepared Fe3O4 modified by PVP, focused on exploration effect of hydrazine hydrate dosage when prepared the catalyst, reducing agent added approach and the catalyst treatment to remove the PVP for reduction of nitrobenzene, the results showed that the presence of PVP greatly enhanced the catalytic activity of Fe₃O₄/PVP.We also tried to prepare FeCl3/PVP colloid and then supporting on activated carbon .we found that free-transition metal exist in the catalyst, the activated carbon still had effection. Especially the activated carbon treated by the hydrochloric acid and in nitrogen atmosphere under the conditions of high temperature calcination, the yield of aniline could reach 100.00% in 2.5h.更多还原