本文選題：鎳基納米催化劑 + 單寧酸��； 參考：《河北大學》2017年碩士論文

【摘要】：在催化反應研究中,不飽和化合物的催化加氫反應一直是國內(nèi)外研究的熱點。目前,以Pd、Pt、Ru、Rh等為代表的貴金屬催化劑在催化加氫反應中表現(xiàn)出高的活性和穩(wěn)定性,部分已經(jīng)應用于實際生產(chǎn)中。但貴金屬催化劑昂貴的價格在一定程度上限制了它的應用。因此,進行價格低廉且具有高活性和穩(wěn)定性的非貴金屬催化劑的設計和制備是非常有必要的。基于此,本文使用價格相對較低的鎳為催化劑的活性組分,設計并制備了一系列高活性的鎳基納米催化劑,并應用于苯甲酸和肉桂酸的加氫反應中。首先,采用化學還原法制備了單寧酸改性的非晶態(tài)鎳硼催化劑NiB-TA,并以苯甲酸加氫制備環(huán)己甲酸為模型反應對多不飽和化合物中的芳環(huán)加氫進行了研究。該催化劑在苯甲酸加氫反應中具有很好的活性,苯甲酸的轉化率為98.8%,環(huán)己甲酸的選擇性為94.1%。通過表征發(fā)現(xiàn),相比于傳統(tǒng)方法制備的鎳硼非晶態(tài)合金催化劑,單寧酸的添加可以有效地提高活性組分的分散性,使催化劑具有更多的活性中心,從而使NiB-TA催化劑的活性顯著提高。然后,為了提高鎳基納米催化劑的穩(wěn)定性,本文還通過對載體的篩選和制備方法的優(yōu)化制備了一系列負載型鎳基納米催化劑。結果表明以介孔二氧化硅為載體,通過蒸氨法制備的負載型鎳基納米催化劑Ni/mSiO2-AE在催化苯甲酸加氫反應中使用4次時,催化劑的活性和選擇性都沒有明顯下降,具有較好的穩(wěn)定性,并通過XRD、TEM、H_2-TPR等表征闡述了該催化劑活性和穩(wěn)定性高的原因。最后,我們又以肉桂酸選擇性加氫制備氫化肉桂酸為模型反應對多不飽和化合物中的碳碳雙鍵加氫進行了研究�？紤]到催化劑的活性、穩(wěn)定性和分離回收效率等問題,設計制備了一種磁性核殼鎳基納米催化劑Fe_3O_4@LDH@NiB。在肉桂酸的加氫反應中,肉桂酸的轉化率和對氫化肉桂酸的選擇性均接近100%,同時,利用催化劑的磁性可實現(xiàn)催化劑與反應物的高效分離,在循環(huán)使用11次后,該催化劑的性能沒有明顯下降,顯示出了良好的穩(wěn)定性。
[Abstract]:The catalytic hydrogenation of unsaturated compounds has been a hot spot in the research of catalytic reaction. At present, the noble metal catalysts, such as PD, PtN, Ruzon Rh and so on, have shown high activity and stability in catalytic hydrogenation, and some of them have been used in practical production. But the expensive price of noble metal catalyst limits its application to some extent. Therefore, it is necessary to design and prepare non-precious metal catalysts with low cost, high activity and stability. Based on this, a series of nickel based nanocrystalline catalysts with high activity were designed and prepared using relatively low price nickel as the active component of the catalyst, and applied to the hydrogenation of benzoic acid and cinnamic acid. Firstly, niB-TAB catalyst modified by tannic acid was prepared by chemical reduction method. The hydrogenation of aromatic rings in polyunsaturated compounds was studied using benzoic acid hydrogenation to cyclohexanoic acid as a model reaction. The catalyst has good activity in the hydrogenation of benzoic acid. The conversion of benzoic acid is 98.8 and the selectivity of cyclohexanoic acid is 94.1. Compared with the Ni-B amorphous alloy catalyst prepared by traditional method, the addition of tannic acid can effectively improve the dispersity of the active component and make the catalyst have more active centers. Thus, the activity of NiB-TA catalyst was improved significantly. Then, in order to improve the stability of Nickel-based nanocatalysts, a series of supported Nickel-based nanocatalysts were prepared by the selection of support and the optimization of preparation methods. The results showed that the catalytic activity and selectivity of the supported nickel based nanometer catalyst Ni/mSiO2-AE, which was prepared with mesoporous silica as the carrier, did not decrease obviously when it was used for 4 times in the hydrogenation of benzoic acid. The reason for the high activity and stability of the catalyst was explained by means of XRDX TEMX H _ 2O _ 2-TPR and so on. Finally, the hydrogenation of carbon and carbon double bonds in polyunsaturated compounds by selective hydrogenation of cinnamic acid to hydrogenated cinnamic acid was studied. Considering the activity, stability and recovery efficiency of the catalyst, a magnetic core-shell nickel nanocatalyst Fe3O _ 4S _ 4 / LDHH@ NiB was designed and prepared. In the hydrogenation of cinnamic acid, the conversion of cinnamic acid and the selectivity to hydrogenated cinnamic acid are close to 100. At the same time, the high efficiency separation of catalyst and reactant can be realized by using the magnetic properties of catalyst. The performance of the catalyst did not decrease obviously and showed good stability.
【學位授予單位】：河北大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O643.36

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本文編號：1964944