本文關(guān)鍵詞： 磁性納米材料 納米催化劑 Knoevenagel縮合反應(yīng) 磁性分離 循環(huán)利用　出處：《浙江大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：磁性納米材料具有特殊的物理性質(zhì)和化學(xué)性質(zhì),在電子、信息、自動(dòng)控制、有機(jī)合成、生物醫(yī)藥等學(xué)科領(lǐng)域有廣泛的應(yīng)用。特別是對(duì)于催化領(lǐng)域,磁性納米粒子作為催化劑或催化劑載體表現(xiàn)出優(yōu)異的性能,且它還具有可磁性分離的特性,為納米級(jí)催化劑的分離提供了新的思路。Knoevenagel縮合反應(yīng)是形成C=C最重要的反應(yīng)之一,其縮合產(chǎn)物是極其有價(jià)值的合成中間體,在化工領(lǐng)域占據(jù)非常重要的地位。因此,拓展磁性納米材料的應(yīng)用范圍,使其作為綠色,環(huán)保的催化劑用于Knoevenagel縮合反應(yīng)的研究,不僅具有基礎(chǔ)研究的創(chuàng)新性,也具有重要的工業(yè)化應(yīng)用意義。本文主要從以下兩個(gè)方面對(duì)磁性納米材料作為Knoevenagel反應(yīng)的催化劑進(jìn)行研究。一方面,通過溶劑熱法和Stober法分兩步制備出Fe3O4@SiO2磁性納米催化劑,采用FTIR、XRD、TEM、VSM等手段確定其結(jié)構(gòu)和組成。以苯甲醛與丙二腈的Knoevenagel縮合作為探針反應(yīng),并優(yōu)化反應(yīng)條件,在最佳條件下實(shí)現(xiàn)苯甲醛的完全轉(zhuǎn)化后,目標(biāo)產(chǎn)物的收率達(dá)到97.8%。同時(shí),通過對(duì)比不同催化劑的實(shí)驗(yàn)結(jié)果,推斷Fe3O4@SiO2催化劑的活性組分為Si02層。循環(huán)實(shí)驗(yàn)表明Fe3O4@SiO2催化劑循環(huán)使用第7次時(shí)仍然能維持90.1%的轉(zhuǎn)化率和93.5%的選擇性,且催化劑的結(jié)構(gòu)和組成在重復(fù)利用中也沒有發(fā)生改變。因此,所制備的催化劑具有優(yōu)異的可循環(huán)利用性和穩(wěn)定性。而且,Fe3O4@SiO2磁性納米催化劑可通過外加磁場(chǎng)進(jìn)行分離,操作簡(jiǎn)便,具有很好的工業(yè)化應(yīng)用前景。此外,將Fe3O4@SiO2運(yùn)用在11種不同結(jié)構(gòu)的醛與丙二腈反應(yīng)中。結(jié)果表明,大部分的反應(yīng)在催化劑的作用下能較快進(jìn)行,且底物中吸電子基以及苯環(huán)的存在對(duì)反應(yīng)效果有積極的作用。另一方面,本文采用一步溶劑熱法制備了一系列MFe2O4(M=Mn,Cu,Co, Zn和Ni)磁性納米粒子,通過FTIR、XRD、TEM、BET、VSM等手段確定其結(jié)構(gòu)和組成。同樣以苯甲醛與丙二腈的Knoevenagel縮合作為模型反應(yīng),考查不同MFe2O4納米粒子對(duì)反應(yīng)的催化效果,結(jié)果表明NiFe2O4催化活性最好,同時(shí)推斷M元素為MFe2O4的關(guān)鍵活性組分。優(yōu)化NiFe2O4催化劑用量使得目標(biāo)產(chǎn)物收率高達(dá)98.6%。通過在最佳條件下的循環(huán)實(shí)驗(yàn),發(fā)現(xiàn)NiFe2O4循環(huán)使用第8次時(shí)活性沒有明顯降低仍然能維持反應(yīng)95.1%的轉(zhuǎn)化率和96.2%的選擇性,且催化劑的結(jié)構(gòu)和組成在重復(fù)利用中也沒有發(fā)生任何改變。因此,所制備的催化劑具有優(yōu)異的可循環(huán)利用性和穩(wěn)定性。將NiFe2O4運(yùn)用在11種不同結(jié)構(gòu)的醛與丙二腈或氰乙酸乙酯反應(yīng)中,發(fā)現(xiàn)催化劑對(duì)反應(yīng)具有良好的普適性,底物醛分子中吸電子取代基以及苯環(huán)的存在對(duì)反應(yīng)效果有積極的影響。另外,活潑亞甲基的活性與其兩端吸電子基團(tuán)的電負(fù)性呈正相關(guān)性。
[Abstract]:Magnetic nanomaterials with special physical and chemical properties have been widely used in the fields of electronics, information, automatic control, organic synthesis, biomedicine and so on, especially in the field of catalysis. As a catalyst or catalyst carrier, magnetic nanoparticles have excellent performance, and it also has magnetic separation properties. Knoevenagel condensation reaction is one of the most important reactions to form CfC, and the condensation product is an extremely valuable synthetic intermediate. Therefore, the application of magnetic nanomaterials as green and environmentally friendly catalysts for the study of Knoevenagel condensation reaction is expanded. It is not only innovative in basic research. Magnetic nanomaterials as catalysts for Knoevenagel reaction are studied in the following two aspects. Fe3O4@SiO2 magnetic nanocrystalline catalyst was prepared by solvothermal method and Stober method. The Knoevenagel condensation of benzaldehyde and malonitrile was used as probe reaction, and the reaction conditions were optimized to realize the complete conversion of benzaldehyde under the optimum conditions. The yield of the target product was 97.8. at the same time, the experimental results of different catalysts were compared. It is inferred that the active component of Fe3O4@SiO2 catalyst is Si02 layer. The cycle experiment shows that Fe3O4@SiO2 catalyst can still maintain the conversion rate of 90.1% and 9% under the 7th cycle. 3.5% selectivity. The structure and composition of the catalyst have not changed in reuse. Therefore, the prepared catalyst has excellent reusability and stability. Fe3O4@SiO2 magnetic nanocrystalline catalyst can be separated by external magnetic field. It is easy to operate and has a good prospect of industrial application. Fe3O4@SiO2 was applied to the reaction of aldehydes with malonitrile with 11 different structures. The results showed that most of the reactions could be carried out quickly under the action of catalyst. On the other hand, a series of MFE _ 2O _ 4 / M _ 2O _ 4 and mn _ (mn) Cu _ (2 +) were prepared by one-step solvothermal method. Zn and Ni) magnetic nanoparticles were prepared by FTIR and XRDX Tem BET. Knoevenagel condensation of benzaldehyde and malonitrile was also used as model reaction to study the catalytic effect of different MFe2O4 nanoparticles on the reaction. The results showed that the catalytic activity of NiFe2O4 was the best. At the same time, it is inferred that M element is the key active component of MFe2O4. Optimizing the amount of NiFe2O4 catalyst can make the yield of target product up to 98.6. It was found that the activity of NiFe2O4 could maintain the conversion of 95.1% and the selectivity of 96.2% after the 8th cycle use. And the structure and composition of the catalyst has not changed in the reuse. The prepared catalyst has excellent reusability and stability. NiFe2O4 was used in the reaction of aldehydes with malonitrile or ethyl cyanoacetate with 11 different structures. It is found that the catalyst has a good universality for the reaction, and the presence of the electron-absorbing substituents and benzene rings in the substrate aldehydes has a positive effect on the reaction effect. The activity of active methylene is positively correlated with the electronegativity of the electron-absorbing groups at both ends.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：O643.36;TB383.1

【參考文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

1 邰玉蕾;四氧化三鐵基磁性聚合物的合成、表征及應(yīng)用研究[D];浙江大學(xué);2013年

相關(guān)碩士學(xué)位論文 前1條

1 卞偉勇;尖晶石型金屬氧化物CoFe_2O_4作為氧電極的雙功能催化劑的研究[D];蘇州大學(xué);2014年

，

本文編號(hào)：1464724