本文關(guān)鍵詞： 介孔二氧化硅納米球 樹枝狀孔道 共表面活性劑　出處：《華東師范大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：介孔硅材料因具有優(yōu)異的孔道結(jié)構(gòu)、大的比表面積、特殊的表面性能,自首次報道合成就備受關(guān)注,它為生物和工業(yè)應(yīng)用提供了載體,打開了負(fù)載大分子功能材料的大門。尺寸小于200 nm的介孔硅球由于短的擴(kuò)散路徑和易于接觸的反應(yīng)活性中心更是在催化反應(yīng)領(lǐng)域引起了廣泛的關(guān)注。本論文在本課題組對樹枝狀介孔材料合成的已有研究基礎(chǔ)上,根據(jù)其合成機(jī)理,進(jìn)一步探究樹枝狀介孔硅球的綠色合成方法,同時以這些納米顆粒為載體制備不同催化劑,對比它們與傳統(tǒng)介孔材料MCM-41的催化性能。文章第一部分以十六烷基三甲基溴化銨為表面活性劑,通過添加不同碳鏈長度的二羧酸鹽為共表面活性劑,成功制備出樹枝狀介孔納米硅球。當(dāng)改變共表面活性劑碳鏈的長度,可以細(xì)微調(diào)控納米顆粒的尺寸并能調(diào)節(jié)樹枝狀孔道的開放程度,而且在實(shí)驗(yàn)探究的范圍內(nèi),使用共表面活性劑的碳鏈越長,其樹枝狀孔道結(jié)構(gòu)也就越明顯。文章第二部分在第一部分的基礎(chǔ)上,通過在合成過程中原位引入鈦源,一步法合成了樹枝狀孔道結(jié)構(gòu)的含鈦納米硅球。而且同樣可以通過調(diào)節(jié)共表面活性劑碳鏈的長度來調(diào)節(jié)樹枝狀孔道的開放程度。由于過渡金屬雜原子易于水解的特性,文章還分別使用水解較慢的TDA與水解較快的TBOT為鈦源制備樹枝狀含鈦納米硅球進(jìn)行環(huán)己烯環(huán)氧化的實(shí)驗(yàn),對比它們與傳統(tǒng)Ti-MCM-41的催化活性,發(fā)現(xiàn)以TDA為鈦源制備的催化劑的催化反應(yīng)性能與Ti-MCM-41相當(dāng),而且其TON值要遠(yuǎn)高于Ti-MCM-41,實(shí)現(xiàn)了鈦源的高度利用。此外文章還考察催化劑結(jié)構(gòu)與鈦源種類、共表面活性劑的關(guān)系,研究鈦源水解速率和共表面活性劑碳鏈長度變化對催化劑反應(yīng)性能的影響。文章第三部分嘗試使用無堿法合成樹枝狀介孔二氧化硅納米顆粒,該方法在不外加堿源的情況下成功利用共表面活性劑合成樹枝狀介孔二氧化硅納米顆粒,該方法操作簡單、成本低、污染小,滿足環(huán)境保護(hù)和可持續(xù)發(fā)展要求。用這種方法制備負(fù)載銀納米顆粒的催化劑進(jìn)行苯甲醇的催化氧化實(shí)驗(yàn),其反應(yīng)性能也要優(yōu)于傳統(tǒng)催化劑。
[Abstract]:Because of its excellent pore structure, large specific surface area and special surface properties, mesoporous silicon has attracted much attention since the first report on synthesis. It provides a carrier for biological and industrial applications. Doors open for loaded macromolecular functional materials. Dimensions less than 200. The mesoporous silica spheres at Nm have attracted much attention in the field of catalytic reaction because of their short diffusion paths and easy to contact reactive centers. In this paper, we have studied the basis of the synthesis of dendritic mesoporous materials. Go. According to the synthesis mechanism, the green synthesis method of dendritic mesoporous silica spheres was further explored, and different catalysts were prepared on these nanoparticles. In the first part, cetyltrimethylammonium bromide was used as surfactant and dicarboxylate with different length of carbon chain was added as cosurfactant. The dendritic mesoporous nanocrystalline silica spheres were successfully prepared. When the length of the carbon chain of the cosurfactant was changed, the size of the nanoparticles and the opening degree of the dendritic channels could be adjusted slightly, and within the scope of experimental investigation. The longer the carbon chain is used, the more obvious the dendritic pore structure will be. The second part is based on the first part, through the in-situ introduction of titanium source in the synthesis process. Titanium nanocrystalline silica spheres with dendritic pore structure were synthesized by one step method. The opening degree of dendritic channels can also be adjusted by adjusting the length of the carbon chain of co-surfactants. Characteristics. The cyclohexene epoxidation of dendrimer nanocrystalline silica spheres was prepared by using slow hydrolyzed TDA and fast hydrolyzed TBOT as titanium source. Comparing their catalytic activity with traditional Ti-MCM-41, it was found that the catalytic activity of the catalyst prepared with TDA as titanium source was comparable to that of Ti-MCM-41. The TON value of the catalyst is much higher than that of Ti-MCM-41, which realizes the high utilization of titanium source. In addition, the relationship between the structure of catalyst and the type of titanium source and the co-surfactant is also investigated. The effects of the hydrolysis rate of titanium source and the length of carbon chain on the reaction performance of the catalyst were studied. In the third part, dendritic mesoporous silica nanoparticles were synthesized by alkaline-free method. The method successfully synthesized dendritic mesoporous silica nanoparticles without adding alkali source. The method is simple in operation, low in cost and less in pollution. In order to meet the requirements of environmental protection and sustainable development, the catalytic oxidation of benzyl alcohol over the catalysts supported on silver nanoparticles by this method is also superior to that of the traditional catalysts.
【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB383.1;O643.36

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本文編號：1485928