發(fā)布時(shí)間：2018-06-20 15:16

  本文選題：異戊醇 + 選擇性氧化　； 參考：《西北大學(xué)》2017年碩士論文

【摘要】：伴隨對(duì)環(huán)境問(wèn)題重視度的提高,醇類(lèi)綠色氧化的發(fā)展也被越來(lái)越廣泛關(guān)注。本文制備了一系列改性HMS催化劑,并在以分子氧(O2)為氧化劑以及無(wú)溶劑條件下將所制備的催化劑用于異戊醇催化氧化制備異戊酸的研究當(dāng)中,探討所制備的催化劑用于異戊醇制備異戊酸的性能差異,并將部分催化劑表征進(jìn)行分析。論文所討論的問(wèn)題主要包括:(1)利用溶膠-凝膠方式制備HMS分子篩以及金屬摻雜分子篩Al-HMS和Co-HMS,并以此為載體將ZnO負(fù)載于載體之上獲得負(fù)載型分子篩催化劑。運(yùn)用不同表征分析了所獲得的催化劑,并研究了所得到的催化劑對(duì)異戊醇催化氧化的反應(yīng)性能。結(jié)果發(fā)現(xiàn):金屬雜原子摻雜改性后的分子篩載體能夠提高負(fù)載于其上的ZnO物種的分散度,其中Co-HMS效果更加明顯;催化劑5wt%ZnO/Co-HMS(100)對(duì)異戊醇催化氧化制異戊酸的性能最佳,使異戊醇的轉(zhuǎn)化率、異戊酸的收率以及選擇性分別達(dá)到了 43.6%、18.9%、43.3%。(2)以5wt%的ZnO物種負(fù)載量,金屬Co摻雜分子篩為載體考察了金屬Co的摻雜量對(duì)催化劑催化性能的影響,并將部分催化劑通過(guò)表征進(jìn)行了分析。結(jié)果顯示:金屬Co的引入量會(huì)對(duì)催化劑的結(jié)構(gòu)性質(zhì)造成影響。適量金屬Co的摻雜能夠改善負(fù)載的活性物種的分散度,提高催化劑的反應(yīng)活性。當(dāng)Si/Co的值等于100時(shí),獲得的催化劑的催化效果較佳。(3)討論了 ZnO物種的負(fù)載量、焙燒溫度以及ZnO前驅(qū)體種類(lèi)對(duì)催化劑效果的影響。研究表明:當(dāng)ZnO的負(fù)載量為3wt%,550℃下焙燒,以Zn(N03)2·6H20作為ZnO的前驅(qū)體時(shí),制備的催化劑對(duì)催化異戊醇氧化制異戊酸的性能最佳。(4)通過(guò)對(duì)制備條件的討論,我們篩選出了最佳的催化劑3wt%ZnO/Co-HMS(100)。并用3wt%ZnO/Co-HMS(100)進(jìn)行優(yōu)化異戊醇氧化合成異戊酸的反應(yīng)條件。實(shí)驗(yàn)結(jié)果表明,合成反應(yīng)的工藝條件明顯影響著底物異戊醇的轉(zhuǎn)化率以及目標(biāo)產(chǎn)物異戊酸的收率和選擇性。當(dāng)?shù)孜锏募尤肓繛?5mL、使用0.5g催化劑在120℃下反應(yīng)8h時(shí),異戊醇的轉(zhuǎn)化率、目標(biāo)產(chǎn)物異戊酸的收率以及選擇性達(dá)到最高值,分別為52.2%、26.9%、51.5%。催化反應(yīng)動(dòng)力學(xué)的結(jié)果表明,催化劑3wt%ZnO/Co-HMS(100)的使用能夠明顯降低該催化反應(yīng)體系的活化能,使異戊醇的氧化反應(yīng)可以在較為溫和的條件下順利進(jìn)行。
[Abstract]:With the increasing attention to environmental problems, the development of green oxidation of alcohols has been paid more and more attention. A series of modified HMS catalysts were prepared in this paper. The catalysts were used in the catalytic oxidation of isopentanol to isopentanoic acid under the conditions of molecular oxygen O _ 2 as oxidant and solvent free. The properties of the catalysts used in isoamyl alcohol to prepare isopentanoic acid were discussed, and some of the catalysts were characterized and analyzed. The main problems discussed in this paper include the preparation of HMS molecular sieve and metal doped molecular sieve Al-HMS and Co-HMS by sol-gel method. The catalysts obtained were analyzed by different characterizations and the catalytic performance of the catalysts for the catalytic oxidation of isopentanol was studied. The results showed that the molecular sieve carrier doped with metal hetero-atom could increase the dispersion of ZnO species loaded on it, and the Co-HMS effect was more obvious, and the catalyst ZnO / Co-HMS100 had the best performance in the catalytic oxidation of isoamyl alcohol to isovaleric acid, and the effect of Co-HMS on the catalytic oxidation of isopentanol to isopentanoic acid was found to be the best. The conversion of isoamyl alcohol, the yield and selectivity of isovaleric acid were 43.6and 18.9%, respectively. The effect of doping amount of Co on the catalytic performance of the catalyst was investigated with 5 wt% ZnO species loading and Co doped molecular sieve as the carrier. Some of the catalysts were characterized and analyzed. The results show that the addition of Co has an effect on the structure and properties of the catalyst. Proper amount of Co doping can improve the dispersion of the supported active species and increase the reaction activity of the catalyst. When the value of Si / Co is equal to 100, the effect of the supported amount of ZnO species, calcination temperature and the type of ZnO precursor on the catalyst effect is discussed. The results showed that when ZnO was calcined at 550 鈩，

本文編號(hào)：2044697