本文選題：生物質(zhì)　切入點：加氫脫氧　出處：《中國科學技術(shù)大學》2017年碩士論文

【摘要】：隨著人類社會的快速發(fā)展,化石資源的日益枯竭以及溫室效應(yīng)的不斷惡化,發(fā)展可再生資源來部分替代傳統(tǒng)化石資源迫在眉睫。通過綠色植物光合作用產(chǎn)生的生物質(zhì)資源,是唯一一種可再生的有機碳資源。生物質(zhì)資源含量豐富,開發(fā)和研究生物質(zhì)轉(zhuǎn)化對代替?zhèn)鹘y(tǒng)化石資源具有非常重大的意義。木質(zhì)素作為木質(zhì)纖維素的重要組成部分,用于制備可再生的生物燃料和化學品具有很大的潛力。然而,木質(zhì)素解聚后獲得的產(chǎn)物主要為甲氧基取代的酚類化合物,這種化合物含有甲氧基官能團并且含氧量較高,很難被直接應(yīng)用。因此,加氫脫氧過程被用于轉(zhuǎn)化木質(zhì)素酚類化合物制備生物燃料和化學品。目前用于催化木質(zhì)素酚類的催化劑主要集中于貴金屬催化劑,如Pd,Ru,Pt等。這些催化劑雖然催化效果較好但催化劑成本較高,不利于工業(yè)中大規(guī)模的應(yīng)用。非貴金屬Ni也被用于加氫脫氧的研究,但反應(yīng)條件較為苛刻。針對以上問題,我們研究并發(fā)展了非貴金屬鈷基催化劑用于催化木質(zhì)素酚類化合物加氫脫氧。在我們第一個工作中,我們使用纖維素為碳源,硝酸鈷為鈷源,氨氣為氮源一步熱解制備CoNx@NC催化劑。以丁香酚為模型物,發(fā)現(xiàn)在650℃下制備的催化劑(CoNx@NC-650)具有最佳的丁香酚加氫脫氧效果。在200℃,2MPaH2條件下反應(yīng)2h,丙基環(huán)己醇收率99.9%。此外,在外加固體酸HZSM-5條件下,丙基環(huán)己烷收率達到99.1%。我們對催化劑進行表征發(fā)現(xiàn),在氨氣氛圍下形成的鈷氮化物(CoNx)在催化加氫脫氧過程中起到了重要作用。通過反應(yīng)動力學研究表明,該催化劑能在較溫和條件下對Caryl-OR鍵具有很高的斷鍵活性�；诘谝粋�工作,我們發(fā)展了一系列負載型鉆基催化劑,研究了不同氧化物載體對鈷金屬催化活性的影響。Co/TiO2催化劑在一系列鉆基催化劑中表現(xiàn)出了最佳的催化活性,在200℃,1 MPa H2下反應(yīng)2 h,丁香酚可以完全轉(zhuǎn)化為丙基環(huán)己醇(99.9%)。通過催化劑的表征結(jié)果,金屬與載體間的不同的相互作用是導致催化活性差異的主要原因。在180℃,0.4MPa反應(yīng)8h的條件下,丙基環(huán)己醇的收率達99%。這是目前報道的使用非貴金屬催化丁香酚加氫脫氧的最低條件。通過機理研究和底物拓展,發(fā)現(xiàn)當甲氧基出現(xiàn)在鄰位時Co/Ti02能在對苯環(huán)加氫之前高效地對鄰位的Cary1-OR鍵進行斷裂。
[Abstract]:With the rapid development of human society, the depletion of fossil resources and the deterioration of Greenhouse Effect, it is urgent to develop renewable resources to partly replace the traditional fossil resources. Is the only renewable organic carbon resource. Biomass resources are rich, the development and graduate material conversion is of great significance to replace the traditional fossil resources. Lignin as an important component of lignocellulose, There is great potential for the preparation of renewable biofuels and chemicals. However, the main product of lignin depolymerization is methoxy substituted phenolic compounds, which contain methoxyl functional groups and have high oxygen content. Therefore, the hydrodeoxidation process is used to convert lignin phenolic compounds to biofuel and chemicals. At present, the catalysts used to catalyze lignin phenols are mainly concentrated on precious metal catalysts. For example, PdN Ru-Pt and so on. Although these catalysts have better catalytic effect, their cost is higher, which is not conducive to large-scale application in industry. Non-noble metal Ni is also used in hydrodeoxidization research, but the reaction conditions are relatively harsh. We have studied and developed non-noble metal cobalt based catalysts for the hydrogenation of lignin phenolic compounds. In our first work, we used cellulose as a carbon source and cobalt nitrate as a cobalt source. CoNx@NC catalyst was prepared by one step pyrolysis of ammonia as nitrogen source. Using eugenol as model material, it was found that the catalyst prepared at 650 鈩，

本文編號：1666430