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短鏈醇中生物質基糠醛和羥甲基糠醛的催化轉化研究

發(fā)布時間:2018-05-23 22:14

  本文選題:短鏈醇 + 糠醛; 參考:《天津理工大學》2017年碩士論文


【摘要】:目前,由于化石燃料大量消耗所引起的環(huán)境污染和能源短缺等問題影響著社會的可持續(xù)發(fā)展,因此,探究生物質可再生資源的高效轉化方法已逐漸成為化工領域的一個重要課題。其中,糠醛和5-羥甲基糠醛(5-HMF)作為重要的生物質基平臺化合物,經過合適的轉化過程可以制備出多種高附加值化學品和液體燃料。因此,開展短鏈醇中糠醛和5-HMF的催化轉化研究具有重要的科學意義和廣泛的應用前景。本論文中,首先研究了短鏈醇溶劑中糠醛的催化氧化-縮合反應過程,使用的催化體系為過渡金屬的CoxOy-N@K-10與CuO-CeO_2兩種納米材料。研究發(fā)現,在“正丙醇-糠醛-氧氣”反應體系中,以CoxOy-N@K-10和Cs2CO3組成催化劑體系,于0.3MPa O_2壓力下,140oC條件下反應4 h后,糠醛轉化率為75.1%,主產物2-甲基-3-(2-呋喃基)丙烯醛的選擇性可達92.8%。進而,詳細考察了CuO-CeO_2催化劑和K2CO3助劑對糠醛催化轉化的促進情況;結果發(fā)現,在0.3 MPa O_2氛圍中,140oC條件下反應4h,糠醛的轉化率為85.4%,主產物2-甲基-3-(2-呋喃基)丙烯醛的選擇性可達95.3%。另外,還分別研究了反應助劑,反應溶劑,以及反應溫度和時間對氧化縮合的影響,在對催化劑進行FT-IR、XRD、BET、SEM、TEM、NH3-TPD等表征測試的基礎上,結合對照實驗的數據和反應現象,提出了糠醛與正丙醇之間發(fā)生氧化縮合反應的反應機理。接下來,論文研究了5-HMF的催化氧化過程;借助液相沉淀法制備了Cu-MnO_2,Cr-MnO_2,V-MnO_2,Mo-MnO_2,Mg-MnO_2,Ca-MnO_2,Al-MnO_2等離子摻雜型氧化錳催化劑,詳細考察了短鏈醇中催化劑的類型、反應溫度和反應時間對于5-HMF選擇性氧化制備2,5-呋喃二甲醛(DFF)的影響情況;研究發(fā)現,以乙醇為溶劑,使用Cu-MnO_2作催化劑,于0.3MPa O_2壓力下,140oC條件下反應5 h時的效果最佳;原料5-HMF的轉化率為86.0%,主產物DFF的選擇性可達96.1%。并且,還針對Cu-MnO_2催化劑進行了5次循環(huán)實驗,發(fā)現5-HMF的轉化率始終可以保持在70%以上,說明催化劑具有良好穩(wěn)定性。最后對不同金屬離子摻雜的氧化錳催化劑進行了XRD、BET、SEM、TEM等表征測試,合理解釋了不同類型催化劑與氧化反應結果之間的關系。
[Abstract]:At present, the problem of environmental pollution and energy shortage caused by the large amount of fossil fuel consumption affects the sustainable development of the society. Therefore, the efficient transformation method of exploring biomass renewable resources has gradually become an important topic in the field of chemical industry. Among them, furfural and 5- hydroxymethyl furfural (5-HMF) are important biomass based platforms. A variety of high value added chemicals and liquid fuels can be prepared by appropriate conversion process. Therefore, the research on catalytic conversion of furfural and 5-HMF in short chain alcohols has important scientific significance and wide application prospects. In this paper, the catalytic oxidation condensation reaction process of furfural in short chain alcohols was first studied, and the process of catalytic oxidation condensation reaction of furfural in short chain alcohol solution was studied. The catalytic system used as a transition metal CoxOy-N@K-10 and CuO-CeO_2 two kinds of nanomaterials. It is found that in the reaction system of "positive propyl alcohol furfural oxygen", the catalyst system is composed of CoxOy-N@K-10 and Cs2CO3, under the pressure of 0.3MPa O_2 and the reaction of 4 h under 140oC condition, the conversion rate of furfural is 75.1%, and the main product 2- methyl -3- (2- furyl) propylene The selectivity of aldehyde can reach 92.8%., and the catalytic conversion of CuO-CeO_2 catalyst and K2CO3 promoter on furfural catalytic conversion is investigated in detail. The results show that in the atmosphere of 0.3 MPa O_2, the reaction 4H is 4h, the conversion rate of furfural is 85.4%, the selectivity of the main product 2- methyl -3- (2- furyl) acrolein can reach 95.3%.. The effects of additives, reaction solvents, reaction temperature and time on the oxidation condensation were tested on the basis of the characterization tests of FT-IR, XRD, BET, SEM, TEM, NH3-TPD, and the reaction mechanism of the oxidation condensation reaction between the furfural and the propanol was proposed. Then, the thesis studied the 5-HMF The catalytic oxidation process of Cu-MnO_2, Cr-MnO_2, V-MnO_2, Mo-MnO_2, Mg-MnO_2, Ca-MnO_2, Al-MnO_2 plasma doped manganese oxide catalyst was prepared by the liquid phase precipitation method. The influence of the catalyst type, reaction temperature and reaction time on the preparation of 2,5- furan two formaldehyde (DFF) by the selective oxidation of 5-HMF was investigated in detail. It is found that with ethanol as the solvent and using Cu-MnO_2 as the catalyst, under the pressure of 0.3MPa O_2, the reaction is best when the reaction is 5 h under the condition of 140oC, the conversion rate of 5-HMF is 86%, the selectivity of the main product DFF is 96.1%. and the 5 cycles of the Cu-MnO_2 catalyst have been carried out, and the conversion rate of 5-HMF can always be kept at 70%. The catalyst has good stability. Finally, the characterization tests of XRD, BET, SEM and TEM are carried out for the manganese oxide catalysts doped with different metal ions. The relationship between different types of catalysts and the results of oxidation is explained.
【學位授予單位】:天津理工大學
【學位級別】:碩士
【學位授予年份】:2017
【分類號】:O626.11

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