【作者】 刘莉；

【导师】 李桂英；

【作者基本信息】 四川大学 ， 绿色化学， 2022， 硕士

【摘要】 由于化石资源的枯竭以及人类当前面临的环境和气候等问题,利用生物质制备高值化学品受到了广泛关注。微藻生物质具有生长周期短、环境适应性强、二氧化碳捕获能力强和不占用耕地等优点。另一方面,湖泊在夏季经常出现藻类泛滥的情况,严重影响了当地的生态平衡和经济发展。催化转化天然微藻,不仅缓解水污染对环境造成的压力,还可制备高附加值的含氮化学品,具有重要的理论和实际意义。本文充分利用天然微藻氮含量较高的特点,通过溶剂和催化剂协同作用,实现微藻各组分的有效转化,制备高附加值的脂肪酰胺和腈。探讨了不同反应条件及催化剂对溶剂热转化太湖藻所得生物油收率及其组成的影响;通过模型化合物反应探究了催化剂的作用;研究了不同浓度盐酸溶液处理对太湖藻三大组分（脂质、蛋白质、糖类）的影响,对比分析了ZrO₂催化溶剂热和热解转化太湖藻所得生物油的组成。主要发现如下:1、六种金属氧化物（ZrO₂、Al₂O₃、TiO₂、ZnO、MgO、CaO）中,ZrO₂为最佳催化剂。加入ZrO₂后,生物油中脂肪酰胺的相对含量为21.4%,脂肪腈的相对含量为8.1%。ZrO₂的催化作用主要是促进脂肪酰胺脱水生成脂肪腈。碱性氧化物会吸附生物油中的酸性物质或与之反应,不适合用于催化转化太湖藻制备脂肪酰胺和腈。2、在最优条件（2.5 g太湖藻,0.3 g ZrO₂,50 mL正庚烷,2.0 MPa N₂,搅拌速率400 rpm,300℃,6 h）下,生物油收率为19.6 wt%,生物油中脂肪酰胺的相对含量为24.4%,脂肪腈为8.9%。3、使用盐酸溶液处理太湖藻可以减少其中糖类组分的含量,增加脂质和蛋白质组分的占比。经2.0 mol/L的盐酸溶液处理后,太湖藻中脂质含量由5.0 wt%增加至11.0 wt%,蛋白质的含量可升至57.5 wt%。4、盐酸处理有助于生物油收率和生物油中碳元素相对含量的提高。经2.0mol/L盐酸溶液处理后的太湖藻,ZrO₂催化溶剂热转化所得生物油收率提高了9.9 wt%,生物油中碳元素的相对含量提高了5.9 wt%;ZrO₂催化热解转化所得生物油收率提高了7.1 wt%,生物油中碳元素的相对含量提高了3.9 wt%。热解所得生物油组成更简单,且生物油中碳元素的相对含量更高。更多还原

【Abstract】 Due to the depletion of fossil resources and the current environmental especially climate problems faced by human beings,the use of biomass to prepare value-added chemicals has received extensive attention.Microalgal biomass has many advantages,such as short growth cycle,strong environmental adaptability,strong carbon dioxide capture ability,and the growth of which does not occupy arable land.On the other hand,algal blooms often occur in lakes in summer,which seriously affects the local ecological balance and economic development.Catalytic conversion of natural microalgae can not only relieve the pressure of water pollution on the environment,but also produce value-added nitrogen-containing chemicals,which has important theoretical and practical significance.In this thesis,taking the advantage of the high nitrogen content of natural microalgae,value-added fatty amides and nitriles were produced through the synergistic effect of solvents and catalysts,achieving effective transformation of various components in microalgae.The effects of different reaction conditions and catalysts on the yield and composition of biocrudes obtained from solvothermal conversion of Taihu Lake algae were discussed.The effect of catalysts was explored through the reaction of model compounds.The composition of biocrudes obtained by ZrO₂ catalyzed solvothermal and pyrolysis transformation of Taihu Lake algae was compared and analyzed.The main findings are as follows:1.Among the six metal oxides（ZrO₂,Al₂O₃,TiO₂,ZnO,MgO,CaO）investigated,ZrO₂ was the best catalyst.After adding ZrO₂,the relative content of fatty amides in the biocrudes was 21.4%,and the relative content of fatty nitriles was 8.1%.The role of ZrO₂ was mainly to promote the dehydration of fatty amides to form fatty nitriles.Alkaline oxides could adsorb or react with acidic substances in biocrudes,and were not suitable for catalytic conversion of Taihu Lake algae to produce fatty amides and nitriles.2.Under optimal conditions（2.5 g Taihu Lake algae,0.3 g ZrO₂,50 mL n-heptane,2.0 MPa N₂,stirring rate 400 rpm,300℃,6 h）,the yield of biocrudes was 19.6 wt%,and the relative content of fatty amides in biocrudes was 24.4%,fatty nitriles was 8.9%.3.Treating Taihu Lake algae with hydrochloric acid solution could reduce the content of sugar components and increase the proportion of lipid and protein components.After treatment with 2.0 mol/L hydrochloric acid solution,the lipid content in Taihu Lake algae increased from 5.0 wt%to 11.0 wt%,and the protein content increased to 57.5 wt%.4.Hydrochloric acid treatment helped to improve the yield of biocrudes and the relative content of carbon in biocrudes.After treatment Taihu Lake algae with 2.0mol/L hydrochloric acid solution,the yield of biocrudes obtained by ZrO₂ catalytic solvothermal conversion increased by 9.9 wt%,and the relative content of carbon in biocrudes increased by 5.9 wt%.The yield of biocrudes obtained by ZrO₂ catalytic pyrolysis increased by 7.1 wt%,and the relative content of carbon in the biocrudes increased by 3.9 wt%.The composition of the biocrudes obtained by pyrolysis was simpler,and the relative content of carbon elements in the biocrudes was higher.更多还原