【作者】 乔仙蓉；

【导师】 李福祥；

【作者基本信息】 太原理工大学 ， 应用化学， 2008， 硕士

【摘要】 随着石油价格的不断攀升以及人们对环境问题的关注，生物柴油成为一个备受关注的领域，生物柴油是一种环境友好的可再生能源。在催化制备生物柴油的各种催化剂中，固体酸催化剂是一种有发展前景的催化剂，和液体酸相比，固体酸具有以下优势：容易从反应介质中分离；可重复使用；不存在腐蚀问题。和碱催化剂相比，固体酸更适用于那些脂肪酸含量高的原料油（比如油煎废油和一些不能食用的油料）。本实验制备了三种固体超强酸催化剂，SO₄^2-/TiO₂-SiO₂（catalyst A），SO₄^2-/SnO₂-SiO₂ （catalyst B），SO₄^2-/Zr-SBA-15（catalyst C）催化大豆油和甲醇的酯交换反应制备生物柴油，考察了催化剂的制备条件和酯交换的反应条件，用吡啶红外和NH₃-TPD考察了催化剂的酸性，研究了催化剂的重复使用性。（1）催化剂A的吡啶红外表明催化剂A具有L酸中心和B酸中心，NH₃-TPD测试表明催化剂A具有超强酸性。催化剂的制备因素中，焙烧温度是形成超强酸的最重要因素，当催化剂的钛硅摩尔比等于1／3，浸渍硫酸溶液的浓度大于1M，于450℃焙烧5h，催化剂表现出最高的催化活性，在最优化的反应条件：醇油摩尔比为13：1，每摩尔油使用1g催化剂，催化剂A在125℃催化反应3h，脂肪酸甲酯收率达90％。（2）催化剂B也具有超强酸性，催化剂B的制备条件类似于催化剂A，催化剂B的催化活性高于催化剂A，在最优化的反应条件：醇油摩尔比为13：1，每摩尔油使用1g催化剂，催化剂B在120℃催化反应3h，脂肪酸甲酯收率达90％。（3）反应体系的水抑制催化剂B的活性，但催化剂的活性不受体系中游离脂肪酸的影响，这意味着催化剂B能高效催化那些未精炼原油和那些不可食用的油料使酯化和酯交换一步完成。（4）从SO₄^2-/ZrO₂、SO₄^2-/ZrO₂-SiO₂和SO₄^2-/Zr-SBA-15对酯交换反应的活性差异，我们可以得出这样的结论：将介孔分子筛的孔结构优势和超强酸的酸性特征结合起来，能得到对酯交换更有前景的分子筛型超强酸材料。（5）实验对催化剂的失活和再生进行了研究，实验表明：催化剂表面的硫酸根被甲醇淋洗掉；催化剂表面的活性位被油和甲酯所覆盖，这两种原因导致了催化剂的失活。然而，可以通过简单的办法将使用过的催化剂再生：450℃焙烧催化剂，浸渍1M的硫酸溶液30分钟，过滤，干燥，再次于450℃焙烧。总之，在本实验制备的三种催化剂中，SO₄^2-/SnO₂-SiO₂的催化活性最高，它能在较低的温度（甚至100℃）催化油脂的酯化酯交换一步完成，通过简单再生使催化活性恢复，是一种有前景的酯交换油脂制备生物柴油的固体酸催化剂。更多还原

【Abstract】 Due to the increase in the price of the petroleum and the environmental concerns, biodiesel is becoming a developing area of high concern. Biodiesel is an environmentally friendly and renewable energy. In different types of catalyst for the production of biodiesel, solid acid catalysts are a promising catalyst. Solid acid catalysts offer several advantages over homogeneous acid catalysts. They are easily removed from the reaction medium, can be reused and avoid corrosion problems. They have more adaptability than the base catalysts when the feed oil （e.g., used deep-frying oils and non-edible oils ） has high acidity.In this paper, biodiesel was obtained through transesterification of soybean oil with methanol, using SO₄^2-/TiO₂-SiO₂ （catalyst A）, SO₄^2-/SnO₂-SiO₂ （catalyst B）, SO₄^2-/ Zr-SBA-15（catalyst C） as solid superacid catalysts, catalyst preparation factors and transesterification reaction factors were investigated. The catalyst’s acidity was characterized by FT-IR and NH₃-TPD. The catalyst’s recyclability was studied.（1） Spectral analysis of absorbing pyridine IR of the catalyst A showed that there were Lewis and Bronsted acid centers on the catalyst. NH₃-TPD curves showed that the catalyst A had superacidity. Among the catalyst A preparation factors, the calcined temperature is most important factor for formation of superacid. The catalyst A exhibited the highest activity for transesterification under the condition of Ti/Si mol ratio 1/3, the concentration of impregnating sulfuric acid solution over 1.0M, calcination at 450℃for 5h. The yield of methylesters reached over 90% at the most optimized reaction factor: 13:1 methanol/oil mole ratio, 1.0g catalyst/mol oil, reacted at 125℃for 3h.（2） The catalyst B also had Lewis and Bronsted acid centers, and had superacidity. The catalyst B was similar to the catalyst A in preparation factors. The catalyst B exhibited higher activity than the catalyst A and gave 90% ME yield at the most optimized reaction factor: 13:1 methanol/oil mole ratio, 1.0g catalyst/mol oil, reacted at 120℃for 3h.（3） The activity of the catalyst B was strongly reduced by the presence of water. The acitivity of the catalyst B was not affected by the presence of fatty acid. This fact shows that a variety of unrefined crude oil and non-edible oils could be transesterificated over the catalyst B with high efficiency. With the catalyst B both the esterification and tranesterification could be conducted in a single-operation.（4） The difference of catalytic activity for transesterification between SO₄^2-/ZrO₂, SO₄^2-/ZrO₂-SiO₂ and SO₄^2-/Zr-SBA-15 was studied. It could be concluded that the combination of the porous structure of mesoporous molecular sieves and the acid properties of superacids could obtain more prospective molecular superacid materials for tranesterification.（5） The study on catalyst’s deactivity and regeneration showed that the spent catalyst was partly deactivated, because SO₄^2- were slowly leached out from the catalyst surface by methanol and activity sites were covered by oil and ME, that the used catalyst could be regenerated by calcined at 450℃, impregnated 1MH₂SO₄ solution for 30 min, filtered, dried, and re-calcined at 450℃.In a word, SO₄^2-/SnO₂-SiO₂ had the most activity among the three catalysts investigated in this study. It could catalyze both the esterification and tranesterification of oil at lower temperature （even at 100℃） in a single-operation. The used catalyst could be easily regenerated and the same activity could be obtained. SO₄^2-/SnO₂-SiO₂ are a promising solid acid catalyst for production of biodiesel from oil by transesterification reaction.更多还原