| 陈汉林.油脂醇解固体碱催化剂的制备及表征[J].中国油脂,2018,43(7):.[CHEN Hanlin.Preparation and characterization of solid base catalyst for oil methanolysis[J].China Oils and Fats,2018,43(7):.] |
| 油脂醇解固体碱催化剂的制备及表征 |
| Preparation and characterization of solid base catalyst for oil methanolysis |
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| DOI： |
| 中文关键词: 金属氧化物 固体碱 催化剂 制备 表征 生物柴油 |
| 英文关键词:metal oxide solid base catalyst preparation characterization biodiesel |
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| 摘要点击次数: 1416 |
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| 中文摘要: |
| 以硝酸钙、硝酸锌、乙酸镁、乙酸铝为原料，碳酸钠为沉淀剂进行共沉淀反应，先制得钙、镁、锌碳酸盐及氢氧化铝混合沉淀，再经陈化、水洗、干燥、焙烧制得钙镁锌铝固体碱催化剂。将蓖麻油甲醇解反应中的蓖麻油转化率作为活性评价指标，采用正交试验考察了制备条件对催化剂活性的影响，得到制备催化剂的优化条件为：n(Ca)∶?n(Mg)∶?n(Zn)∶?n(Al) = 2∶?0.5∶?0.5∶?1，混合溶液pH 8，焙烧温度850?℃，焙烧时间7 h。将优化条件下制备的固体碱催化剂用于催化蓖麻油甲醇解反应，蓖麻油转化率达93.2%。采用热重分析、X射线衍射、N2吸附-脱附、扫描电镜及Hammett指示剂滴定法对催化剂及其前驱体进行了表征。结果显示：催化剂前驱体在700~800?℃温区有1个明显的失重台阶，在800?℃以后质量基本不随温度变化；固体碱催化剂主要由CaO、ZnO及MgO 3种晶体构成，其比表面积为44.08 m2/g、孔容为0.062 65 cm3/g，特征为多孔连续型蜂窝状结构；固体碱催化剂的碱强度在7.2～15.0之间，总碱位量为14.895 mmol/g。 |
| 英文摘要: |
| The precipitates of calcium, magnesium, zinc carbonate and aluminum hydroxide were prepared by coprecipitation with calcium nitrate, zinc nitrate, magnesium acetate and aluminum acetate as raw materials and sodium carbonate as precipitation agent, and then the calcium magnesium zinc aluminum solid base catalyst was prepared by the aging, washing, drying and calcination. The effects of preparation conditions on the catalytic activity were investigated by orthogonal experiment, with castor oil conversion rate in methanolysis reaction of castor oil as the activity evaluation index. The optimal conditions for the preparation of the catalyst were obtained as follows: n(Ca)∶?n(Mg)∶?n(Zn)∶?n(Al)=2∶?0.5∶?0.5∶?1, pH of the mixed solution 8, calcination temperature 850?℃, and calcination time 7 h. With the solid base obtained under these conditions as catalyst in methanolysis reaction of castor oil, the castor oil conversion rate was up to 93.2%. The catalyst and its precursor were characterized by thermogravimetric analysis, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy and Hammett indicator method. The results showed that the catalyst precursor had a significant weight loss step in the temperature range of 700-800?℃, and the mass did not change with temperature above 800?℃.The solid base catalyst was mainly constituted of three kinds of crystals CaO, ZnO and MgO. The specific surface area and pore volume of the catalyst were 44.08 m2/g and 0.062 65 cm3/g respectively, and it was porous continuous honeycomb structure. The alkali strength of the solid base catalyst was between 7.2 and 15.0, and the total alkali amount was 14.895 mmol/g. |
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