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| 中空介孔二氧化硅负载磷钨酸催化剂的制备及其在生物柴油合成中的应用 |
| Preparation of phosphotungstic acid supported on hollow mesoporous silica and its application in biodiesel synthesis |
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| DOI： |
| 中文关键词: 固体酸催化剂 中空介孔纳米材料 生物柴油 酯化反应 |
| 英文关键词:solid-acid catalyst hollow mesoporous nanomaterials biodiesel esterification |
| 基金项目:国际交流与合作项目 (BX 2019018) |
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| 中文摘要: |
| 以正硅酸乙酯为硅源，使用改进后的Stber法合成实心二氧化硅球（SiO2），然后用Na2CO3和十六烷基三甲基溴化铵(C16TAB）对其进行选择性地一步刻蚀，得到中空介孔二氧化硅纳米球（HMSN），最后使用改进后的浸渍法引入磷钨酸作为活性中心，由此得到中空介孔二氧化硅负载磷钨酸的纳米催化剂（HPW/HMSN）。用FTIR、XPS、XRD、BET、SEM、TEM、EDS、TGA等对制备的催化剂进行表征，并用间接滴定法测定其酸量。结果证明，磷钨酸被成功引入载体表面，所合成的催化剂具有中空介孔结构，并且粒径均一、单分散性好，催化剂比表面积高达481 m2/g。酸量（H+）高达340.4 μmol/g。通过单因素试验确定催化剂对油酸和甲醇合成生物柴油的最佳反应条件为反应温度80 ℃、反应时间2 h、醇油摩尔比10∶ 1和催化剂用量为原料总质量的3%，在此条件下油酸转化率可达98.7%。此外，催化剂具有良好的可重复使用性，在重复使用5次时仍保持了852%的油酸转化率。 |
| 英文摘要: |
| Using ethyl orthosilicate as raw material, solid silica spheres (SiO2) were synthesized by the improved Stber method. Then Na2CO3 and C16TAB were used for selective one-step etching to obtain hollow mesoporous silica nanospheres (HMSN). Finally, the modified impregnation method was applied to introduce phosphotungstic acid as the active centre, thus the nano-catalyst of phosphotungstic acid supported on hollow mesoporous silica (HPW/HMSN) was obtained. The prepared catalyst were characterized with FTIR, XPS, XRD, BET, SEM, TEM, EDS, TGA, etc, and the acidity of the catalyst was determined. The results showed that phosphotungstic acid was successfully introduced into the surface of the carrier, and the synthesized catalyst had hollow mesoporous structure, uniform particle size and good monodispersity, the specific surface area of the catalyst was up to 481 m2/g, and the acid content (H+) was up to 340.4 μmol/g. The optimal reaction conditions of synthesizing biodiesel from oleic acid and methanol with the catalyst were obtained by single factor experiment as follows: reaction temperature 80 ℃, reaction time 2 h, molar ratio of methanol to oil 10∶ 1 and catalyst dosage 3% of total mass of materials. Under these conditions, the conversion rate of oleic acid could reach 98.7%. In addition, the catalyst had good reusability, and it maintained 85.2% conversion rate when reused for five times. |
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